Substituted diketopyrrolopyrroles as input energy units in soluble donor-acceptor dyads

Article abstract of DOI:10.1002/chem.201001953

Dual for a transfer! A strategy has been devised for functionalizing fluorescent diketopyrrolopyrroles (DPP) dyes with a borondipyromethene (BODIPY) unit acting as an energy acceptor (see scheme). Quantitative intramolecular electronic energy transfer is

Full text of DOI:10.1002/chem.201001953

DOI: 10.1002/chem.201001953
Substituted Diketopyrrolopyrroles as Input Energy Units in
Soluble Donor–Acceptor Dyads
Delphine Hablot,[a] Pascal Retailleau,[b] and Raymond Ziessel*[a]
Diketopyrrolopyrroles (DPP) are highly colored pigments
In light of the diverse spectroscopic properties of DPP
and BODIPY dyes, it is tempting to link both kinds of dyes
together to form soluble dyads in which the DPP moieties
would serve as input energy absorbers under irradiation and
favor EET to the BODIPY subunit. To the best of our
knowledge, such combination has not been studied up to
now. Many requirements have to be fulfilled to facilitate ef-
ficient fluorescence energy transfer and to avoid aggrega-
tion, although it may be noted that a DPP conjugated
framework has been engineered to chelate boron and to
promote near-infrared emission.[10]
As the first step towards the formation of a soluble deriv-
ative of DPP, we alkylated the bis-lactam 1 with benzylbro-
mide using standard conditions[11,12] (Scheme 1); the intent
being to inhibit the formation of hydrogen bonds and p–p
stacking responsible for the extreme insolubility of pigment 1.
The X-ray crystal structure of the compound 2 has been
determined (Figure 1). The molecule adopts a centrosym-
metric conformation and is flanked by two solvent DMF
discovered about 35 years ago and characterized by their
strong red color, extreme insolubility, and remarkable stabil-
ity.[1,2] Many academic and industrial research development
programs have since scrutinized the synthetic scope and
spectroscopic potential of this interesting class of bicyclic
lactams.[3,4] Of the many known pigments and dyes, DPP re-
sembles a five-membered ring equivalent of epindolindione
and quinacridone species, both of which find interesting ap-
plications after proper functionalization.[5] Given limitations
in the availability of the starting materials, only a few means
of preparing relatively soluble DPP dyes have been devel-
oped.[2–4]
In previous studies, we have demonstrated that the draw-
back of weak Stokes shifts of borondipyrromethene
(BODIPY) dyes can be overcome by tethering polyaromatic
fragments as energy input units.[6] Thus, due to very efficient
intramolecular excitonic energy transfer (EET), large shifts
(over 10000 cmꢀ1) were routinely obtained.[7,8] Despite this
advantage, due to the hydrophobic nature of pyrene and
perylene substituents, the solubility in polar solvents was
rather limited, prohibiting the use of such dyes under bio-
logical conditions. However, water-soluble BODIPY–fluo-
rescein cassettes have recently been prepared as ratiometric
pH reporters for imaging protein–dye conjugates in living
cells.[9]
molecules. Substitution around the pyrrolo
[3,4ꢀc]pyrrole
ꢀ
ring results in some distorted bond lengths (e.g., C1 C11
1.439 ꢀ vs. 1.481 ꢀ usually observed) and angles (bond and
torsional), as revealed by the program MOGUL.[13]
The antiparallel benzyl substituents on N1 and N1a are
quasi-perpendicular to the central plane (making a dihedral
angle of 89.7(2)8, whereas the lateral bromophenyl rings are
twisted out of this plane by only 23.45(18)8. In the crystal,
the molecules form infinite chains along the [1 ꢀ1 0] direc-
ꢀ
[a] D. Hablot, Dr. R. Ziessel
tion through paired C Br···p(benzyl at 1+x,yꢀ1,z) orthogo-
Laboratoire de Chimie Molꢁculaire et Spectroscopies Avancꢁes
(LCOSA)
Ecole Europꢁenne de Chimie, Polymꢂres et Matꢁriaux
CNRS, 25 rue Becquerel, 67087 Strasbourg Cedex 02 (France)
Fax : (+33)3-90-24-26-89
nal interactions 3.583(2) ꢀ apart. The DPP platforms lie
parallel to the (ꢀ2 ꢀ1 2) plane, generating intramolecular
p–p interactions between a bromophenyl ring at a general
position and its symmetry-related one at (1ꢀx,1ꢀy,1ꢀz),
with an interplanar distance of 3.562(2), 1.255(2) ꢀ of slip-
ꢀ
E-mail: ziessel@chimie.u-strasbg.fr
Homepage: http://www-lmspc.u-strasbg.fr/lcosa
page, and 3.010(2) ꢀ long C HACTHNUTRGENUGN(benzyl)···p (phenyl-Br at
[b] Dr. P. Retailleau
ꢀx,ꢀy,1ꢀz) hydrogen bonds (Figure 2). In combination,
these interactions result in a ladderlike substructure with
benzyl groups and intercalated DMF molecules as lateral
bars running along the [0 ꢀ1 1] direction (Figure S1 in the
Supporting Information).
