3,9-Disubstituted Bis[1]benzothieno[3,2-b;2′,3′-e][1,4]thiazines with Low Oxidation Potentials and Enhanced Emission

Low Oxidation Potentials and Enhanced Emission

Article

,9-Disubstituted Bis[1]benzothieno[3,2‑b;2′,3′‑e][1,4]thiazines with

Henning R. V. Berens, Kausar Mohammad, Guido J. Reiss, and Thomas J. J. Muller*

Cite This: J. Org. Chem. 2021, 86, 8000 −8014

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sı Supporting Information

ABSTRACT: Dibrominated bis[1]benzothieno[3,2-b;2′,3′-e][1,4]-

thiazines (BBTT) are eﬃciently synthesized and applied in Suzuki

and Buchwald−Hartwig cross-coupling reactions to give access to

,9-disubstituted BBTT derivatives with extended π-conjugation and

enhanced electronic properties. For instance, 3,9-di(hetero)aryl

substituted BBTT derivatives surpass their parent congeners

phenothiazines with lower oxidation potentials and pronounced

yellow to orange-red ﬂuorescence (Φ ≈ 30−45%). In addition, 3,9-

bis(di(hetero)arylamino substituted BBTT possess very high lying

HOMO energy (E_H_O_M_O= −4.46 to −4.83 eV), a favorable property

of hole transport molecules. A representative X-ray structure analysis

reveals that the central BBTT core in these extended π-systems is

essentially planarized. Upon protonation of a 3,9-bis(di(hetero)-

arylamino) substituted BBTT, the absorption color shifts from yellow

to deep blue with a concomitant loss of the emission. The optical properties of these novel BBTT derivatives can be plausibly

rationalized by time-dependent density functional theory (TD(DFT)) calculations and correlation between experimentally

−

determined oxidation potentials and σ parameters as well as between photophysical data and the speciﬁc substituent parameter σ

by establishing electronic structure−property relationships.

INTRODUCTION

e][1,4]thiazines (abbreviated as follows: anti,anti bis[1]-

benzothieno[1,4]thiazines or anti,anti BBTT) restored the

luminescent behavior, simultaneously maintaining low rever-

sible redox potentials and even redshifting absorption bands by

■

The steadily increasing application of organic heterocycles in

photonic devices, such as organic light emitting diodes

−5

6−9

(

OLEDs)

and organic solar cells (OSCs)

has consid-

∼

0.8 eV. These compounds ﬂuoresce intensely compared to

erably stimulated the quest for substance libraries with tunable

photophysical and electrochemical properties in recent years.

While di- and tri(hetero)arylamines have already been

related phenothiazines and dithienothiazines with remarkably

high ﬂuorescence quantum yields. Interestingly, some BBTT

derivatives deviate from the 1,4-thiazine typical behavior of

adapting the butterﬂy structure by forming fully planarized

solid state conformations, which essentially can be interpreted

as antiaromatic systems. Therefore, we became interested in

scrutinizing the electronic eﬀects of remote benzo core

substituents on the electronic and solid-state structure of

BBTT. Since planar molecules and dense crystal packing are

11−15

established as donors,

phenothiazines are increasingly

This is due to their low oxidation

6−19

attracting attention.

0,21

potentials,

reversible formation of stable radical cati-

and, thus, their suitability as dye sensitizers in dye

sensitized solar cells (DSSCs) or as emitters in OLED

2,23

ons,

7,24,25

cells.

Still, stable electron-rich molecules with low

oxidation potentials remain a major challenge. Recently, we

identiﬁed thieno anellation of the 1,4-thiazine core to give

dithieno[2,3-b:3′,2′-e] [1,4]thiazines as a rational approach to

particularly favorable for molecular electronics applications,

the closer inspection of crystal structures in conjunction with

the substitution pattern are particularly important. Herein we

present syntheses of π-conjugation expanded anti-anti-BBTT

26,27

enhance the electron density of the triheterocyclic scaﬀold.

Cathodically shifted oxidation potentials of about 300 mV

supported the enhanced electron density of these systems;

however, visible luminescence became absent. By introduction

of speciﬁc N-substituents, emission could not be reestablished,

although bathochromic shift in the absorption bands as well as

slight cathodic shifts of the oxidation potentials were feasible.

Like phenothiazines, dithienothiazines form stable radical

Received: February 17, 2021

Published: June 8, 2021

cations and dications with oxidizing agents. Additional

benzo anellation resulting in bis[1]benzothieno[3,2-b;2′,3′-

2021 The Authors. Published by

American Chemical Society

000

J. Org. Chem. 2021, 86, 8000−8014

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Article

with electronically diverse substituent patterns employing

cross-coupling methodology to a novel dibromo-BBTT

building block. In addition, the solid-state structure, electronic

properties (absorption, emission, redox potentials), and the

electronic structure by density functional theory (DFT) and

time-dependent DFT (TD-DFT) calculations are investigated

and discussed.

with compound 8b to provide solubility for variable polar

systems. Caused by solvent incorporation into the aliphatic

chains, puriﬁcation eﬀorts led to lower yields.

With compound 8a in hand, we set out to utilize a variety of

(hetero)aryl bromides 9 as substrates to synthesize π-expanded

systems 10 by Suzuki cross-coupling. The title compounds

were successfully synthesized by bromine-lithium-exchange-

borylation-Suzuki-coupling sequence (BLEBS), converting 8a

into a boronic ester derivative with a following Suzuki cross-

RESULTS AND DISCUSSION

■

Synthesis. Recently, we established the synthesis of anti-

coupling in a one-pot fashion (Scheme 3). The BLEBS

sequence gives signiﬁcantly higher yields and leads to easier

puriﬁcation than the standard Suzuki coupling employing

compound 8a and boronate esters. Using this modular

approach, a series of 3,9-di(hetero)aryl substituted BBTT

with an electronically diverse substitution pattern from

electron-rich to electron-poor (10a−10h) including redox

active donor substituents (10k) were obtained in moderate to

mostly excellent yields.

anti BBTT. However, due to formation of radical cations,

simple electrophilic aromatic substitution starting from BBTT

appeared to not be feasible. Therefore, we set out to design an

alternative synthetic approach to a dibrominated anti-anti

BBTT as a pivotal starting point for functionalized BBTT

derivatives. Our synthesis commences by bromination of

benzo[b]thiophene (1) to give 2,3,6-tribromobenzo[b]-

thiophene (2), which was then site-selectively debrominated

to give 3,6-dibromobenzo[b]thiophene (3) (Scheme 1). The

In addition, we employed substrate 8a for coupling three

secondary (hetero)arylamines 11 under Buchwald−Hartwig

conditions giving rise to the formation of 3,9-bis(di(hetero)-

aryl aminated) anti-anti BBTT 12 in very good to excellent

yields (Scheme 4).

Scheme 1. Synthetic Route to Substrate 6 Starting from

Benzo[b]thiophene 1

Structure. The structure and purity of all compounds was

unambiguously assigned by means of H, C{ H} NMR, mass

spectrometry, and elemental analysis. The structural assign-

ment of the solid-state structure was additionally corroborated

by X-ray structure analyses for two generic compounds 8a

(

Figure 1) and 10b. Interestingly, both examined structures

reveal signiﬁcant planarization in the solid state. The bright

orange compound 8a crystallizes in the monoclinic space

group C2/c. The two planes of the benzo[b]thiophene

fragments adopt an interplanar dihedral angle of θ = 178.9°,

which accounts for an almost planar conformation. This

folding angle even increases by 1.3° compared to the angle in

the previously reported, unsubstituted analogue (177.6°).

With a torsion angle of α = 73.3°, the N-aryl ring is less twisted

against the BBTT core plane than in the unsubstituted

congener, which exhibits an almost orthogonal orientation (α

= 88.5°). The long interhalogen distances of the bromine

atoms of 8a in the crystal structure (4.1−10.3 Å) and their lack

of a linear orientation toward each other do not advocate for

dibrominated species 3 was then transformed by site-selective

halogen-lithium exchange followed by thio ligation with BPSS

(

bis(phenylsulfonyl)sulﬁde, 4)

to give bis(benzo[b]-

thiophen-3-yl)sulﬁde 5, which was subsequently brominated

to furnish substrate 6 for the ﬁnal thiazine formation.

Intermolecular-intramolecular 2-fold Buchwald−Hartwig

amination of compound 6 and selected anilines 7 furnished

the brominated BBTTs 8a and 8b in good to excellent yields in

the sense of a (5 + 1)-cyclization (Scheme 2). To ease

crystallization, compound 8a was synthesized bearing a tert-

butyl substituent that has previously proven to be expedient.

In addition, a long aliphatic side chain was also introduced

halogen−halogen interactions. The crystal packing shows

multiple molecules in double sets displaced in an anti-parallel

fashion with centroid distances of 3.6 Å. The twisted phenyl

ring forms T-shaped stacking between the o/m-protons and

the neighboring benzo-ring of the next BBTT system, with a

centroid distance of 3.0 Å.

Preliminary results indicate that also 3,9-di(p-anisyl)

derivative 10b exhibits some planarization, however, not as

strongly as for compound 8a and previously reported

unsubstituted analogues (see the Supporting Information for

Scheme 2. (5 + 1)-Cyclizing Buchwald−Hartwig Synthesis

of BBTT Derivatives 8

crystallographic data). The interplanar angle of the benzo-

b]thiophene fragments accounts for θ = 169.4°. Although this

[

does not reﬂect a full planarization, however, it represents a

considerably wider angle than for 10H-phenothiazine (θ =

53.3°) or selected dithienothiazines (θ = ∼133°). The

elementary cell consists of two distinct molecules exhibiting

diﬀerent geometries. Within the crystal cell, the molecules are

arranged in T-shaped conformations with head-to-plane

distances of 2.9−3.7 Å. The expected torsion of the p-anisyl

substituents is considerable (θ = 27.9°) and might hamper the

001

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Scheme 3. BLEBS Synthesis of 3,9-Di(hetero)aryl Substituted BBTT 10

Cs CO was employed as a base, omitting H O as a cosolvent and [n-Bu N]Cl as a phase transfer catalyst.

Scheme 4. Buchwald−Hartwig Synthesis of 3,9-

Bis(di(hetero)aryl Aminated) anti-anti BBTT 12

fully coplanar stacking and results in an incomplete

planarization of the structure.

Using the crystal structure geometry of 8a and 10b as

starting coordinates, DFT calculations were conducted on the

two compounds (using Gaussian 09 with B3LYP/6-31G).

The resulting HOMO energy values were compared to the

results of de novo calculations of the optimized solvated

38,39

geometries of 8a and 10b (B3LYP/6-31G with PCM

The results reveal planarization causing a rise of FMO energies

in the crystal structure as observed in our previous study

(

Table 1). For structure 8a, the HOMO energy increases

strongly upon planarization (+0.552 eV), with the LUMO

energy exhibiting a far lesser elevation (+0.159 eV). This leads

to a computed HOMO−LUMO band gap of only 3.323 eV for

a planar crystal geometry compared to 3.716 eV for the

optimized PCM geometry indicating a band gap diminution of

0.393 eV upon transition from the solution to the solid state.

