Cyanine dyes as optical contrast agents for ophthalmological surgery

ARTICLE

pubs.acs.org/jmc

Cyanine Dyes as Optical Contrast Agents for Ophthalmological

Surgery

Heinz Langhals,*^,†Ana Varja,^†Peter Laubichler,^‡Marcus Kernt,^‡Kirsten Eibl,^‡and Christos Haritoglou^‡

^†Department of Chemisty, LMU University of Munich, Butenandtstrasse 13, D-81377 Munich, Germany

^‡Department of Ophthalmology, Eye Hospital, LMU University of Munich, Mathildenstrasse 8, D-80336 Munich, Germany

S Supporting Information

b

ABSTRACT: Cyanine dyes were prepared as optical contrast

media for supporting the surgery of the lamina limitans interna

(LLI) of the retina and other structures of the human eye. Their

absorption spectra were adapted both to the spectral sensitivity

of the human eye and to standard illumination. The contrast

could be further ampliﬁed by the application of the strong

ﬂuorescence of the dyes used. The binding of the dyes to various

surfaces was studied. No toxic eﬀects could be detected for the

applied dyes.

’ INTRODUCTION

properties to human tissues may be modulated by peripheral

structures not being involved into the chromophoric system.

The progress in the development of intraocular surgical techni-

ques requires the visualization of delicate and barely visible structures

reaching the limit of a surgeon's visual performance. For example, a

relevant target structure in ophthalmic surgery is the lamina limitans

interna (LLI) of the retina, a delicate and barely visible basement

membrane of only a few micrometers thickness. Therefore, the use of

visualizing agents has become a ﬁeld of great interest for ophthalmic

surgeons. The recognition of small structures can be improved by the

application of optical contrast media¹and promises to induce further

progress in vitreoretinal surgery. The optical contrast for surgical

interventions at the level of the LLI could be successfully improved

by the application²of indocyanine green^3,4(ICG, RN 3599-32-4).⁵

The latter was previously used in cardiology. However, ICG proved

not to be an optimal dye for ophthalmologic surgery. The toxic

response^6,7in the macula caused problems in application and may be

caused by metabolic products;^8ꢀ10ICG must be applied in compar-

ably high concentrations because most of its light absorption lies in

the near-infrared (NIR) and is therefore useless for visible detection;

see Figure 1.

We targeted cyanine dyes because of their strong light abso-

rption, their limited stability, and a matched light absorption expected

for pentamethin cyanine dyes. The termini of the cyanine structure

were stabilized by naphthalene units. Thus, we started synthesis with

the trimethyl benzindole¹¹1 where peripheral structures for the

selectivity of binding to tissues were introduced by nucleophilic

substitution reactions¹²to form 2; see Figure 2. Compound 2 was

condensed under basic conditions according to a similarly reported¹⁵

procedure with orthoformic ester to form 3; 3a has been previously

described;¹⁶however, the reported UV/vis spectra could not be

reproduced. The less toxic 2-picoline could replace pyridine as the

base; however, the latter gave better yields for some derivatives; see

the Experimental Section. Carboxylic groups and their derivatives

were applied as well as the sulfonic acid groups in 3t...3v as the polar

building blocks for the binding to tissues; 3t has been previously

mentioned,^13,14however, without an explicit preparation procedure

or spectroscopic data. The water solubility of the cyanine dyes being

important for applications in surgery was appreciably increased by

the sulfonic acid groups in 3t...3v. As a consequence, we introdcuced

sulfonic acid groups into the aromatic nuclei of 3 and started with the

sulfonation of 1 in nitrobenzene with oelum. The problem of

removing residual nitrobenzene can be solved with the application

of steam distillation. The sulfonation allows the preparation of 4 in a

one-step synthesis, whereas a multistep synthesis was reported in the

literature.¹⁷Compound 4 was alkylated similarly to the reaction of 1

to form 5. Alternatively, 2 could be sulfonated to 5. The sulfonation

of the nucleus allows the introduction of multiple sulfonic acid

groups either by an alkylation of 4withasulfonicacidderivativeorby

The tendency of ICG for aggregation at high concentration shifts

its light absorption slightly hypsochromic; however, the improve-

ment is not fundamental; see Figure 1. A more hypsochromic shift

of the absorption would bring about an appreciable beneﬁt.

’ RESULTS AND DISCUSSION

An optical contrast medium should match both the spectral sensi-

tivity of the visible detection and the spectral light intensity of the

applied lamps for illumination. An additional criterion for detec-

tion such as ﬂuorescence would bring about a further improvement.

Targeted substances should exhibit a moderate stability because

residual material should be degraded quickly. Speciﬁc binding

Received: February 28, 2011

Published: April 27, 2011

r

2011 American Chemical Society

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dx.doi.org/10.1021/jm2001986 J. Med. Chem. 2011, 54, 3903–3925

|

Journal of Medicinal Chemistry

ARTICLE

Figure 1. UV/vis spectra. Dashed line, ICG in water; dotted line,

aggregated ICG; straight line, spectral sensitivity of the human eye; and

gray line, spectral radiation characteristic of a tungsten lamp (3200 K).

the nucleophilic substitution of X = Br in 5 with sulﬁte. Compound 5

was condensed with orthoformic ethylester to form 6. Both steps, the

alkylation of 4 and the condensation to 6, could be done in one pot.

The arrangement of polar and lipophilic groups in 3 and 6,

respectively, was organized by the length n of an alkyl spacer.

Special care was taken for the puriﬁcation of 3 and especially the

sulfonic acids of 3 and 6, respectively. Standard chromatographic

procedures proved to be problematic. Better results were obtained

with the application of reversed-phase silica column separation

(RP18); compare refs 17 and 18.

The UV/vis absorption spectra of 3 and 6, respectively, are essen-

tially independent from the selectivity controlling side chains and only

slightly dependent on the medium and are reported in Figure 3 for the

example 3i. The molar absorptivity of 3b at the absorption maximum

at 591 in ethanol was thoroughly measured and found to be 100000

and may be applied for the determination of the concentration of

other derivatives in solution; a maximum at 590 nm was found in the

lipophilic chloroform. The absorption of 3 corresponds quite well

with the spectral sensitivity of the human eye. The point of gravity

of the spectrum is slightly more bathochromic than the spectral

sensitivity; this may be advantageous for the surgeon because standard

tungsten lamps are applied for illumination with more intense

radiation in the bathochromic region; see Figure 3. Dyes 3 exhibit

an appreciable red ﬂuorescence of some 40% quantum yield being

hypsochromic enough for visual contrast. Thus, there are two indica-

tors for the surgeon concerning the target tissue: The blue staining can

be seen even at low intensity of illumination, and the red ﬂuorescence

becomes visually dominating at higher intensities.

Figure 2. Synthesis_ꢀof the cyanine dyes 3 and 6. (i) Butanesultone for

n = 4 and X = SO₃or Br(CH₂)_nX. (ii) Pyridine or 2-picoline. (iii)

Oleum in nitrobenzene.

polypeptides and to cotton with cellulose as a typical polysaccharide;

see Table 1 (no staining eﬀect was observed for ICG). The aﬃnity to

cellulose was generally higher than to polypeptides, although an

inﬂuence of the net charge of the dye is expected because positive

charges dominate at the surface of wool and negative at the surface of

cellulose; the dyes 3h...3q are positively charged, and 3t is negatively

charged because of the dissociated sulfonic acid groups, whereas

3a...3g are positively charged in strong acid and negatively charged

in the applied neutral to weakly basic media. The aﬃnity to the

The selectivity of the aﬃnity to various surfaces of natural

polymers controlled by the side chains in 3 and 6, respectively,

was investigated with the adsorption to wool and hair as typical

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ARTICLE

Table 1. Adsorption of the Cyanine Dyes 3 to the Natural

Polymers Hair, Wool, and Cotton from Ethanol Solution

Followed by Washing with Water^a

subjective staining eﬀect coloration of the BSS solution for surgery

3

hair

wool

cotton

0.5%

0.25%

0.025%

0.0025%

a

ꢀ

þ

ꢀ

þþ

þ

þþ

--

þ

þþ

þ

þþ

þ

þþ

þ

b

c

d

e

f

þ

þþ

þ

ꢀ

þ

þþ

ꢀ

b

þ

g

h

i

þ

þþ

þ

ꢀ

þ

ꢀ

þ

ꢀ

Figure 3. UV/vis spectra. Dashed line, absorption of 3i; dotted line,

ﬂuorescence of 3i (ethanol); straight line, spectral sensitivity of the

human eye; and gray line, spectral radiation characteristic of a tungsten

lamp (3200 K).

þþ

ꢀ

þþ

ꢀ

j

ꢀ

þ-

þþ

ꢀ

k

l

þþ

þ

ꢀ

polypeptides can be controlled by the size of the side groups indi-

cated by n where a tendency for lower selectivity is observed for

longer chains. A low aﬃnity was observed for the alkynyl derivative

3q, whereas carbonyl derivatives and sulfonic acids give better

results.

þþ

þ

m

n

o

p

q

r

þþ

ꢀ

þ

A good aﬃnity was observed for the methyl esters (3h...3k) for

short and long chain lengths, whereas generally good aﬃnities were

found for the ethyl esters (3l...3o) for chain lengths larger than 3.

Pig's lens capsule is a good model for staining because it is a

basement membrane similar to the human LLI of the retina, and both

represent important target structures for surgery; the intensity of the

staining of such lens capsules varied and was concentration dependent

as presented. Good staining was obtained at comparably high

concentrations of dyes; see Table 2. A decrease of the concentration

lowers the aﬃnity; however, a visual detection is still possible. The red

ﬂuorescence of the dyes forms a second criterion and is helpful for the

visible detection; this is even more important for low concentrations.

The staining with 3t is of special interest because of its very good water

solubility. Good staining was observed with 3c in the carboxylic series

and 3l for the ethyl esters. The methyl esters (3h...3k) were generally

not eﬃcient. Short chain and long chain carboxylic acids and ethyl

esters (3a, 3c, 3e, 3l, 3m, and 3o), respectively, gave generally better

results than the derivatives with medium chain lengths (3d and 3n).

The tetrasulfonic acid 6a and the carboxylic acid 6b gave very good

staining eﬀects; the long chain carboxylic ester 6g was acceptable,

whereas the decomposition of the other derivatives of 6 is proble-

matic. The results in Table 2 were compared with the staining eﬀect of

the biopolymers of Table 1 where an acceptable similarity was obtained

with the staining of cotton exposing a surface of carbohydrates;

obviously, such a surface seems to present the binding eﬃciencies of

the dyes to the capsule better than the surface of peptides in wool and

hair. This may be a consequence of either charges or carbohydrate-

containing structures at the surface of the lens capsule.

--

þ

ꢀ

--

s

ꢀ

t

-

þ

þþ

þ

u

v

w

x

--

þ

--

þ

--

þ

--

þþ

þ

þþ

þ

6a --

6b --

6c --

6d --

6e --

6f --

6g --

6h --

6i --

þþ

ꢀ

þþ

ꢀ

þ

ꢀ

þ

ꢀ

^aStaining of the BSS plus solution (BSS and content of dye in %). þþ

stands for visually estimated eﬃcient adsorption, þ stands for medium

adsorption, ꢀ stands for low adsorption, and -- stands for no visible

adsorption. For BSS plus solution, see the Experimental Section. No

staining eﬀect was observed for ICG. ^bSolubility too small for

measurements.

’ CONCLUSION

Cyanine dyes with the structures 3 and 6, respectively, are useful as

optical contrast media for the staining of tissues that are relevant for

intraocular microsurgery. Compounds 3t and 6a proved intersting

dyes for staining basement membranes, and 6b gave surprising results

because it decomposes comparably readily in solution; however, it is

eﬀective in staining and even induces a strong ﬂuorescence. The UV/

vis spectral characteristics of the dyes are suitable for the optical

detection both in absorption and in ﬂuorescence. Toxic eﬀects of the

dyes were not detected. The variable, structure-dependent coloration

in the region of the basement membrane of the eye indicates a relation

between molecular structure and binding to the target structure of the

A toxicity test was performed for the chromophore of the

cyanine dyes 3. The very good water-soluble dye 3t was investi-

gated as a model compound. Possible toxic eﬀects were studied using

the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide

(MTT) assay where cells were incubated with dye concentrations

higher than those being relevant for surgery to detect even minor toxic

eﬀects. The vitality of cells concerning proliferation was measured

with the reduction of tetrazolium compounds (modiﬁed MTT

assay); control experiments were performed without the addition

of dyes and with the addition of hydrogen peroxide, respectively.

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ARTICLE

Table 2. Staining of Porcine Lens Capsules (ꢀ, Absent; þ,

Fair; þþ, Good; and þþþ, Excellent) with Various Dye

Concentrations in BSS in %^a

distilled water (1 mL), adding it to BSS solution (7 mL), and treating it with

a sodium chloride solution (1 mL) of an osmolarity of 620 (ca. 2%) to re-

establish the genuine osmolarity of the BSS solution (308). This stock

solution may be diluted according to the requirements.

dye

1.0%

0.5%

0.25%

0.025%

0.0025%

Synthesis of Carbocyanine Dyes with Carboxylic Groups

3a

3c

3d

3e

3g

3h

3i

þþ

þþþ

þ

þþ

þ

þþþ

þþ

þ

þþ

þ

ꢀ

þ

ꢀ

þ

ꢀ

þ

ꢀ

þþþ

þþ

þþþ

þþ

3j

þþ

3,3⁰-Di-(2-carboxyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbo-

cyanine Bromide (3a). 3-(2-Carboxyethyl)-1,1,2-trimethyl-1H-benz[e]indo-

lenium bromide (2a, 540 mg, 1.50 mmol) was dissolved in pyridine

(2.00 mL) under argon atmosphere, heated to 116 °C, treated dropwise

slowly with orthoformic triethylester (0.250 mL, 3.00 mmol, color change to

bluish violet), heated to reflux for 2 h, allowed to cool, treated with diethyl

ether (10.0 mL, precipitation of the golden shiny dye), decanted, dissolved

repeatedly in a small amount of ethanol, precipitated with diethylether,

collected by vacuum filtration, dried in vacuo, and purified by flash chroma-

tography (RP 18, methanol/H₂O/acetic acid 1:1:0.4 for adsorption to the

stationary phase, methanol/H₂O/acetic acid 2:1:0.4 for the elution of

byproduct, methanol/H₂O/acetic acid 10:1:0.4 for the elution of the dye).

Yield, 600 mg (70%) of a golden shiny solid forming violet, red fluorescent

solutions; mp 199 °C. R_f(RP18, methanol/H₂O/acetic acid 10:1:0.4) = 0.62.

IR (ATR): ν = 3344 (w, br), 2921 (m, br), 1723 (s), 1633 (w), 1586 (w),

1552 (s), 1519 (m), 1471 (m), 1422 (s), 1350 (m), 1279 (w), 1226 (m),

1153 (m), 1127 (m), 1011 (m), 924 (s), 876 (w), 803 (w), 787 (w), 747

(w), 729 (w), 681 (w), 651 cm^ꢀ1(w). ¹H NMR (200 MHz, CD₃OD): δ =

8.27 (d, 2 H, H_aromatic, ³J= 8.7 Hz), 8.01 (t, 4 H, H_aromatic, ³J=7.6Hz), 7.67(t,

5H, H_aromatic, ³J=6.6Hz), 7.50(t, 2H, H_aromatic, H_allyl, ³J= 7.5 Hz), 6.57 (d, 2

H, H_allyl,³J_E= 12.9 Hz), 4.68ꢀ4.45 (m, 4 H, 2 ꢁ NCH₂), 2.95ꢀ2.75 (m, 4 H,

2ꢁ CH₂), 2.06 ppm (s, 12 H, 4 ꢁ CH₃). ¹³C NMR (100 MHz, CD₃OD): δ

= 176.1, 149.4, 139.2, 133.5, 132.2, 130.4, 129.7, 127.9, 127.4, 124.9, 121.9,

110.9, 110.9, 110.8, 65.5, 51.0, 26.6, 14.0 ppm. UV/vis (ethanol): λ_max(E_rel)

591 (1.0), 554 nm (0.68). UV/vis (solid state/cotton): λ_max(E_rel) 599 (1.0),

555 nm (0.98). UV/vis (solid state/wool): λ_max(E_rel) 559 (1.0), 595 nm

(0.98). UV/vis (solid state/hair): λ_max(E_rel) 595 (1.0), 555 nm (0.98).

Fluorescence (ethanol): λ_max(I_rel) 622 (1.0), 664 nm (0.70). Fluorescence

(solid state/cotton): λ_max(I_rel) 667 (1.0), 643 nm (0.85). Fluorescence (solid

state/wool): λ_max(I_rel) 635 (1.0), 667 nm (0.95). Fluorescence (solid state/

hair): λ_max(I_rel) 624 (1.0), 665 nm (0.69). Fluorescence quantum yield

(CHCl₃, λ_exc= 562 nm, E_562/1cm= 0.0146; reference: S-13 with Φ = 1.00):

0.35. High-resolution mass spectrum (HRMS) (ESI) (C₃₇H₃₇N₂O₄^þ):

calcd, 573.2748; found, 573.2747; Δ = ꢀ0.1 mmu.

3k

3l

þþþ

þþ

3m

3n

3o

3t

þþ

þþþ

ꢀ

3u

3v

6a

6b

6c

6d

6e

6f

þ

ꢀ

þþþ

þþ

dec.

þþ

dec.

þþþ

þþ

dec.

6g

6h

6i

þþ

dec.

^a“dec.” stands for the decomposition of the dyes during staining. The

solubility of 3b and 3f, respectively, was not high enough, and 3q and 3p,

respectively, were precipitated with BSS.

tissue. The wide variation of the properties of dyes by means of

peripheral substituents makes these dyes attractive for the adaption to

various requirements of the surgery of eyes.

’ EXPERIMENTAL SECTION

General. IR spectra, Perkin-Elmer Spektrum BX II with ATR; UV/vis

spectra, Varian Cary; fluorescence spectra, Varian Eclispe; NMR spectrosco-

py, Varian Vnmrs 600 (600 MHz), Vnmrs 400 (400 MHz), Mercury 200

(200 MHz); and mass spectroscopy, Thermo Finnigan LQT FT. The

prepared dyes were estimated to be typically more than 95% pure; the purity

was controlled by ¹H NMR spectroscopy and HPLC; see the Supporting

Information. Dye 3b was further characterized by an elemental analysis, and

the molar absorptivity of this sample was determined; the latter can be applied

for the determination of the dye content of solutions for the other derivatives.

BSS Plus. Abacterial solution for intraocular spilling was obtained by

a 1:1 mixture of two liquid components. Component 1: 1 mL contained

7.44 mg of NaCl, 0.395 mg of KCl, and 0.433 mg of Na₂HPO₄, in water

where HCl and NaOH, respectively, were added for the adjustment of a

physiological pH value. Component 2: 1 mL contained 3.85 mg of

CaCl₂2H₂O, 5 mg of MgCl₂6H₂O, 23 mg of glucose, and 4.6 mg of

3,3⁰-Di-(4-carboxybutyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocar-

bocyanine Bromide (3b). 3-(4-Carboxybutyl)-1,1,2-trimethyl-1H-benz-

[e]indolenium bromide (2b, 140 mg, 0.36 mmol), 3-picoline (1.00 mL),

andorthoformictriethylester (0.12 mL, 0.72 mmol) were allowed to react

as was described for 3,3⁰-di-(2-carboxyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibe-

nz[e]indocarbocyanine bromide (3a). Yield, 100 mg (39%) of golden shiny

solid forming violet, red fluorescent solutions. R_f(RP 18, methanol/H₂O/acetic

3

glutathiondisulfide in water.

Five milligrams of the dye was dissolved in ethanol (500 μL) for the test

staining and diluted to 2 mL by means of BSS to form the stock solution and

then diluted according to the requirements for staining. Alternatively, stock

solutions of dye 4 was prepared by dissolving dye 4 (for example, 5 mg) in

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Journal of Medicinal Chemistry

ARTICLE

acid 10:1:0.4) = 0.43. IR (ATR): ν = 2922 (s), 2348 (m), 2213 (w), 1707

(m), 1555 (s), 1519 (s), 1479 (m), 1427 8s), 1360 (m), 1226 (m), 1154

(m), 1014 (m), 936 (m), 805 (8w), 746 (w) cm^ꢀ1. ¹H NMR (400 MHz,

667 nm (0.88). Fluorescence (solid state/hair): λ_max(I_rel) 623 (1.0),

660 nm (0.71). Fluorescence quantum yield (CHCl₃, λ_exc= 559 nm, E_562/

= 0.0126; reference: S-13 with Φ = 1.00): 0.50. HRMS (ESI)

1cm

(C₄₃H₄₉N₂O₄^þ): calcd, 657.3687; found, 657.3691; Δ = 0.4 mmu.

CD₃OD): δ = 8.28 (d, 2 H, H_aromatic, J = 8.5 Hz), 8.03 (dd, 5 H, H_aromatic

,

3

H_allyl

,

³J = 8.5 Hz, J_E= 12.3 Hz), 7.70ꢀ7.64 (m, 4 H, H_aromatic),

3

7.55ꢀ7.48 (m, 2 H, H_aromatic), 6.55 (d, 2 H, H_allyl, J_E= 13.0 Hz),

4.39ꢀ4.28 (m, 4 H, 2 ꢁ NCH₂), 2.49ꢀ2.35 (m, 4 H, 2 ꢁ CH₂), 2.09 (s,

12 H, 4 ꢁ CH₃), 2.00ꢀ1.91 (m, 4 H, 2 ꢁ CH₂) 1.90ꢀ1.80 ppm (m, 4 H,

2 ꢁ CH₂). ¹³C NMR (100 MHz, CD₃OD): δ = 175.9, 149.3, 139.4,

133.5, 132.2, 130.5, 129.7, 127.9, 127.4, 124.8, 121.9, 110.8, 101.9, 101.9,

50.9, 43.8, 26.6 ppm. UV/vis (CHCl₃): λ_max(ε) 598.9 (100000),

559.0 nm (60830). UV/vis (ethanol): λ_max(ε) 591.4 (110800),

554.5 nm (76920). UV/vis (solid state/cotton): λ_max(E_rel) 598 (1.0),

559 nm (0.98). UV/vis (solid state/wool): λ_max(E_rel) 558 (1.0), 591 nm

(0.95). UV/vis (solid state/hair): λ_max(E_rel) 598 (1.0), 560 nm (0.81).

Fluorescence (ethanol): λ_max(I_rel) 608 (1.0), 652 nm (0.30). Fluores-

cence (solid state/cotton): λ_max(I_rel) 667 (1.0), 628 nm (0.66).