Laboratoire de Cristallochimie, ICSN–CNRS
Bꢃt 27-1 avenue de la Terrasse
91198 Gif-sur-Yvette Cedex (France)
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.201001953.
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Chem. Eur. J. 2010, 16, 13346 – 13351

COMMUNICATION
raphy. Cross-linking was effec-
tive, leading to dyes 3a and 3b
depending upon the relative
amounts
of
substrates
(Scheme 1). The unreacted and
less polar starting material 2
was easily recovered and recy-
cled. Subsequently, two options
were considered for coupling
the blue BODIPY energy ac-
ceptors to the remaining
phenyl-Br residue of compound
3a. One was the attempted cou-
pling of 3a with trimethylsilyl-
acetylene, followed by a depro-
tection step leading to the ter-
ꢁ
minal alkyne (X1 =C CH, X2 =
ꢁ
C CCH2NMe2 in 3), but this
failed due to the lack of reactiv-
ity of the terminal alkyne. Ulti-
mately, the second option of
post-functionalization of 3a by
using the stable BODIPY dyes
4a–c pre-functionalized with
the terminal alkyne was found
to be successful. The cross-cou-
pling was straightforward when
Scheme 1. i) Benzylbromide (10 equiv), DMF, K2CO3 (11 equiv), 1208C, 2 h, 36%; ii) dimethylaminopropyne
(1 equiv), benzene, triethylamine, [Pd(PPh3)2Cl2] (10 mol%), CuI (15 mol%), 408C, 60 h, 27% 3a, 11% 3b;
(PPh3)4] (10 mol%), 508C, 15 h; 99% 4a (1.2 equiv), 62% 4b (1.0 equiv), 86%
AHCTUNGTRENNUNG
iii) benzene, triethylamine, [PdACTHUNGTRENNNUG
4c (1.0 equiv).
using [Pd0
ACHTNUGTRNEUNG(PPh3)4] as the cata-
The next challenge in the synthesis consisted of chemical
differentiation of both phenyl-Br groups by using an alkyne
cross-coupling reaction promoted by palladium(0) and with
dimethylaminopropyne as the substrate. The key tenet here
was to introduce a polar function to easily separate the
mono- and disubstituted derivatives by standard chromatog-
lyst precursor and triethylamine as the acid quencher. Aver-
age yields of about 50% were routinely obtained. Purifica-
tion was facilitated by the polarity imported by the dimethy-
lamino residues and/or the polyethylenegycol side chains in
the case of 4c. All dual dyes were unambiguously by charac-
terized by NMR and FTIR spectroscopy, EI-MS and ele-
mental analysis, and all data were consistent with their pro-
posed molecular structures. The well-resolved NMR spectra
confirmed the absence of aggregates and showed no clear
indications of electronic perturbation of one substructure by
another.