Compound 10b reveals the same tendency with a rise of the

HOMO energy by 0.704 eV, compared to a rise of 0.344 eV for

the LUMO energy. The computed band gap of 10b thus

diminishes from 3.583 eV in (butterﬂy structured) solution to

.223 eV in the (planarized) crystal structure. The decrease of

.360 eV of compound 10b causes a redshift of the solid-state

absorption bands and thus a lower excitation energy (vide

infra).

Electrochemical Properties. Both 3,9-disubstituted

BBTT systems 10 and 12 contain BBTT as the central

electrophore core unit with low oxidation potentials. There-

fore, these compounds were studied by cyclic voltammetry in

dichloromethane solutions at ambient temperature (Table 2).

Figure 1. Crystal structure of dibrominated BBTT 8a.

3,9-Di(hetero)aryl substituted BBTT analogues 10 undergo

Table 1. HOMO and LUMO Energy Levels of the Computed Gas Phase Geometries and Obtained Crystal

a (optimized geometry)

8a (crystal geometry)

10b (optimized geometry)

10b (crystal geometry)

HOMO

LUMO

ΔE_H_O_M_O₋_L_U_M_O

−5.116 eV

−1.400 eV

3.716 eV

−4.564 eV

−1.241 eV

3.323 eV

−4.941 eV

−1.358 eV

3.583 eV

−4.237 eV

−1.014 eV

3.223 eV

Computed with Gaussian 09, using B3LYP/6-31G with PCM. Computed with Gaussian 09, using B3LYP/6-31G.

002

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two reversible one-electron transitions in the range from −150

to 760 mV (Figure 2).

Table 2. Selected Redox Potentials and HOMO Energies of

Compounds 8, 10, and 12

/+1

+1/+2

+2/+3

cmpd

[V]

0.05

[V]

HOMO [eV]

0.76

0.29

−4.85

−4.65

−4.73

−4.74

−4.75

−4.78

−4.80

−4.79

−4.81

−4.84

−4.73

−4.62

−4.46

−4.74

−0.15

−0.08

−0.06

−0.05

−0.02

0.00

0.94

0.59

0.64

0.65

0.66

0.65

0.70

0.69

0.72

0.73

0.22

0.30

0.10

0.13

−0.01

0.02

0.03

−0.07

−0.18

−0.34

−0.06

0.67

0.88

0.52

0.30

−3

Recorded in CH Cl at RT, c = 10 M, referenced to internal

standard decamethylferrocene E = −552 mV (vs ferrocene E (Fc/

Fc ) = 0 V). Determined from the electrochemical data (E

Simultaneous two-electron transfers occur.

Fourth to sixth oxidation potentials E

HOMO

/+1

41 c

−

(E₀+ 4.80 eV).

+3/+4

+4/+5

= 0.52 V, E₀

= 0.98 V,

5/+6

= 0.08 V.

Figure 2. Cyclic voltammograms (CVs) of 3,9-di(hetero)aryl

substituted BBTT 10b−10j (A) and CVs of 3,9-di(hetero)aryl

substituted BBTT 10a, 10k (B) (CVs recorded in CH Cl , RT,

All ﬁrst oxidations qualify as electrochemically reversible

processes with peak potential separations of 40−80 mV.

Likewise, most second oxidation processes are also reversible,

with the exception of the potentials of 10a, 10f, 10k, and 12a

exhibiting peak potential separations of more than 80 mV.

Compounds 10a and 10k furthermore deviate upon under-

going two-electron oxidations at 290 and 220 mV, respectively,

which is followed by a third oxidation at 940 mV (10a) or at

−

electrolyte 0.1 M [n-Bu N][PF ], v = 100 mVs , Pt working and

counter electrode, Ag/AgCl reference electrode, referenced to

decamethylferrocene E = −552 mV [vs ferrocene E (Fc/Fc ) = 0

V]).

00 mV (10k). The reason for this deviating behavior lies in

the redox active nature of these substituents (dimethylamino

and phenothiazinyl). Consequently, the second oxidation of

0a does not lead to a thiazine centered dication but a cyanine-

type coupled conjugation embedding the thiazine nitrogen and

the dimethylamino groups. The third oxidation ﬁnally

incorporates the second dimethylamino group into the cationic

system, giving a coupled trication without forming an aromatic

thiazine dication. Phenothiazinyl substituted 10k behaves

similarly and undergoes primary oxidation presumably

localized on the BBTT core nitrogen. This leads to an

electronic decoupling of both substituents, which then undergo

simultaneous two one-electron oxidations. This is indicated by

highly intense peaks in the cyclic voltammogram (see Figure

B). The third observable transition very likely furnishes

dicationic phenothiazinyl substituents.

The oxidation potentials of compounds 10b−10j correlate

well with the respective Hammett substituent parameters σ

0/+1

(

Figure 3) and a LFER between E₀and σ can be readily

established (eq 1).

Figure 3. Linear correlation between the ﬁrst oxidation potentials of

3,9-di(hetero)aryl substituted BBTT 10b−10j and the Hammett

/+1

^E0

= 0.104V·σ − 0.053V; R = 0.98

(1)

parameters σ .

The remote substituent eﬀect in the BBTT redox system 10

is smaller than those of N-p-aryl substitutents on both BBTT

0.289 V). The greater impact of N-aryl substitution on the

thiazine oxidation in comparison to substitution on the benzo

core of BBTT supports the assumption that the initial

/+1

(

17) and the phenothiazine congeners 13 (BBTT, E

0/+1

.155 V·σ + 0.108 V; phenothiazines, E

= 0.197 V·σ +

003

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oxidation, occurring on the thiazine part, is predominantly

governed by the electronic nature of the N-aryl substituent.

However, remote substitution also acts via conjugative

pathways onto the nitrogen centered thiazine oxidation. In

addition, σ_pcorrelations indicate a joint transmittance of

electronic eﬀects via resonance and ﬁeld eﬀects, as often seen

solution and were therefore studied by UV/vis and emission

spectroscopy (Table 4).

All 3,9-di(hetero)aryl substituted compounds 10 experience

signiﬁcant bathochromic shifts of the longest wavelength

absorption bands with increasing substituent acceptor strength

(Figure 6) and appear in a range between 440 and 496 nm

with molar decadic absorption coeﬃcients ε in a range

for phenothiazines. However, conjugatively placing strongly

electron releasing amino and phenothiazinyl substituents on

the benzo core changes the electronic ground state structure

considerably. Indeed, upon oxidation amino- and phenothia-

zinyl-substituted derivatives generate highly delocalized,

coupled cyanine-type and decoupled triradical cations. Based

−

−1

between 11200 and 20000 L mol cm . In addition, however

with the exception of nitro derivative 10j, all compounds 10

ﬂuoresce with signiﬁcantly higher quantum yields than their

unsubstituted BBTT predecessors with Φ

47%.

between 32 and

on a very good correlation (R = 0.98), a substituent parameter

Furthermore, the absorption and emission maxima of 10b−

−

σ for the 10-hexyl-10H-phenothiazin-3-yl substituent can be

10j correlate with Hammett substituent parameters σ

0/+1

derived. Insertion of E₀(10k) = −0.07 V into eq 1 calculates

σ_pfor the 10-hexyl-10H-phenothiazin-3-yl substituent to

(Figure 9) and linear free enthalpy relationships between

the longest wavelength absorption and emission maximum

−

0.16.

energies ν

established (eqs 2 and 3).

ax,abs and ν

ax,em, respectively, and σ

can be

Bis(di(hetero)aryl amino substitution in the 3- and 9-

position of the BBTT core further shifts the ﬁrst oxidation

potentials anodically (Table 2). For the diphenylamino

derivatives 12a and 12b, a third oxidation potential at 520

and 880 mV appears, while the oxidation behavior of

phenothiazinyl derivative 12c is more complex. The cyclic

voltammogram of compound 12c reveals a multistep redox

system with up to six separated reversible one-electron

oxidations in a range from −0.06 to 1.02 V (referenced to

ferrocene) (Figure 4 ).

= −1371 cm ·σ_p⁻₊₂₂₅₁₄_c_m−1_;R = 0.86

−1

max,abs

(

= −1112 cm ·σ ₊₁₈₃₉₄_c_m−1_;R = 0.91

−1

−

max,em

The correlation with σ_p⁻parameters indicates that for both

the longest wavelength absorption and ﬂuorescence maxima,

an eﬀective delocalization by charge transfer from the BBTT

core upon excitation is predominantly favored by acceptor

moieties.

In addition to luminescence in solution, compounds 10a−

0i,k also intensively ﬂuoresce in the solid state (Figures 10

and 11).

Fluorescence and absorption measurements of the generic

derivatives 10b, 10d, and 10i revealed bathochromic shifts of

both absorption and emission bands in a range between 0.1

and 1 eV relative to the corresponding maxima in solution

(

Tables 4 and 5). The absorption band redshifting from

solution to the solid state further depends on the substituent

pattern. With bands of donor-substituted 10b and 10d shifted

from approximately 440 nm to approximately 460 nm, it

−

represents a bathochromic shift of 950 cm (or 0.118 eV).

This eﬀect is signiﬁcantly stronger for the cyano-substituted

derivative 10i. Here the band at 467 nm in solution appears at

505 nm in the solid state, representing a shift of 1600 cm⁻(or

0.198 eV). A comparable value is determined for nitro-

substituted 10j, which experiences a redshift from 496 to 541

Figure 4. Cyclic voltammogram (CVs) of 3,9-bis(di(hetero)-

arylamino substituted BBTT 12 (CVs recorded in CH Cl , at RT,

−

electrolyte 0.1 M [n-Bu N][PF ], v = 100 mVs , Pt working and

counter electrode, Ag/AgCl reference electrode, referenced to

−1

nm (1700 cm or 0.211 eV). These bathochromic shifts in

decamethylferrocene E = −552 mV [vs ferrocene E (Fc/Fc ) = 0

solid state can be explained by the crystallization behavior, as

V]).

previously discussed. Increased intermolecular interactions in

the solid state causes the BBTT core system to planarize,

which ultimately leads to a leveraged HOMO energy level. As a

consequence, the HOMO−LUMO gap becomes smaller and

absorption and emission are shifted bathochromically. The

Comparison of the electrochemical behavior of the new

derivatives 10 and 12 to their predecessors reveals the strong

impact of the substitution modes. The (hetero)aryl substituted

derivatives 10 range similarly to the unsubstituted BBTTs 17

and do not exceed the anti,anti-dithienothiazines 14. The

bis(di(hetero)arylamino) substituted derivatives 12 however

outperform all their congeners 13 and 14 with oxidation

potentials lowered, thus HOMO energy level raised by 0.18 eV

compared to dithienothiazines 14 (Table 3).

Stokes shifts Δν of the solid-state ﬂuorescence increase by

−

approximately 1000 cm , again, due to the shorter distance

intermolecular interactions in the solid state are larger than in

solution. Only compound 10i is an exception in this series with

−

a slight decrease of ΔΔν (−100 cm ). The intersection of the

normalized absorption and emission spectra gives the optical

band gap ΔE_g_,_o_p_t. Comparing solid-state ΔE_g_,_o_p_tto the zero

point transition energy ΔE as obtained from the solution

Photophysical Properties. The ﬁrst generation of anti-

anti BBTT already revealed unexpected photophysical proper-

ties. The novel 3,9-disubstituted anti-anti BBTT 10 (Figures

and 6) and 12 (Figures 7 and 8) display intense emission in

spectra (Table 4) indicates a narrowing optical band gap by

about 0.2−0.3 eV.