Fluorescence (solid state/wool): λ_max(I_rel) 635 (1.0), 668 nm (0.97).

Fluorescence (solid state/hair): λ_max(I_rel) 624 (1.0), 665 nm (0.68).

Fluorescence quantum yield (CHCl₃, λ_exc= 559 nm, E_559/1cm= 0.0120,

reference: S-13 with Φ = 1.00): 0.49. HRMS (ESI) (C₄₁H₄₅N₂O₄):

calcd, 629.3374; found, 629.3380; Δ = 0.6 mmu. C₄₁H₄₅N₂O₄Br (709.7)

calcd: C, 69.39; H, 6.39; N, 3.95. Found: C, 70.21; H, 6.79; N, 3.91.

3,3⁰-Di-(7-carboxyheptyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocar-

bocyanine Bromide (3d). 3-(7-Carboxyheptyl)-1,1,2-trimethyl-1H-benz-

[e]indolenium bromide (2d, 150 mg, 0.35 mmol), 3-picoline (1.00 mL), and

orthoformic triethylester (0.12 mL, 0.70 mmol) were allowed to react as was

described for 3,3⁰-di-(2-carboxyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz-

[e]indocarbocyanine bromide (3a). Yield, 80.0 mg (54%) of golden shiny

solid forming violet, red fluorescent solutions. IR (ATR): ν = 2927 (s), 2348

(w), 2233 (w), 1720 (s, br), 1552 (s), 1519 (m), 1479 (w), 1422 (s), 1351

(m), 1225 (m), 1141 (m), 1011 (m), 931 (m), 806 (w) cm^ꢀ1. ¹H NMR

(400 MHz, CD₃OD): δ = 8.78 (t, 1 H, H_allyl, ³J_E= 13.5 Hz), 8.30 (d, 2 H,

H_aromatic, ³J= 8.3 Hz), 8.05 (t, 4 H, H_aromatic, ³J=7.8Hz), 7.73ꢀ7.61 (m, 4 H,

H_aromatic), 7.57ꢀ7.49 (m, 2 H, H_aromatic), 6.53 (d, 2 H, H_allyl, ³J_E= 13.3 Hz),

4.29 (t, 4 H, 2 ꢁ NCH₂, ³J = 7.7 Hz), 2.29 (t, 4 H, 2 ꢁ CH₂CO₂H, ³J =

7.3 Hz) 2.11 (s, 12 H, 4 ꢁ CH₃), 1.99ꢀ1.84 (m, 4 H, 2 ꢁ CH₂), 1.63ꢀ

1.40 ppm (m, 16 H, 8 ꢁ CH₂). ¹³C NMR (100 MHz, CD₃OD): δ = 175.9,

133.5, 132.2, 130.5, 129.7, 127.9, 127.4, 125.2, 124.9, 121.9, 112.4, 110.7,

101.7, 57.0, 51.0, 26.6, 16.9 ppm. UV/vis (ethanol): λ_max(E_rel) 591 (1.0),

554 nm (0.70). UV/vis (solid state/cotton): λ_max(E_rel) 599 (1.0), 554 nm

(0.99). UV/vis (solid state/wool): λ_max(E_rel) 558 (1.0), 595 nm (0.97). UV/

vis (solid state/hair): λ_max(E_rel) 599 (1.0), 555 nm (0.92). Fluorescence

(ethanol): λ_max(I_rel) 602 (1.0), 661 nm (0.25). Fluorescence (solid state/

cotton): λ_max(I_rel) 669 (1.0), 646 nm (0.94). Fluorescence (solid state/

wool): λ_max(I_rel) 632 (1.0), 668 nm (0.89). Fluorescence (solid state/hair):

λ_max(I_rel) 635 (1.0), 666 nm (0.86). Fluorescence quantum yield (CHCl₃,

λ_exc= 558 nm, E_562/1cm= 0.0161, reference: S-13 with Φ= 1.00): 0.43. HRMS

(ESI) (C₄₇H₅₇N₂O₄^þ): calcd, 713.4313; found, 713.4324; Δ = 1.1 mmu.

3,3⁰-Di-(5-carboxypentyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocar-

bocyanine Bromide (3c). 3-(5-Carboxypentyl)-1,1,2-trimethyl-1H-benz-

[e]indolenium bromide (2c, 150 mg, 0.37 mmol), 3-picoline (2.00 mL),

and orthoformic triethylester (0.10 mL, 0.74 mmol) were allowed to react

as was described for 3,3⁰-di-(2-carboxyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-

dibenz[e]indocarbocyanine bromide (3a). Yield, 150 mg (55%) of golden

shiny solid forming violet, red fluorescent solutions. R_f(RP 18, methanol/

H₂O/acetic acid 10:1:0.4) = 0.66. IR (ATR): ν = 3416 (w, br), 3054 (w),

2978 (w), 2935 (w), 2859 (w), 1727 (s), 1626 (w), 1588 (w), 1547 (s),

1519 (m), 1487 (m), 1469 (w), 1424 (s), 1370 (w), 1348 (w), 1275 (w),

1227 (s), 1170 (m), 1140 (m), 1125 (m), 1031 (w), 1011 (m), 977 (m),

926 (s), 891 (w), 878 (w), 865 (w), 829 (w), 805 (m), 787 (w), 769 (w),

748 (w), 725 (w), 684 (w), 652 (w) cm^ꢀ1

.

¹H NMR (400 MHz,

CD₃OD): δ = 8.78 (t, 1 H, H_allyl, ³J = 13.5 Hz), 8.30 (d, 2 H, H_aromatic

,

3,3⁰-Di-(9-carboxynonyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocar-

bocyanine Bromide (3e). 3-(9-Carboxynonyl)-1,1,2-trimethyl-1H-benz-

[e]indolenium bromide (2e, 100 mg, 0.21 mmol), 3-picoline (1.00 mL),

and orthoformic triethylester (0.07 mL, 0.43 mmol) were allowed to react

as was described for 3,3⁰-di-(2-carboxyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-

dibenz[e]indocarbocyanine bromide (3a). Yield, 41.0 mg (23%) of golden

shiny solid forming violet, red fluorescent solutions. R_f(RP 18, methanol/

H₂O/acetic acid 10:1:0.4) = 0.4. IR(ATR): ν = 3381 (w), 3056 (w), 2923

(s), 2852 (s), 2350 (w), 2287 (w), 1711 (m), 1626 (w), 1588 (w), 1554

(s), 1520 (m), 1479 (m), 1423 (s), 1357 (m), 1277 (w), 1224 (m), 1168

(m), 1142 (m), 1127 (m), 1012 (m), 971 (w), 930 (s), 898 (w), 867 (w),

806 (m), 786(w), 746(w), 726 (w), 685 (w), 676 (w), 652 (m) cm^ꢀ1. ¹H

NMR (400 MHz, CD₃OD): δ = 8.78 (t, 1 H, H_allyl, ³J_E= 13.2 Hz), 8.29 (d,

2 H,H_aromatic, ³J =8.6 Hz),8.06(d, 2H,H_aromatic, ³J =8.8 Hz),8.03(d, 2H,

H_aromatic, ³J = 8.1 Hz), 7.72ꢀ7.62 (m, 4 H, H_aromatic), 7.55ꢀ7.50 (m, 2 H,

³J = 8.5Hz), 8.06 (d, 2 H, H_aromatic, ³J = 8.8Hz), 8.02 (d, 2 H, H_aromatic, ³J =

8.2 Hz), 7.68 (ddd, 2 H, H_aromatic, ⁴J = 1.3 Hz, ³J = 6.9 Hz, ³J = 8.4 Hz), 7.64

(d, 2 H, H_aromatic, ³J =8.9 Hz), 7.52 (ddd, 2 H, H_aromatic, ⁴J =1.0 Hz, ³J=6.9

Hz, ³J = 8.1 Hz), 6.53 (d, 2 H, H_allyl, ³J_E= 13.5 Hz), 4.30 (t, 4 H, 2 ꢁ

NCH₂, ³J = 7.5 Hz), 2.35 (t, 4 H, 2 ꢁ CH₂CO₂H, ³J = 7.2 Hz), 2.11 (s,

12H, 4 ꢁ CH₃), 2.04ꢀ1.86 (m, 4H, 2 ꢁ CH₂), 1.79ꢀ1.70 (m, 4H, 2 ꢁ

CH₂), 1.63ꢀ1.55 ppm (m, 4 H, 2 ꢁ CH₂). ¹³C NMR (100 MHz,

CD₃OD): δ = 175.9, 149.3, 139.4, 133.5, 132.2, 130.5, 129.7, 127.9, 127.4,

124.9, 121.9, 110.8, 101.7, 51.0, 43.9, 27.1, 26.6, 26.1, 22.8, 16.9 ppm. UV/

vis (ethanol): λ_max(E_rel) 591 (1.0), 554 nm (0.68). UV/vis (solid state/

cotton): λ_max(E_rel) 598 (1.0), 554 nm (0.99). UV/vis (solid state/wool):

λ_max(E_rel) 558 (1.0), 594 nm (0.97). UV/vis (solid state/hair): λ_max(E_rel)

598 (1.0), 556 nm (0.90). Fluorescence (ethanol): λ_max(I_rel) 611 (1.0),

655 nm (0.50). Fluorescence (solid state/cotton): λ_max(I_rel) 661 (1.0),

644 nm (0.93). Fluorescence (solid state/wool): λ_max(I_rel) 632 (1.0),

3907

dx.doi.org/10.1021/jm2001986 |J. Med. Chem. 2011, 54, 3903–3925

Journal of Medicinal Chemistry

ARTICLE

H_aromatic), 6.51 (d, 2 H, H_allyl, ³J_E= 13.5 Hz), 4.29 (t, 4 H, 2 ꢁ NCH₂, ³J =

7.5Hz), 2.20(t, 4H, 2ꢁ CH₂CO₂H, ³J= 7.2 Hz), 2.11 (s, 12 H, 4 ꢁ CH₃),

1.96ꢀ1.88 (m, 8 H, 4 ꢁ CH₂), 1.60ꢀ1.50 (m, 8 H, 4 ꢁ CH₂), 1.49ꢀ1.40

(m, 4 H, 2 ꢁ CH₂), 1.33ꢀ1.30 ppm (m, 8 H, 4 ꢁ CH₂). ¹³C NMR (100

MHz, CD₃OD): δ = 175.9, 149.3, 139.4, 133.5, 132.2, 130.5, 129.8, 127.9,

127.5, 124.9, 121.9, 110.8, 101.6, 51.0, 44.0, 28.9, 28.9, 28.8, 27.4, 26.6, 26.3,

25.2, 16.9 ppm. UV/vis (ethanol): λ_max(E_rel) 594 (1.0), 555 nm (0.65).

UV/vis (solid state/cotton): λ_max(E_rel) 569 (1.0), 557 nm (0.99). UV/vis

(solid state/wool): λ_max(E_rel) 565 (1.0), 597 nm (0.90). UV/vis (solid

state/hair): λ_max(E_rel) 603 (1.0), 557 nm (0.95). Fluorescence (ethanol):

λ_max(I_rel) 604 (1.0), 651 nm (0.25). Fluorescence (solid state/cotton):

λ_max(I_rel) 669 (1.0), 645 nm (0.94). Fluorescence (solid state/wool): λ_max

(I_rel) 632 (1.0), 668 nm (0.89). Fluorescence (solid state/hair): λ_max(I_rel)

3,3⁰-Di-(11-carboxyundecyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indo-

carbocyanine Bromide (3g). 3-(11-Carboxyundecyl)-1,1,2-trimethyl-1H-

benz[e]indolenium bromide (2g, 340 mg, 7.00 μmol), 3-picoline

(1.00 mL), and orthoformic triethylester (0.020 mg, 0.020 mL, 0.014

mmol) were allowed to react as was described for 3,3⁰-di-(2-carboxyethyl)-

1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbocyanine bromide (3a) (chro-

matography with aqueous 2 N HCl instead of acetic acid). Yield, 12.0 mg

(19%) of golden shiny solid forming violet, red fluorescent solutions. R_f(RP

18, methanol/H₂O/HCl 10:1:0.4) = 0.8. IR (ATR): ν = 3350 (w), 2922

(s), 2851 (m), 1710 (m), 1625 (w), 1587 (w), 1553 (s), 1519 (m), 1479

(m), 1422 (s), 1356 (m), 1278 (w), 1259 (w), 1224 (m), 1169 (m), 1141

(w), 1127 (m), 1012 (m), 973 (w), 931 (s), 896 (w), 806 (m), 786 (w),

746 (w), 726 (w), 685 (w), 675 (w) cm^ꢀ1. ¹H NMR (400 MHz, CD₃OD):

δ = 8.78 (t, 2 H, H_allyl, ³J_E= 13.5 Hz), 8.29 (d, 2 H, H_aromatic, ³J = 8.5 Hz),

8.06 (d, 2 H, H_aromatic, ³J = 8.8 Hz), 8.03 (d, 2 H, H_aromatic, ³J = 8.2 Hz), 7.68

(ddd, 3 H, H_aromatic, ⁴J = 1.2 Hz, ³J = 6.9 Hz, ³J = 8.4 Hz), 7.64 (d, 2 H,

H_aromatic, ³J = 8.9 Hz), 7.53 (ddd, 2 H, H_aromatic, ⁴J = 0.9 Hz, ³J = 6.9 Hz, ³J =

8.0 Hz), 6.50 (d, 2 H, H_allyl, ³J_E= 13.5 Hz), 4.29 (t, 4 H, 2 ꢁ NCH₂, ³J = 7.4

Hz), 2.18 (t, 4 H, 2 ꢁ CH₂CO₂H, ³J = 7.4 Hz), 2.11 (s, 12 H, 4 ꢁ CH₃),

1.96ꢀ1.88 (m, 4 H, 2 ꢁ CH₂), 1.57ꢀ1.49 (m, 8 H, 4 ꢁ CH₂), 1.47ꢀ1.40

(m, 4 H, 2 ꢁ CH₂), 1.36ꢀ1.28 ppm (m, 20 H, 10 ꢁ CH₂). ¹³C NMR

(100 MHz, CD₃OD): δ = 178.6, 175.9, 149.2, 139.4, 133.5, 132.2, 130.5,

129.7, 127.9, 127.5, 124.9, 121.9, 110.8, 101.7, 56.9, 51.0, 44.0, 29.1, 29.0,

29.0, 29.0, 28.9, 27.3, 26.6, 26.3, 25.4, 16.9 ppm. UV/vis (ethanol): λ_max

(E_rel) 590 (1.0), 553 nm (0.70). UV/vis (solid state/cotton): λ_max(E_rel)

600 (1.0), 555 nm (0.97). UV/vis (solid state/wool): λ_max(E_rel) 603 (1.0),

556 nm (0.95). UV/vis (solid state/hair): λ_max(E_rel) 607 (1.0),

556 nm (0.93). Fluorescence (ethanol): λ_max(I_rel) 604 (1.0), 656 nm

(0.20). Fluorescence (solid state/cotton): λ_max(I_rel) 667 (1.0), 643 nm

(0.94). Fluorescence (solid state/wool): λ_max(I_rel) 638 (1.0), 667 nm

(0.93). Fluorescence (solid state/hair): λ_max(I_rel) 634 (1.0), 668 nm

635 (1.0), 666 nm (0.87). Fluorescence quantum yield (CHCl₃, λ_exc

=

557 nm, E_562/1cm= 0.0180; reference: S-13 with Φ = 1.00): 0.59. HRMS

(ESI) (C₅₁H₆₅N₂O₄^þ): calcd, 769.4939; found, 769.4941; Δ = 0.2 mmu.

3,3⁰-Di-(10-carboxydecyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocar-

bocyanine Bromide (3f). 3-(10-Carboxy-decyl)-1,1,2-trimethyl-1H-benz-

[e]indolenium bromide (2f, 117 mg, 0.25 mmol), pyridine (2.5 mL), and

orthoformic triethylester (0.08 mL, 0.5 mmol) were allowed to react

(120 °C) as was described for 3,3⁰-di-(2-carboxyethyl)-1,1,1⁰,1⁰-tetra-

methyl-1H-dibenz[e]indocarbocyanine bromide (3a). Yield, 118 mg

(54%) of golden shiny solid forming violet, red fluorescent solutions. IR

(ATR): ν = 3381 (w), 3056 (w), 2923 (s), 2852 (s), 2350 (w), 2287 (w),

1711 (m), 1626 (w), 1588 (w), 1554 (s), 1520 (m), 1479 (m), 1423 (s),

1357 (m), 1277 (w), 1224 (m), 1012 (m), 971 (w), 930 (s), 898 (w), 867

(0.88). Fluorescence quantum yield (CHCl₃, λ_exc= 560 nm, E_562/1cm

0.0127; reference: S-13 with 1.00): 0.35. HRMS (ESI)

(C₅₅H₇₃N₂O₄^þ): calcd, 825.5565; found, 825.5567; Δ = 0.2 mmu.

=

Φ

=

Synthesis of Carbocyanine Dyes with Methylester Groups

(w), 806 (m), 786 (w), 746(w), 726 (w), 685 (w), 676(w), 652 (m) cm^ꢀ1

.

¹H NMR (400 MHz, CD₃OD): δ=8.77(t, 1H, CH_allyl, ³J_E= 13.4 Hz), 8.29

(d,2H,CH_aromatic,³J=8.6Hz),8.05(d,2H, CH_aromatic, ³J=8.7Hz),8.02(d,

2 H, CH_aromatic, ³J = 8.4 Hz), 7.70ꢀ7.62 (m, 4 H, CH_aromatic), 7.52 (t, 2 H,

CH_aromatic, ³J= 7.5 Hz), 6.50 (d, 2 H, CH_allyl, ³J_E= 13.6 Hz), 4.28(t, 4 H, 2ꢁ

NCH₂, ³J= 7.1 Hz), 2.30ꢀ2.13(m, 4H, 2ꢁ CH₂CO₂H), 2.10 (s, 12 H, 4 ꢁ

CH₃), 1.98ꢀ1.88 (m, 4 H, 2 ꢁ CH₂), 1.58ꢀ1.50 (m, 8 H, 4 ꢁ CH₂),

1.35ꢀ1.22 ppm(m, 20 H, 10ꢁ CH₂). ¹³C NMR (100 MHz, CD₃OD): δ=

175.9, 149.2, 139.4, 133.5, 132.2, 131.3, 130.5, 129.7, 127.9, 127.5, 124.9,

121.9, 114.7, 110.8, 101.6, 51.0, 44.0, 29.0, 29.0, 28.9, 27.4 26.6, 26.3, 22.8

ppm. UV/vis (ethanol): λ_max(E_rel) 590 (1.0), 553 nm (0.70). UV/vis (solid

state/cotton): λ_max(E_rel) 597 (1.0), 555 nm (0.99). UV/vis (solid state/

wool): λ_max(E_rel) 557 (1.0), 596 nm (0.96). UV/vis (solid state/hair): λ_max

(E_rel) 601 (1.0), 556 nm (0.97). Fluorescence (ethanol): λ_max(I_rel) 610

(1.0), 656 nm (0.54). Fluorescence (solid state/cotton): λ_max(I_rel) 670

(1.0), 641 nm (0.83). Fluorescence (solid state/wool): λ_max(I_rel) 667 (1.0),

641 nm (0.98). Fluorescence (solidstate/hair):λ_max(I_rel) 640 (1.0), 667 nm

3,3⁰-Di-(2-methoxycarbonylethyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz-

[e]indocarbocyanine Bromide (3h). 3-(2-Methoxycarbonylethyl)-1,1,2-

trimethyl-1H-benz[e]indolenium bromide (2h, 300 mg, 0.797 mmol),

3-picoline (2.0 mL), and orthoformic triethylester (0.26 mL, 1.60 mmol)

were allowed to react (100 °C) as was described for 3,3⁰-di-(2-carb-

oxyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbocyanine bromide

(3a) and isolated wihout chromatography. Yield, 290 mg (53%) of golden

shiny solid forming violet, red fluorescent solutions. IR (ATR): ν = 2925

(s), 2856 (w), 2541 (w), 1960 (w), 1722 (s), 1625 (m), 1567 (m), 1555

(s), 1519 (m), 1476 (m), 1422 (s), 1352 (m), 1278 (m), 1232 (w), 1155

(m), 1126 (w), 1011 (m), 924 (m, br), 875 (w), 804 (m), 786 (w), 804

(m), 786 (w), 744 (m) cm^ꢀ1. ¹H NMR (200 MHz, CD₃OD): δ = 8.42 (t,

2 H,H_allyl, ³J_E=13.4 Hz),8.11(d, 4H,H_aromatic, H_allyl, ³J=8.0 Hz), 7.96(d,

2 H, H_aromatic, ³J = 8.5 Hz), 7.40ꢀ7.30 (m, 4 H, H_aromatic), 7.16 (t, 2 H,

H_aromatic, ³J = 7.5 Hz), 6.38 (d, 2 H, H_allyl, ³J_E= 13.4 Hz), 4.35ꢀ4.30 (m, 4

H, 2 ꢁ NCH₂), 3.31 (s, 6 H, 2 ꢁ OCH₃), 2.68 (t, 4 H, 2 ꢁ CH₂CO₂CH₃,

³J = 6.6 Hz), 1.71 ppm (s, 12 H, 4 ꢁ CH₃). ¹³C NMR (100 MHz,

CD₃OD): δ = 177.7, 172.5, 151.1, 140.5, 134.9, 133.7, 131.9, 131.3, 131.2,

129.3, 129.0, 126.5, 123.5, 112.3, 52.5, 41.5, 33.0, 28.2, 24.2 ppm. UV/vis

(0.93). Fluorescence quantum yield (CHCl₃, λ_exc= 557 nm, E_562/1cm

0.0131; reference: S-13 with 1.00): 0.33. HRMS (ESI)

(C₅₃H₆₉N₂O₄^þ): calcd, 797.5252; found, 797.5267; Δ = 1.5 mmu.