The electroactivity of the new dyes was measured by
cyclic voltammetry and the data are gathered in Table 1. For
2, a single oxidation peak was seen that could be ascribed to
formation of the DPP p-radical cation. This peak was elec-
trochemically reversible and corresponded to a one-electron
process (Figure 3a). On reductive scans, two peaks were ob-
served corresponding to reduction of DPP to its p-radical
anion and dianion, respectively. The latter process was irre-
versible. As anticipated for 3a, an additional irreversible ox-
idative peak attributed to the oxidation of the dimethylami-
no moiety was found at +1.11 V. The intensity of this wave
at around +1.10 V increased in compounds 3b, 4b, and 4c
due to the increase of the number of dimethylamino subu-
nits.
The anodic portion of the cyclic voltammogram recorded
for 5a–c was more complex than for the other compounds
(Figure 3b). Based on the electrochemical properties re-
corded for 4a–c, the first oxidation step was assigned to the
Figure 1. ORTEP view of the X-ray structure of compound 2. Ellipsoids
are drawn at the 50% probability level, H atoms as small spheres of arbi-
trary radii. The two solvent DMF molecules are omitted for clarity.
Chem. Eur. J. 2010, 16, 13346 – 13351
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13347

R. Ziessel et al.
Figure 2. Part of the crystal structure of 2 showing the formation of a [1 ꢀ1 0] chain.
Table 1. Selected electrochemical data.[a]
0 0
0 0
removal of one electron from the BODIPY unit. The addi-
tional broad irreversible wave at higher cathodic potential
was assigned to overlapping of the oxidation of the DPP
and dimethylamino residues. Interestingly, the DPP append-
age in the dual dyes 5a–c exerts no notable electronic effect
on the overall electron donation and affinity of the
BODIPY nucleus. These data indicate that the two partners
DPP and BODIPY in 5a–c are in weak electronic interac-
tion, a situation generated by the twisted diphenylacetylene
central linker as well as by the well-admitted orthogonality
of the phenyl ring in the blue dyes 4a–c. This latter situation
is due to the presence of the bulky methyl groups in the 1,7-
substitution position.[14]
Close examination of the spectroscopic properties reveals
interesting features. Absorption spectra recorded for com-
pounds 2, 3a, and 3b in dioxane displayed features typical
of the soluble DPP dyes, namely, a strong absorption in the
visible region at around 480 nm. Along with other parent
DPP dyes, the fluorescence spectra exhibited a maximum at
around 550 nm with a shoulder at approximately 595 nm
upon excitation at 446 nm (Figure 4a).[15] Since the intensity
of the maximum band relative to the shoulder was inde-
pendent of the concentration and nature of the solvent, it
E
, V (DE [mV])
E
, V (DE [mV])
red
ox
DPP
BODIPY
DPP
BODIPY
2
+1.21 (60)
–
ꢀ1.14 (70);
ꢀ1.86 (irr.)
ꢀ1.15 (70);
ꢀ1.82 (irr.)
–
–
3a +1.22 (60),
–
–
+1.11 (irr.)[b]
4a
4b
4c
–
+0.82 (60),
+1.35 (irr.)[c]
+0.76 (irr.),
+1.12 (irr.)[b]
+0.66 (irr.),
+1.10 (irr.)[b]
+0.80 (irr.)
ꢀ0.96 (70);
ꢀ1.80 (irr.)
ꢀ1.14 (70)
–
–
–
–
ꢀ1.16 (80)
ꢀ0.97 (60)
ꢀ1.15 (60)
ꢀ1.16 (70)
5a +1.29 (irr.)
5b +1.27 (irr.)
5c +1.27 (irr.)
ꢀ1.10 (60);
ꢀ1.72 (irr.)
ꢀ1.10 (60);
ꢀ1.68 (irr.)
ꢀ1.14 (70);
ꢀ1.74 (irr.)
+0.74 (irr.)
+0.64 (irr.)
[a] Potentials determined by cyclic voltammetry in deoxygenated CH2Cl2,
containing 0.1m TBAPF6, at a solute concentration range of 1.5ꢅ10ꢀ3 m,
at 208C. Potentials were standardized by using added ferrocene (Fc) as
an internal reference and converted to SCE by assuming that E1/2 (Fc/
Fc+)=+0.38 V (DEp =70 mV) versus SCE. Error in half-wave potentials
is ꢂ15 mV. When the redox process is irreversible (irr.), the peak poten-
tial (Eap or Ecp) are quoted. [b] Corresponds to the irreversible oxidation
of the tertiary amine. [c] Two-electron oxidation of the styryl/BODIPY
subunit.