004

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Article

Table 3. Oxidation Potentials and HOMO Energies of Representative Compounds for Phenothiazines (13), Dithienothiazines

(14), and BBTT (17/10d/12b)

−3

Lowest potentials and HOMO-levels are highlighted in bold. Recorded in CH Cl at RT, c = 10 M, referenced to internal standard

0/+1

decamethylferrocene E = −552 mV (vs ferrocene E (Fc/Fc ) = 0 V). Determined from the electrochemical data (E

= −(E₀+ 4.80 eV).

HOMO

Figure 5. 3,9-Di(hetero)aryl substituted BBTT 10a−10j under

daylight (top) and under UV light (bottom) (in CH Cl , c(10) =

Figure 7. 3,9-Bis(di(hetero)arylamino)substituted anti-anti BBTT 12

under daylight (top) and under UV light (bottom) (in CH Cl , c(12)

−

M, hand-held UV lamp. λ _e _x _c = 365 nm at T = 298 K).

−

10 M, hand-held UV lamp. λ _e _x _c = 365 nm at T = 298 K).

Figure 8. Normalized absorption and emission spectra of 3,9-

bis(di(hetero)arylamino)substituted anti-anti BBTT 12 (recorded in

−

−1

CH Cl c(12) = 10 mol L at T = 298 K).

with the increasing electron density imposed by the strongly

electron releasing di(hetero)arylamino substituents.

Figure 6. Normalized absorption and emission spectra of 3,9-

di(hetero)aryl substituted BBTT 10 (recorded in CH Cl c(10) =

In comparison to 3,9-di(hetero)aryl substituted derivatives

0, the ﬂuorescence quantum yields of 3,9-bis(di(hetero)aryl-

amino) substituted anti-anti BBTT 12 drop signiﬁcantly to

6−17% (Table 4). This is in accordance with the quantum

yield of the unsubstituted derivative (Φ = 24% (vs coumarin

−

−1

mol L at T = 298 K).

In the series of the three 3,9-bis(di(hetero)arylamino)-

substituted anti-anti BBTT 12, the longest wavelength

153 in MeOH)).

absorption maxima appear between 421 to 433 nm (Figure

Comparison of the BBTT derivatives with the predecessor

families of phenothiazine and dithienothiazine reveals some

trends in their photophysical characteristics. The absorption

) with molar decadic absorption coeﬃcients ε between 5000

and 23200 L mol cm (Table 4). This blue shift correlates

−

−1

005

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Article

Table 4. Selected Photophysical Properties of 3,9-

Disubstituted anti-anti BBTT 10 and 12

^λmax,abs [nm]

λ_m_a_x_,_e_m[_bnm]

(Φ_f)

Δν

ΔE

0,0

(ε [L mol cm⁻¹])^a

−

[cm

−1

]

[eV]

cmpd

337 (12600), 433 (6400)

545 (0.23)

538 (0.38)

541 (0.35)

540 (0.32)

542 (0.38)

541 (0.43)

549 (0.45)

556 (0.46)

575 (0.43)

583 (0.42)

4700

4100

4200

3900

4100

4300

2.492

2.444

2.451

2.457

2.436

2.422

2.442

2.384

2.338

2.311

2.066

2.423

2.479

2.689

2.477

0a 323 (70900), 440 (16500)

0b 290 (71900), 441 (12200)

0c 278 (71600), 446 (13400)

0d 274 (52000), 443 (10800)

0e 286 (56600), 443 (11200)

292 (54900), 448 (11500)

0g 286 (60500), 454 (11200)

0h 299 (56300), 462 (16000)

0k 272 (67300), 442 (14300)

2a 319 (51900), 433 (10600)

2b 316 (87700), 421 (23200)

2c 324 (15000), 435 (5000)

Figure 10. Powders of compounds 8a and 10b, 10d, and 10i under

daylight (top) and under UV light (bottom) (hand-held UV lamp, λ_e_x_c

299 (56300), 467 (17900)

314 (45100), 496 (20000)

365 nm).

545 (0.47)

540 (0.17)

524 (0.16)

4300

3900

4700

4200

531 (0.31)

−5

−1

Recorded in CH Cl , c(8, 10, 12) = 10 mol L at T = 298 K.

−7

−1

Recorded in CH Cl , c(8, 10, 12) = 10 mol L at T = 298 K,

quantum yields for 10 were determined by a relative method with

coumarin 6 (in EtOH, Φ = 0.78 ) and coumarin 343 (in EtOH, Φ

0.63 ) as standards; quantum yields for 8 and 12 were determined

by a relative method with coumarin 153 (in EtOH, Φ = 0.38 ) as a

standard. Δν

= _λ

− _λ

ΔE₀_,₀was determined from the

max,abs

max.em

intersection of normalized absorption and emission spectra for 8,

0a−10i,k, and 12 and from the intersection of the inﬂection point

tangent of 10j .

Figure 9. Linear correlation between the longest wavelength

absorption maximum energies (red) and the emission maximum

energies (black) of 3,9-di(hetero)aryl substituted BBTT 10b−10j and

−

Hammett parameters σ .

Figure 11. (A) Normalized solid state absorption spectra of

compounds 10b,d,i,j (solid lines, recorded as ﬁlms on glass substrate)

and emission spectra of compounds 10b,d,i (dashed lines, recorded as

loose powders). (B) Normalized solid state and solution absorption

bands of compounds 10 and 12 are signiﬁcantly red-shifted,

because of extending the π-systems, and 3,9-disubstituted anti-

anti BBTT 10 and 12 span a range between 420 nm (12b) and

(

solid lines) and emission spectra (dashed lines) of compound 10b

−

−1

solution spectra recorded in CH Cl , c(10b) = 10 mol L

−7

−1

absorption) and c(10b) = 10 mol L (emission) at T = 298 K).

70 nm (10h). The absorptions of some derivatives fall into

the same range as their phenothiazine and dithienothiazine

congeners. More striking, however, is the emission behavior of

BBTTs in general and more speciﬁcally of 3,9-disubstituted

anti-anti BBTTs. While generic phenothiazines 13 luminesce

phenyl substitution, the ﬂuorescence quantum yields increases

from 24 (compound 17) to 38% (compound 10d).

Calculated Electronic Structure. A deeper insight into

the absorption behavior of 3,9-disubstituted anti-anti BBTTs

was sought by TD(DFT) calculations on the three selected

generic structures 10a, 10d, and 10i representing electron-rich,

weakly and syn,syn-dithienothiazine 14 generally does not,

anti,anti-DTTs display weak ﬂuorescence, and BBTTs

become strongly emissive (Table 6). Upon benzo core

006

J. Org. Chem. 2021, 86, 8000−8014

The Journal of Organic Chemistry

Article

Table 5. Selected Solid-State Photophysical Properties of

Compounds 8a and 10b,d,i,j

further to the 3- and 9-aryl substituents according to the

analysis of the computed Kohn−Sham FMOs (Figure 12).

[cm⁻¹

cmpd λ_m_a_x_,_a_b_s[nm]

λ_m_a_x_,_e_m[nm] (Φ_f)

Δν

]

ΔE_g_,_o_p_t[eV]

CONCLUSION

■

440

460

456

505

541

582 (0.12)

596 (0.19)

587 (0.18)

641 (0.02)

5600

5000

4900

4200

2.238

2.181

2.236

2.059

1.773

In conclusion, starting from commercially available benzo[b]-

thiophene, we developed a novel four-step synthesis of 3,9-

dibromo anti-anti bis[1]benzothieno[1,4]thiazines (BBTT) in

a good overall yield of 40%. With this key building block in

hand, π-extended 3,9-disubstituted BBTT derivatives can be

eﬃciently synthesized by Suzuki and Buchwald−Hartwig cross

coupling reactions in good to excellent yields. The title

compounds are reversible redox chromophores with low

−

Recorded as ﬁlm on glass surface at T = 298 K. Recorded scattering

light from excitation at λ_m_a_x_,_a_b_sat T = 298 K, solid state ﬂuorescence

quantum yields were determined by an absolute method.

Δν

= _λ

− _λ

^Δ^Eg,opt. was determined from intersection of

0/+1

max,abs

max.em

tunable oxidation potentials at E₀= −0.15 to 0.05 V for

the 3,9-di(hetero)aryl substituted BBTT series and at E

0.34 to 0.06 V for the 3,9-bis(di(hetero)arylamino

/+1

normalized absorption and emission spectra. Compound 10j exhibits

no detectable emission in the solid state.

−

substituted BBTT derivatives. They are also tunable in their

absorption behavior with the longest wavelength absorption

bands between 450 and 500 nm, and they are as well as intense

green to orange luminophores with ﬂuorescence quantum

yields exceeding 40%. In addition, crystal structures reveal

predominantly maintained planarity in the solid state. The

comparison to phenothiazines and dithienothiazines reveals

that the 3,9-diaryl substitution additionally expands the π-

electron delocalization of BBTT derivatives and particularly

lead to systems with enhanced emission intensity. The

electronic structure correlates with Hammett substituent

parameters according to the physical organic structure−

property relationship and allows prediction of electronic

properties for weakly electron-releasing to strongly electron-

withdrawing remote substituents. Experimentally determined

photophysical properties can be plausibly rationalized by

TD(DFT) calculations and open new alleys to a rational

design of molecular emitters and charge transport materials.

Studies directed to approach and design electron-rich emitters

on the basis of conjugation expanded anti-anti bis[1]-

benzothieno[1,4]thiazines are currently underway.

electroneutral, and electron-deﬁcient substitutions. Geometry

optimizations were carried out using Gaussian 09 with the

B3LYP functional and 6-31G basis set. The polarizable

continuum model (PCM) was used to reﬂect the eﬀects of

dichloromethane as a solvent of the measurements. The

optimized geometries all exhibit a folded structure along the

S−N axis of approximately 145−150°, while the phenyl

substituents again twist the BBTT planes with a torsion angle

of 33−35°. These values represent the solvated molecular

structures and diﬀer from the experimentally obtained crystal

structure geometries. According to TD(DFT) calculations, the

experimentally observed longest wavelength absorption bands

can be assigned to HOMO−LUMO transitions (Table 7).

As shown in Figure 12, the HOMO coeﬃcient density

resides predominantly on the central thiazine core, independ-

ent of the remote substituents’ electronic nature. The LUMO

coeﬃcient distribution however is not uniform but depends on

the electron releasing or withdrawing properties of the

substituents. The LUMO coeﬃcient density extends into aryl

rings in all cases, however, with a variable intensity. This is in

agreement with the observation that the aryl substituents only

exert a minor inﬂuence on the absorption and emission

maxima of compounds 10, unless an acceptor substituent is

installed. Apparently, BBTT’s donor strength overrides the

donor capacity of other remote donors. Remote acceptor

substitution in turn leads to a considerable delocalization of

the electron density. Strongly increasing absorption coeﬃcients

EXPERIMENTAL SECTION

■

General Considerations. Reactions were carried out in a

nitrogen atmosphere in heat-gun dried Schlenk glassware. Oil baths

were used as a heating source for all thermal reactions. Dry solvents

were obtained from a solvent drying system. Commercially available

reagents 7, 9, and 11, catalysts, and ligands were purchased and

employed without further puriﬁcation. Bis(phenylsulfonyl)sulﬁde

(

oscillatory strength) in the case of acceptor-substituted

(

BPSS) (4) was synthesized according to the literature. The

system 10i additionally supports this assumption (Table 7).