=

Φ

=

3908

dx.doi.org/10.1021/jm2001986 |J. Med. Chem. 2011, 54, 3903–3925

Journal of Medicinal Chemistry

ARTICLE

(ethanol): λ_max(E_rel) 592 (1.0), 553 nm (0.67). UV/vis (solid state/

cotton): λ_max(E_rel) 600 (1.0), 554 nm (0.99). UV/vis (solid state/wool):

λ_max(E_rel) 597 (1.0), 560 nm (0.97). UV/vis (solid state/hair): λ_max(E_rel)

597 (1.0), 558 nm (0.98). Fluorescence (ethanol): λ_max(I_rel) 609 (1.0),

656 nm (0.53). Fluorescence quantum yield (CHCl₃, λ_exc= 562 nm,

E_562/1cm= 0.0178; reference: S-13 with Φ = 1.00): 0.24. HRMS (ESI)

(C₃₉H₄₁N₂O₄^þ): calcd, 601.3061; found, 601.3044; Δ = ꢀ1.7 mmu.

xyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbocyanine bromide

(3a) and isolated without chromatography. Yield, 113 mg (20%) of golden

shiny solid forming violet, red fluorescent solutions. IR (ATR): ν = 3413

(s, br), 3032 (m), 2971 (w), 2932 (m), 2855 (w), 2361 (s), 2339 (m),

2066 (w), 1729 (m), 1634 (s), 1591 (w), 1555 (m), 1505 (s), 1483 (w),

1429 (s), 1385 (w), 1357 (w), 1324 (w), 1246 (w), 1230 (w), 1204 (w),

1160 (s), 1096 (w), 1051 (w), 1014 (w), 981 (w), 934 (m), 893 (w), 810

(s), 751 (w), 728 (w), 685 (s) cm^ꢀ1. UV/vis (ethanol): λ_max(E_rel) 591

(1.0), 551 nm (0.73). UV/vis (solid state/cotton): λ_max(E_rel) 600 (1.0),

559 nm (0.94). UV/vis (solid state/wool): λ_max(E_rel) 599 (1.0), 559 nm

(0.92). UV/vis (solid state/hair): λ_max(E_rel) 699 (1.0), 558 nm (0.95).

Fluorescence (ethanol): λ_max(I_rel) 610 (1.0), 658 nm (0.51). Fluorescence

quantum yield (CHCl₃, λ_exc= 559 nm, E_559/1cm= 0.0145; reference: S-13

with Φ = 1.00): 0.47. HRMS (ESI) (C₅₃H₆₉N₂O₄^þ): calcd, 797.5252;

found, 797.5252; Δ = 0.03 mmu.

3,3⁰-Di-(4-methoxycarbonylbutyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz-

[e]indocarbocyanine Bromide (3i). 3-(4-Methoxycarbonylbutyl)-1,1,2-

trimethyl-1H-benz[e]indolenium bromide (2i, 253 mg, 0.626 mmol),

3-picoline (2.2 mL), and orthoformic triethylester (0.2 mL, 1.3 mmol)

were allowed to react (120 °C) as was described for 3,3⁰-di-(2-

carboxyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbocyanine

bromide (3a) (chromatography with aqueous 2 N HCl instead of

acetic acid). Yield, 50 mg (11%) of golden shiny solid forming violet,

red fluorescent solutions. IR (ATR): ν = 3354 (w, br), 3140 (w), 3030

(w), 2960 (w), 2924 (s), 2855 (w), 2167 (w), 1705 (m, br), 1623 (w),

1587 (w), 1554 (s), 1520 (m), 1479 (m), 1425 (s), 1353 (m), 1278

(w), 1260 (w), 1226 (m), 1153 (s), 1128 (m), 1066 (w), 1013 (m),

982 (w), 937 (m), 917 (w), 895 (w), 865 (w), 807 (m), 786 (w), 746

(w), 727 (w) cm^ꢀ1. ¹H NMR (400 MHz, CD₃OD): δ = 8.79ꢀ8.76

(m, 1 H, H_aromatic), 8.30 (d, 2 H, H_aromatic, ³J = 8.4 Hz), 8.04 (dd, 4 H,

3,3⁰-Di-(10-methoxycarbonyldecyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz-

[e]indocarbocyanine Bromide (3k). 3-(10-Methoxycarbonyldecyl)-1,1,2-

trimethyl-1H-benz[e]indolenium bromide (2k, 300 mg, 0.633 mmol),

pyridine (1.0 mL), and orthoformic triethylester (0.16 mL, 0.94 mmol)

were allowed to react (115 °C) as was described for 3,3⁰-di-(2-

carboxyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbocyanine bromide

(3a) and isolated without chromatography. Yield, 149 mg (35%) of golden

shiny solid forming violet, red fluorescent solutions. IR (ATR): ν = 3403

(s, br), 3131 (w), 3055 (w), 2972 (w), 2927 (s), 2853 (m), 2361(w), 2337

(w), 2170 (w), 1731 (s), 1633 (m), 1586 (w), 1553 (s), 1519 (m), 1484

(m), 1425 (s), 1392 (w), 1356 (w), 1277 (w), 1227 (m), 1171 (s), 1143

(w), 1128 (w), 1050 (w), 1012 (m), 975 (w), 930 (m), 897 (w), 808 (w),

780 (w), 748 (w), 726 (w), 682 (w) cm^ꢀ1. UV/vis (ethanol): λ_max(E_rel)

591 (1.0), 550 nm (0.69). UV/vis (solid state/cotton): λ_max(E_rel)

603(1.0), 559 nm (0.95). UV/vis (solid state/wool): λ_max(E_rel) 596

(1.0), 557 nm (0.97). UV/vis (solid state/hair): λ_max(E_rel) 600 (1.0),

557 nm (0.95). Fluorescence (ethanol): λ_max(I_rel) 610 (1.0), 657 nm

3

H_aromatic, H_allyl, J = 8.5 Hz, J_E= 14.9 Hz), 7.71ꢀ7.64 (m, 4 H,

3

H_aromatic), 7.55ꢀ7.51 (m, 2 H, H_aromatic), 6.54 (d, 2 H, H_allyl, J_E=

13.5 Hz), 4.31 (t, 4 H, 2 ꢁ NCH₂³J = 7.3 Hz), 2.48 (t, 4 H, 2 ꢁ

CH₂CO₂CH₃, ³J = 7.0 Hz), 2.10 (s, 12 H, 4 ꢁ CH₃), 1.99ꢀ1.92 (m, 4

H, 2 ꢁ CH₂), 1.87ꢀ1.80 ppm (m, 4 H, 2 ꢁ CH₂). ¹³C NMR (100

MHz, CD₃OD): δ = 175.9, 174.0, 149.3, 149.2, 139.4, 133.5, 132.2,

130.5, 129.7, 127.5, 125.0, 121.9, 110.8, 101.8, 51.0, 43.6, 32.7, 26.6,

21.7 ppm. UV/vis (ethanol): λ_max(E_rel) 592 (1.0), 555 nm (0.72).

UV/vis (solid state/cotton): λ_max(E_rel) 602(1.0), 555 nm (0.98).

UV/vis (solid state/wool): λ_max(E_rel) 557 (1.0), 556 nm (0.98). UV/

vis (solid state/hair): λ_max(E_rel) 602 (1.0), 558 (0.92), 631 nm

(0.89). Fluorescence (ethanol): λ_max(I_rel) 608 (1.0), 658 nm (0.49).

Fluorescence (solid state/cotton): λ_max(I_rel) 668 (1.0), 630 nm

(0.55). Fluorescence (solid state/wool): λ_max(I_rel) 667 (1.0), 635 nm

(0.98). Fluorescence (solid state/hair): λ_max(I_rel) 667 (1.0), 623 nm

(0.53). Fluorescence quantum yield (CHCl₃, λ_exc= 560 nm, E_562/1cm

0.0174; reference: S-13 with 1.00): 0.36. HRMS (ESI)

(C₅₅H₇₃N₂O₄^þ): calcd, 825.5565; found, 8525.5569; Δ = 0.4 mmu.

=

Φ

=

(0.66). Fluorescence quantum yield (CHCl₃, λ_exc= 558 nm, E_558/1cm

=

0.0114; reference: S-13 with Φ = 1.00): 0.40. HRMS (ESI)

(C₄₃H₄₉N₂O₄^þ): calcd, 657.3687; found, 657.3675; Δ = ꢀ1.2 mmu.

3,3⁰-Di-(2-ethoxycarbonylethyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]in-

docarbocyanine Bromide (3l). 3-(2-Ethoxycarbonylethyl)-1,1,2-trimeth-

yl-1H-benz[e]indolenium bromide (2l, 200 mg, 0.51 mmol), 3-picoline

(1.1 mL), and orthoformic triethylester (0.17 mL, 1.02 mmol) were allowed

to react (120 °C) as was described for 3,3⁰-di-(2-carboxyethyl)-1,1,1⁰,1⁰-

tetramethyl-1H-dibenz[e]indocarbocyanine bromide (3a) (chromatography

with aqueous 2 N HCl instead of acetic acid). Yield, 121 mg (33%) of golden

3,3⁰-Di-(9-methoxycarbonylnonyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz-

[e]indocarbocyanine Bromide (3j). 3-(9-Methoxycarbonylnonyl)-1,1,2-

trimethyl-1H-benz[e]indolenium bromide (2j, 300 mg, 0.633 mmol),

3-picoline (2.0 mL), and orthoformic triethylester (0.20 mL, 1.26 mmol)

were allowed to react (100 °C) as was described for 3,3⁰-di-(2-carbo-

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shiny solid forming violet, red fluorescent solutions. IR (ATR): ν = 3054 (w),

2973 (w), 2927 (w), 2574 (w), 2366 (w), 1723 (s), 1626 (w), 1587 (w),

1554 (s), 1520 (m), 1477 (m), 1425 (s), 1393 (w), 1353 (m), 1279 (w),

1227 (m), 1154 (m), 1128 (w), 1047 (w), 1012 (m), 987 (w), 925(s), 877

(w), 806 (m), 786 (w), 746 (w), 728 (w), 684 (w) cm^ꢀ1. ¹H NMR (400

E_562/1cm= 0.0132; reference: S-13 with Φ = 1.00): 0.61. HRMS (ESI)

(C₄₃H₄₉N₂O₄^þ): calcd, 657.3687; found, 657.3695; Δ = 0.8 mmu.

MHz, CD₃OD): δ = 8.80ꢀ8.75 (m, 1 H, H_aromatic), 8.28 (d, 2 H, H_aromatic

,

³J = 8.6 Hz), 8.03 (dd, 4 H, H_aromatic, H_allyl, ³J = 8.6 Hz, ³J_E= 13.5 Hz),

7.70ꢀ7.65 (m, 4 H, H_aromatic), 7.54ꢀ7.49 (m, 2 H, H_aromatic), 6.54 (d, 2 H,

H_allyl, ³J_E= 13.4 Hz), 4.13(t, 4 H, 2 ꢁ NCH₂, ³J =6.8 Hz), 3.60 (q, 4 H, 2 ꢁ

CH₂CH₃, ³J = 7.0 Hz), 2.73 (t, 4 H, 2 ꢁ CH₂CO₂CH₂, ³J = 6.9 Hz), 1.58

(s, 12 H, 4 ꢁ CH₃), 1.17 ppm (t, 6 H, 2 ꢁ CH₂CH₃, ³J = 7.1 Hz). ¹³

C

NMR (100 MHz, CD₃OD): δ = 178.1, 172.9, 151.4, 140.8, 135.2, 134.0,

132.2, 131.5, 129.6, 129.3, 126.8, 123.1, 112.6, 111.6, 52.8, 41.7, 37.6, 33.2,

28.4, 24.5 ppm. UV/vis (ethanol): λ_max(E_rel) 598 (1.0), 561 nm (0.69).

UV/vis (solid state/cotton): λ_max(E_rel) 560 (1.0), 555 nm (0.99). UV/vis

(solid state/wool): λ_max(E_rel) 597 (1.0), 555 nm (0.98). UV/vis (solid

state/hair): λ_max(E_rel) 560 (1.0), 554 nm (0.94). Fluorescence (ethanol):

λ_max(I_rel) 608 (1.0), 659 nm (0.54). Fluorescence (solid state/cotton):

λ_max(I_rel) 666 (1.0), 642 nm (0.93). Fluorescence (solid state/wool): λ_max

(I_rel) 664 (1.0), 639 nm (0.98). Fluorescence (solid state/hair): λ_max(I_rel)

3,3⁰-Di-(4-Ethoxycarbonylbutyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]in-

docarbocyanine Bromide (3n). 3-(4-Ethoxycarbonylbutyl)-1,1,2-trimeth-

yl-1H-benz[e]indolenium bromide (2n, 250 mg, 0.6 mmol), 3-picoline

(1.1mL), andorthoformictriethylester (0.2 mL, 1.2 mmol) were allowed to

react (100 °C) as was described for 3,3⁰-di-(2-carboxyethyl)-1,1,1⁰,1⁰-

tetramethyl-1H-dibenz[e]indocarbocyanine bromide (3a) (chromato-

graphy with aqueous 2 N HCl instead of acetic acid). Yield, 105 mg

(23%) of golden shiny solid forming violet, red fluorescent solutions.

IR (ATR): ν = 3420 (w), 2921 (s), 2851 (m), 1726 (s), 1622 (m),

1589 (w), 1555 (s), 1520 (s), 1477 (m), 1428 (s), 1352 (m), 1227

(m), 1154 (s), 1123 (w), 1067 (w), 1014 (m), 941 (m), 899 (w), 805

(m), 785 (w), 744 (m), 728 (w), 685 (w), 652 (m) cm^ꢀ1. ¹H NMR

(400 MHz, CD₃OD): δ = 8.76 (t, 1 H, H_aromatic, ³J = 13.1 Hz), 8.28

(d, 2 H, H_aromatic, ³J = 8.3 Hz), 8.03 (dd, 4 H, H_aromatic, H_allyl, ³J = 8.6

Hz, ³J_E= 12.3 Hz), 7.75ꢀ7.60 (m, 4 H, H_aromatic), 7.55ꢀ7.49 (m, 2 H,

H_aromatic), 6.51 (d, 2 H, H_allyl, ³J_E= 13.0 Hz), 4.35ꢀ4.28 (m, 4 H, 2 ꢁ

NCH₂), 4.10 (q, 4 H, 2 ꢁ CH₂CH₃, ³J = 7.1 Hz), 2.45 (t, 4 H, 2 ꢁ

CH₂CO₂CH₂, ³J = 6.5 Hz), 2.09 (s, 12 H, 4 ꢁ CH₃), 2.00ꢀ1.92 (m, 4

H, 2 ꢁ CH₂), 1.20 ppm (t, 6 H, 2 ꢁ CH₂CH₃, ³J = 7.1 Hz). ¹³C NMR

(100 MHz, CD₃OD): δ = 177.5, 174.9, 169.4, 150.8, 140.8, 133.7,

132.0, 131.2, 129.3, 129.0, 126.4, 123.4, 112.2, 103.2, 79.5, 69.2, 61.6,

52.5, 34.5, 28.1, 23.2, 14.5 ppm. UV/vis (ethanol): λ_max(E_rel) 598

(1.0), 558 nm (0.64). UV/vis (solid state/cotton): λ_max(E_rel) 560

(1.0), 556 nm (0.97). UV/vis (solid state/wool): λ_max(E_rel) 598

(1.0), 557 nm (0.98). UV/vis (solid state/hair): λ_max(E_rel) 598 (1.0),

555 nm (0.94). Fluorescence (ethanol): λ_max(I_rel) 610 (1.0), 660 nm

(0.52). Fluorescence (solid state/cotton): λ_max(I_rel) 670 (1.0), 643 nm

(0.95). Fluorescence (solid state/wool): λ_max(I_rel) 631 (1.0), 664 nm

(0.95). Fluorescence (solid state/hair): λ_max(I_rel) 625 (1.0), 664 nm (0.96).

Fluorescence quantum yield (CHCl₃, λ_exc= 559 nm, E_562/1cm= 0.0128;

reference: S-13 with Φ = 1.00): 0.43. HRMS (ESI) (C₄₅H₅₃N₂O₄^þ): calcd,

685.4000; found, 685.4010; Δ = 1.0 mmu.

636 (1.0), 664 nm (0.92). Fluorescence quantum yield (CHCl₃, λ_exc

=

561 nm, E_561/1cm= 0.0135; reference: S-13 with Φ = 1.00): 0.33. HRMS

(ESI): (C₄₁H₄₅N₂O₄^þ): calcd, 629.3374; found, 629.3385; Δ = 1.1 mmu.

3,3⁰-Di-(3-ethoxycarbonylpropyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]in-

docarbocyanine Bromide (3m). 3-(3-Ethoxycarbonylpropyl)-1,1,2-tri-

methyl-1H-benz[e]indolenium bromide (2m, 250 mg, 0.620 mmol), 3-pico-

line (1.0 mL), and orthoformic triethylester (0.200 mL, 1.24 mmol) were

allowed to react (100 °C) as was described for 3,3⁰-di-(2-carboxy-

ethyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbocyanine bromide (3a)

(chromatography with aqueous 2 N HCl instead of acetic acid). Yield,

215 mg (47%) of golden shiny solid forming violet, red fluorescent solutions.

IR (ATR): ν = 3391 (w), 2969 (w), 2921 (m), 1726 (s), 1622 (m), 1589

(w), 1557 (s), 1520 (m), 1477 (m), 1427 (s), 1352 (m), 1227 (m), 1154 (s),

1123 (w), 1067 (w), 1014 (m), 941 (s), 899 (w), 805 (m), 791 (w), 757

1

(m), 728 (w), 675 (w), 652 (m), 638 (w) cm^ꢀ1. H NMR (400 MHz,

CD₃OD): δ = 8.81ꢀ8.73 (m, 1 H, H_aromatic), 8.28 (d, 2 H, H_aromatic, ³J = 8.4

Hz), 8.01(dd, 4H, H_aromatic, H_allyl, ³J=8.3Hz, ³J_E=14.5Hz), 7.71ꢀ7.62 (m,

4 H, H_aromatic), 7.52ꢀ7.47 (m, 2 H, H_aromatic), 6.54 (d, 2 H, H_allyl, ³J_E= 13.8

Hz), 4.34ꢀ4.28 (m, 4 H, 2 ꢁ NCH₂), 4.11 (q, 4 H, 2 ꢁ CH₂CH₃, ³J = 7.1

Hz), 2.62ꢀ2.57 (m, 4 H, 2 ꢁ CH₂CO₂CH₂), 2.20ꢀ2.13 (m, 4 H, 2 ꢁ

CH₂),2.07(s, 12H, 4ꢁ CH₃), 1.20 ppm (t, 6 H, 2 ꢁ CH₂CH₃, ³J=7.1Hz).

¹³C NMR (100 MHz, CD₃OD): δ = 176.1, 173.0, 149.5, 139.3, 133.5, 132.2,

130.6, 129.8, 127.9, 125.0, 121.9, 110.7, 101.8, 60.4, 51.0, 46.9, 43.2, 30.2, 26.6,

22.8, 13.1 ppm. UV/vis (ethanol): λ_max(E_rel) 598 (1.0), 559 nm (0.63). UV/

vis (solid state/cotton): λ_max(E_rel) 600 (1.0), 555 nm (0.99). UV/vis (solid

state/wool): λ_max(E_rel) 559 (1.0), 594 nm (0.98). UV/vis (solid state/hair):

λ_max(E_rel) 597 (1.0), 554 nm (0.96). Fluorescence (ethanol): λ_max(I_rel)

610 (1.0), 657 nm (0.56). Fluorescence (solid state/cotton): λ_max(I_rel)

667 (1.0), 642 nm (0.88). Fluorescence (solid state/wool): λ_max(I_rel)

635 (1.0), 665 nm (0.97). Fluorescence (solid state/hair): λ_max(I_rel) 665

(1.0), 639 nm (0.97). Fluorescence quantum yield (CHCl₃, λ_exc= 560 nm,

3,3⁰-Di-(5-ethoxycarbonylpentyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]in-

docarbocyanine Bromide (3o). 3-(5-Ethoxycarbonylpentyl)-1,1,2-trimeth-

yl-1H-benz[e]indolenium bromide (2o, 400 mg, 0.93 mmol), pyridine

(1.5 mL), and orthoformic triethylester (0.30 mL, 1.85 mmol) were allowed

to react (100 °C) as was described for 3,3⁰-di-(2-carboxyethyl)-1,1,1⁰,1⁰-

tetramethyl-1H-dibenz[e]indocarbocyanine bromide (3a); a chromato-

graphic purification was left out because the material decomposes with the

contact of the stationary phase to form the carboxylic acid. Yield, 363 mg

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3,3⁰-Di-(4-propargylcarbonylbutyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz-

[e]indocarbocyanine Bromide (3q). 3-(4-Propargyloxycarbonylbutyl)-

1,1,2-trimethyl-1H-benz[e]indolenium bromide (2q, 200 mg, 0.467 mmol),

pyridine (1.0 mL), orthoformic triethylester (0.160 mL, 0.934 mmol),

and diethylether (30 mL) were allowed to react (105 °C, 2 h) as was

described for 3,3⁰-di-(2-carboxyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]-

indocarbocyanine bromide (3a), decanted, and dried in vacuo. Yield, 165 mg

(90%) of golden shiny solid forming violet, red fluorescent solutions; mp >

120 °C(dec.). IR(ATR):ν= 3393 (s), 3058 (w), 2972 (w), 2933 (m), 2865

(w), 2119 (w), 1734 (s), 1645 (s), 1587 (w), 1554 (s), 1520 (m), 1482 (m),

1425 (s), 1354 (m), 1278 (w), 1227 (m), 1169 (w), 1152 (w), 1128 (w),

1013 (m), 974 (w), 937 (m), 917 (w), 896 (w), 808 (m), 786 (w), 749 (w),

727 (w), 682 (m), 652 (m) cm^ꢀ1. ¹H NMR (200 MHz, CD₃OD): δ = 8.79

(t, 1H, H_dien, ³J_E= 13.4 Hz), 8.30 (d, 2H, H_aromat, ³J=8.4Hz), 8.13ꢀ8.05(m,

4H, H_aromat), 7.68 (t, 4H, H_aromat, ³J = 8.6 Hz), 7.53 (t, 2H, H_aromat, ³J = 7.2

Hz), 6.57 (d, 2H, H_dien, ³J_E=13.5Hz), 4.69(d, 4H, OCH₂CCH, ⁴J=2.5Hz),

4.33 (t, 4H, 2 ꢁ NCH₂, ³J = 6.8 Hz), 2.86 (t, 2H, OCH₂CCH, ⁴J = 2.5 Hz),

2.53(t, 4H, 2ꢁ CH₂CO₂H, ³J= 7.7 Hz), 2.11 (s, 12H, 4 ꢁ CH₃), 1.98ꢀ1.83

ppm (m, 8H, 4 ꢁ CH₂). ¹³C NMR (100 MHz, CD₃OD): δ = 175.9, 172.4,

145.4, 144.2, 133.5, 132.2, 130.6, 129.7, 128.1, 127.9, 121.9, 110.8, 106.8, 101.9,

77.4, 74.8, 51.4, 43.6, 38.8, 33.3, 32.7, 26.6, 25.3, 24.6, 21.7 ppm. UV/vis

(EtOH): λ_max(E_rel) 591 (1.0), 554 nm (0.71). UV/vis (solid state/cotton):

λ_max(E_rel) 598 (1.0), 555 nm (0.99). UV/vis (solid state/wool): λ_max(E_rel)

546 (1.0), 600 nm (0.98). Fluorescence (ethanol): λ_max(I_rel) 608 (1.0),

652 nm (0.12). Fluorescence (solid state/cotton): λ_max(I_rel) 659 (1.0),

647 nm (0.98). Fluorescence (solid state/wool): λ_max(I_rel) 635(1.0), 668nm

(50%) of golden shiny solid forming violet, red fluorescent solutions. IR

(ATR): ν = 3312 (w), 2930 (m), 2859 (m), 2361 (w), 2338 (w), 1724 (s),

1626 (w), 1587 (w), 1553 (s), 1520 (m), 1480 (m), 1423 (s), 1356 (m),

1278 (w), 1225 (m), 1169 (w), 1143 (w), 1126 (w), 1071 (w), 1012 (m),

972 (w), 927 (m), 898 (w), 877 (w), 806 (m), 747 (w), 726 (w), 685

(w) cm^ꢀ1. ¹H NMR (200 MHz, CD₃OD): δ = 8.78 (t, 1 H, H_aromatic, ³J =

13.6 Hz), 8.31 (d, 2 H, H_aromatic, ³J = 7.8 Hz), 8.10ꢀ8.00 (m, 4 H, H_aromatic

,

H_allyl), 7.75ꢀ7.63 (m, 4 H, H_aromatic),7.57ꢀ7.49 (m, 2 H, H_aromatic),6.55(d,

2 H, H_allyl, ³J_E=13.4Hz), 4.30(t, 4H, 2ꢁ NCH₂, ³J=7.5 Hz), 4.07 (q, 4H,

2 ꢁ CH₂CH₃, ³J = 7.1 Hz), 2.37 (t, 4 H, 2 ꢁ CH₂CO₂CH₂, ³J = 7.0 Hz),

2.11(s, 12H, 4ꢁ CH₃), 2.00ꢀ1.81 (m, 4 H, 2 ꢁ CH₂), 1.79ꢀ1.55 (m, 8 H,

4 ꢁ CH₂), 1.18 ppm (t, 6 H, 2 ꢁ CH₂CH₃, ³J = 7.1 Hz). ¹³C NMR (100

MHz, CD₃OD): δ = 177.4, 175.3, 150.8, 145.7, 140.9, 135.0, 133.7, 132.0,

131.2, 129.6, 126.4, 123.4, 112.3, 103.3, 61.5, 52.5, 45.9, 34.9, 28.6, 28.1, 27.3,

25.8, 16.8, 14.8 ppm. UV/vis (ethanol): λ_max(E_rel) 591 (1.0), 554 nm

(0.73). UV/vis (solid state/cotton): λ_max(E_rel) 598 (1.0), 554 nm (0.97).