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Chem. Eur. J. 2010, 16, 13346 – 13351

Substituted Diketopyrrolopyrroles as Input Energy Units
COMMUNICATION
Figure 3. Cyclic voltammograms of a) 2 full window (plain line), limited
to ꢀ1400 mV (dashed line); b) 3a (dotted line), 4a (plain line), and 5a
(dashed line) in dichloromethane at RT. Fc corresponds to added ferro-
cene.
was concluded that this shoulder was not due to excimer
emission. Quantum yields are gathered in Table 2 and the
nanosecond excited-state lifetime regime is in keeping with
a singlet excited state.
The absorption spectra of compounds 5a–c is almost a
linear combination of the absorption of the two separate
Table 2. Optical data measured at 298 K.
Figure 4. Absorption (c), emission (a), and excitation (g) spectra
of a) dye 3a, b) dye 4c, and c) dual dye 5c in dioxane at room tempera-
ture.
[a]
[b]
[c]
labs
e
lF
FF
tF [ns]
ꢂ0.01
kr[c]
knr
[nm]
m1 cmꢀ1
[nm]
108 sꢀ1
107 sꢀ1
3a
3b
5a
483
488
496
633
495
644
494
644
19900
23300
27700
117500
29700
119500
33100
127000
547
554
–
644
–
657
–
657
0.90
0.89
–
0.90
–
0.74
–
0.69
6.40
5.05
–
7.26
–
6.76
–
7.93
1.41
1.76
–
1.24
–
1.09
–
0.87
1.56
2.18
–
1.38
–
3.85
–
3.91
modules 3a and 4a–c, with a pronounced intramolecular
charge transfer band (ICT) at 360 nm belonging to the blue
part of the dual dye, a broad band characteristic of the DPP
module, and the well-structured absorption of the S0!S1
transition of the blue module at 650 nm (Figure 4c). In all
three cases selective excitation in the DPP band at 470 nm
revealed the absence of any residual DPP fluorescence and
just the exclusive emission of the blue module at 660 nm.
From the quantum yield determinations it appears that
5b
5c
[a] By excitation at 480 nm. [b] Determined in dioxane (cꢃ1.10ꢀ6 m) by
using rhodamine 6G as a reference (FF =0.78 in water, lexc =488 nm).[16]
All FF are corrected for changes in refractive index. [c] Calculated by
using the following equations, assuming that the emitting state is pro-
duced with unit quantum efficiency: kr =FF/tF, knr =(1ꢀFF)/tF.
Chem. Eur. J. 2010, 16, 13346 – 13351
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13349

R. Ziessel et al.
quantitative energy transfer from the DPP to the blue dye
occurs, excluding any determination of the residual excited-
state lifetime. The rate of EET was estimated from our reso-
lution limits to be very fast (>2ꢅ1010 sꢀ1). Consistent with
this result, the excitation spectra perfectly matched the ab-
sorption spectra over the entire spectral range (Figure 4c).
Interestingly, alkylation of 5c with methyliodide in anhy-
drous THF, followed by anion metathesis by using silver ni-
trate in methanol, afforded compound 6 in 92% yield. This
form of 6 was highly soluble in methanol as well as in water/
methanol mixtures, but unfortunately not in pure water.