The electronic nature of the longest wavelength absorption

bands predominantly represents a charge transfer character

from the central thiazine core to the benzo moieties and even

puriﬁcation of the crude products was carried out by column

chromatography with silica gel 60 (particle size 0.04−0.063 mm)

from Macherey and Nagel. Crude products were adsorbed on Celite

545 (0.02−0.10 mm) prior to chromatographic puriﬁcation.

Table 6. Relevant Photophysical Properties of Representative Compounds for Phenothiazines (13), Dithienothiazines (14),

and BBTT (17/10d)

Most bathochromically shifted bands and highest ﬂuorescence quantum yield are highlighted in bold.

007

J. Org. Chem. 2021, 86, 8000−8014

The Journal of Organic Chemistry

Computed using Gaussian 09 (B3LYP/6-31G with PCM).

Article

Table 7. TD(DFT) Calculations (B3LYP/6-31G) of the UV−Visible Absorption Maxima of Compounds 10a, 10d, and 10i

Using PCM with CH Cl as Dielectric Medium

λ_m_a_x_,_e_x_p[nm] (ε [L mol⁻cm⁻¹])^a

λ_m_a_x_,_c_a_l_c_d[nm]

oscillator strength

most dominant contributions

cmpd

NMe₂

440 (16500)

430

327

422

336

462

353

0.9614

0.4319

0.4905

0.0321

0.6779

0.0169

HOMO → LUMO (91%)

HOMO − 1 → LUMO + 1 (86%)

HOMO → LUMO (96%)

HOMO → LUMO + 2 (74%)

HOMO → LUMO (95%)

HOMO → LUMO + 2 (78%)

23 (70900)

443 (10800)

38 (13600)

467 (20000)

51 (16600)

Figure 12. Selected Kohn−Sham FMOs of BBTT 10a, 10d, and 10i (B3LYP/6-31G and PCM with CH Cl as solvent).

Preparative ﬂash column chromatography was conducted with silica

gel (0.04−0.063 mm) and a pressure of 1.0 bar (nitrogen) was

employed. The reaction progress was observed qualitatively using

TLC silica gel 60 F254 aluminum sheets. The spots were detected

with UV light at 254 and 365 nm and with iodine vapor. Chemical

140.2 (C ). MS (EI): 374 ([C H Br S] , 38), 372

8 3 3

quat

([C H Br Br S] , 100), 370 ([C H Br BrS] , 98), 368

([C H Br S] , 34), 293 (([C H Br S] , 15), 291

([C H Br BrS] , 31), 289 ([C H Br S] , 15), 212

([C H BrS] , 41), 210 ([C H BrS] , 42), 131 ([C H S] , 36),

106 (23), 105 (31), 106 (23), 105 (31), 93 (17), 87 (33), 86 (17), 85

(11), 8 (12), 69 (11), 65 (14), 61 (11). IR: ν [cm ] 3101 (w), 3080

(w), 3062 (w), 2953 (w), 1489 (m), 1384 (m), 1371 (m), 1311 (m),

1292 (m), 1192 (m), 1087 (m), 1053 (m), 1026 (w), 985 (m), 891

(s), 860 (m), 800 (s), 785 (m), 773 (m), 732 (m). Anal. Calcd for

C H Br S (370.9): C 25.91, H 0.82, S 8.64. Found: C 25.65, H 0.95,

shifts δ in the H and C{ H} NMR spectra are reported in ppm

−

relative to the signal of the remaining proton resonances of the

deuterated solvent (THF-d : H δ 1.72, 3.58, C δ 25.31, 67.21;

CDCl : H δ 7.26, C δ 77.16; DMSO-d : H δ 3.58, C δ 25.31).

The assignments of C_q_u_a_t, CH, CH , and CH signals were made by

using DEPT spectra. Melting points (uncorrected values) were

measured using a Buchi Melting Point B-535 apparatus.

S 8.73.

Synthesis of Precursor 6. Starting from benzo[b]thiophene (1)

precursor 6 was synthesized in four steps.

3,6-Dibromobenzo[b]thiophene (3). In a ﬂame-dried 500 mL two-

neck ﬂask with a magnetic stir bar, 2,3,6-tribromobenzo[b]thiophene

(2) (37.1 g, 100 mmol, 1.00 equiv) was dissolved in anhydrous THF

(300 mL) and the solution was cooled to −78 °C. Upon vigorous

stirring, a 1.52 M n-butyllithium solution in n-hexane (66.2 mL, 100

mmol, 1.00 equiv) was slowly added via syringe. After stirring for 30

min at −78 °C, methanol (10 mL) was added and the reaction

mixture was warmed up to room temperature. The solvent was

removed in vacuo and the crude product was adsorbed on Celite

before being puriﬁed by column chromatography (eluent: n-hexane/

THF = 10/1). Recrystallization from hexanes gave 3 as colorless

,3,6-Tribromobenzo[b]thiophene (2). In a 1 L three-neck ﬂask

with a magnetic stir bar, condenser, and dropping funnel, benzo[b]-

thiophene (49.1 g, 366 mmol, 1.00 equiv) and potassium acetate (145

g, 1.65 mol, 4.50 equiv) were suspended in dry dichloromethane (490

mL). Upon vigorous stirring, elemental bromine (84.5 mL, 264 g,

1.65 mol, 4.50 equiv) was added via dropping funnel. During the

addition, the reaction mixture’s viscosity increased strongly. After

complete addition, the reaction mixture was heated to reﬂux for 16 h

before being quenched by addition of aqueous sodium sulﬁte solution.

The resulting precipitate was ﬁltered oﬀ and dissolved in dichloro-

methane. The aqueous phase was separated and extracted with

dichloromethane. The combined organic phases were washed with

saturated sodium chloride solution and dried with anhydrous

magnesium sulfate, and the solvent was removed in vacuo.

crystals (28.6 g, 98 mmol, 98%), Mp 81−82 °C, R : 0.51 (n-hexane).

H NMR (300 MHz, CDCl ) δ 7.41 (s, 1 H), 7.57 (dd, J = 8.6, J =

1.7 Hz, 1 H), 7.69 (dd, J = 8.6, J = 0.6 Hz, 1 H), 8.00 (dd, J = 1.7,

J = 0.6 Hz, 1 H). C{ H} NMR (75 MHz, CDCl ) δ 107.7 (C_q_u_a_t),

119.7 (C_q_u_a_t), 124.1 (CH ), 124.4 (CH ), 125.3 (CH ), 128.7 (CH ),

Recrystallization from ethyl acetate gave 2 as light brown crystals

136.6 (C ), 140.1 (C ). MS (EI): 294 ([C H Br S] , 48), 292

quat

quat 8 4 2

(

96.1 g, 259 mmol, 71%), Mp 120−121 °C, R : 0.55 (n-hexane). H

([C H Br BrS] , 100), 290 ([C H Br S] , 51), 213

8 4 8 4 2

NMR (300 MHz, CDCl ) δ 7.53 (dd, J = 8.6, J = 1.7 Hz, 1 H), 7.60

dd, J = 8.6, J = 0.6 Hz, 1 H), 7.87 (dd, J = 1.7, J = 0.6 Hz, 1 H).

C{ H} NMR (75 MHz, CDCl ) δ 111.7 (C_q_u_a_t), 114.9 (C_q_u_a_t),

([C H BrS] , 13), 211 ([C H BrS] , 13), 132 ([C H S] , 56),

8 4 8 4 8 4

−1

(

93 (11), 87 (12), 82 (10), 66 (15). IR: ν [cm ] 3101 (w), 3055 (w),

2954 (w), 2924 (w), 1585 (m), 1533 (m), 1485 (m), 1446 (m), 1431

(m), 1382 (m), 1315 (m), 1295 (m), 1276 (m), 1197 (m), 1149 (m),

19.9 (C_q_u_a_t), 124.5 (CH ), 124.6 (CH ), 129.2 (CH ), 136.5 (C_q_u_a_t),

3 3 3

008

J. Org. Chem. 2021, 86, 8000−8014

The Journal of Organic Chemistry

Article

132 (m), 1080 (m), 1064 (m), 1047 (m), 954 (w), 927 (s), 858 (s),

39 (w), 800 (s), 765 (s), 746 (m), 727 (m), 704 (m), 690 (m). Anal.

50.0 mmol, 1.00 equiv) was dissolved in acetone (250 mL).

Potassium carbonate (10.4 g, 150 mmol, 3.00 equiv), potassium

iodide (415 mg, 2.50 mmol, 5.00 mol %), and 11-(bromomethyl)-

tricosane (25.0 g, 60.0 mmol, 1.20 equiv) were added and the reaction

mixture was reﬂuxed for 48 h. After completion, the mixture was

ﬁltrated, the solvent was reduced in vacuo, and concentrated

hydrochloric acid (100 mL) was added. The mixture was heated to

110 °C for 21 h, then neutralized by addition of sodium hydroxide

solution and extracted three times with dichloromethane. The crude

product was adsorbed on Celite and puriﬁed by column

chromatography (eluent: n-hexane/THF = 10/1). The product 7b

Calcd for C H Br S (292.0): C 32.91, 1.38, S 10.98. Found: C 33.18,

H 1.58, S 11.24.

Bis(6-bromobenzo[b]thiophen-3-yl)sulfane (5). In a ﬂame-dried

00 mL two-neck ﬂask with magnetic stir bar was placed 3,6-

dibromobenzo[b]thiophene (3) (23.4 g, 80.0 mmol, 1.00 equiv) and

dissolved in diethyl ether (320 mL). The solution was cooled to −78

C, leading to a turbid solution. Then a 1.52 M solution of n-

butyllithium in hexane (52.6 mL, 80.0 mmol, 1.00 equiv) was added,

and the reaction mixture was stirred for 2 h at −78 °C, before

bis(phenylsulfonyl)sulﬁde (BPSS) (4) (12.6 g, 40.0 mmol, 0.50

equiv) were added. The reaction mixture was then stirred and allowed

to come to room temperature over the course of 16 h. After the

reaction was complete, water was added and the mixture was ﬁltered.

The aqueous phase was extracted three times with ethyl acetate, and

the combined organic phases were washed with saturated sodium

chloride solution and dried with magnesium sulfate. The crude

product was adsorbed on Celite and puriﬁed via column

chromatography (eluent: n-hexane/ethyl acetate = 10/1) to give 5

was obtained as a brown oil (14.5 g, 32.5 mmol, 65%), R : 0.59 (n-

hexane/THF = 1/1). H NMR (300 MHz, CDCl ) δ 0.78−0.97 (m,

6 H), 1.12−1.53 (m, 40 H), 1.72 (q, J = 5.6 Hz, 1 H), 3.40 (s, 2 H),

3.75 (d, J = 5.7 Hz, 2 H), 6.60−6.68 (m, 2 H), 6.70−6.78 (m, 2 H).