UV/vis (solid state/wool): λ_max(E_rel) 599 (1.0), 554 nm (0.99). UV/vis

(solid state/hair): λ_max(E_rel) 600 (1.0), 554 nm (0.95). Fluorescence

(ethanol): λ_max(I_rel) 615 (1.0), 655 nm (0.57). Fluorescence (solid state/

cotton): λ_max(I_rel) 666 (1.0), 642 nm (0.93). Fluorescence (solid state/

wool): λ_max(I_rel) 664 (1.0), 638 nm (0.98). Fluorescence (solid state/hair):

λ_max(I_rel) 636 (1.0), 665 nm (0.92). Fluorescence quantum yield (CHCl₃,

λ_exc= 558 nm, E_558/1cm= 0.0138; reference: S-13 with Φ = 1.00): 0.36.

HRMS (ESI) (C₄₇H₅₇N₂O₄^þ): calcd, 713.4313; found, 713.4331; Δ =

1.8 mmu.

(0.98). Fluorescence quantum yield (CHCl₃, λ_exc= 555 nm, E_{555 nm/1cm}

=

0.0189; reference S-13 with

Φ = 1.00): 0.20. HRMS (ESI)

(C₄₇H₄₉N₂O₄^þ): calcd, 705.3687; found, 705.3680; Δ = ꢀ0.7 mmu.

3,3⁰-Di-(6-ethoxycarbonylhexyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]in-

docarbocyanine Bromide (3p). 3-(6-Ethoxycarbonylhexyl)-1,1,2-trimethyl-

1H-benz[e]indolenium bromide (2p, 95.0 mg, 0.213 mmol), 3-picoline

(1.00 mL), and orthoformic triethylester (0.070 mL, 0.426 mmol) were

allowed to react (100 °C) as was described for 3,3⁰-di-(2-carboxyethyl)-

1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbocyanine bromide (3a); a chro-

matographic purification was left out because the material decomposes with

the contact of the stationary phase to form the carboxylic acid. Yield, 49 mg

(28%). IR (ATR): ν = 3064 (w), 2936 (s), 2864 (w), 2540 (w), 2361 (s),

2338 (s), 2162 (w), 1718 (s, br), 1654 (w), 1636 (w), 1558 (m), 1522 (m),

1507(w), 1431(s), 1362(w), 1226(w), 1174(m), 1155(w), 1017(w), 938

(m), 814 (w), 750 (w), 668 (m) cm^ꢀ1. UV/vis (ethanol): λ_max(E_rel) 588

(1.0), 553 nm (0.76). Fluorescence (ethanol): λ_max(I_rel) 608 (1.0), 655 nm

3,3⁰-Di-(10-propargyloxycarbonyldecyl)-1,1,1⁰,1⁰-tetramethyl-1H-dib-

enz[e]indocarbocyanine Bromide (3r). 3-(10-Propargyloxycarbonyldecyl)-

1,1,2-trimethyl-1H-benz[e]indolenium bromide (2r) (900 mg, 1.76 mmol),

pyridine (2.0 mL), and orthoformic triethylester (0.6 mL, 3.51 mmol) were

allowed to react (100 °C) as was described for 3,3⁰-di-(2-carboxyethyl)-

1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbocyanine bromide (3a, a chro-

matographic purification was leaved out because the material decomposes

with the contact of the stationary phase to form the carboxylic acid). Yield,

621 mg (37%) of golden shiny solid forming violet, red fluorescent solutions.

UV/vis (ethanol): λ_max(E_rel) 591 (1.0), 550 nm (0.77). Fluorescence

(ethanol): λ_max(I_rel) 609 (1.0), 655 nm (0.50). HRMS (ESI)

(C₅₉H₇₃N₂O₄^þ): calcd, 873.5565; found, 873.5571; Δ = 0.6 mmu.

(0.51). Fluorescence quantum yield (CHCl₃, λ_exc= 561 nm, E_562/1cm

=

0.0154; reference: S-13 with Φ= 1.00): 0.35. HRMS (ESI) (C₄₉H₆₁N₂O₄^þ):

calcd, 741.4626; found, 741.4613; Δ = 1.3 mmu.

3,3⁰-Di-(2-cyanoethyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocar-

bocyanin Bromide (3s). 3-(2-Cyanoethyl)-1,1,2-trimethyl-1H-

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benz[e]indolenium bromide (2s, 100 mg, 0.291 mmol) under nitrogen was

dissolved in pyridine (1.0 mL), heated at 90 °C, treated slowly dropwise

with orthoformic ethylester (0.10 mL, 0.58 mmol, color change to bluish

violet), heated at 105 °C for 1 h at 105 °C, allowed to cool, precipitated with

diethylether (15 mL), and collected by vacuum filtration. Yield, 80 mg

(89%) of golden shiny solid forming violet, red fluorescent solutions; mp

>100 °C (dec.). IR (ATR): ν = 3391 (s, br), 3133 (w), 3060 (m), 2978

(w), 2941 (w), 2054 (w), 1633 (s), 1584 (w), 1558 (w), 1521 (w), 1487

(s), 1454 (w), 1433 (w), 1390 (w), 1355 (w), 1318 (w), 1234 (w), 1216

(w), 1173 (s), 1133 (w), 1094 (w), 1059 (w), 1017 (w), 974 (w), 937 (m),

868 (w), 808 (w), 778 (m), 764 (w), 680 (m) cm^ꢀ1. UV/vis (ethanol):

λ_max(E_rel) 591 (1.0), 557 nm (0.80). UV/vis (solid state/cotton): λ_max

(E_rel) 603 (1.0), 557 nm (0.98). UV/vis (solid state/wool): λ_max(E_rel) 560

(1.0), 594 nm (0.95). Fluorescence (ethanol): λ_max(I_rel) 618 (1.0), 663 nm

(0.46). Fluorescence (solid state/cotton): λ_max(I_rel) 634 (1.0), 671 nm

(0.98). Fluorescence (solid state/wool): λ_max(I_rel) 633 (1.0), 666 nm

3,3⁰-Di-(5-sulfopentyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocar-

bocyanine Bromide (3u). 3-(5-Sulfopentyl)-1,1,2-trimethyl-1H-benz-

[e]indoleniumbromide sodium salt (2u, 122 mg, 0.264 mmol), pyridine

(1.3 mL), methanol (1 mL), and orthoformic triethylester (0.080 mL,

0.52 mmol) were allowed to react analogously to 3,3⁰-di(pentyl)-

1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbocyanine bromide (3w, 2 h

at 100 °C), dissolved in a small amount of ethanol, precipitated with

diethylether, decanted, evaporated in vacuo, and purified by flashchro-

matograpy (RP 18, methanol/H₂O/1 M HCl 1:1:0.4 for absorption,

methanol/H₂O/1 M HCl 2:1:0.4 for removing byproduct, and metha-

nol/H₂O/1 M HCl 10:1:0.4 for collection). Yield, 56.0 mg (51%) of

golden shiny solid forming violet, strongly red fluorescent solutions. IR

(ATR): ν = 3376 (w), 3058 (w), 2969 (w), 2931 (m), 2860 (w), 1702

(w), 1626 (w), 1586 (w), 1553 (s), 1520 (s), 1479 (m), 1422 (s), 1357

(m), 1224 (m), 1184 (m), 1171 (m), 1142 (m), 1126 (m), 1074 (w),

1036 (w), 1013 (m), 968 (w), 926 (s), 899 (w), 884 (w), 870 (w), 810

(m), 786 (w), 745 (w), 698 (w), 686 (w), 676 (w), 652 (w) cm^ꢀ1. ¹H

NMR (200 MHz, CD₃OD): δ = 8.78 (t, 1H, H_dien, ³J_E= 13.8 Hz), 8.30

(d, 2H, H_aromat, ³J = 8.7 Hz), 8.04 (t, 4H, H_aromat, ³J = 7.8 Hz), 7.68 (t,

(0.87). Fluorescence quantum yield (CHCl₃, λ_exc= 474 nm, E_{474 nm/1cm}

=

0.0141; reference S-13 with Φ = 1.00): 0.10. HRMS (ESI) (C₃₇H₃₅N₄^þ):

calcd, 535.2856; found, 535.2856; Δ = 0 mmu.

3

4H, H_aromat, J = 8.0 Hz), 7.57ꢀ7.48 (m, 2H, H_aromat), 6.60 (d, 2H,

H_dien, ³J_E= 13.9 Hz), 4.32 (t, 4H, 2 ꢁ NCH_2,³J = 7.8 Hz), 2.85ꢀ2.81

(m, 4H, 2 ꢁ CH₂SO₃H), 2.11 (s, 12H, 4 ꢁ CH₃), 1.99ꢀ1.69 ppm (m,

12H, 6 ꢁ CH₂). UV/vis (ethanol): λ_max(E_rel) 590 (1.0), 553 nm (0.68).

UV/vis (solid state/cotton): λ_max(E_rel) 599 (1.0), 553 nm (0.97). UV/

vis (solid state/wool): λ_max(E_rel) 600 (1.0), 553 nm (0.96). Fluores-

cence (ethanol): λ_max(I_rel) 611 (1.0), 655 nm (0.54). Fluorescence

(solid state/cotton): λ_max(I_rel) 664 (1.0), 636 nm (0.93). Fluorescence

(solid state/wool): λ_max(I_rel) 667 (1.0), 644 nm (0.84). Fluorescence

quantum yield (CHCl₃, λ_exc= 553 nm, E_{553 nm/1cm}= 0.0158; reference:

S-13 with Φ = 1.00): 0.13. HRMS (ESI) (C₄₁H₄₇N₂Na₂O₆S₂^þ): calcd,

773.2671; found, 773.2669; Δ = ꢀ0.2 mmu.

3,3⁰-Di-(4-sulfobutyl)-1,1,1⁰,1⁰-tetramethyl-di-1H-benz[e]indoca-

rbocyanine (3t). 3-(4-Sufobutyl)-1,1,2-trimethyl-1H-benz[e]indole (2t,

500 mg, 1.40 mmol), pyridine (2.00 mL), and orthoformic triethylester

(0.500 mL, 2.90 mmol) were allowed to react as was described for 3,3⁰-di-(2-

carboxyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbocyanine bromide

(3a). Yield, 522 mg (53%) of golden shiny solid forming violet, red fluorescent

solutions; mp >250 °C. R_f(RP 18, methanol/CHCl₃/acetic acid 10:1:0.4) =

0.62. IR (ATR): ν = 3454 (w), 3054 (m), 2973 (w), 2933 (w), 2860 (w),

1626 (w), 1588 (w), 1555 (s), 1519 (m), 1490 (s), 1426 (s), 1369 (m), 1348

(w), 1124 (w), 1030 (m), 1012 (m), 977 (w), 948 (m), 925 (m), 891 (w),

805 (w), 767(w), 740(w), 728 (w), 688(w), 650(w) cm^ꢀ1. ¹HNMR(200

MHz, CD₃OD): δ=8.28(d,2H,H_aromatic,³J=8.2Hz),8.02(t,4H,H_aromatic

,

³J = 7.5 Hz), 7.67 (t, 5 H, H_aromatic, ³J= 8.5 Hz), 7.50 (t, 2 H, H_aromatic, H_allyl, ³J

=7.5Hz),6.59(d,2H,H_allyl,³J_E=13.7Hz),4.42ꢀ4.26(m,4H,2ꢁ NCH₂),

3.05ꢀ2.87 (m, 4 H, 2 ꢁ CH₂CO₂H), 2.02ꢀ2.19 ppm (m, 20 H, 4 ꢁ CH₃, 4

ꢁ CH₂). ¹³C NMR (100 MHz, CD₃OD): δ = 176.8, 149.3, 139.5, 133.4,

132.2, 130.5, 129.7, 127.9, 127.4, 124.8, 121.9, 110.9, 56.9, 51.0, 43.8, 26.6, 26.2,

22.8, 22.2, 16.9 ppm. UV/vis (ethanol): λ_max(E_rel) 591 (1.0), 553 nm (0.68).

UV/vis (solid state/cotton): λ_max(E_rel) 593 (1.0), 559 nm (0.99). UV/vis

(solid state/hair): λ_max(E_rel) 553 (1.0), 593 nm (0.90). Fluorescence

(ethanol): λ_max(I_rel) 620 (1.0), 660 nm (0.50). Fluorescence (solid state/

cotton): λ_max(I_rel) 662 (1.0), 630 nm (0.96). Fluorescence (solid state/

wool): λ_max(I_rel) 667 (1.0), 640 nm (0.98). Fluorescence (solid state/hair):

λ_max(I_rel) 621 (1.0), 661 nm(0.67). Fluorescence quantumyieldCHCl₃, λ_exc

= 559 nm, E_559/1cm= 0.0124, reference: S-13 with Φ = 1.00): 0.32. HRMS

(ESI) (C₃₉H₄₅N₂O₆S₂): calcd, 701.2719; found, 701.2726; Δ = 0.7 mmu.

3,3⁰-Di-(10-sulfodecyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocar-

bocyanin-Bromide (3v). 3-(10-Sulfodecyl)-1,1,2-trimethyl-1H-benz-

[e]indoleniumbromide sodium salt (2v, 152 mg, 0.285 mmol), 3-pico-

line (1.5 mL), and orthoformic triethylester (0.09 mL, 0.57 mmol) were

allowed to react analogously to 3,3⁰-di(pentyl)-1,1,1⁰,1⁰-tetramethyl-1H-

dibenz[e]indocarbocyanine bromide (3w, 2 h, 100 °C). Flash chroma-

tography (RP 18, methanol/H₂O/1 M HCl) caused decomposition. As

a consequence, the dye was applied without further purification. Yield,

185 mg. IR (ATR): ν = 3409 (w), 3055 (w), 2974 (w), 2926 (s), 2853

(m), 1705 (m), 1624 (w), 1588 (w), 1554 (s), 1519 (m), 1479 (m),

1425 (s), 1352 (m), 1278 (w), 1227 (m), 1169 (w), 1144 (w), 1124 (w),

1044 (w), 1012 (m), 974 (w), 931 (s), 898 (w), 806 (m), 787 (w), 747

(w), 727 (w), 684 (w), 652 (w), 637 (w), 612 (w) cm^ꢀ1. ¹H NMR (200

MHz, CD₃OD): δ = 8.76ꢀ8.64 (m, 1H, H_dien), 8.34ꢀ8.32 (m, 2H,

H_aromat), 8.03ꢀ7.96 (m, 4H, H_aromat), 7.71ꢀ7.67 (m, 4H, H_aromat),

7.37ꢀ7.31 (m, 2H, H_aromat), 6.55 (d, 2H, H_dien

,

³J_E= 13.9 Hz),

4.38ꢀ4.20 (m, 4H, 2 ꢁ NCH₂), 2.51ꢀ2.40 (m, 4H, 2 ꢁ CH₂SO₃H),

2.10ꢀ1.99 (m, 16H, 4 ꢁ CH₃, 2 ꢁ CH₂), 1.95ꢀ1.80 (m, 8H, 4 ꢁ CH₂),

1.52ꢀ1.25 ppm (m, 20H, 10 ꢁ CH₂). UV/vis (ethanol): λ_max(E_rel) 592

(1.0), 553 nm (0.72). UV/vis (solid state/cotton): λ_max(E_rel) 601 (1.0),

559 nm (0.95). UV/vis (solid state/wool): λ_max(E_rel) 599 (1.0), 556 nm

(0.97). Fluorescence (ethanol): λ_max(I_rel) 609 (1.0), 658 nm (0.52).

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Fluorescence (solid state/cotton): λ_max(I_rel) 637 (1.0), 665 nm (0.97).

Fluorescence (solid state/wool): λ_max(I_rel) 630 (1.0), 662 nm (0.92).

553 nm (0.73). UV/vis (solid state/cotton): λ_max(E_rel) 601 (1.0),

557 nm (0.96). UV/vis (solid state/wool): λ_max(E_rel) 602 (1.0), 570 nm

(0.97). Fluorescence (ethanol): λ_max(I_rel) 608 (1.0), 658 nm (0.53).

Fluorescence (solid state/cotton): λ_max(I_rel) 672 (1.0), 650 nm (0.89).

Fluorescence (solid state/wool): λ_max(I_rel) 671 (1.0), 651 nm (0.87).

Fluorescence quantum yield (CHCl₃, λ_exc= 554 nm, E_{554 nm/1cm}

0.0170; reference: S-13 with Φ = 1.00): 0.14.

=

Fluorescence quantum yield (CHCl₃, λ_exc= 558 nm, E_{558 nm/1cm}

0.0125; reference S-13 with Φ = 1.00): 0.10. HRMS (ESI): (M^þ

C₄₁H₄₇N₂^þ): calcd, 567.3734; found, 567.3736; Δ = 0.2 mmu.

=

ꢀ

3,3⁰-Di-(5-bromopentyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbo-

cyanine Bromide (3w). 3-(5-Bromopentyl)-1,1,2-trimethyl-1H-benz-

[e]indoleniumbromide (2w, 400 mg, 0.911 mmol), pyridine (2.0 mL),

and orthoformic triethylester (0.300 mL, 1.82 mmol) were allowed to

react analogously to 3,3⁰-di(pentyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz-

[e]indocarbocyanine bromide (3w, 2.5 h at 120 °C). Flash chromatogr-

apy (RP 18, methanol/H₂O/1 M HCl 10:1:0.4) caused decomposition.

As a consequence, the dye was applied without further purification; mp >

100 °C. IR (ATR): ν = 3408 (m), 2970 (s), 2927 (m), 2865 (m), 2362

(w), 1728 (w), 1627 (w), 1588 (w), 1558 (m), 1520 (w), 1430 (m),

1372 (m), 1296 (w), 1278 (w), 1249 (w), 1226 (w), 1191 (w), 1100 (s),

1013 (m), 936 (m), 863 (w), 809 (w), 787 (w), 748 (w), 728(w), 701

3,3⁰-Di(pentyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbocyanine

Bromide (3y). 1,1,2-Trimethyl-3-pentyl-1H-benz[e]indoleniumbromide

(2y, 100 mg, 0.277 mmol) was dissolved under N₂atmosphere in

pyridine (1.0 mL), heated at 100 °C, treated slowly dropwise with

othoformic ethylester (0.1 mL, 0.5 mmol), heated at 100 °C for 2 h,

allowed to cool, treated with diethylether (20 mL), and collected by

vacuum filtration. Yield, 71 mg (79%) of golden shiny solid forming

violet, strongly red fluorescent solutions; mp >150 °C (dec.). IR (ATR):

ν = 3393 (s), 3133 (w), 3060 (m), 2979 (w), 2941 (w), 2871 (w), 2054

(w), 1634 (s), 1584 (w), 1555 (m), 1519 (w), 1487 (s), 1466 (w), 1446

(w), 1428 (w), 1388 (w), 1356 (w), 1318 (w), 1227 (w), 1173 (s), 1127

(w), 1060 (w), 1029 (w), 973 (w), 937 (w), 880 (w), 807 (w), 778 (m),

680 (s) cm^ꢀ1. ¹H NMR (200 MHz, CD₃OD): δ = 8.79 (t, 1H, H_dien, ³J_E=

13.5 Hz), 8.30 (d, 2H, H_aromat, ³J = 8.5 Hz), 8.07ꢀ8.02 (m, 4H, H_aromat),

7.71ꢀ7.67 (m, 2H, H_aromat), 7.64 (d, 2H, H_aromat³J = 8.8 Hz), 7.55ꢀ7.51

1

(w), 653 (w) cm^ꢀ1. H NMR (200 MHz, CD₃OD): δ = 8.82 (t, 1H,

H_dien, ³J_E= 13.7 Hz), 8.27ꢀ8.26 (m, 2H, H_aromat), 8.16ꢀ8.09 (m, 4H,

H_aromat), 7.71ꢀ7.64 (m, 4H, H_aromat), 7.56ꢀ7.51 (m, 2H, H_aromat), 7.08

3

(d, 2H, H_dien, J_E= 13.8 Hz), 4.34ꢀ4.33 (m, 8H, 2 ꢁ NCH₂, 2 ꢁ

CH₂Br), 2.11 (s, 12H, 4 ꢁ CH₃), 2.05ꢀ1.94 ppm (m, 12H, 6 ꢁ CH₂).