ference between the input energy at 480 nm for DPP and
the output energy at 657 nm for the blue BODIPY). The
process is so efficient that no residual emission is observed,
consistent with the operation of a Fçrster energy-transfer
mechanism favored by the spectral overlap between the
emission of DPP and the absorption of the blue dye. This
discovery also holds true in polar solvents, including aque-
ous media. Further chemical modifications at the DPP are
currently in progress to produce donor–acceptor systems
suitable for incorporation in solar cells.[18]
Experimental Section
Selected data for compound 5a:
1H NMR (300 MHz, CDCl3): d=1.26
(s, 6H), 2.37 (s, 6H), 2.38 (s, 6H), 3.50
(s, 2H), 5.00 (s, 2H), 5.02 (s, 2H), 6.64
(s, 2H), 7.16–7.40 (m, 8 lines, 16H),
7.43–7.86 ppm (m, 14 lines, 18H);
13C NMR (75.46 MHz, CDCl3): d=
15.0, 21.6, 29.8, 44.3, 45.9, 48.7, 85.0,
88.1, 90.3, 91.8, 110.2, 110.4, 118.0,
118.4, 123.7, 126.1, 126.6, 126.7, 126.8,
127.2, 127.7, 128.5, 128.7, 129.0, 129.1,
129.2, 129.7, 132.1, 132.2, 132.3, 132.5,
133.1, 133.9, 135.8, 136.6, 137.4, 137.6,
The absorption spectra of 6 in methanol/water (80/20, v/v)
showed similar features to those of 5c and no significant ag-
gregation was indicated by the absence of new absorption
bands as commonly observed for BODIPY or DPP dyes
(Figure 5).[17] Further, irradiation in the DPP subunit at
484 nm resulted in the exclusive emission from the blue dye
unit at 644 nm as observed in apolar solvents. In this case,
quantitative intramolecular energy transfer is also occurring
(Figure 5a). We, however, noticed that quantum yield de-
creased from 19% in pure methanol to 12% with 5% water
and to 9% with 20% water. This observation is not unusual
ꢀ
and promoted by vibronic deactivation through the O H
bonds. We notice that, by increasing the water concentration
to 20%, a weak residual emission of the DPP subunit is ob-
served at 555 nm (Figure 5b). However, despite this weak
decrease in intramolecular energy transfer, this result is aus-
picious for the use of such cassettes in biological conditions
for multi-FRET (fluorescence resonant energy transfer)
analysis.
In short, in this facile and straightforward route to soluble
DPP-linked BODIPY dyes, the key step is the introduction
of benzyl residues on the bicyclic lactam subunits. Differen-
tiation of the two bromophenyl entities is feasible with a di-
methylaminopropyne function, enabling the tethering of a
blue BODIPY as an energy acceptor. Very weak interaction
between the chromophores arising from the twisting of both
phenyl fragments on the DPP side and the BODIPY sides,
severely limits the electronic interactions between both pho-
toactive modules. By excitation of the DPP module, a cas-
cade energy transfer is effective with photons channeled to
the blue dye, providing virtual Stoke shifts of about
5610 cmꢀ1 (calculated by taking into account the energy dif-
Figure 5. Absorption (c), emission (a), and excitation (g) spectra
of: the tricationic dye 6 in a) methanol with 5% water, b) methanol with
20% water.
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Substituted Diketopyrrolopyrroles as Input Energy Units
COMMUNICATION
139.4, 141.8, 148.2, 148.6, 153.1, 162.8 ppm; ESI-MS (CH2Cl2 +1% TFA,
+ve mode): m/z (%): 1100.3 (100); elemental analysis calcd (%) for
C74H60BF2N5O2: C 80.79, H 5.50, N 6.37; found: C 80.50, H 5.23, N 5.98.
Compound 5b: 1H NMR (300 MHz, CDCl3): d=1.43 (s, 6H), 2.20 (s,
[1] D. G. Farnum, G. Mehta, G. G. Moore, F. P. Siegal, Tetrahedron Lett.
1974, 15, 2549–2552.
[2] Z. Hao, A. Iqbal, Chem. Soc. Rev. 1997, 26, 203–213.
[3] a) A. Iqbal, L. Cassar, US Patent 4,415,685, 1983; b) J. Pfenninger,
A. Iqbal, A. C. Rochat, Eur. Patent 184-981, 1986; c) M. Jost, A.
Iqbal, A. C. Rochat, Eur. Patent 224-445, 1987.
[4] A. Iqbal, M. Jost, R. Kirchmayr, J. Pfenninger, A. Rochat, O. Wall-
quist, Bull. Soc. Chim. Belg. 1988, 97, 615–643.