C{ H} NMR (75 MHz, CDCl ) δ 14.3 (CH), 22.9 (CH ), 27.0

(CH ), 29.51 (CH ), 29.52 (CH ), 29.80 (CH ), 29.83 (CH ), 29.85

(CH ), 30.2 (CH ), 31.5 (CH ), 32.1 (CH ), 38.2 (CH ), 71.8

(CH ), 115.8 (CH), 116.5 (CH), 139.8 (C_q_u_a_t), 152.8 (C_q_u_a_t). MS

(EI): 445 ([M] , 5), 109 (C H NO] , 100).

as brown solid (14.5 g, 31.8 mmol, 80%), Mp 116−117 °C, R : 0.25

Synthesis of 3,9-Dihalogenated bis[1]benzothieno[1,4]-

thiazines 8. General Procedure (GP 1) for the Synthesis of 3,9-

Dibrominated anti-anti Bis[1]benzothieno[1,4]thiazines 8. In an

oven-dried and nitrogen ﬂushed screw-cap Schlenk tube with magnetic

stir bar, bis(2,6-dibromobenzo[b]thiophen-3-yl)sulfane (6) 1.00

equiv), bis(dibenzylideneacetone)palladium(0) (3.00 mol %), 2,2′-

bis(diphenylphosphano)-1,1′-binaphthyl (BINAP, 5.00 mol %), and

sodium tert-butoxide (3.00 equiv) were placed and nitrogen ﬂushed

before dry toluene (4 mL/mmol) and aniline 7 (1.00 equiv) were

added. The reaction mixture was degassed for 5 min and then heated

to 100 °C for 16 h. After a complete reaction, water was added and

the aqueous phases were extracted three times with dichloromethane.

The organic phases were washed with saturated sodium chloride

solution, dried with magnesium sulfate and adsorbed on Celite. The

crude product 8 was puriﬁed by column chromatography under a

nitrogen atmosphere.

(n-hexane). H NMR (500 MHz, CDCl ) δ 7.30 (s, 2 H), 7.50 (dd, J

8.6, J = 1.8 Hz, 2 H), 7.73 (d, J = 8.5 Hz, 2 H), 8.00 (dd, J = 1.8,

.5 Hz, 2 H). ¹³C{ H} NMR (126 MHz, CDCl ) δ 119.4 (C_q_u_a_t),

(

23.8 (CH), 125.0 (C_q_u_a_t), 125.7 (CH), 128.2 (CH), 128.4 (CH),

37.1 (C_q_u_a_t), 141.6 (C ). MS (EI): 459 ([ C CH Br S ] ,

quat

79 81

2 3

1), 458 ([C H Br S ] , 57), 457 (([ C CH Br BrS ] , 26),

56 ([C H Br BrS ] , 100), 455 ([ C CH Br S ] , 16), 454

2 3

([C

Br S ] , 48), 377 ([C₁₆H₈BrS ] , 32), 376

2 3 3

(

[ C CH₈BrS ] , 27), 375 ([C H BrS ] , 28), 374 (19), 344

12), 342 (10), 298 (13), 297 (15), 296 ([C H S ] ,74), 295 (12),

64 (16), 251 (14), 201 (14), 199 (14), 164 ([C H S ] , 16), 148

8 3

4 2

(

40), 132 ([C H S] , 31), 120 (35), 119 (15), 93 (13), 88 (12), 87

8 4

−

12), 82 (14), 69 (15). IR: ν

010 (w), 2953 (w), 2922 (w), 1577 (m), 1539 (m), 1436 (m), 1381

m), 1363 (w), 1303 (m), 1246 (m), 1132 (m), 1080 (m), 1051 (m),

54 (m), 920 (w), 862 (m), 827 (m), 806 (s), 790 (s), 775 (s), 742

m), 709 (m), 690 (w), 615 (m). Anal. Calcd for C H Br S (456.2):

[cm ] 3107 (w), 3089 (w), 3064 (w),

N-(4-tert-Butylphenyl)bis(6-bromobenzo[b]thieno)[2,3-b:3′,2′-

e][1,4]thiazine (8a). The synthesis was conducted according to GP 1

from 6 (9.21 g, 15.0 mmol, 1.00 equiv), sodium-tert-butoxide (4.32 g,

2 3

C 42.12, H 1.77, S 21.08. Found: C 42.41, H 1.74, S 21.23.

Bis(2,6-dibromobenzo[b]thiophen-3-yl)sulfane (6). In a 250 mL

round-bottom ﬂask with a magnetic stir bar was placed bis(6-

bromobenzo[b]thiophen-3-yl)sulfane (5) (13.7 g, 30.0 mmol, 1.00

equiv) and dissolved in DMF (75 mL). The solution was then cooled

to 0 °C, and in the dark was added N-bromosuccinimide(21.4 g, 120

mmol, 4.00 equiv) in ﬁve equal portions. The reaction mixture was

stirred for 90 min at 0 °C. After a complete reaction, water and a

saturated aqueous solution of sodium sulﬁte were added and the

formed precipitate was ﬁltered oﬀ and washed several times with

water. After drying at reduced pressure, the light orange crude

product was washed with 50 mL of diethyl ether and dried again to

give 6 as a colorless solid (17.5 g, 28.5 mmol, 95%), Mp 232−233 °C,

45.0 mmol, 3.00 equiv), Pd(dba) (259 mg, 0.450 mmol, 3.00 mol

%), BINAP (467 mg, 0.450 mmol, 5.00 mol %), and 4-tert-

butylaniline (7a, 1.49 g, 10.0 mmol, 1.00 equiv) in dry toluene (60

mL). The crude product was puriﬁed via column chromatography

(eluent: n-hexane/dichloromethane = 2/1 + 2% NEt ), the aﬀorded

brown amorphous solid was dissolved in a small volume of

dichloromethane and precipitated in 100 mL of acetone. Filtration

and drying gave 8a as a bright orange solid (8.65 g, 14.4 mmol, 96%),

Mp 284−285 °C (dec.), R

: 0.28 (n-hexane/ethyl acetate = 50/1). H

NMR (600 MHz, THF-d

) δ 1.40 (s, 9 H), 7.20 (dd, J = 8.5, J = 2.4

Hz, 2 H), 7.49 (dt, J = 8.4, J = 2.2 Hz, 2 H), 7.55−7.62 (m, 2 H),

7.66 (dt, J = 8.6, J = 3.1 Hz, 2 H), 7.78 (t, J = 2.1 Hz, 2 H).

R : 0.45 (n-hexane). H NMR (500 MHz, CDCl ) δ 7.42 (dd, J =

C{ H} NMR (151 MHz, THF-d ) δ 31.7 (CH ), 35.8 (Cquat), 99.0

8 3

.6, J = 1.8 Hz, 2 H), 7.60 (d, J = 8.6 Hz, 2 H), 7.84 (d, J = 1.7 Hz,

(Cquat), 117.0 (Cquat), 121.3 (CH), 125.5 (CH), 128.5 (CH), 129.1

H). ¹³C{ H} NMR (126 MHz, CDCl ) δ 119.6 (C_q_u_a_t), 122.1

(CH), 129.5 (CH), 136.0 (C_q_u_a_t), 136.1 (C_q_u_a_t), 140.6 (C ), 143.5

quat

(

C_q_u_a_t), 124.0 (CH), 124.6 (C_q_u_a_t), 124.7 (CH), 129.1 (CH), 137.8

C_q_u_a_t), 140.6 (C ). MS (EI): 616 ([C H Br Br S ] , 12), 614

[C H Br₂Br S ] , 15), 457 (11), 456 ([C H Br S ] , 52), 455

21), 454 ([C H Br BrS ] , 100), 452 ([C H Br S ] , 43), 376

(C_q_u_a_t), 154.4 (C_q_u_a_t). MS (EI): 604 (15), 603 ([C H Br NS ] ,

26 19 2 3

50), 602 (29), 601 ([C₂₆H₁₉Br BrNS ] , 100), 599

([C H Br NS ] , 40), 470 ([C H Br NS ] , 25), 468

([C H Br BrNS ] , 48), 466 ([C H Br NS ] , 22), 456

16 6 3 16 6 2 3

([C H Br S ] , 42), 455 ([C CH₆Br BrS ] , 14), 454

([C H Br BrS ] , 74), 452 ([C H Br S ] , 35), 389

16 6 3 16 6 2 3

BrNS , 19), 387 ([C₁₈H₁₆BrNS , 17), 375

([C H BrS , 19), 373 ([C H BrS , 17), 310 (10), 295

quat

26 19

79 81

2 3 16 6 2 3

79 81

31), 375 (23), 374 (33), 373 (18), 295 (15), 294 (36), 250 (20),

16 6 2 3 15 3

49 (13), 244 (17), 242 (16), 228 (26), 27 (45), 226 (19), 212 (11),

00 (10), 188 (29), 187 (23), 163 (22), 148 (13), 147 (49), 131

([C₁₈

−

(20), 125 (13), 119 (37), 93 (15), 87 (19), 69 (14). IR: ν

[cm ]

18 16

074 (w), 2985 (w), 2931 (w), 2808 (w), 1575 (m), 1435 (m), 1369

([C₁₇CH S , 12), 294 ([C H S , 36), 280 (11), 250 (20), 249

(15), 228 (11), 227 (17), 188 (12), 186 (15), 147 ([C H N] , 22),

10 13

16 2 18 16 2

(

m), 1234 (m), 1134 (s), 1087 (s), 1051 (m), 995 (m), 906 (s), 858

s), 812 (s), 789 (s), 638 (m). Anal. Calcd for C H Br S (614.0): C

1.30, H 0.98, S 15.66. Found: C 31.47, H 0.88, S 15.78.

135 (16), 125 (13), 119 (19), 17 (13), 93 (11), 91 (12), 86 (10), 84

4 3

−

(13), 69 (11), 57 (10), 49 (13). IR: ν [cm ] 3103 (w), 3034 (w),

Synthesis of Precursor 7b. Precursor 7b was synthesized by

2985 (w), 2960 (m), 2900 (m), 2868 (w), 1564 (m), 1541 (m), 1508

(s), 1436 (s), 1406 (w), 1394 (m), 1361 (w), 1340 (w), 1307 (m),

1271 (s), 1234 (s), 1201 (w), 1188 (w), 1163 (w), 1130 (w), 1109

(w), 1082 (m), 1049 (m), 1018 (m), 997 (w), 950 (m), 943 (m), 896

Williamson ether synthesis from p-acetaminophenol.

-(2-Decyl-1-tetradecoxy)aniline (7b). In a 500 mL two-neck ﬂask

with a magnetic stir bar and condenser, p-acetaminophenol (7.56 g,

009

J. Org. Chem. 2021, 86, 8000−8014

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Article

(

w), 844 (m), 825 (w), 792 (s), 773 (s), 738 (m), 628 (w). Anal.

120.3 (C_q_u_a_t), 124.6 (CH), 128.2 (CH), 129.1 (CH), 129.6 (C_q_u_a_t),

135.4 (C_q_u_a_t), 137.9 (C_q_u_a_t), 141.5 (C_q_u_a_t), 141.9 (C_q_u_a_t), 151.2

(C_q_u_a_t), 153.6 (C ). MS (ESI) calcd. for C H N S : 681.2; Found:

Calcd for C H Br NS (601.4): C 51.92, H 3.18, N 2.33, S 15.99.