UV/vis (ethanol): λ_max(E_rel) 592 (1.0), 553 nm (0.86). UV/vis (solid

state/cotton): λ_max(E_rel) 558 (1.0), 597 nm (0.98). UV/vis (solid state/

wool): λ_max(E_rel) 556 (1.0), 598 nm (0.97). Fluorescence (ethanol):

λ_max(I_rel) 612 (1.0), 662 nm (0.61). Fluorescence (solid state/cotton):

λ_max(I_rel) 678 (1.0), 632 nm (0.51). Fluorescence (solid state/wool):

λ_max(I_rel) 678 (1.0), 628 nm (0.46). Fluorescence quantum yield

(CHCl₃, λ_exc= 549 nm, E_{549 nm/1cm}= 0.0254; reference S-13 with Φ =

1.00): 0.15. HRMS (ESI): (M^þꢀ C₃₆H₃₇N₂^þ) calcd, 497.2951; found,

497.2951; Δ = 0 mmu.

(m, 2H, H_aromat), 6.54 (d, 2H, H_dien,

³J_E= 13.5 Hz), 4.29

3

(t, 4H, 2 ꢁ NCH₂, J = 7.5 Hz), 2.11 (s, 12H, 4 ꢁ CH₃), 1.96ꢀ1.89

(m, 4H, 2 ꢁ CH₂), 1.55ꢀ1.44 (m, 8H, 4 ꢁ CH₂), 0.97 ppm (t, 6H, 2 ꢁ

CH₃, ³J = 7.2 Hz). ¹³C NMR (100 MHz, CD₃OD): δ = 177.8, 147.2,

146.1, 141.3, 134.1, 132.4, 131.6, 130.0, 126.8, 112.6, 103.5, 59.0, 52.8,

45.9, 30.5, 29.0, 28.5, 24.0, 17.1, 14.7 ppm. UV/vis (ethanol): λ_max(E_rel)

590 (1.0), 552 nm (0.70). UV/vis (solid state/cotton): λ_max(E_rel) 600

(1.0), 553 nm (0.98). UV/vis (solid state/wool): λ_max(E_rel) 539 (1.0),

600 nm (0.93). Fluorescence (ethanol): λ_max(I_rel) 607 (1.0), 657 nm

(0.50). Fluorescence (solid state/cotton): λ_max(I_rel) 671 (1.0). Fluor-

escence (solid state/wool): λ_max(I_rel) 623 (1.0), 662 nm (0.79).

Fluorescence quantum yield (CHCl₃, λ_exc= 553 nm, E_{553 nm/1cm}

=

0.0133; reference: S-13 with Φ = 1.00): 0.20. HRMS (ESI)

(C₄₁H₄₉N₂^þ): calcd, 569.3890; found, 569.3884; Δ = ꢀ0.6 mmu.

3,3⁰-Di-(5-bromodecyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbo-

cyanine Bromide (3x). 3-(10-Bromodecyl)-1,1,2-trimethyl-1H-benz-

[e]indoleniumbromide (2x, 250 mg, 0.491 mmol), pyridine (2.0 mL),

and orthoformic triethylester (0.16 mL, 0.98 mmol) were allowed to

react analogously to 3,3⁰-di(pentyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz-

[e]indocarbocyanine bromide (3w, 2 h at 120 °C) and purified by flash

chromatography (RP 18, methanol/H₂O/1 M HCl 1:1:0.4 for absorp-

tion, methanol/H₂O/1 M HCl 2:1:0.4 for removing byproduct, and

methanol/H₂O/1 M HCl 10:1:0.4 for collection). Yield, 170 mg (73%)

of golden shiny solid forming violet, strongly red fluorescent solutions;

mp 113 °C. IR (ATR): ν = 3387 (m), 3058 (w), 2919 (s), 2851 (s), 1722

(m), 1627 (w), 1588 (w), 1555 (m), 1520 (m), 1479 (w), 1468 (w),

1427 (s), 1358 (m), 1226 (m), 1171 (w), 1144 (w), 1111(m), 1013 (w),

933 (m), 898 (w), 808 (m), 787 (w), 748 (w), 727 (w), 700 (w), 686

3,3⁰-Di-(4-sulfobutyl)-1,1,1⁰,1⁰-tetramethyl-1H-disulfobenz[e]indo-

carbocyanine (6a). 3-(4-Sulfobutyl)-1,1,2-trimethyl-1H-sulfobenz-

[e]indole (5a, 140 mg, 0.276 mmol), pyridine (1.5 mL), orthoformic

triethylester (0.090 mL, 0.55 mmol), and diethylether (15 mL) were

allowed to react analogously to 3,3⁰-di(pentyl)-1,1,1⁰,1⁰-tetramethyl-

1H-dibenz[e]indocarbocyanine bromide (3w, 2 h at 120 °C),

(w), 653 (w) cm^ꢀ1

.

¹H NMR: strong aggregation in concentrated

solution caused broad signals. UV/vis (ethanol): λ_max(E_rel) 593 (1.0),

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ARTICLE

repeatedly dissolved in a small amount of ethanol, precipitated with

diethylether, and purified by flash chromatograpy (RP 18, methanol/

H₂O/1 M HCl 1:1:0.4 for adsoption and methanol/H₂O/1 M HCl

10:1:0.4 for collection). Yield, 100 mg (77%) of golden shiny solid

forming violet, strongly red fluorescent solutions; mp >150 °C.

IR(ATR): ν = 3774 (w), 3450 (s, br), 2976 (w), 2938 (w), 2873

(w), 2361 (w), 2331 (w), 2008 (w), 1691 (w), 1640 (w), 1556 (s),

1515 (m), 1484 (m), 1431 (s), 1364 (m), 1277 (w), 1173 (s, br), 1103

(w), 1034 (m), 940 (m), 900 (w), 812 (w), 783 (w), 756 (w), 692 (w),

636 (w), 610 (w) cm^ꢀ1. ¹H NMR (200 MHz, CD₃OD): δ = 8.71ꢀ8.54

(m, 7H, H_dien, H_aromat), 8.40ꢀ8.33 (m, 2H, H_aromat), 7.80ꢀ7.64 (m, 2H,

reference: S-13 with Φ = 1.00): 0.21. MS (FAB^þ): m/z 733.6 [M^þ

(C₃₇H₃₇N₂O₁₀S^þ].

3

3,3⁰-Di-(10-carboxydecyl)-1,1,1⁰,1⁰-tetramethyl-1H-disulfobenz-

[e]indocarbocyanine Bromide (6c). 3-(10-Carboxyldecyl)-1,1,2-tri-

methyl-1H-sulfobenz[e]indole (5c, 100 mg, 0.180 mmol) under N₂

atmosphere was dissolved in pyridine (1.0 mL) and methanol (0.3 mL),

heated at 120 °C, treated very slowly dropwise with orthoformic

triethylester (0.06 mL, 0.36 mmol), treated with a second portion of

pyridine (0.5 mL) and orthoformic triethylester (0.03 mL, 0.18 mmol,

2 h auf 120 °C), allowed to cool, precipitated with diethylether (20 mL),

collected by vacuum filtration, and purified by flashchromatograpy (RP

18, methanol/H₂O/1 M HCl 1:1:0.4 for adsorption, methanol/H₂O/

1 M HCl 2:1:0.4 for removing byproduct, and methanol/H₂O/1 M HCl

10:1:0.4 for collection). Yield, 66.0 mg (71%) of golden shiny solid

forming violet, strongly red fluorescent solutions; mp >150 °C

(dec.). IR (ATR): ν = 3392 (w), 2922 (s), 2852 (s), 2362 (w), 1718

(s, br), 1585 (w), 1554 (s), 1515 (m), 1480 (m), 1420 (s), 1361 (m),

1274 (w), 1224 (w), 1166 (m), 1131 (m), 1100 (m), 1029 (w), 1015

(w), 932 (s), 898 (w), 827 (w), 806 (w), 746 (w), 689 (m), 657 (w), 630

(w) cm^ꢀ1. ¹H NMR (200 MHz, CD₃OD): δ = 8.79 (t, 1H, H_dien, ³J_E=

13.4 Hz), 8.47ꢀ8.35 (m, 4H, H_aromat), 8.22ꢀ8.05 (m, 4H, H_aromat), 7.72

(t, 2H, H_aromat, ³J = 7.7 Hz), 6.54 (d, 2H, H_dien, ³J_E= 13.7 Hz), 4.29 (t,

4H, 2 ꢁ NCH₂, ³J = 8.7 Hz), 2.31ꢀ2.21 (m, 4H, 2 ꢁ CH₂CO₂H), 2.11

(s, 12H, 4 ꢁ CH₃), 1.97ꢀ1.85 (m, 4H, 2 ꢁ CH₂) 1.59ꢀ1.13 ppm (m,

28H, 14 ꢁ CH₂). UV/vis (ethanol): λ_max(E_rel) 593 (1.0), 554 nm

(0.68). UV/vis (solid state/cotton): λ_max(E_rel) 594 (1.0), 553 nm

(0.94). UV/vis (solid state/wool): λ_max(E_rel) 598 (1.0), 556 nm (0.94).

Fluorescence (ethanol): λ_max(I_rel) 608 (1.0), 656 nm (0.48). Fluores-

cence (solid state/cotton): λ_max(I_rel) 663 (1.0), 646 nm (0.89).

Fluorescence (solid state/wool): λ_max(I_rel) 664 (1.0), 641 nm (0.91).

H_aromat), 6.63 (d, 2H, H_dien, J_E= 13.2 Hz), 4.37ꢀ4.34 (m, 4H, 2 ꢁ

NCH₂), 2.98ꢀ2.97 (m, 4H, 2 ꢁ CH₂SO₃H), 2.11ꢀ2.00 (m, 16H, 4 ꢁ

3

CH₃, 2 ꢁ CH₂), 1.65 ppm (t, 4H, 2 ꢁ CH₂, J = 7.7 Hz). UV/vis

(ethanol): λ_max(E_rel) 593 (1.0), 556 nm (0.66). UV/vis (solid state/

cotton): λ_max(E_rel) 546 (1.0), 586 nm (0.94). UV/vis (solid state/wool):

λ_max(E_rel) 554 (1.0), 588 nm (0.92). Fluorescence (ethanol): λ_max(I_rel)

608 (1.0), 655 nm (0.47). Fluorescence (solid state/cotton): λ_max(I_rel)

654 (1.0), 629 nm (0.94). Fluorescence (solid state/wool): λ_max(I_rel)

631 (1.0), 661 nm (0.99). Fluorescence quantum yield (CHCl₃, λ_exc

=

556 nm, E_{556 nm/1cm}= 0.0099; reference: S-13 with Φ = 1.00): 0.33.

HRMS (ESI) (C₃₉H₄₅N₂O₁₂S₄^þ): calcd, 861.1850; found, 861.1851;

Δ = 0.1 mmu.

3,3⁰-Di-(2-carboxyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-disulfobenz[e]indo-

carbocyanin Bromide (6b). 1,1,2-Trimethyl-1H-sulfobenz[e]indole

(4, 245 mg, 0.847 mmol) was dissolved under N₂in 3-picoline

(1.0 mL) and methanol (0.3 mL), heated at 120 °C, treated with

3-bromopropionic acid (388 mg, 2.54 mmol), stirred at 120 °C for

10 min, treated with orthoformic triethylester (0.300 mL, 1.69 mmol,

color change to bluish violet), stirred at 120 °C for 2 h, allowed to cool,

precipitated with diethylether (20 mL), collected by vacuum filtration,

and purified by flash chromatography (RP 18, methanol/H₂O/1 M

HCl 1:1:0.4 for absorption, methanol/H₂O/1 M HCl 2:1:0.4 for

removing byproduct, and methanol/H₂O/1 M HCl 10:1:0.4 for

collection). Yield, 200 mg (58%) of golden shiny solid forming violet,

strongly red fluorescent solutions; mp >180 °C (dec.). IR (ATR): ν =

3387 (w), 2972 (w), 2927 (w), 2858 (w), 2367 (w), 1719 (w), 1626

(w), 1562 (s), 1490 (s), 1453 (s), 1414 (m), 1384 (m), 1168 (m, br),

1124 (w), 1097 (w), 1060 (w), 1046 (w), 1025 (s), 979 (m), 927 (m),

808 (m), 761 (w), 735 (w), 689 (m), 643 (m) cm^ꢀ1. ¹H NMR (200

MHz, CD₃OD): δ = 8.80 (t, 1H, H_allyl, ³J_E= 13.4 Hz), 8.35ꢀ8.25 (m,

4H, H_aromat), 8.08ꢀ7.97 (m, 4H, H_aromat), 7.58ꢀ7.47 (m, 2H,

Fluorescence quantum yield (CHCl₃, λ_exc= 554 nm, E_{554 nm/1cm}

=

0.0157; reference: S-13 with Φ = 1.00): 0.31. HRMS (ESI)

(C₅₃H₆₉N₂O₁₀S₂^þ): calcd, 957.4388; found, 957.4392; Δ = ꢀ0.4 mmu.

3,3⁰-Di-(10-methoxycarbonyldecyl)-1,1,1⁰,1⁰-tetramethyl-1H-disul-

fobenz[e]indocarbocyanine Bromide (6d). 1,1,2-Trimethyl-1H-

sulfobenz[e]indole (4, 267 mg, 0.923 mmol) under N₂, pyridine

(0.5 mL), methanol (0.25 mL), 11-bromoundecaneacidmethylester

(0.700 mL, 2.78 mmol, 10 min, 120 °C), orthoformic triethylester

(0.300 mL, 1.86 mmol), and diethylether (20 mL) were allowed to

react analogously 3,3⁰-di-(2-carboxyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-

disulfobenz[e]indocarbocyanine bromide (6b, 1.5 h at 120 °C). Flash

chromatography (RP 18, methanol/H₂O/1 M HCl) causes decom-

position. Alternatively, the product was dissolved several times in the

minimal amount of ethanol and precipitated with diethylether. Yield,

3

H_aromat), 6.56 (d, 2H, H_allyl, J_E=13.6 Hz), 4.59ꢀ4.53 (m, 4H, 2 ꢁ

NCH₂), 2.94 (t, 4H, 2 ꢁ CH₂CO₂H, ³J = 7.3 Hz), 2.10 ppm (s, 12H, 4

ꢁ CH₃). UV/vis (ethanol): λ_max(E_rel) 588 (1.0), 554 nm (0.74). UV/

vis (solid state/cotton): λ_max(E_rel) 591 (1.0), 550 nm (0.99). UV/vis

(solid state/wool): λ_max(E_rel) 565 (1.0), 589 nm (0.99). Fluorescence

(ethanol): λ_max(I_rel) 612 (1.0), 657 nm (0.41). Fluorescence (solid

state/cotton): λ_max(I_rel) 648 (1.0), 662 nm (0.94). Fluorescence (solid

state/wool): λ_max(I_rel) 629 (1.0), 664 nm (0.72). Fluorescence

quantum yield (CHCl₃, λ_exc= 482 nm, E₄₈₂

= 0.0197;

nm/1cm

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200 mg (41%) of golden shiny solid forming violet, strongly red

fluorescent solutions; mp >150 °C (dec.). IR (ATR): ν = 3430 (m),

3180 (w), 3140 (w), 3072 (m), 2927 (m), 2855 (w), 2158 (w), 1712

(m), 1637 (s), 1583 (w), 1544 (m), 1489 (s), 1466 (w), 1393 (w),

1316 (w), 1176 (s), 1100 (m), 1044 (w), 1021 (s), 931 (w), 857 (w),

3,3⁰-Di-(4-ethoxycarbonylbutyl)-1,1,1⁰,1⁰-tetramethyl-1H-disulfo-

benz[e]indocarbocyanine Bromide (6f). 1,1,2-Trimethyl-1H-sulfo-

benz[e]indole (4, 250 mg, 0.864 mmol), 3-picoline (1.0 mL), methanol

(0.2 mL), 5-bromopentaneacidethylester (0.40 mL, 2.6 mmol, 10 min,

120 °C), orthoformic triethylester (0.300 mL, 1.73 mmol), and diethyl-

ether (20 mL) were allowed to react analogously to 3,3⁰-di-(2-

carboxyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-disulfobenz[e]indocarbocyanine

bromide (6b, 2 h, 120 °C, the dye decomposes within 1 day with

yellowing) and purified by flash chromatography (RP 18, methanol/

H₂O/1 M HCl 1:1:0.4 for adsorption and methanol/H₂O/1 M HCl

10:1:0.4 for collection). Yield, 33.0 mg (8%) of golden shiny solid

forming violet, strongly red fluorescent solutions; mp >150 °C (dec.). IR

(ATR): ν = 3362 (w), 2971 (w), 2931 (w), 1724 (w), 1623 (w), 1564

(m), 1519 (w), 1492 (s), 1455 (m), 1416 (m), 1386 (m), 1185 (s, br),

1099 (m), 1060 (w), 1046 (w), 1027 (s), 980 (m), 929 (m), 809 (m),

763 (w), 736 (w), 691 (m), 643 (m) cm^ꢀ1. UV/vis (ethanol): λ_max

(E_rel) 588 (1.0), 556 nm (0.76). UV/vis (solid state/cotton): λ_max(E_rel)

591 (1.0), 550 nm (0.98). UV/vis (solid state/wool): λ_max(E_rel) 559

(1.0), 591 nm (0.95). Fluorescence (ethanol): λ_max(I_rel) 613 (1.0),

662 nm (0.40). Fluorescence (solid state/cotton): λ_max(I_rel) 636

(1.0), 671 nm (0.76). Fluorescence (solid state/wool): λ_max(I_rel) 637

1

754 (s), 681 (s), 658 (m), 643 (w), 608 (w) cm^ꢀ1. H NMR (200

MHz, CD₃OD): δ = 8.50ꢀ8.42 (m, 1H, H_dien), 8.40ꢀ8.24 (m, 6H,

H_aromat), 7.90ꢀ7.64 (m, 4H, H_aromat), 6.56 (d, 2H, H_dien, ³J_E= 13.9

Hz), 4.35ꢀ4.30 (m, 4H, 2 ꢁ NCH₂), 3.31 (s, 6H, 2 ꢁ OCH₃),

2.29ꢀ2.20 (m, 4H, 2 ꢁ CH₂CO₂CH₃), 2.10 (s, 12H, 4 ꢁ CH₃),

1.98ꢀ1.88 (m, 4H, CH₂), 1.65ꢀ1.45 (m, 12H, 6 ꢁ CH₂), 1.38ꢀ1.30

ppm (m, 16H, 8 ꢁ CH₂). UV/vis (ethanol): λ_max(E_rel) 587 (1.0),

556 nm (0.78). UV/vis (solid state/cotton): λ_max(E_rel) 588 (1.0),

555 nm (0.97). UV/vis (solid state/wool): λ_max(E_rel) 551 (1.0),

586 nm (0.87). Fluorescence (ethanol): λ_max(I_rel) 607 (1.0), 657 nm

(0.48). Fluorescence (solid state/cotton): λ_max(I_rel) 624 (1.0),

660 nm (0.74). Fluorescence (solid state/wool): λ_max(I_rel) 617

(1.0), 660 nm (0.60). Fluorescence quantum yield (CHCl₃, λ_exc

=

556 nm, E_{556 nm/1cm}= 0.0159; reference S-13 with Φ = 1.00): 0.25.

MS (FAB^ꢀ): m/z 1063.3 [M^ꢀ(C₅₅H₇₂BrN₂O₁₀S^ꢀ].

(1.0), 664 nm (0.93). Fluorescence quantum yield (CHCl₃, λ_exc

=

478 nm, E_{478 nm/1cm}= 0.0170; reference: S-13 with Φ = 1.00): 0.11.

HRMS (ESI) (C₄₅H₅₁N₂O₁₀S₂^ꢀ): calcd, 843.2991; found, 843.3797;

Δ = 80.6 mmu.

3,3⁰-Di-(2-ethoxycarbonylethyl)-1,1,1⁰,1⁰-tetramethyl-1H-disulfo-

benz[e]indocarbocyanine Bromide (6e). 3-(2-Ethoxycarbonylethyl)-

1,1,2-trimethyl-1H-sulfobenz[e]indole (5e, 210 mg, 0.446 mmol), 3-pi-

coline (1.0 mL), and orthoformic triethylester (0.15 mL, 0.89 mmol)

were allowed to react analogously to 3,3⁰-di(pentyl)-1,1,1⁰,1⁰-tetramethyl-

1H-dibenz[e]indocarbocyanine bromide (3w, 2 h, 120 °C) and purified

by flash chromatography (RP 18, methanol/H₂O/1 M HCl 1:1:0.4 for

adsorption and methanol/H₂O/1 M HCl 10:1:0.4 for collection). Yield,

100 mg (52%) of golden shiny solid forming violet, strongly red

fluorescent solutions; mp >150 °C (dec.). IR (ATR): ν = 3411 (w),

3068 (w), 2951 (w), 2924 (s), 2854 (m), 1725 (m), 1623 (w), 1584 (w),

1559 (w), 1514 (w), 1478 (w), 1458 (w), 1426 (m), 1390 (w), 1362 (w),

1168 (s), 1100 (m), 1060 (w), 1030 (s), 940 (m), 827 (w), 809 (w), 762

(w), 692 (m), 649 (w), 624 (w) cm^ꢀ1. ¹H NMR (CDCl₃): Strong line-

broadening was caused by aggregation. UV/vis (ethanol): λ_max(E_rel) 596

(1.0), 569 nm (0.79). UV/vis (solid state/cotton): λ_max(E_rel) 599 (1.0),

564 nm (0.97). UV/vis (solid state/wool): λ_max(E_rel) 563 (1.0), 597 nm

(0.94). Fluorescence (ethanol): λ_max(I_rel) 610 (1.0), 660 nm (0.51).

Fluorescence (solid state/cotton): λ_max(I_rel) 654 (1.0), 633 nm (0.98).

Fluorescence (solid state/wool): λ_max(I_rel) 627 (1.0), 662 nm (0.88).