[5] a) G. Lincke, Dyes Pigm. 2000, 44, 101–122; b) G. Lincke, Dyes
Pigm. 2002, 52, 169–181.
12H), 2.36 (s, 6H), 3.22 (s, 4H), 3.49 (s, 2H), 3.86 (s, 6H), 5.00 (s, 2H),
3
5.02 (s, 2H), 6.64 (s, 2H), 6.93 (d, J=8.6 Hz, 4H), 7.08–7.41 (m, 10 lines,
14H), 7.45–7.85 (m, 12 lines, 14H), 8.23 ppm (d, 3J=16.2 Hz, 2H);
13C NMR (75.46 MHz, CDCl3): d=15.2, 27.1, 44.1, 44.4, 45.9, 48.8, 49.9,
55.5, 84.9, 88.3, 90.3, 90.5, 92.1, 92.3, 110.2, 110.4, 114.4, 118.1, 119.6,
123.4, 126.2, 126.7, 126.8, 127.2, 127.7, 128.9, 129.0, 129.1, 129.2, 130.2,
131.4, 132.1, 132.2, 132.4, 133.9, 136.5, 137.4, 140.0, 148.3, 148.6, 152.2,
160.3, 162.8 ppm; ESI-MS (CH2Cl2 +1% TFA, +ve mode): m/z (%):
1258.5 (100); elemental analysis calcd (%) for C84H76BN7O4: C 80.18, H
6.09, N 7.79; found: C 79.96, H 5.63, N 7.59.
[6] A. Harriman, G. Izzet, R. Ziessel, J. Am. Chem. Soc. 2006, 128,
10868–10875.
[7] a) G. Ulrich, R. Ziessel, A. Harriman, Angew. Chem. 2008, 120,
1202–1219; Angew. Chem. Int. Ed. 2008, 47, 1184–1201; b) A.
Loudet, K. Burgess, Chem. Rev. 2007, 107, 4891–4932.
[8] C. Goze, G. Ulrich, R. Ziessel, J. Org. Chem. 2007, 72, 313–322.
[9] J. Han, A. Loudet, R. Barhoumi, R. Burghardt, K. Burgess, J. Am.
Chem. Soc. 2009, 131, 1642–1643.
[10] a) G. M. Fischer, A. P. Ehlers, A. Zumbusch, E. Daltrozzo, Angew.
Chem. 2007, 119, 3824–3827; Angew. Chem. Int. Ed. 2007, 46, 3750–
3753; b) G. M. Fischer, M. Isomꢆki-Krondahl, I. Gçttker-Schnet-
mann, E. Daltrozzo, A. Zumbusch, Chem. Eur. J. 2009, 15, 4857–
4864.
[11] G. Colonna, T. Pilati, F. Rusconi, G. Zecchi, Dyes Pigm. 2007, 75,
125–129.
[12] a) T. Yamagata, J. Kuwabara, T. Kanbara, Tetrahedron Lett. 2010,
51, 1596–1599; b) J. Kuwabara, T. Yamagata, T. Kanbara, Tetrahe-
dron 2010, 66, 3736–3741.
[13] I. J. Bruno, . J. C. Cole, M. Kessler, J. Luo, W. D. S. Motherwell,
L. H. Purkis, B. R. Smith, R. Taylor, R. I. Cooper, S. E. Harris, A. G.
Orpen, J. Chem. Inf. Comput. Sci. 2004, 44, 2133–2144.
[14] R. Ziessel, P. Retailleau, K. J. Elliott, A. Harriman, Chem. Eur. J.
2009, 15, 10369–10374.
[15] a) L. Bꢇrgi, M. Turbiez, R. Pfeiffer, F. Bienewald, H. Kimer, C. Win-
newisser, Adv. Mater. 2008, 20, 2217–2224; b) A. B. Tamayo, B.
Walker, T. Nguyen, J. Phys. Chem. C 2008, 112, 11545–11551;
c) M. M. Wienk, M. Turbiez, J. Gilot, R. A. J. Janssen, Adv. Mater.