Found: 51.63, H 3.28, N 2.17, S 16.17.

N-(4-((2-Decyl-1-tetradecoxy)phenyl))bis(6-bromobenzo[b]-

thieno)[2,3-b:3′,2′-e][1,4]thiazine (8b). The synthesis was conducted

according to GP 1 from 4-(2-decyl-1-tetradecoxy)aniline (7b) (4.45

g, 10.0 mmol, 1.00 equiv). The crude product was puriﬁed via column

chromatography (eluent: n-hexane/THF = 100/1 + 2% NEt ), the

obtained yellow amorphous solid was washed in 10 mL of acetone.

Filtration and drying gave 8b as a bright yellow solid (3.96 g, 4.41

quat

42 39

3 3

−

681.4. IR: ν [cm ] 2959 (w), 2947 (w), 2897 (w), 2860 (w), 2805

(w), 1613 (m), 1593 (w), 1555 (m), 1522 (m), 1508 (s), 1479 (m),

1460 (s), 1443 (m), 1429 (w), 1412 (w), 1397 (w), 1358 (m), 1269

(m), 1242 (m), 1233 (m), 1204 (m), 1188 (w), 1167 (m), 1128 (w),

1109 (w), 1067 (m), 1055 (w), 1018 (w), 945 (m), 885 (w), 864

(w), 847 (w), 826 (m), 808 (s), 781 (w), 740 (w), 700 (w). Anal.

Calcd for C H N S (682.0): C 73.97, H 5.76, N 6.16, S 14.10.

3 3

mmol, 44%), Mp 91−92 °C, R : 0.18 (n-hexane). H NMR (300

Found: C 73.71, H 5.65, N 6.01, S 14.26.

MHz, THF-d ) δ 0.78−0.97 (m, 6 H), 1.18−1.63 (m, 40 H), 1.84 (d,

N-(4-tert-Butylphenyl)bis(6-(4-methoxyphenyl)benzo[b]thieno)-

[2,3-b:3′,2′-e][1,4]thiazine (10b). According to GP 2 with 4-

bromoanisole (9b) (281 mg, 1.50 mmol, 3.00 equiv), the crude

product was puriﬁed via column chromatography (eluent: n-hexane/

J = 6.2 Hz, 1 H), 3.97 (d, J = 5.5 Hz, 2 H), 7.09−7.17 (m, 2 H),

.19 (d, J = 8.5 Hz, 2 H), 7.50 (dd, J = 8.5, J = 1.8 Hz, 2 H), 7.52−

4 13 1

.60 (m, 2 H), 7.79 (d, J = 1.8 Hz, 2 H). C{ H} NMR (75 MHz,

THF-d ) δ 14.6 (CH), 23.7 (CH ), 28.0 (CH ), 30.5 (CH ), 30.80

dichloromethane = 2/1 + 2% NEt

) to give compound 10b as a bright

: 0.24

(n-hexane/THF = 5:1). H NMR (600 MHz, THF-d ) δ 1.41 (s, 9

(

CH ), 30.84 (CH ), 31.2 (CH ), 32.5 (CH ), 33.1 (CH ), 39.3

CH ), 72.1 (CH ), 99.0 (C_q_u_a_t), 116.9 (C_q_u_a_t), 117.1 (CH), 121.3

orange solid (204 mg, 0.311 mmol, 62%), Mp 302−303 °C, R

CH), 125.4 (CH), 129.5 (CH), 131.1 (CH), 135.6 (C_q_u_a_t), 136.0

), 136.2 (C ), 144.0 (C ), 161.7 (C ). MS (EI): 901

H), 3.80 (s, 6 H), 6.94−6.99 (m, 4 H), 7.35 (d, J = 8.3 Hz, 2 H),

7.54−7.59 (m, 4 H), 7.59−7.68 (m, 7 H), 7.82 (d, J = 1.6 Hz, 2 H).

quat

[ C C H Br NOS ] , 11), 900 ([ C CH₅₉Br NOS ] ,

C{ H} NMR (151 MHz, THF) δ 31.8 (CH ), 35.8 (Cquat), 55.6

7 ) , 8 9 9 ( [ C

B r N O S ] , ₇₉6 2 ) , 8 9 8

(CH ), 99.7 (Cquat), 115.2 (CH), 120.3 (CH), 120.4 (CH), 125.0

5 9

[ C CH₅₉⁷⁹Br NOS ] , 47), 897 ([C H Br BrNOS ] ,

(

(CH), 128.3 (CH), 128.8 (CH), 129.1 (CH), 129.8 (Cquat), 134.2

(Cquat), 136.0 (Cquat), 137.3 (Cquat), 141.2 (Cquat), 142.5 (Cquat),

46 59

1 3

7 9

0 0 ) , 8 9 6 ( [ C ₄₅C H ₅₉B r N O S ] , 2 3 ) , 8 9 5

2 3

[C H Br NOS ] , 41), 563 ([ C C H Br NOS ] , 16),

153.8 (Cquat), 160.5 (Cquat). MS (EI): 657 ([ C38

2 3

33NO

] ,

] , 100),

H23NO ] , 19), 522

62 ([ C CH Br NOS ] , 13), 561 ([C H Br NOS ] ,

0), 560 ([ C CH Br NOS ] , 12), 559 ([C H Br NOS ] ,

5), 470 ([C H Br NS ] , 17), 468 ([C H Br BrNS ] , 33),

66 ([C H Br NS ] , 15), 109 (17), 97 (16), 85 (31), 83 (20), 82

22), 656 ([ C39 CH33NO

] , 43), 655 ([C40

] , 15), 549 ([C40

] , 20), 479 (14), 329 (12), 328 (26). IR: ν [cm ]

H33NO S

22 10

625 ([C40

33OS

22 10

79 81

−1

([C30 20NO

3053 (w), 3030 (w), 2999 (w), 2954 (m), 2931 (w), 2900 (w), 1608

(m), 1555 (m), 1541 (m), 1508 (s), 1460 (s), 1437 (m), 1420 (m),

1397 (m), 1356 (m), 1289 (m), 1271 (s), 1252 (s), 1182 (s), 1113

(m), 1067 (m), 1038 (m), 1020 (m), 945 (m), 924 (m), 872 (m),

833 (s), 808 (s), 789 (m), 764 (m), 731 (m), 700 (m), 656 (m), 613

−

(

10), 71 (47), 69 (24), 57 (79), 56 (16), 55 (35). IR: ν

m), 2916 (s), 2850 (s), 1606 (w), 1581 (m), 1564 (m), 1544 (m),

506 (s), 1471 (m), 1446 (s), 1390 (m), 1379 (m), 1340 (m), 1276

m), 1246 (s), 1232 (s), 1168 (m)1,1 32 (w), 1101 (w), 1083 (m),

[cm ] 2953

(

051 (m), 1012 (m), 948 (m), 931 (m), 852 (m), 837 (m), 798 (s),

69 (s), 748 (m), 721 (m). Anal. Calcd for C H Br NOS (898.0):

(m). Anal. Calcd for C40H33NO S (655. 9): C 73.25, H 5.07, N 2.14,

2 3

S 14.66. Found: C 73.52, H 5.10, N 2.17, S 14.69.

C 61.53, H 6.62, N 1.56, S 10.71. Found: C 61.63, H 6.41, N 1.59, S

0.47.

General Procedure (GP 2) for the Synthesis of 3,9-Di(hetero)aryl

Substituted anti-anti Bis[1]benzothieno[1,4]thiazines 10. In a

ﬂame-dried and nitrogen ﬂushed 20 mL screw cap Schlenk-tube

with a magnetic stir bar was placed 8a (301 mg, 0.50 mmol, 1.00

equiv) and dissolved in 2 mL of anhydrous THF. After addition of

TMEDA (139 mg, 1.20 mmol, 2.40 equiv), the tube was closed and

heated via a heat gun until all substrate was dissolved, then cooled to

N-(4-tert-Butylphenyl)bis(6-(4-tert-butylphenyl)benzo[b]-

thieno)[2,3-b:3′,2′-e][1,4]thiazine (10c). According to GP 2 with 4-

tert-butylbromobenzene (9c) (320 mg, 1.50 mmol, 3.00 equiv), the

crude product was puriﬁed via column chromatography (eluent: n-

hexane/dichloromethane = 2/1 + 2% NEt

an orange solid (315 mg, 0.445 mmol, 89%), Mp 214−215 °C, R

) to give compound 10c as

0.47 (n-hexane/THF = 5:1). H NMR (300 MHz, THF-d ) δ 1.35 (s,

18 H), 1.42 (s, 9 H), 7.37 (dd, J = 8.3, 0.6 Hz, 2 H), 7.46 (d, J = 8.5

Hz, 4 H), 7.53−7.71 (m, 10 H), 7.86 (dd, J = 1.7, J = 0.6 Hz, 2 H).

C{ H} NMR (75 MHz, THF) δ 31.8 (CH ), 31.8 (CH ), 35.3

−

78 °C upon vigorous stirring, leading to slight precipitation. To the

cooled solution was added a solution of n-butyllithium in hexane

1.20 mmol, 2.40 equiv). After 15 min, trimethylborate (125 mg, 1.20

3 3

(C_q_u_a_t), 35.8 (C_q_u_a_t), 99.6 (C_q_u_a_t), 120.3 (CH), 120.7 (CH), 125.3

(CH), 126.7 (CH), 127.5 (CH), 128.3 (CH), 129.1 (CH), 135.3

(Cquat), 136.3 (Cquat), 137.4 (Cquat), 137.7 C(quat), 139.0 (Cquat),

141.0 (Cquat), 142.8 (Cquat), 150.9 (Cquat). MS (EI): 709

(

mmol, 2.40 equiv) was added and the reaction mixture was allowed to

come to room temperature. Then, Pd(PPh ) (28.9 mg, 25 μmol, 5.00

mol %), K CO (207 mg, 1.50 mmol, 3.00 equiv), Bu NCl (139 mg,

([ C44

([C46

([C36

45NS

] , 24), 708 ([ C45 CH45NS

] , 43), 707

1.50 mmol, 3.00 equiv), the aryl bromide 9 (1.50 mmol, 3.00 equivs)

45NS

] , 100), 575 ([ C35 CH31NS

] , 16), 561 (11), 560 (29), 545 (14), 346 (13), 325

] , 19), 574

and 2 mL of distilled H O were added and the reaction mixture was

32NS

heated to 100 °C for 16 h. After cooling to room temperature, water

was added, the mixture was diluted with dichloromethane, and the

phases were separated. The aqueous phase was extracted with

dichloromethane (3 × 20 mL), and the combined organic phases

were washed with brine and dried (anhydrous magnesium sulfate).

The crude product was adsorbed on Celite and puriﬁed by column

chromatography under a nitrogen atmosphere.

N-(4-tert-Butylphenyl)bis(6-(4-dimethylaminophenyl)benzo[b]-

thieno)[2,3-b:3′,2′-e][1,4]thiazine (10a). According to GP 2, with 4-

bromo-N,N-dimethylaniline (9a) (300 mg, 1.50 mmol, 3.00 equiv),

the crude product was puriﬁed via column chromatography (eluent:

(14), 311 (22), 57 (13). IR: 2956 (m), 2902 (w), 2864 (w), 1506 (s),

1456 (s), 1269 (s), 1234 (s), 837 (m), 806 (s). HRMS (ESI) m/z:

[M] calcd. for [C46

Calcd for C46

45NS

] : 707.2714; Found: 707.2708. Anal.