3,3⁰-Di-(5-ethoxycarbonylpentyl)-1,1,1⁰,1⁰-tetramethyl-1H-disulfo-

benz[e]indocarbocyanine Bromide (6g). 3-(5-Ethoxycarbonylpentyl)-

1,1,2-trimethyl-1H-sulfobenz[e]indole (5g, 100 mg, 0.195 mmol), 3-pico-

line (1.0 mL), methanol (0.3 mL), orthoformic triethylester (0.06 mL,

0.39 mmol), and diethylether (20 mL) were allowed to react analogously to

3,3⁰-di(pentyl)-1,1,1⁰,1⁰-tetramethyl-1H-dibenz[e]indocarbocyanine bromide

(3w, 2 h, 120 °C) and purified by flash chromatograpy (RP 18, methanol/

H₂O/1 M HCl 1:1:0.4 for adsorption and methanol/H₂O/1 M HCl 10:1:0.4

for collection). Yield, 20 mg (2%) of golden shiny solid forming violet, strongly

red fluorescent solutions; mp >150 °C (dec.). IR (ATR): ν = 3410 (w),

3069 (w), 2926 (m), 2856 (w), 1710 (s), 1623 (w), 1556 (m), 1515 (m),

1480 (m), 1426 (s), 1362 (m), 1157 (s), 1135 (w), 1100 (m), 1029 (s),

1018 (s), 932 (s), 901 (w), 808 (w), 764 (w), 693 (m), 627 (w) cm^ꢀ1

.

3

¹H NMR (200 MHz, CD₃OD): δ = 8.79 (t, 1H, H_dien, J_E= 13.9 Hz),

Fluorescence quantum yield (CHCl₃, λ_exc= 559 nm, E_{559 nm/1cm}

0.0145; reference: S-13 with Φ = 1.00): 0.18.

=

8.45ꢀ8.34 (m, 4H, H_aromat), 8.21ꢀ8.04 (m, 4H, H_aromat), 7.72 (t, 2H,

H_aromat, ³J = 7.7 Hz), 6.55 (d, 2H, H_dien, ³J_E= 13.8 Hz), 4.35ꢀ4.24

(m, 4H, 2 ꢁ NCH₂), 3.88ꢀ3.77 (m, 4H, 2 ꢁ CH₂CH₃), 2.38ꢀ2.31

(m, 4H, 2 ꢁ CH₂CO₂), 2.10 (s, 12H, 4 ꢁ CH₃), 1.99ꢀ1.87 (m, 8H,

4 ꢁ CH₂), 1.78ꢀ1.61 (m, 4H, 2 ꢁ CH₂), 1.00ꢀ0.90 ppm (m, 6H,

2 ꢁ CH₂CH₃). Additional signals of the carboxylic acid as the

product of saponification. ¹³C NMR (100 MHz, CD₃OD): δ =

175.9, 142.2, 133.1, 132.7, 131.6, 129.9, 128.6, 127.7, 126.6, 125.6,

123.9, 113.3, 112.4, 52.6, 45.5, 34.7, 28.3, 27.4, 25.8, 24.5, 13.8 ppm.

UV/vis (ethanol): λ_max(E_rel) 593 (1.0), 557 nm (0.69). UV/vis (solid

state/cotton): λ_max(E_rel) 597 (1.0), 556 nm (0.97). UV/vis (solid

state/wool): λ_max(E_rel) 561 (1.0), 596 nm (0.98). Fluorescence

(ethanol): λ_max(I_rel) 610 (1.0), 660 nm (0.51). Fluorescence (solid

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state/cotton): λ_max(I_rel) 622 (1.0), 654 nm (0.97). Fluorescence

(solid state/wool): λ_max(I_rel) 660 (1.0), 641 nm (0.96). Fluorescence

(0.75). UV/vis (solid state/wool): λ_max(E_rel) 551 (1.0), 591 nm

(0.95). Fluorescence (ethanol): λ_max(I_rel) 614 (1.0), 661 nm (0.42).

Fluorescence (solid state/cotton): λ_max(I_rel) 620 (1.0), 655 nm

(0.70). Fluorescence (solid state/wool): λ_max(I_rel) 628 (1.0),

quantum yield (CHCl₃, λ_exc= 559 nm, E₅₅₉

reference: S-13 with Φ = 1.00): 0.22.

= 0.0115;

nm/1cm

665 nm (0.77). Fluorescence quantum yield (CHCl₃, λ_exc

=

481 nm, E_{481 nm/1cm}= 0.0181; reference: S-13 with Φ = 1.00):

0.13.

3,3⁰-Di-(5-brompentyl)-1,1,1⁰,1⁰-tetramethyl-1H-disulfobenz[e]in-

docarbocyanine Bromide (6h). 1,1,2-Trimethyl-1H-sulfobenz[e]indole

(4, 215 mg, 0.743 mmol), 3-picoline (1.5 mL), methanol (1.0 mL), 1,5-

dibromopentane (0.30 mL, 2.2 mmol, 10 min, 120 °C), orthoformic

triethylester (0.250 mL, 1.45 mmol), and diethylether (20 mL) were

allowed to react analogously to 3,3⁰-di-(2-carboxyethyl)-1,1,1⁰,1⁰-tetra-

methyl-1H-disulfobenz[e]indocarbocyanine bromide (6b, 2 h, 120 °C)

and purified by flash chromatography (RP 18, methanol/H₂O/1 M

HCl 1:1:0.4 for adsorption and methanol/H₂O/1 M HCl 10:1:0.4 for

collection). Yield, 98 mg (27%) of golden shiny solid forming violet,

strongly red fluorescent solutions; mp >75 °C (dec.). IR (ATR):

ν = 3398 (s, br), 3056 (m), 3036 (w), 2866 (w), 2074 (w), 1634 (m),

1592 (w), 1559 (w), 1505 (s), 1483 (w), 1463 (w), 1387 (w), 1325

(w), 1250 (w), 1202 (m), 1155 (m), 1098 (w), 1048 (m), 1031 (m),

928 (w), 808 (m), 749 (w), 683 (m), 657 (w) cm^ꢀ1. UV/vis

(ethanol): λ_max(E_rel) 590 (1.0), 559 nm (0.78). UV/vis (solid

state/cotton): λ_max(E_rel) 600 (1.0), 565 nm (0.95). UV/vis (solid

state/wool): λ_max(E_rel) 558 (1.0), 587 nm (0.95). Fluorescence

(ethanol): λ_max(I_rel) 611 (1.0), 659 nm (0.50). Fluorescence (solid

state/cotton): λ_max(I_rel) 626 (1.0), 660 nm (0.83). Fluorescence

(solid state/wool): λ_max(I_rel) 615 (1.0), 658 nm (0.60). Fluorescence

3-(2-Carboxyethyl)-1,1,2-trimethyl-1H-benz[e]indolenium Bromide

(2a)¹¹. 1,1,2-Trimethylbenz[e]indole (1, 2.0 g, 9.5 mmol) and 3-bro-

mopropioic acid (1.5 g, 9.5 mmol) were dissolved in 1,2-dichloroben-

zene (30 mL), heated at 100 °C for 20 h, allowed to cool, collected by

vacuuum filtration (brown solid), and washed with dichloromethane

until colorless. Yield, 2.38 g (69%) of colorless solid; mp 192 °C. IR

(ATR): ν = 3353 (m), 3188 (w), 2904 (s, br), 1746 (m), 1724 (s), 1633

(m), 1612 (w), 1577 (m), 1523 (m), 1463 (m), 1455 (m), 1387 (s),

1284 (w), 1205 (s), 1183 (s), 1123 (m), 1063 (w), 1034 (m), 994 (w),

916 (w), 873 (w), 813 (m), 802 (s), 791 (m), 757 (s), 690 (w), 658

(w) cm^ꢀ1. ¹H NMR (400 MHz, DMSO-d₆): δ = 8.37 (d, 1H, H_aromat

,

3

³J = 8.4 Hz), 8.28 (d, 1H, H_aromat, J = 8.9 Hz), 8.26ꢀ8.14 (m, 2H,

H_aromat), 7.78 (ddd, 1H, H_aromat, ⁴J = 1.3 Hz, ³J = 7.0 Hz, ³J = 8.4 Hz),

7.74ꢀ7.70 (m, 1H, H_aromat,), 4.79 (t, 2H, NCH₂, ³J = 7.0 Hz), 3.06 (t,

2H, CH₂CO₂H, ³J = 7.0 Hz), 2.98 (s, 3H, CH₃), 1.76 ppm (s, 6H, 2 ꢁ

CH₃). ¹³C NMR (100 MHz, DMSO-d₆): δ = 189.2, 171.9, 138.8, 137.2,

133.4, 131.1, 130.1, 128.8, 127.7, 127.6, 123.8, 113.9, 31.8, 21.9, 14.7

ppm. HRMS (ESI) (C₁₈H₁₉BrNO₂^ꢀ): calcd, 360.0605; found,

360.0612; Δ = 0.7 mmu.

quantum yield (CHCl₃, λ_exc= 553 nm, E₅₅₃

reference: S-13 with Φ = 1.00): 0.19.

= 0.0124;

nm/1cm

3,3⁰-Di-(10-bromdecyl)-1,1,1⁰,1⁰-tetramethyl-1H-disulfobenz[e]-

indocarbocyanin Bromide (6i). 1,1,2-Trimethyl-1H-sulfobenz-

[e]indole (4, 205 mg, 0.708 mmol), 3-picoline (1.0 mL), methanol

(0.3 mL), 1,10-dibromodecane (0.50 mL, 2.1 mmol, 10 min, 120 °C),

orthoformic triethylester (0.24 mL, 1.4 mmol), and diethyl-

ether (20 mL) were allowed to react analogously to 3,3⁰-di-(2-

carboxyethyl)-1,1,1⁰,1⁰-tetramethyl-1H-disulfobenz[e]indocarbocyanine

bromide (6b, 2 h, 120 °C) and purified by flash chromatography (RP

18, methanol/H₂O/1 M HCl 1:1:0.4 for adsorption and methanol/

H₂O/1 M HCl 10:1:0.4 for collection). Yield, 58 mg (14%) of golden

shiny solid forming violet, strongly red fluorescent solutions; mp

>100 °C (dec.). IR (ATR): ν = 3387 (s), 3059 (w), 2927 (s), 2855

(s), 1706 (m), 1635 (m), 1591 (w), 1562 (m), 1504 (m), 1489 (m),

1456 (m), 1414 (w), 1388 (w), 1364 (w), 1186 (s), 1098 (m), 1047

(w), 1029 (s), 981 (m), 932 (m), 811 (m), 765 (w), 734 (w), 688 (m),

645 (m) cm^ꢀ1. UV/vis (ethanol): λ_max(E_rel) 587 (1.0), 555 nm

(0.77). UV/vis (solid state/cotton): λ_max(E_rel) 500 (1.0), 591 nm

3-(4-Carboxybutyl)-1,1,2-trimethyl-1H-benz[e]indolenium Bromide

(2b). 1,1,2-Trimethylbenz[e]indole (1, 360 mg, 1.65 mmol) and

5-bromovalerianic acid (300 mg, 1.65 mmol) were heated to reflux for

1 h (bath 145 °C), allowed to cool, stirred with diethylether (50 mL) for

3 h, collected by vacuum filtration, and washed with dichloromethane.

Yield, 243 mg (38%) of colorless solid, mp 187 °C. IR (ATR): ν = 2984

(w), 2913 (w), 1713 (s), 1581 (m), 1524 (m), 1474 (m), 1455 (m),

1397 (m), 1368 (w), 1258 (w), 1236 (w), 1208 (m), 1171 (s), 1157 (s),

1084 (w), 896 (w), 869 (w), 811 (s), 791 (m), 762 (m), 747 (w), 692

(w), 641 (w) cm^ꢀ1. ¹H NMR (200 MHz, DMSO-d₆): δ = 8.49ꢀ8.31

(m, 1 H, H_aromatic), 8.30ꢀ8.13 (m, 2 H, H_aromatic), 8.09ꢀ7.96 (m, 1 H,

H_aromatic), 7.85ꢀ7.70 (m, 1 H, H_aromatic), 7.68ꢀ7.50 (m, 1 H, H_aromatic),

4.60 (t, 2 H, NCH₂, ³J = 7.0 Hz), 2.94 (s, 3 H, CH₃), 2.32 (t, 2 H, CH₂,

³J = 7.2 Hz), 1.99ꢀ1.84 (m, 2 H, CH₂), 1.76 (s, 6 H, 2 ꢁ CH₃),

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1.73ꢀ1.63 ppm (m, 2 H, CH₂). HRMS (ESI) (C₂₀H₂₄NO₂^þ): calcd,

310.1802; found, 310.1801; Δ = ꢀ0.1 mmu.

16.0 ppm. HRMS (ESI) (C₂₃H₃₀NO₂^þ): calcd, 352.2271; found,

352.2271; Δ = 0 mmu.

3-(9-Carboxynonyl)-1,1,2-trimethyl-1H-benz[e]indolenium Bromide

(2e). 1,1,2-Trimethylbenz[e]indole (1, 345 mg, 1.65 mmol) and 10-

bromodecanoic acid (414 mg, 1.65 mmol) were heated at 120 °C for

1 h, allowed to cool, stirred with diethylether (50 mL) for 16 h,

collected by vacuum filtration, dissolved in dichlormethane, and

precipitated with ethylacetate (2 d). Yield, 112 mg (15%) of blue

oil. IR (ATR): ν = 2925 (s), 2851 (s), 1720 (s), 1633 (w), 1615 (w),

1580 (m), 1522 (m), 1463 (m), 1371 (s), 1242 (w), 1211 (w), 1173

(m), 1098 (w), 1044 (m), 997 (w), 866 (w), 825 (m), 790 (m), 746 (m),

3-(5-Carboxypentyl)-1,1,2-trimethyl-1H-benz[e]indolenium Bromide

(2c). 1,1,2-Trimethylbenz[e]indole (1, 500 mg, 2.30 mmol) and 6-bro-

mohexanoic acid (1.15 g, 6.00 mmol) were dissolved in DMPU

(10.0 mL), heated under argon at 120 °C for 2 days, collected by

vacuum filtration, and washed with diethylether and dichloro-

methane. Yield, 350 mg (37%) of slightly bluish solid. ¹H NMR

(400 MHz, CD₃OD): δ = 8.33 (d, 1 H, H_aromatic, ³J = 8.5 Hz), 8.25 (d,

1 H, H_aromatic, ³J = 9.1 Hz), 8.17 (d, 1 H, H_aromatic, ³J = 8.3 Hz), 8.01

(d, 1 H, H_aromatic, ³J = 9.0 Hz), 7.81 (ddd, 1 H, H_aromatic, ⁴J = 1.3 Hz,

³J = 6.9 Hz, ³J = 8.4 Hz), 7.73 (ddd, 1 H, H_aromatic, ⁴J = 1.1 Hz, ³J = 7.0

Hz, ³J = 8.1 Hz), 4.70ꢀ4.60 (m, 2 H, NCH₂), 2.89 (s, 3 H, CH₃), 2.36

(t, 2 H, CH₂, ³J = 7.0 Hz), 2.18ꢀ1.97 (m, 2 H, CH₂), 1.85 (s, 6 H, 2 ꢁ

1

694 (w) cm^ꢀ1. H NMR (200 MHz, CDCl₃): δ = 8.14ꢀ8.05 (m, 3 H,

H_aromatic), 7.79ꢀ7.65 (m, 3 H, H_aromatic), 4.85 (t, 2 H, NCH₂, ³J = 8.8 Hz),

3.21 (s, 3 H, CH₃), 2.35(t, 2H, CH₂, ³J=7.1Hz), 2.03ꢀ1.93(m, 2H, CH₂),

1.87(s,6H,2ꢁ CH₃),1.69ꢀ1.29 ppm (m, 12 H, 6 ꢁ CH₂).¹³CNMR(150

MHz, CDCl₃):δ= 195.5, 177.0, 171.2, 138.2, 137.2, 133.7, 131.5, 130.1, 128.7,

127.9, 127.6, 122.8, 112.4, 60.4, 55.8, 49.8, 34.0, 28.5, 26.5, 24.4, 22.7, 21.0, 16.1,

14.2 ppm. HRMS (ESI) (C₂₅H₃₄NO₂^þ): calcd, 380.2584; found, 380.2582;

Δ = ꢀ0.2 mmu.

CH₃), 1.79ꢀ1.68 (m, 2 H, CH₂), 1.68ꢀ1.53 ppm (m, 2 H, CH₂). ¹³

C

NMR (100 MHz, CD₃OD): δ = 196.1, 175.7, 174.2, 138.3, 137.3,

131.0, 129.6, 128.3, 127.7, 127.3, 123.0, 112.3, 55.9, 32.8, 27.3, 25.6,

24.0, 20.9 ppm. HRMS (ESI) (C₂₁H₂₆NO₂^þ): calcd, 324.1958;

found, 324.1956; Δ = ꢀ0.2 mmu.

3-(10-Carboxydecyl)-1,1,2-trimethyl-1H-benz[e]indoleniumBromide

(2f). 1,1,2-Trimethylbenz[e]indole (1, 345 mg, 1.65 mmol) and 11-

bromoundecanoic acid (437 mg, 1.65 mmol) were heated at 120 °C

for 1 h, allowed to cool, stirred with diethylether (50.0 mL) for 16 h,

and isolated by decanting the solvent. Yield, 640 mg (82%) of brown

oil. IR (ATR): ν = 3059 (w), 2964 (w), 2925 (s), 2852 (s), 1937 (w),

1709 (s), 1624 (w), 1598 (w), 1574 (m), 1520 (m), 1463 (m), 1429

(w), 1384 (w), 1362 (w), 1350 (w), 1244 (m), 1218 (m), 1118 (w),

1023 (w), 979 (w), 862 (w), 819 (s), 747 (s), 722 (w), 694 (w), 668

(w), 640 (w), 609 (w) cm^ꢀ1. ¹H NMR (600 MHz, CDCl₃): δ = 8.01

(d, 1 H, H_aromatic, ³J = 8.4 Hz), 7.94 (d, 1 H, H_aromatic, ³J = 7.8 Hz),

7.85 (d, 1 H, H_aromatic, ³J = 8.6 Hz), 7.82 (d, 1 H, ³J = 8.5 Hz) 7.54

(ddd, 1 H, H_aromatic, ⁴J = 1.3 Hz, ³J = 6.8 Hz, ³J = 8.3 Hz), 7.44 (ddd, 1

H, H_aromatic, ⁴J = 1.1 Hz, ³J = 6.8 Hz, ³J = 8.0 Hz), 3.40 (t, 2 H, NCH₂,

3-(7-Carboxyheptyl)-1,1,2-trimethyl-1H-benz[e]indolenium Bromide

(2d). 1,1,2-Trimethylbenz[e]indole (1, 938 mg, 4.48 mmol) and

8-bromooctanoic acid (1.00 g, 4.48 mmol) were heated at 120 °C for

2 h, allowed to cool, stirred with diethylether (50 mL) for 16 h, collected

by vacuum filtration, dissolved in a small amount of dichlormethane, and

precipitated with diethylether. Yield, 1.69 mg (87%) of black solid; mp

150 °C. IR (ATR): ν = 3055 (w), 2928 (s), 2854 (w), 1720 (s), 1633

(w), 1580 (m), 1522 (m), 1463 (m), 1382 (w), 1178 (w), 1085 (w), 827

(w), 744 (w) cm^ꢀ1. ¹H NMR (600 MHz, CD₃Cl₃): δ = 8.12 (d, 1 H,

H_aromatic, ³J = 8.8 Hz), 8.10ꢀ8.04 (m, 2 H, H_aromatic, ³J = 8.3 Hz,), 7.80

(d, 1 H, H_aromatic, ³J = 8.9 Hz), 7.73 (ddd, 1 H, H_aromatic, ⁴J = 1.1 Hz, ³J =

7.0 Hz, ³J = 8.3 Hz), 7.68ꢀ7.65 (m, 1 H, H_aromatic), 4.86ꢀ4.82 (m, 2

3

³J = 6.9 Hz), 2.41 (s, 3 H, CH₃), 2.36 (t, 2H, CH₂, J = 7.5 Hz),

H, NCH₂), 3.22 (s, 3 H, CH₃), 2.36 (t, 1 H, CH₂, J = 7.1 Hz),

2.01ꢀ1.97 (m, 2 H, CH₂), 1.86 (s, 6 H, 2 ꢁ CH₃), 1.65ꢀ1.60 (m, 2 H,

CH₂), 1.57ꢀ1.51 (m, 2 H, CH₂), 1.46ꢀ1.40 (m, 2 H, CH₂),

1.39ꢀ1.33 ppm (m, 2 H, CH₂). ¹³C NMR (150 MHz, CDCl₃):

δ = 195.6, 176.5, 138.2, 137.1, 133.7, 131.5, 130.1, 128.6, 127.9,

127.6, 122.8, 112.5, 55.9, 49.6, 34.0, 28.3, 28.1, 28.0, 26.2, 24.2, 22.7,

1.87ꢀ1.82 (m, 2 H, CH₂), 1.71ꢀ1.63 (m, 2 H, CH₂,), 1.55 (s, 6 H,

2 ꢁ CH₃), 1.45ꢀ1.39 (m, 2 H, CH₂), 1.38ꢀ1.33 (m, 2 H, CH₂),

1.32ꢀ1.27 ppm (m, 8 H, 4 ꢁ CH₂). ¹³C NMR (150 MHz, CDCl₃):

δ = 189.9, 178.6, 149.9, 138.4, 132.3, 129.6, 128.9, 128.6, 126.3,

124.4, 122.4, 119.6, 55.2, 34.2, 33.9, 32.8, 29.3, 29.2, 29.1, 28.6, 28.1,

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24.8, 22.6, 14.9 ppm. HRMS (ESI) (C₂₆H₃₆NO₂^þ): calcd, 394.2740;

found, 394.2743; Δ = 0.3 mmu.

120 °C for 2 h, allowed to cool, treated with diethylether (50.0 mL),

stirred for 16 h, and collected by vacuum filtration. Yield, 253 mg (28%,

1

content 46% besides starting material according to H NMR spectro-

scopy) of grayish solid. ¹H NMR (200 MHz, CDCl₃): δ = 8.15ꢀ8.01

(m, 4 H, CH_aromatic), 7.87ꢀ7.63 (m, 2 H, CH_aromatic), 4.97 (t, 2 H,

NCH₂, ³J = 7.4 Hz), 3.64 (s, 3 H, OCH₃), 3.25 (s, 3 H, CH₃), 2.46 (t, 2

3

H, J = 6.8 Hz), 2.19ꢀ1.98 (m, 2 H, CH₂), 1.89 (s, 6 H, 2 ꢁ CH₃),

1.78ꢀ1.70 ppm (m, 2 H, CH₂). HRMS (ESI) (C₂₁H₂₆NO₂^þ): calcd,

324.1958; found, 324.1949; Δ = ꢀ0.9 mmu.