2008, 20, 2556–2560; d) K. Zhang, B. Tieke, Macromolecules 2008,
41, 7287–7295; e) D. Cao, Q. Liu, W. Zeng, S. Han, J. Peng, SZ. Liu,
Macromolecules 2006, 39, 8347–8355.
[16] J. Olmsted, J. Phys. Chem. 1979, 83, 2581–2584.
[17] a) I. Mikhalyov, N. Gretskaya, F. Bergstrçm, L. B.-ꢀ. Johansson,
Phys. Chem. Chem. Phys. 2002, 4, 5663; b) D. Marushchak, S. Kali-
nin, I. Mikhalyov, N. Gretskaya, L. B.-ꢀ. Johansson, Spectrochim.
Acta Part A 2006, 65, 113–122.
Compound 5c: 1H NMR (400 MHz, CDCl3): d=1.48 (s, 6H), 2.19 (s,
12H), 2.36 (s, 6H), 3.21 (s, 4H), 3.41 (s, 6H), 3.49 (s, 2H), 3.57–3.63 (m,
4 lines, 4H), 3.72–3.77 (m, 4 lines, 4H), 3.90 (t, 3J=4.6 Hz, 4H), 4.20 (t,
3J=4.6 Hz, 4H), 5.00 (s, 2H), 5.02 (s, 2H), 6.64 (s, 2H), 6.94 (d, 3J=
9.2 Hz, 4H), 7.08–7.41 (m, 11 lines, 14H), 7.46–7.84 (m, 11 lines, 14H),
8.22 ppm (d, 3J=16.2 Hz, 2H); 13C NMR (100.61 MHz, CDCl3): d=15.2,
44.1, 44.4, 45.9, 48.8, 49.0, 59.3, 67.7, 69.9, 71.0, 72.1, 84.9, 88.6, 88.4, 90.2,
90.6, 92.0, 110.2, 110.4, 115.1, 118.1, 119.7, 123.4, 126.2, 126.8, 127.2,
127.7, 128.9, 129.0, 129.1, 129.2, 130.3, 131.4, 132.1, 132.2, 132.4, 133.9,
136.5, 137.4, 140.0, 148.3, 148.6, 152.2, 159.5, 162.8 ppm; ESI-MS
(CH2Cl2 +1% TFA, +ve mode): m/z (%): 1435.0 (100); elemental analy-
sis calcd (%) for C92H92BN7O8: C 77.03, H 6.46, N 6.83; found: C 76.83,
H 6.22, N 6.61.
Compound 6: 1H NMR (200 MHz, CD3OD+D2O): d=1.57 (s, 6H), 3.09
(s, 18H), 3.27 (s, 9H), 3.44 (s, 6H), 3.57–3.69 (m, 4H), 3.78–3.92 (m, 4H),
3.85–4.03 (m, 4H), 4.23–4.42 (m, 4H), 4.47 (s, 4H), 4.78 (s, 2H), 5.17 (s,
4H), 6.99 (s, 2H), 7.15–7.76 (m, 10 lines, 18H), 7.87–8.99 (m, 8 lines,
14H), 8.34 ppm (d, 3J=16.2 Hz, 2H); ESI-MS (CH2Cl2 +1% TFA, +ve
mode): m/z (%): 1602.6 (100), 513.6 (35); elemental analysis calcd (%)
for C95H101BN10O17.2H2O: C 66.89, H 6.44, N 8.21; found: C 66.79, H
6.04, N 8.07.
Acknowledgements
We thank the Centre National de la Recherche Scientifique (CNRS) for
financial support of this work and Professor Jack Harrowfield (ISIS in
Strasbourg) for a critical reading of this manuscript prior to publication.
[18] L. Huo, J. Hou, H.-Y. Chen, S. Zhang, Y. Jiang, T. L. Chen, Y. Yang,
Macromolecules 2009, 42, 6564–6571.
Keywords: diketopyrroles · dyes/pigments · energy transfer ·
pi conjugation · redox chemistry
Received: July 9, 2010
Published online: October 29, 2010
Chem. Eur. J. 2010, 16, 13346 – 13351
ꢄ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
13351