45NS

(708.1): C 78.03, H 6.41, N 1.98, S 13.58.

Found: C 77.81, H 6.18, N 1.89, S 13.33.

N-(4-tert-Butylphenyl)bis(6-phenylbenzo[b]thieno)[2,3-b:3′,2′-

e][1,4]thiazine (10d). According to GP 2 with bromobenzene (9d)

(

236 mg, 1.50 mmol, 3.00 equiv), the crude product was puriﬁed via

column chromatography (eluent: n-hexane/dichloromethane = 2/1 +

2% NEt ) to give compound 10d as a bright orange solid (267 mg,

0.450 mmol, 90%), Mp 296−297 °C, R : 0.45 (n-hexane/THF = 5:1).

) δ 1.41 (s, 9 H), 7.24−7.31 (m, 2 H),

n-hexane/dichloromethane = 2/1 + 2% NEt ) to give compound 10a

H NMR (300 MHz, THF-d

7.36−7.44 (m, 6 H), 7.56−7.73 (m, 10 H), 7.88 (dd, J = 1.7, J = 0.6

Hz, 2 H). C{ H} NMR (75 MHz, THF) δ 31.8 (CH ), 35.8 (C ),

as a bright orange solid (101 mg, 0.148 mmol, 30%), Mp 308−309

C, R : 0.23 (n-hexane/THF = 5:1). H NMR (300 MHz, THF-d ) δ

3 quat

.41 (s, 9 H), 2.96 (s, 12 H), 6.73−6.84 (m, 4H), 7.32 (d, J = 8.2 Hz,

99.6 (C_q_u_a_t), 120.3 (CH), 121.0 (CH), 125.4 (CH), 127.9 (CH),

128.0 (CH), 128.4 (CH), 129.1 (CH), 129.8 (CH), 135.3 (C_q_u_a_t),

136.5 (C_q_u_a_t), 137.4 (C_q_u_a_t), 141.1 (C ), 141.9 (C ), 143.0

H), 7.44−7.55 (m, 4 H), 7.55−7.69 (m, 6 H), 7.78 (d, J = 1.5 Hz,

H). ¹³C{ H} NMR (75 MHz, THF) δ 31.8 (CH ), 35.8 (C ),

quat

0.7 (CH ), 99.8 (C_q_u_a_t), 113.7 (CH), 119.7 (CH), 120.2 (CH),

(C_q_u_a_t), 154.0 (C_q_u_a_t). MS (EI): 597 ([ C C H NS ] , 20), 596

36 2 29 3

010

J. Org. Chem. 2021, 86, 8000−8014

The Journal of Organic Chemistry

Article

(

[ C

CH NS ] , 42), 595 ([C H NS ] , 100), 519

(CH), 129.9 (q, J = 32.2 Hz, C_q_u_a_t), 135.5 (C_q_u_a_t), 135.7 (C_q_u_a_t),

38 29

[C H NS] , 14), 463 ([C H ] , 17), 462 ([C H ] , 62), 404

19), 310 (11), 298 (22), 294 (13), 219 (13), 135 (14), 129 (22), 91

10). IR: ν

w), 1557 (m), 1541 (m), 1505 (s), 1489 (m), 1460 (s), 1445 (m),

398 (m), 1354 (w), 1339 (w), 1290 (m), 1265 (m), 1240 (m), 1186

w), 1140 (w), 1111 (w), 1063 (w), 1017 (m), 999 (w), 945 (w), 914

w), 878 (m), 845 (m), 824 (m), 758 (s), 729 (m), 692 (s), 679 (m),

137.3 (C_q_u_a_t), 141.0 (C_q_u_a_t), 143.8 (C_q_u_a_t), 145.7 (C_q_u_a_t), 154.3

(C_q_u_a_t). F NMR (282 MHz, THF-d ) δ −62.3. MS (EI): 733

−1

13 12 + 13 12 +

[cm ] 3053 (w), 3024 (w), 2961 (w), 2868 (w), 1597

([ C C H F NS ] , 20), 732 ([ C C H F NS ] , 40), 731

2 38 27 6 3 39 27 6 3

13 12

([C H F NS ] , 100), 599 ([ C C H F NS ] , 17), 598

29 14

([C₃₀H₁₄F NS ] , 52), 587 ([C₃₃H₂₄F NS ] , 27), 454

6 3 3 3

−1

([C H F NS ] , 19), 367 (11), 366 (28), 344 (12). IR: ν [cm ]

23 11 3 3

3034 (w), 2956 (w), 2866 (w), 1614 (m), 1556 (w), 1543 (w), 1504

(w), 1462 (m), 1394 (w), 1328 (m), 1294 (m), 1273 (m), 1232 (m),

1166 (m), 1116 (s), 1107 (/s), 1074 (m), 1060 (m), 1014 (m), 995

(w), 983 (w), 968 (w), 954 (w), 947 (w), 920 (w), 879 (w), 869 (w),

839 (m), 806 (s), 785 (w), 763 (w), 744 (w), 729 (w), 702 (w), 690

(w), 623 (w). Anal. Calcd for C H F NS (731.8): C 65.65, H 3.72,

67 (m). Anal. Calcd for C H NS (595.8): C 76.60, H 4.91, N

.35, S 16.14. Found: C 76.50, H 4.90, N 2.26, S 16.01.

38 29 3

N-(4-tert-Butylphenyl)bis(6-(4-ﬂuorophenyl)benzo[b]thieno)-

[

2,3-b:3′,2′-e][1,4]thiazine (10e). According to GP 2 with 4-bromo-

ﬂuorobenzene (9e) (263 mg, 1.50 mmol, 3.00 equiv), the crude

product was puriﬁed via column chromatography (eluent: n-hexane/

N 1.91, S 13.41. Found: C 65.72, H 4.00, N 1.81, S 13.91.

dichloromethane = 2/1 + 2% NEt ) to give compound 10e as a bright

orange solid (295 mg, 0.467 mmol, 93%), Mp 301−302 °C (dec.), R :

.44 (n-hexane/THF = 5:1). H NMR (300 MHz, THF-d ) δ 1.41 (s,

H), 7.09−7.21 (m, 4 H), 7.38 (dd, J = 8.3, J = 0.6 Hz, 2 H), 7.55−

.73 (m, 10 H), 7.86 (dd, J = 1.7, J = 0.6 Hz, 2 H). C{ H} NMR

75 MHz, THF-d ) δ 31.8 (CH ), 35.8 (C_q_u_a_t), 99.6 (C_q_u_a_t), 116.5 (d,

J = 21.5 Hz, CH), 120.4 (CH), 120.9 (CH), 125.3 (CH), 128.4

CH), 129.1 (CH), 129.6 (d, J = 8.0 Hz, CH), 138.2 (d, J = 3.2 Hz,

N-(4-tert-Butylphenyl)bis(6-(4-methylcarboxyphenyl)benzo[b]-

thieno)[2,3-b:3′,2′-e][1,4]thiazine (10h). According to GP 2 with

methyl 4-iodo-benzoate (9h) (338 mg, 1.50 mmol, 3.00 equiv), the

crude product was puriﬁed via column chromatography (eluent:

dichloromethane + 2% NEt ) to give compound 10h as a bright red

solid (75.2 mg, 0.105 mmol, 21%), Mp 348−349 °C, R : 0.38

(CH Cl ). H NMR (600 MHz, DMSO-d , 373 K) δ 1.41 (s, 9 H),

(

3.90 (s, 6 H), 7.45 (d, J = 8.4 Hz, 2 H), 7.69 (q, J = 8.5 Hz, 4 H),

C_q_u_a_t), 135.4 C₍_q_u_a_t), 136.4 (C_q_u_a_t), 136.5 (C ), 163.6 (d, J = 245.5

7.83 (m, 6 H), 8.04 (d, J = 8.0 Hz, 4 H), 8.17 (s, 2 H). C{ H}

NMR (151 MHz, DMSO, 373 K) δ 30.6 (CH ), 51.1 (CH ), 118.6

(CH), 123.9 (CH), 126.0 (CH), 126.6 (CH), 129.0 (CH). MS (EI):

quat

Hz, C ). MS (EI): 633 ([ C C H F NS ] , 20), 632

quat

(

[ C CH F NS ] , 42), 631 ([C H F NS ] , 100), 538

38 27

13 12

[C H S ] , 11), 537 ([C H S ] , 29), 499 (19), 498 (61), 404

713 ([ C

711 ([C42

([C32

33NO

] , 25), 712 ([ C C41

33NO

] , 44),

] , 18), 578

] , 14), 357 (11), 356

(26), 341 (16), 340 (43), 273 (16), 272 (18), 207 (22), 135 (28), 91

38 17 2

−

13 12

22), 316 (23), 294 (11), 90 (11). IR: ν

866 (w), 1541 (m), 1512 (s), 1501 (m), 1460 (s), 1418 (m), 1393

m), 1364 (w), 1269 (m), 1238 (m), 1188 (w), 1159 (m), 1098 (m),

067 (w), 1011 (w), 957 (w), 837 (s), 810 (s), 795 (m), 768 (m),

52 (m), 729 (m), 679 (w), 654 (m), 611 (m). Anal. Calcd for

[cm ] 2967 (w), 2901 (w),

33NO S ] , 100), 579 ([ C C31H20NO S

20NO

] , 52), 519 ([C30

H17NO

−

(50), 57 (52), 55 (55). IR: ν [cm ] 3649 (w), 2987 (w), 2964 (w),

2951 (w), 2900 (w), 2870 (w), 1716 (s), 1681 (w), 1606 (m), 1554

(w), 1541 (w), 1504 (s), 1460 (m), 1433 (m), 1415 (w), 1394 (w),

1365 (w), 1278 (s), 1238 (s), 1182 (m), 1103 (m), 1082 (w), 1066

(m), 1014 (m), 964 (w), 947 (w), 900 (w), 850 (m), 812 (m), 765

(s), 731 (w), 698 (m). Anal. Calcd for C H NO S (664.7): C

C H F NS (631.8): C 72.24, H 4.31, N 2.22, S 15.22. Found: C

2.02, H 4.42, N 2.15, S 14.96.