3-(11-Carboxyundecyl)-1,1,2-trimethyl-1H-benz[e]indolenium Bro-

mide (2g). 1,1,2-Trimethylbenz[e]indole (1, 450 mg, 2.15 mmol) and

12-bromododecanoate (200 mg, 0.72 mmol) were allowed to react (2.5

h) and purified analogously to 3-(9-carboxynonyl)-1,1,2-trimethyl-1H-

benz[e]indolenium bromide (2e). Yield, 297 mg (84%) of brown solid.

IR (ATR): ν = 2926 (m), 2850 (m), 2489 (w), 1779 (w), 1750(w), 1716

(s), 1634 (s), 1615 (w), 1581 (s), 1523 (s),1476 (w), 1463 (s), 1388

(m), 1317 (w), 1270 (m), 1212 (w), 1174 (m), 1113 (w), 1101 (w),

1036 (w), 1026 (w), 998 (m), 940 (w), 900 (w), 865 (m), 827 (s), 789

(m), 745 (s), 719 (m), 694 (m), 616 (w) cm^ꢀ1. ¹H NMR (200 MHz,

CDCl₃): δ = 8.14ꢀ8.01 (m, 3 H, H_aromatic), 7.82ꢀ7.60 (m, 3 H,

H_aromatic), 4.84 (t, 2 H, NCH₂, ³J = 7.4 Hz), 3.20 (s, 3 H, CH₃), 2.31

(t, 2H, CH₂, ³J=7.3Hz), 1.86(s, 6H, 2ꢁ CH₃), 1.62ꢀ1.20 ppm (m, 18 H,

9 ꢁ CH₂). ¹³C NMR (150 MHz, CDCl₃): δ = 176.0, 138.3, 137.2, 133.7,

131.4, 130.1, 128.7, 128.0, 127.6, 122.8, 112.3, 55.8, 33.6,0 28.7, 28.6, 28.4,

28.4, 28.3, 28.3, 28.1, 26.4, 24.4, 22.7, 16.0, 3.1, 3.0, 2.7 ppm. HRMS (ESI)

(C₂₇H₃₈NO₂^þ): calcd, 408.2897; found, 408.2895; Δ = ꢀ0.2 mmu.

3-(9-Methoxycarbonylnonyl)-1,1,2-trimethyl-1H-benz[e]indo-

lenium Bromide (2j).1,1,2-Trimethylbenz[e]indole(1, 947 mg, 4.52 mmol)

and methyl-10-bromodecanoate (400 mg, 1.50 mmol) were allowed to react

and purified analogously to 3-(4-methoxycarbonylbutyl)-1,1,2-trimethyl-

1H-benz[e]indolenium bromide (2i). Yield, 310 mg (18% content 40%

1

besides starting material according to H NMR spectroscopy) of grayish

solid. ¹H NMR (200 MHz, CDCl₃): δ = 8.14ꢀ8.00 (m, 4 H, CH_aromatic),

7.79ꢀ7.60(m,2H,CH_aromatic), 4.86 (t, 2 H, NCH₂,³J=7.7Hz),3.64(s,3H,

OCH₃),3.22(s,3H,CH₃), 2.27 (t, 2 H, ³J= 7.3 Hz), 2.08ꢀ1.90 (m, 4 H, 2 ꢁ

CH₂), 1.88 (s, 6 H, 2 ꢁ CH₃), 1.60ꢀ1.30 ppm (m, 10 H, 5 ꢁ CH₂). HRMS

(ESI) (C₂₆H₃₆NO₂^þ): calcd, 394.2741; found, 394.2729; Δ = ꢀ1.2 mmu.

3-(2-Methoxycarbonylethyl)-1,1,2-trimethyl-1H-benz[e]indoleni-

um Bromide (2h). 1,1,2-Trimethylbenz[e]indole (1, 250 mg, 1.19

mmol) and methyl-3-bromopropionate (400 mg, 2.39 mmol) were heated

at 120 °C for 1 h, allowed to cool, treated with diethylether (50.0 mL), stirred

for 16 h, collected by vacuum filtration, dissolved in chloroform, precipitated

with diethylether, and collected by vacuum filtration. Yield, 321 mg (49%,

content 68% besides starting material according to ¹H NMR spectroscopy)

3-(10-Methoxycarbonyldecyl)-1,1,2-trimethyl-1H-benz[e]indolenium

Bromide (2k). 1,1,2-Trimethylbenz[e]indole (1, 1.2 g, 5.73 mmol) and

methyl-11-bromoundecanoate (400 mg, 1.43 mmol) were allowed to

react (1.5 h) and purified analogously to 3-(4-methoxycarbonylbutyl)-1,1,2-

trimethyl-1H-benz[e]indolenium bromide (2i). Yield, 270 mg (25%, con-

tent 65% besides starting material according to ¹H NMR spectroscopy) of

grayish blue solid. ¹H NMR (400 MHz, CDCl₃): δ = 8.11ꢀ7.99 (m, 4 H,

CH_aromatic), 7.75ꢀ7.60 (m, 2 H, CH_aromatic), 4.86 (t, 2 H, NCH₂, ³J = 7.7

Hz), 3.64 (s, 3 H, OCH₃), 3.22 (s, 3 H, CH₃), 2.27 (t, 2 H, ³J = 7.5 Hz),

2.01ꢀ1.93 (m, 2 H, CH₂), 1.88 (s, 6 H, 2 ꢁ CH₃), 1.61ꢀ1.54 (m, 2 H,

CH₂), 1.51ꢀ1.44 (m, 2 H, CH₂), 1.40ꢀ1.32 (m, 2 H, CH₂), 1.29ꢀ1.21

ppm (m, 8 H, 4 ꢁ CH₂). HRMS (ESI) (C₂₇H₃₈NO₂^þ): calcd, 408.2897;

found, 408.2895; Δ = ꢀ0.2 mmu.

1

of brown solid. H NMR (200 MHz, CDCl₃): δ = 8.10ꢀ7.98 (m, 4 H,

CH_aromatic), 7.78ꢀ7.59 (m, 2 H, CH_aromatic), 5.24 (t, 2 H, NCH₂, ³J = 5.9

Hz), 3.58 (s, 3 H, OCH₃), 3.27 (t, 2 H, CH₂COOCH₃, ³J = 6.0 Hz), 3.24 (s,

3 H, CH₃), 1.84 ppm (s, 6 H, 2 ꢁ CH₃). HRMS (ESI) (C₁₉H₂₂NO₂^þ):

calcd, 296.1645; found, 296.1638; Δ = ꢀ0.7 mmu.

3-(4-Methoxycarbonylbutyl)-1,1,2-trimethyl-1H-benz[e]indolenium

Bromide (2i). 1,1,2-Trimethylbenz[e]indole (1, 214 mg, 1.02 mmol)

and methyl-5-bromopentanoate (200 mg, 1.02 mmol) were heated at

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2 ꢁ CH₃), 1.73ꢀ1.66 (m, 2 H, CH₂), 1.14 ppm (t, 3 H, OCH₂CH₃, ³J =

7.1 Hz). HRMS (ESI) (C₂₂H₂₈NO₂^þ): calcd, 338.2115; found, 338.2118;

Δ = 0.3 mmu.

3-(2-Ethoxycarbonylethyl)-1,1,2-trimethyl-1H-benz[e]indolenium

Bromide (2l). 1,1,2-Trimethylbenz[e]indole (1, 462 mg, 2.21 mmol)

and ethyl-3-bromopropionate (2 g, 11 mmol) were allowed to react and

purified analogously to 3-(9-carboxynonyl)-1,1,2-trimethyl-1H-benz-

[e]indolenium bromide (2e). Yield, 656 mg (62%, content 81% besides

starting material according to ¹H NMR spectroscopy) of brown solid. IR

(ATR): ν = 3381 (m), 3056 (w), 2923 (w), 2852 (w), 2350 (w), 2287

(w), 1711 (s), 1626 (m), 1588 (s), 1554 (w), 1520 (s), 1479 (w), 1423

(m), 1357 (m), 1277 (w), 1224 (w), 1168 (w), 1142 (w), 1127 (w),

1012 (m), 971 (w), 930 (w), 898 (w), 867 (w), 806 (s), 786 (m), 746 (s),

726 (w), 685 (w), 676 (w), 652 (w) cm^ꢀ1. ¹H NMR (200 MHz, CDCl₃):

δ=8.13ꢀ8.01(m, 4H, CH_aromatic), 7.75ꢀ7.60 (m, 2 H, CH_aromatic), 5.23(t,

2 H, NCH₂, ³J = 6.0 Hz), 4.09 (q, 2 H, OCH₂CH₃, ³J = 7.2 Hz), 3.0 (s, 3 H,

CH₃), 2.41ꢀ2.39 (m, 2 H, CH₂COOCH₂CH₃), 1.77 (s, 6 H, 2 ꢁ CH₃),

1.14 ppm (t, 3 H, OCH₂CH₃, ³J = 7.2 Hz). HRMS (ESI) (C₂₀H₂₄NO₂^þ):

calcd, 310.1796; found, 310.1762; Δ = ꢀ0.4 mmu.

3-(5-Ethoxycarbonylpentyl)-1,1,2-trimethyl-1H-benz[e]indolenium

Bromide (2o). 1,1,2-Trimethylbenz[e]indole (1, 31 mg, 0.15 mmol) and

ethyl-6-bromohexanoate (100 mg, 0.45 mmol) were allowed to react

(1 h) and purified analogously to 3-(7-carboxyheptyl)-1,1,2-trimethyl-

1H-benz[e]indolenium bromide (2d). Yield, 41 mg (63%) of grayish

solid. IR (ATR): ν = 3851 (w), 3420 (s), 2921 (m), 2851 (w), 1726 (s),

1622 (w), 1589 (m), 1556 (w), 1520 (m), 1477 (w), 1352 (m), 1227 (w),

1067 (w), 1014 (m), 941 (w), 899 (w), 805 (m), 786 (w), 744 (m), 728

(w), 652 (w) cm^ꢀ1. ¹H NMR (200 MHz, CD₃OD): δ = 8.36ꢀ8.15 (m, 3

H, CH_aromatic), 8.02 (d, 1 H, CH_aromatic, ³J = 9.1 Hz), 7.86ꢀ7.66 (m, 2 H,

CH_arom), 4.65 (t, 2 H, NCH₂, ³J = 7.5 Hz), 4.07 (q, 2 H, OCH₂CH₃, ³J =

7.2 Hz), 2.38 (t, 2 H, CH₂COOCH₂CH₃, ³J = 7.0 Hz), 2.10ꢀ2.02 (m, 2 H,

CH₂), 1.99 (s, 3 H, CH₃), 1.85 (s, 6 H, 2 ꢁ CH₃), 1.77ꢀ1.52 (m, 4 H,

CH₂), 1.20 ppm (t, 3 H, OCH₂CH₃, ³J = 7.1 Hz). HRMS (ESI)

(C₂₃H₃₀NO₂^þ): calcd, 352.2271; found, 352.2275; Δ = 0.4 mmu.

3-(3-Ethoxycarbonylpropyl)-1,1,2-trimethyl-1H-benz[e]indolenium

Bromide (2m). 1,1,2-Trimethylbenz[e]indole (1, 429 mg, 2.05 mmol) and

ethyl-4-bromobutyrate (2 g, 10 mmol) were allowed to react (2 h) and

purified analogously to 3-(9-carboxynonyl)-1,1,2-trimethyl-1H-benz-

[e]indolenium bromide (2e). Yield, 496 mg (21%, content 35% besides

starting material according to ¹H NMR spectroscopy) of gray solid. IR (ATR):

ν = 3381 (w), 3056 (m), 2350 (w), 2287 (w), 1711 (s), 1626 (m), 1588 (s),

1520 (m), 1276 (m), 971 (w), 867 (m), 786 (m), 746 (m), 726 (w), 685

(m), 676 (w), 652 (w) cm^ꢀ1. ¹H NMR (200 MHz, CDCl₃): δ = 8.13ꢀ7.97

(m,4H,CH_aromatic),7.76ꢀ7.58(m,2H,CH_aromatic),5.00(t,2H,NCH₂,³J=

8.1 Hz), 4.08 (q, 2 H, OCH₂CH₃, ³J = 7.2 Hz), 3.27 (s, 3 H, CH₃), 2.76 (t, 2

H, CH₂COOCH₂CH₃, ³J = 6.8 Hz), 2.37ꢀ2.21 (m, 2 H, CH₂), 1.85 (s, 6 H,

3

2 ꢁ CH₃), 1.21 ppm (t, 3 H, OCH₂CH₃, J = 7.2 Hz). HRMS (ESI)

(C₂₁H₂₆NO₂^þ): calcd, 324.1958; found, 324.1962; Δ = 0.4 mmu.

3-(6-Ethoxycarbonylhexyl)-1,1,2-trimethyl-1H-benz[e]indolenium

Bromide (2p). 1,1,2-Trimethylbenz[e]indole (1, 1.05 g, 5.04 mmol) and

ethyl-7-bromoheptanoate (400 mg, 1.68 mmol) were heated at 120 °C for

2 h, allowed to cool, treated with diethylether (50 mL), stirred for 16 h, and

collected by vacuum filtration. Yield, 348 mg (22%, content 48% besides

starting material according to ¹H NMR spectroscopy) of grayish solid. ¹H

NMR (600 MHz, CDCl₃): δ = 8.11ꢀ8.07 (m, 4 H, CH_aromatic), 7.75ꢀ7.70

3

(m, 2 H, CH_aromatic), 4.88 (t, 2 H, NCH₂, J = 7.3 Hz), 4.09 (q, 2 H,

OCH₂CH₃, ³J = 7.1 Hz), 3.23 (s, 3 H, CH₃), 2.28 (t, 2 H,

CH₂COOCH₂CH₃, ³J = 7.3 Hz), 2.03ꢀ1.99 (m, 2 H, CH₂), 1.88 (s, 6 H,

2 ꢁ CH₃), 1.65ꢀ1.59 (m, 2 H, CH₂), 1.56ꢀ1.52 (m, 2 H, CH₂), 1.46ꢀ1.40

(m, 2 H, CH₂), 1.22 ppm (t, 3 H, OCH₂CH₃, ³J = 7.1 Hz). HRMS (ESI)

(C₂₄H₃₂NO₂^þ): calcd, 366.2428; found, 366.2426; Δ = ꢀ0.2 mmu.

3-(4-Ethoxycarbonylbutyl)-1,1,2-trimethyl-1H-benz[e]indolenium

Bromide (2n). 1,1,2-Trimethylbenz[e]indole (1, 400 mg, 1.91 mmol) and ethyl-

5-bromopentanoate (2 g, 9.56 mmol) were allowed to react and purified

analogously to 3-(9-carboxynonyl)-1,1,2-trimethyl-1H-benz[e]indolenium bro-

mide (2e). Yield, 513 mg (26%, content 40% besides starting material according

to ¹H NMR spectroscopy) of blue solid. IR (ATR): ν = 3381 (m), 3056 (w),

2350 (w), 2287 (w), 1711 (s), 1626 (w), 1588 (s), 1520 (m), 1277 (w), 971

(w), 898 (w), 867 (w), 786 (m), 746 (s), 726 (w), 685 (m), 676 (w), 652

1

(w) cm^ꢀ1. H NMR (200 MHz, DMSO-d₆): δ = 8.40ꢀ8.03 (m, 4 H,

3

CH_aromatic), 7.83ꢀ7.53 (m, 2 H, CH_aromatic), 4.61 (t, 2 H, NCH₂, J = 7.2

Hz), 4.03 (q, 2 H, OCH₂CH₃, ³J = 6.9 Hz), 2.95 (s, 3 H, CH₃), 2.10 (t, 2 H,

3

CH₂COOCH₂CH₃, J = 7.3 Hz), 1.99ꢀ1.83 (m, 2 H, CH₂), 1.76 (s, 6 H,

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3-(4-Sufobutyl)-1,1,2-trimethyl-1H-benz[e]indole (2t)³. 1,1,2-Trim-

ehylbenz[e]indole (1, 1.0 g, 4.8 mmol) and 1,4-butanesultone

(0.50 mL, 4.8 mmol) were heated at 130 °C for 2.5 h, allowed to

cool, collected by vacuum filtration, washed with acetone, and dried at

100 °C for 3 h. Yield, 1.13 g (70%) of slightly greyish solid; mp 263 °C

(ref 1, 266 °C). IR (ATR): ν = 3435 (m), 2939 (w), 1636 (w), 1584

(w), 1523 (w), 1468 (m), 1199 (s), 1034 (s), 872 (w), 824 (m), 791

(w), 758 (m), 737 (w) cm^ꢀ1. ¹H NMR (400 MHz, CD₃OD): δ = 8.32

(d, 1H, H_aromat, ³J = 8.5 Hz), 8.24 (d, 1H, H_aromat, ³J = 8.9 Hz), 8.16 (d,

1H, H_aromat, ³J = 8.2 Hz), 8.06 (d, 1H, H_aromat, ³J = 9.0 Hz), 7.80 (ddd,

3-(4-Propargyloxycarbonylbutyl)-1,1,2-trimethyl-1H-benz[e]indo-

lenium Bromide (2q).1,1,2-Trimethylbenz[e]indole(1, 450 mg, 1.14 mmol)

and 4-bromovaleric propargylester (716 mg, 3.42 mmol) were heated at

120 °C for 2 h, allowed to cool, precipitated with diethylether (50 mL), stirred

for 16 h, and collected by vacuum filtration. Yield, 200 mg (41%) of green

decomposible solid; mp 205 °C. IR (ATR): ν = 3289 (w), 3057 (m), 2966

(m), 2930(s), 2866 (m), 2123 (w), 1952 (w), 1736 (s), 1650 (s), 1621 (m),

1592 (w), 1568 (s), 1519 (s), 1463 (w), 1441 (w), 1380 (w), 1350 (w),

1242 (w), 1207 (m), 1152 (m), 1024 (w), 977 (w), 948 (w), 931 (w), 864

(m), 819 (s), 764 (s), 693 (w), 666 (w) cm^ꢀ1. HRMS (ESI)

(C₂₃H₂₆NO₂^þ): calcd, 348.1958; found, 348.1956; Δ = ꢀ0.2 mmu.

4

3

1H, H_aromat, J = 1.3 Hz, J = 6.9 Hz, J = 8.4 Hz), 7.71 (ddd, 1H,

4

3

H_aromat, J = 1.1 Hz, J = 6.9 Hz, J = 8.1 Hz), 4.70- 4.64 (m, 2H,

NCH₂), 2.91 (t, 2H, CH₂SO₃^ꢀ, ³J = 7.1 Hz), 2.26- 2.18 (m, 2H, CH₂),

2.03- 1.94 (m, 2H, CH₂), 1.84 (s, 6H, 2 ꢁ CH₃), 1.30 ppm (s, 3H,

CH₃). ¹³C NMR (100 MHz, CD₃OD): δ = 196.6, 138.7, 137.5, 134.1,

131.3, 129.9, 128.5, 127.9, 127.5, 123.2, 112.7, 56.1, 49.9, 26.4, 23.0,

22.1, 21.2 ppm. HRMS (ESI) (C₁₉H₂₄NO₃S): calcd, 346.1471; found,

346.1473; Δ = 0.2 mmu.

3-(10-Propargyloxycarbonyldecyl)-1,1,2-trimethyl-1H-benz[e]ind-

olenium Bromide (2r). 1,1,2-Trimethylbenz[e]indole (1, 517 mg,

2.47 mmol) and propargyl-11-bromoundecanoate¹⁹(250 mg, 0.82

mmol) were allowed to react (1.5 h) and purified analogously to 3-(4-

methoxycarbonylbutyl)-1,1,2-trimethyl-1H-benz[e]indolenium bromide

(2i). Yield, 148 mg (35%) of black solid. HRMS (ESI)

(C₂₉H₃₈NO₂^þ): calcd, 432.2897; found, 432.2899; Δ = 0.2 mmu.

3-(5-Sulfopentyl)-1,1,2-trimethyl-1H-benz[e]indoleniumbromide

Sodium Salt (2u). 1,1,2-Trimethylbenz[e]indole (1, 744 mg, 3.56 mmol)

and sodium 5-bromopentanesulfonate (300 mg, 1.18 mmol) were heated at

150 °C for 2 h, allowed to cool, treated with diethylether (30 mL), stirred

for 16 h, collected by vacuum filtration, dissolved in a small amount of

methanol, and precipitated with diethylether. Yield, 59% of bluish black

solid; mp 213 °C. IR (ATR): ν = 3054 (w), 2963 (m), 2928 (m), 2866 (w),

2661 (w), 2614 (w), 2587 (w), 2456 (w), 1960 (w), 1915 (w), 1819 (w),

1782 (w), 1700 (w), 1645 (m), 1621 (m), 1570 (s), 1519 (s), 1466 (s),

1431 (m), 1377 (m), 1346 (m), 1282 (w), 1263 (w), 1242 (m), 1218 (s),

1206 (m), 1180 (m), 1036 (w), 1022 (w), 974 (m), 929 (m), 871 (s), 827

(s), 803 (s), 755 (s), 756 (s), 682 (w), 666 (m), 608 (m) cm^ꢀ1. ¹H NMR

(200 MHz, CDCl₃): δ = 8.35ꢀ8.00 (m, 4H, H_aromat), 7.82ꢀ7.64 (m, 2H,

H_aromat), 4.64 (t, 2H, NCH_2,³J = 7.5 Hz), 3.56 (t, 2H, CH₂SO₃H, ³J = 6.3

Hz), 2.11ꢀ1.98 (m, 2H, CH₂), 1.82 (s, 6H, 2 ꢁ CH₃), 1.79 (s, 3H, CH₃),

1.62ꢀ1.50 ppm (m, 4H, 2 ꢁ CH₂). HRMS (ESI) (C₂₀H₂₅NNaO₃S^þ):

calcd, 328.1447; found, 328.1447; Δ = 0 mmu.

3-(2-Cyanoethyl)-1,1,2-trimethyl-1H-benz[e]indolenium Bromide

(2s). 1,1,2-Trimethylbenz[e]indole (1, 340 mg, 1.62 mmol) and 3-bromo-

propionitrile (108 mg, 0.812 mmol) were heated at 120 °C for 2 h, allowed

to cool, precipitated with diethylether (50 mL), stirred for 16 h, and collected

by vacuum filtration. Yield, 311 mg (6%, content 5% besides the starting

material) ofblacksolid. IR(ATR):ν= 3398 (m), 2969 (m), 2774 (m), 2434

(w), 1708 (s), 1624 (s), 1579 (w), 1555 (w), 1520 (m), 1462 (s), 1438 (w),

1389 (w), 1354 (w), 1279 (w), 1250 (m), 1198 (w), 1128 (w), 1104 (w),

1020 (s), 984 (w), 935 (w), 886 (w), 864 (w), 815 (s), 788 (w), 748 (s),

1

685 (w) cm^ꢀ1. H NMR (200 MHz, CDCl₃): δ = 8.14ꢀ8.00 (m, 4H,

H_aromat), 7.75ꢀ7.64 (m, 2H, H_aromat), 5.54ꢀ5.52 (m, 2H, NCH₂), 3.51 (t,

2H, CH₂CN, ³J = 6 Hz), 3.29 (s, 3H, CH₃), 1.96 ppm (s, 6H, 2 ꢁ CH₃);

additional signals from the staring material 1. HRMS (ESI) (C₁₈H₁₉N₂^þ):

calcd, 263.1543; found, 263.1544; Δ = 0.1 mmu.

3-(10-Sulfodecyl)-1,1,2-trimethyl-1H-benz[e]indoleniumbromide

Sodium Salt (2v). 3-(10-Bromodecyl)-1,1,2-trimethyl-1H-benz[e]indo-

leniumbromide (2x, 600 mg, 1.18 mmol) and sodium sulfite (50 mg,

0.39 mmol) were dissolved in a mixture of ethanol (5.0 mL) and distilled

water (3.0 mL), heated to reflux for 6 h, allowed to cool, separated from

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the organic phase (1,10-dibromdecan), extracted with chloroform (3 ꢁ

50 mL), dried with megnesiumsulfate, and evaporated in vacuo. Yield,

165 mg (79%) of colorless solid. IR (ATR): ν = 2923 (s), 2853 (m),

1703 (m), 1521 (m), 1465 (w), 1352 (w), 1208 (m), 1035 (m), 810 (s),

750 (m) cm^ꢀ1. ¹H NMR (200 MHz, CDCl₃): δ = 8.09ꢀ7.91 (m, 4H,

H_aromat), 7.77ꢀ7.64 (m, 2H, H_aromat), 3.93ꢀ3.90 (m, 2H, NCH₂),

3.65ꢀ3.54 (m, 2H, CH₂SO₃H), 2.38 (s, 3H, 2 ꢁ CH₃), 2.07ꢀ1.97 (m,

2H, CH₂), 1.83ꢀ1.76 (4H, 2 ꢁ CH₂), 1.55 (s, 6H, 2 ꢁ CH₃), 1.39ꢀ1.22

ppm (m, 10H, 5 ꢁ CH₂). MS (EI^þ): m/z (%) 556.6 [M^þ2HNa].

the spectrum. HRMS (ESI) (C₂₅H₃₅BrN^þ): calcd, 428.1947; found,

428.1948; Δ = 0.1 mmu.

1,1,2-Trimethyl-3-pentyl-1H-benz[e]indoleniumbromide (2y). 1,1,2-

Trimethylbenz[e]indole (1, 690 mg, 3.31 mmol) and 1-bromopentane

(0.20 mL, 1.6 mmol) were heated at 120 °C for 1.5 h, allowed to cool,

treated with diethylether (20 mL), stirred for 16 h, and collected by vacuum

filtration. Yield, 182 mg (24%, content 80% besides the starting material

according to ¹H NMR) of brown solid, applied for the subsequent

condensation without further purification; mp 241 °C. IR (ATR): ν =

3398 (w), 3052 (w), 2929 (w), 2869 (w), 2709 (w), 2588 (w), 1819 (w),

1643 (m), 1584 (s), 1524 (m), 1464 (s), 1394 (m), 1218 (w), 1204 (w),

1148 (w), 1007 (w), 846 (w), 802 (s), 744 (s) cm^ꢀ1. ¹H NMR (200 MHz,

CDCl₃): δ = 8.15ꢀ8.01 (m, 4H, H_aromat), 7.75ꢀ7.62 (m, 2H, H_aromat),

4.88 (t, 2H, NCH₂, ³J = 7.7 Hz), 3.23 (s, 3H, CH₃), 2.05ꢀ1.96 (m, 2H,

CH₂), 1.89 (s, 6H, 2 ꢁ CH₃), 1.71ꢀ1.68 (m, 2H, CH₂), 1.56ꢀ1.40 (m,

2H, CH₂), 0.92 ppm (t, 3H, CH₂CH₃, ³J = 7.0 Hz); there are additional

signals from the starting material. HRMS (ESI) (C₂₀H₂₆N^þ): calcd,

280.2060; found, 280.2057; Δ = ꢀ0.3 mmu.

3-(5-Bromopentyl)-1,1,2-trimethyl-1H-benz[e]indoleniumbromide

(2w). 1,1,2-Trimethylbenz[e]indole (1, 1.0 g, 4.8 mmol) and 1,5-

dibromopentane (0.22 mL, 1.6 mmol) were heated at 120 °C for 2 h,

allowed to cool, treated with diethylether (30 mL), stirred for 16 h,

collected by vacuum filtration, dissolved in a small amount of dichlor-

omethane, and precipitated with diethylether. Yield, 860 mg (54%,

content 44% besides the starting material by ¹H NMR) of brown solid;

mp 123 °C. IR (ATR): ν = 3393 (s), 3058 (w), 2976 (m), 2928 (m),

2867 (w), 2714 (w), 2667 (w), 2588 (w), 2362 (m), 2336 (w), 1982

(w), 1739 (w), 1702 (w), 1632 (w), 1618 (w), 1582 (s), 1522 (s), 1464

(s), 1388 (w), 1367 (w), 1352 (w), 1279 (w), 1206 (m), 1148 (w), 1130

(w), 1039 (w), 1007 (w), 938 (w), 897 (w), 871 (w), 817 (s), 803 (s),

790 (m), 746 (s), 711 (w), 692 (w), 668 (w) cm^ꢀ1. ¹H NMR (200 MHz,

CDCl₃): δ = 8.04ꢀ7.91 (m, 4H, H_aromat), 7.70ꢀ7.49 (m, 2H, H_aromat),

4.95 (t, 2H, NCH₂, ³J = 7.3 Hz), 3.30 (s, 3H, CH₃), 3.25ꢀ3.19 (m, 4H, 2

ꢁ CH₂), 2.41ꢀ2.25 (m, 2H, CH₂), 2.17ꢀ2.03 (m, 2H, CH₂), 1.77

ppm (s, 6H, 2 ꢁ CH₃).

3-(4-Sulfobutyl)-1,1,2-trimethyl-1H-sulfobenz[e]indole (5a). 3-(4-

Sufobutyl)-1,1,2-trimethyl-1H-benz[e]indole (2f, 300 mg, 0.868 mmol),

nitrobenzene (5.0 mL), and fuming sulfuric acid (0.11 mL, 0.87 mmol, SO₃

content 65%) were allowed to react analogously to 5b (2 days of stirring at

room temperature). Yield, 200 mg (46%) of black, viscous oil, applied for

the subsequent condensation without further purification. HRMS (ESI)

(C₁₉H₂₄NO₆S₂^þ): calcd, 426.1040; found, 426.1039; Δ = ꢀ0.1 mmu.

3-(10-Bromodecyl)-1,1,2-trimethyl-1H-benz[e]indoleniumbromide

(2x). 1,1,2-Trimethylbenz[e]indole (1, 2.0 g, 10 mmol) and 1,10-

dibromodecane (0.75 mL, 3.3 mmol) were heated at 120 °C for 40 min,

allowed to cool, treated with diethylether (30 mL), stirred for 16 h, and

collected by vacuum filtration. Yield, 1.3 g (32%, content 40% besides the

starting material); mp 109 °C. IR (ATR): ν = 3394 (s, br), 3056 (w), 2977

(w), 2926 (s), 2854 (m), 2717 (w), 2665 (w), 2616 (w), 2591 (w), 2455

(w),2038(w),1824(w),1633(w),1316(w),1582(s),1523(m),1465(s),

1391 (w), 1368 (w), 1352 (w), 1334 (w), 1281 (w), 1216 (m), 1175 (w),

1147 (w), 1130 (w), 1040 (w), 1007 (w), 982 (w), 932 (w), 896 (w), 870

(w), 817 (m), 790 (w), 746 (s), 692 (w), 659 (w) cm^ꢀ1. ¹H NMR (200

MHz, CDCl₃): δ = 8.14ꢀ7.98 (m, 4H, H_aromat), 7.76ꢀ7.58 (m, 2H,

H_aromat), 4.93ꢀ4.82 (m, 2H, NCH₂), 3.29 (s, 3H, CH₃), 2.10ꢀ1.84 (m,

2H, CH₂), 1.86(s, 6H, 2 ꢁ CH₃), 1.84ꢀ1.76 (m, 4H, 2 ꢁ CH₂), 1.70ꢀ1.20

ppm (m, 12H, 6 ꢁ CH₂); there are also the signals of the starting material in

3-(10-Carboxyldecyl)-1,1,2-trimethyl-1H-sulfobenz[e]indole (5c).

3-(10-Carboxydecyl)-1,1,2-trimethyl-1H-benz[e]indolenium bromide

(2f, 300 mg, 0.632 mmol), nitrobenzene (5.0 mL), and fuming sulfuric

acid (0.08 mL, 0.63 mmol, SO₃content 65%) were allowed to react

analogously to 1,1,2-trimethyl-1H-sulfobenz[e]indole (4, 3 d). Yield,

300 mg (85%) of black, viscous oil, applied for the subsequent

condensation without further purification. ¹H NMR (200 MHz,

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1,1,2-Trimethyl-1H-sulfobenz[e]indole (4). 1,1,2-Trimethylbenz-

[e]indole (1, 1.0 g, 5.0 mmol) were dissolved in nitrobenzene (5.0 mL),

treated cautiously dropwise with ice cooling with fuming sulfuric acid

(0.65 mL, 5.0 mmol, SO₃content 65%, temperature increase until 20 °C,

cooling until the end of the evolution of smoke), allowed to warm to room

temperature, stirred for 4 h, separated from the nitrobenzene by decanting

and subsequent steam distillation until odorless, and evaporated in vacuo.

Yield, 1.00 g (69%) of black, viscous oil, applied for the subsequent con-

densation without further purification. HRMS (ESI) (C₁₅H₁₄NO₃S^ꢀ):

calcd, 288.0700; found, 288.0698; Δ = ꢀ0.2 mmu.

CD₃OD): δ = 8.41ꢀ8.01 (m, 4H, H_aromat), 7.87ꢀ7.66 (m, 1H, H_aromat),

3

4.63 (t, 2H, NCH₂, J = 7.3 Hz), 3.35 (s, 3H, CH₃), 2.28 (t, 2H,

CH₂CO₂CH₃, ³J = 7.3 Hz), 2.69ꢀ1.93 (m, 2H, CH₂), 1.82 (s, 6H, 2 ꢁ

CH₃), 1.64ꢀ1.30 ppm (m, 14H, 7 ꢁ CH₂). HRMS (ESI)

(C₂₆H₃₄NO₅S^ꢀ): calcd, 472.2169; found, 472.2159; Δ = ꢀ1 mmu.

Sodium 2-Bromoethansulfonate²¹. 1,2-Dibromoethane (6.2 mL, 72

mmol) and sodium sulfite (3 g, 24 mmol) were heated to reflux for 6 h in

a mixture of ethanol (25 mL) and distilled water (20 mL), allowed to

cool, extracted with chloroform (3 ꢁ 25 mL), dried with magnesium

sulfate, and evaporated in vacuo. Yield, 8.3 g (55%) of colorless solid; mp

289 °C. IR (ATR): ν = 3600 (w), 3528 (w), 3408 (s), 2980 (w), 2946

(w), 2087 (w), 1635 (w), 1615 (s), 1435 (m), 1411 (m), 1294 (m), 1263

(w), 1202 (m), 1168 (m), 1112 (w), 1041 (s) 794 (w), 779 (w), 750

(w), 674 (w), 617 (w) cm^ꢀ1. HRMS (ESI) (C₂H₄BrO₃S^ꢀ): calcd,

186.9070; found, 186.9070; Δ = 0 mmu.

3-(2-Ethoxycarbonylethyl)-1,1,2-trimethyl-1H-sulfobenz[e]indole

(5e). 3-(2-Ethoxycarbonylethyl)-1,1,2-trimethyl-1H-benz[e]indolenium-

bromide (2l, 300 mg, 0.768 mmol), nitrobenzene (5.0 mL) and fuming

sulfuric acid (0.10 mL, 0.77 mmol, SO₃content 65%) were allowed to

react analogously to 5b. Yield, 250 mg (69%) of black, viscous oil, applied

for the subsequent condensation without further purification. ¹H NMR

(200 MHz, CD₃OD): δ = 8.37ꢀ8.03 (m, 4H, H_aromat), 7.84ꢀ7.66 (m,

1H, H_aromat), 4.96ꢀ4.87 (m, 2H, NCH₂), 4.22ꢀ4.20 (m, 2H,

OCH₂CH₃), 3.32ꢀ3.13 (m, 2H, CO₂CH₂CH₃), 2.95ꢀ2.85 (m, 3H,

OCH₂CH₃), 1.82 ppm (s, 6H, 2 ꢁ CH₃). The protons of the methyl

group in position 2 exchange with the solvent.

Sodium 5-Bromopentanesulfonate. 1,5-Dibromopentane (16.4 g,

71 mmol), sodium sulfite (3 g, 24 mmol), ethanol (25 mL), and distilled

water (20 mL) were allowed to react analogously to sodium 2-bro-

moethansulfonate. Yield, 7.4 g (41%) of colorless solid. IR (ATR): ν =

3485 (m), 3411 (w), 2978 (w), 2930 (m), 2908 (w), 2895 (w), 2867

(w), 2851 (w), 1636 (w), 1616 (w), 1487 (w), 1466 (m), 1410 (w),

1390 (w), 1329 (w), 1314 (w), 1293 (w), 1262 (w), 1224 (m), 1207 (s),

1180 (s), 1044 (s), 988 (w), 938 (w), 823 (w), 804 (w), 792 (w), 729

(w), 618 (w) cm^ꢀ1. HRMS (ESI) (C₅H₁₁BrNaO₃S^þ): calcd, 252.9504;

found, 252.9820; Δ = 31.6 mmu.

Sodium 10-Bromdecanesulfonate²². 1,10-Dibromodecane (7.5 g,

25 mmol), sodium sulfite (1.4 g, 11 mmol), ethanol (25 mL), and

distilled water (20 mL) were allowed to react analogously to sodium

2-bromoethansulfonate. Yield, 1.8 g (23%) of colorless solid; mp 342 °C.

IR (ATR): ν = 3541 (s), 3481 (s), 2916 (s), 2874 (m), 2853 (s), 2095

(w), 1627 (m), 1472 (m), 1307 (w), 1281 (w), 1250 (w), 1230 (m),

1197 (m), 1178 (s), 1055 (m), 1044 (m), 968 (w), 796 (m), 721 (w),

640 (w), 608 (m) cm^ꢀ1. HRMS (ESI) (C₁₀H₂₁BrNaO₃S^þ): calcd,

323.0287; found, 323.0602; Δ = 31.5 mmu.

Staining of the Porcine Lens Capsule. Porcine eyes with a post-

mortem time of approximately 3 h were obtained for the evaluation of

the staining effect. After the cornea was removed, the iris was carefully

removed, and the zonules were exposed. Then, the lens was prepared,

and great care was taken not to affect the lens capsule. The lenses were

then placed in BSS. Then, 2ꢀ3 drops of the respective dye concentration

was applied on the lens surface. After a few seconds, the dye was washed

out using BSS, and the staining effect was assessed using the following

scale: excellent (þþþ), good (þþ), fair (þ), or absent (ꢀ). Photo-

graphs were taken from each stained lens.

3-(5-Ethoxycarbonylpentyl)-1,1,2-trimethyl-1H-sulfobenz[e]indole

(5g). 3-(5-Ethoxycarbonylpentyl)-1,1,2-trimethyl-1H-benz[e]indolenium-

bromide (2o, 230 mg, 0.532 mmol), nitrobenzene (5.0 mL) and fuming

sulfuric acid (0.06 mL, 0.53 mmol, SO₃content 65%) were allowed to react

analogously to 5b. Yield, 111 mg (41%) of black, viscous oil, applied for the

subsequent condensation without further purification. ¹H NMR (200

MHz, CD₃OD): δ = 8.39ꢀ8.29 (m, 2H, H_aromat), 8.18ꢀ8.01 (m, 2H,

H_aromat), 7.87ꢀ7.74 (m, 1H, H_aromat), 4.64 (t, 2H, NCH₂, ³J = 7.6 Hz),

4.20ꢀ4.17 (m, 2H, OCH₂CH₃), 2.95ꢀ2.85 (m, 3H, OCH₂CH₃), 2.37 (t,

2H, CH₂CO₂CH₂CH₃, ³J = 6.9 Hz), 2.10ꢀ1.95 (m, 2H, CH₂), 1.81 (s,

6H, 2 ꢁ CH₃), 1.74ꢀ1.50 ppm (m, 4H, 2 ꢁ CH₂). The protons of the

methyl group in position 2 exchange with the solvent. HRMS (ESI)

(C₂₃H₃₀NO₅S^þ): calcd, 432.1839; found, 432.1484; Δ = 35.5 mmu.

Studies of Toxicity by Means of Established Models of Cell Structure:

MTT Assay. ARPE-19 cell and RPE cell material, respectively, were kept

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Figure 4. Continued

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Figure 4. Number of cells of the type ARPE-19 and primary RPE, rescpectively, measured by means of a colorimetric test (MTT) after the treatment

with dyes; incubation time varied from 30, 60, and 120 to 300 s. ARPE-19: (A) 0.5, (B) 0.25, and (C) 0.1% of dye 3t. RPE: (D) 0.5, (E) 0.25, and (F)

0.1% of dye 3t. ICG served as a reference dye in the same concentrations and exposure times. Compound 3t as a triple test and three times repeated.

Control tests were performed without any addition of dyes and with the addition of hydrogen peroxide (not presented). The presented results are means

of three triplicate tests in relation to the control experiments; error bars, SEM. The observed variations are statistically insigniﬁcant.

under serum-free conditions for 24 h for the investigation of the impact

of dyes. After they were grown to confluency (100%), the cells were

washed with BSS plus solution for three times and then incubated with

700 μL of BSS plus solution containing 0.5, 0.25, and 0.1% 3,3⁰-di-(4-

sulfobutyl)-1,1,1⁰,1⁰-tetramethyl-di-1H-benz[e]indocarbocyanine (4)

each for 30, 60, 120, and 300 s. The comparably long incubation times

are necessary for the detection of comparably weak toxicity, although

they are far beyond the clinical applications of the dyes. ICG (0.5, 0.25,

and 0.1%; exposure times 30, 60, 120, and 300 s) was used as a reference

since this dye is still used in vitreoretinal surgery and also represents a

cyanine dye. The excess of dye was removed by three washing steps of

the cells with BSS plus solution preceding the proliferation assay. After

24 h of incubation with serum-containing media, the cell proliferation

assay was performed. Control experiments were carried out with BSS

plus without any additives and with the addition of H₂O₂(200 μL/mL).

The tetrazolium dye reduction assay [MTT; 3-(4,5-dimethylthiazol-

2-yl)-2,5-diphenyl tetrazolium bromide] was applied for the determina-

tion of the amount of cellular survival. The MTT test according to

Mosmann was modiﬁed as was reported in ref 20. The medium was

removed, and the cells were treated with PBS and 1000 μL/well MTT

solution (1.5 mL of MTT stock solution, 2 mg/mL in PBS, and 28.5 mL

of DMEM), RPE cells were incubated at 37 °C for 1 h, the formed

crystals of formazane in dimethylsulfoxide (DMSO) were dissolved

(1000 μL/well), and the UV/vis absorption was measured with a

scanning multiwell spectrophotometer at 550 nm (Molecular Probes,

Garching, Germany). The results were related to an averaged control

proliferation. The experiments were repeated three times in 3-fold tests.

ARPE-19 cells of the same series incubated in BSS were used for control.

The results for various dye concentrations were statistically analyzed by

means of SPSS (MannꢀWhitney U test).

The applied MTT test is well-established for the determination of the

cell activity and depends on the colorimetric determination of a blue

formazane (550 nm) as the product. The absorption of the latter

overlaps partially with the spectrum of the investigated dyes. As a

consequence, control experiments were performed for the estimation of

possible interference in the test. Monolayers of cells were incubated with

the dye; however, the read-out of the absorption was carried out without

application of MTT. No inﬂuence was found of the treatment with dyes

compares with the BSS control experiments. These control experiments

were repeated three times.

A comparison of the survival of ARPE-19 and RPE cells, respectively, in

BSS after 30, 60, 120, and 300 s indicated for the time of incubation that the

cell vitality is statistically not signiﬁcantly inﬂuenced by the addition of 0.1,

0.25, and 0.5% of the dye 3,3⁰-di-(4-sulfobutyl)-1,1,1⁰,1⁰-tetramethyl-di-1H-

benz[e]indocarbocyanine (4), respectively; see Figure 4.

’ ASSOCIATED CONTENT

S

Supporting Information.

Staining of pig's eye, stabi-

b

lity of naphthocyanine dyes, NMR spectra, and HPLC analyze.

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Journal of Medicinal Chemistry

ARTICLE

This material is available free of charge via the Internet at http://

pubs.acs.org.

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’ AUTHOR INFORMATION

Corresponding Author

*Fax: þ49-89-2180-77699. E-mail: Langhals@lrz.uni-muenchen.de.

’ ACKNOWLEDGMENT

This work was supported by the Fonds der Chemischen

Indutrie and the CIPS cluster in Munich.

’ ABBREVIATIONS USED

LLI, lamina limitans interna; ICG, indocyanine green; NIR, near-

infrared; BSS, balanced salt solution where BSS plus is a commer-

cial name; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetra-

zolium bromide; RP 18, reversed phase coated silica by 18

carbon chains; SEM, standard error of the mean; ARPE 19, a

human adult retinal pigment epithelial cell line; RPE, RPE 19

cells are a commercially available cell line [American Type

Culture Collection (ATCC)]; HRMS, high-resolution mass

spectrum

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Cyanine dyes as optical contrast agents for ophthalmological surgery

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