N-(4-tert-Butylphenyl)bis(6-(4-chlorophenyl)benzo[b]thieno)-

[

2,3-b:3′,2′-e][1,4]thiazine (10f). According to GP 2 with 4-bromo-

4 3

chlorobenzene (9f) (287 mg, 1.50 mmol, 3.00 equiv), the crude

product was puriﬁed via column chromatography (eluent: n-hexane/

70.86, H 4.67, N 1.97, S 13.51. Found: C 71.09, H 4.71, N 1.95, S

13.51.

dichloromethane = 2/1 + 2% NEt ) to give compound 10f as a bright

N-(4-tert-Butylphenyl)bis(6-(4-cyanophenyl)benzo[b]thieno)-

[2,3-b:3′,2′-e][1,4]thiazine (10i). According to GP 2 with 4-

bromobenzonitrile (9i) (273 mg, 1.50 mmol, 3.00 equiv), the crude

product was puriﬁed via column chromatography (eluent: n-hexane/

orange solid (334 mg, 0.498 mmol, 99%), Mp 257−258 °C (dec.), R :

.38 (n-hexane/THF = 5:1). H NMR (300 MHz, THF-d ) δ 1.41 (s,

H), 7.34−7.47 (m, 6 H), 7.57−7.72 (m, 10 H), 7.89 (d, J = 1.7 Hz,

H). ¹³C{ H} NMR (75 MHz, THF) δ 31.8 (CH ), 35.8 (C ),

dichloromethane = 1/1 + 2% NEt

) to give compound 10i as a dark

: 0.19 (n-

) δ 1.42 (s,

quat

9.6 (C_q_u_a_t), 120.4 (CH), 121.0 (CH), 125.3 (CH), 128.4 (CH),

29.1 (CH), 129.3 (CH), 129.9 (CH), 134.0 (C_q_u_a_t), 135.4 (C_q_u_a_t),

36.0 (C_q_u_a_t), 136.8 (C_q_u_a_t), 140.5 (C ), 141.0 (C ), 143.3

red solid (257 mg, 0.397 mmol, 79%), Mp 365−366 °C, R

hexane/THF = 5:1). H NMR (600 MHz, THF-d

+ CS

9 H), 7.40 (d, J = 8.2 Hz, 2 H), 7.61 (d, J = 8.2 Hz, 2 H), 7.67 (d, J

quat

(

C_q_u_a_t), 154.1 (C ). MS (EI): 667 ([ C C H Cl NS ] , 22),

66 ([ C CH Cl NS ] , 36), 665 ([C H Cl NS ] , 74), 664

= 8.2 Hz, 2H), 7.74 (t, J = 8.1 Hz, 6 H), 7.82 (d, J = 8.0 Hz, 4 H),

quat

7.95 (s, 2 H). C{ H} NMR (151 MHz, THF-d

+CS ) δ 31.8

8 2

38 27

(

[C H Cl NS ] , 52), 663 ([C H Cl NS ] , 100), 534

[C H ClS] , 13), 533 ([C H ClS] , 19), 532 ([C H ClS] ,

1), 531 ([C H ClS] , 27), 530 ([C H ClS] , 67), 498 (12), 332

(CH ), 35.8 (Cquat), 99.8 (Cquat), 112.0 (Cquat), 119.2 (Cquat), 120.6

38 25

(CH), 121.5 (CH), 125.5 (CH), 128.4 (CH), 128.5 (CH), 129.1

(CH), 133.6 (CH), 135.1 (Cquat), 135.4 (Cquat), 137.4 (Cquat), 140.6

(Cquat), 144.0 (Cquat), 145.9 (Cquat), 154.2 (Cquat). MS (EI): 647

(

18), 332 (18), 118 (12), 117 (18), 115 (14), 91 (16), 90 (19), 77

−1

10). IR: ν

m), 1541 (m), 1508 (s), 1460 (s), 1414 (m), 1389 (m), 1364 (m),

354 (w), 1310 (m), 1292 (m), 1271 (m), 1238 (m), 1202 (w), 1184

w), 1167 (w), 1107 (m), 1094 (m), 1067 (m), 1049 (w), 1009 (m),

93 (w), 943 (m), 872 (w), 806 (s), 782 (m), 747 (m), 720 (m), 698

w), 638 (w). Anal. Calcd for C H Cl NS (664.7): C 68.66, H

[cm ] 2963 (w), 2930 (w), 2901 (w), 2866 (w), 1557

([ C38

([C40

28), 512 ([C40

] , 23), 646 ([ C39 CH27

] , 45), 645

] , 100), 514 ([C40

20N] , 15), 513 ([C40

19N] ,

−1

18N] , 84), 480 (17), 90 (14). IR: ν

[cm ] 2961

(w), 2901 (w), 2222 (m), 1605 (m), 1591 (w), 1497 (s), 1460 (s),

1412 (m), 1391 (m), 1364 (m), 1341 (w), 1314 (m),1292 (m), 1271

(m), 1236 (m), 1204 (m), 1179 (m), 1169 (m), 1152 (m), 1109 (m),

1094 (m), 1067 (m), 1044 (m), 1013 (m), 955 (m), 872 (m), 841

(m), 806 (s), 783 (m), 774 (m), 735 (m), 687 (m), 658 (m). Anal.

Calcd for C H N S (645.9): C 74.39, H 4.21, N 6.51, S 14.89.

.09, N 2.11, S 14.47. Found: C 68.84, H 4.33, N 2.01, S 14.36.

N-(4-tert-Butylphenyl)bis(6-(4-triﬂuoromethylphenyl)benzo[b]-

thieno)[2,3-b:3′,2′-e][1,4]thiazine (10g). According to GP 2 with 4-

bromobenzotriﬂuoride (9g) (338 mg, 1.50 mmol, 3.00 equiv). The

crude product was puriﬁed via column chromatography (eluent: n-

3 3

Found: C 74.12, H 4.32, N 6.43, S 15.06.

N-(4-tert-Butylphenyl)bis(6-(4-nitrophenyl)benzo[b]thieno)[-2,3-

b:3′,2′-e][1,4]thiazine (10j). According to GP 2 with 4-bromoni-

trobenzene (9i) (303 mg, 1.50 mmol, 3.00 equiv), the crude product

was puriﬁed via column chromatography (eluent: n-hexane + 2%

hexane/dichloromethane = 2/1 + 2% NEt ) to give compound 10g as

a bright orange solid (334 mg, 0.457 mmol, 91%), Mp 273−274 °C,

R : 0.61 (n-hexane/CH Cl = 10:1). H NMR (500 MHz, THF-d ) δ

(

.42 (s, 9 H), 7.42 (d, J = 8.3 Hz, 2 H), 7.59−7.65 (m, 2 H), 7.65−

NEt

) to give compound 10i as a black solid with a metal shine (239

: 0.23 (n-hexane/

THF = 5:1). H NMR (300 MHz, THF-d ) δ 1.42 (s, 9 H), 7.44 (d,

.70 (m, 2 H), 7.70−7.76 (m, 6 H), 7.84 (d, J = 8.1 Hz, 4 H), 7.96

mg, 0.348 mmol, 70%), Mp 360−361 °C (dec.), R

d, J = 1.6 Hz, 2 H). C{ H} NMR (126 MHz, THF-d ) δ 31.8

CH ), 35.8 (C ), 99.8 (C_q_u_a_t), 120.5 (CH), 121.5 (CH), 125.5

CH), 126.7 (q, J = 3.8 Hz, CH), 128.3 (CH), 128.4 (CH), 129.1

J = 8.3 Hz, 2 H), 7.61−7.68 (m, 2 H), 7.68−7.74 (m, 2 H), 7.82 (dd,

quat

J = 8.4, J = 1.7 Hz, 2 H), 7.87−7.97 (m, 4 H), 8.05 (d, J = 1.7 Hz, 2

011

J. Org. Chem. 2021, 86, 8000−8014

The Journal of Organic Chemistry

Article

H), 8.24−8.35 (m, 4 H). C{ H} NMR (75 MHz, THF-d ) δ 31.8

H), 6.95 (td, J = 7.2, J = 1.2 Hz, 4 H), 6.99−7.07 (m, 8 H), 7.13

(

CH ), 35.9 (C ), 99.6 (C_q_u_a_t), 120.6 (CH), 121.8 (CH), 125.0

CH), 125.7 (CH), 128.5 (CH), 128.6 (CH), 129.2 (CH), 134.7

C_q_u_a_t), 135.5 (C_q_u_a_t), 137.7 (C_q_u_a_t), 140.7 (C_q_u_a_t), 144.3 (C_q_u_a_t),

(dd, J = 8.6, J = 2.0 Hz, 2 H), 7.16−7.25 (m, 10 H), 7.30 (d, J = 1.9

13 1

quat

Hz, 2 H), 7.49−7.55 (m, 2 H), 7.55−7.63 (m, 2 H). C{ H} NMR

(75 MHz, THF) δ 31.7 (CH ), 35.7 (C ), 100.1 C(_q_u_a_t), 104.2

quat

48.0 (C ), 148.1 (C ), 154.5 (C ). MS (EI): 687

C(_q_u_a_t), 119.0 (CH), 120.8 (CH), 123.5 (CH), 124.2 (CH), 124.7

(CH), 125.0 (CH), 128.1 (CH), 128.8 (C_q_u_a_t), 130.2 (CH), 133.2

(C_q_u_a_t), 135.8 (C ), 145.1 (C_q_u_a_t), 149.1 (C ), 153.6 (C ). MS

quat

(

[ C C H N O S ] , 18), 686 ([ C CH N O S ] , 40), 685

36 2 27 3 4 3 37 27 3 4 3

[C₃₈H₂₇N O S ] , 97), 639 ([C

H O S ] , 13), 552

38 23 4 3

quat

[C H N O ] , 19), 506 ([C H N O] , 17), 460 (15), 459

11), 458 (11), 310 (12), 281 (16), 209 (15), 208 (22), 207 (100),

91 (17), 147 (10), 135 (20), 133 (14), 96 (10), 91 (14), 73 (13).

(EI): 780 ([ C C H N S ] , 24), 779 ([ C CH N S ] , 44),

38 22

3 3

777 ([C50

([ C39 CH26

] , 100), 646 ([ C38

] , 30), 644 ([C40

] , 15), 645

] , 76), 390 (20), 389

−

IR: ν

[cm ] 2959 (w), 2901 (w), 2866 (w), 2835 (w), 1591 (m),

(50), 323 (25), 322 (25), 270 (14), 168 ([C38

] , 12), 77

([C H ] , 11). IR: ν [cm ] 3061 (w), 2960 (w), 2929 (w), 2864

6 5

−1

(

541 (m), 1505 (s), 1493 (s), 1456 (s), 1418 (m), 1395 (m), 1333

s), 1312 (m), 1292 (m), 1271 (m), 1236 (m), 1194 (m), 1169 (m),

144 (w), 1107 (m), 1067 (m), 1045 (w), 1018 (m), 995 (w), 970

w), 937 (w), 891 (w), 850 (s), 818 (m), 802 (m), 777 (m), 752 (s),

(w), 1585 (m), 1544 (m), 1514 (m), 1489 (s), 1446 (s), 1408 (m),

1325 (m), 1311 (m), 1271 (s), 1234 (m), 1168 (m), 1157 (w), 1109

(w), 1056 (m), 1020 (w), 958 (m), 881 (w), 812 (m), 748 (s), 725

29 (m), 692 (m), 667 (m). HRMS (ESI) m/z: [M] calcd. for

(m), 692 (s), 640 (s). Anal. Calcd for C50H N S (777.2): C 77.19,

39 3 3

[

C H N O S ] : 685.1164. Found: 685.1150.

H 5.05, N 5.40, S 12.36. Found: C 76.92, H 5.08, N 5.14, S 12.22.

N-(4-tert-Butylphenyl)bis(6-(N,N-di(4-methoxyphenyl)amino)-

benzo[b]thieno)[2,3-b:3′,2′-e][1,4]thiazine (12b). According to GP

3 with 4,4′-dimethoxydiphenylamine (11b) (287 mg, 1.25 mmol, 2.50

equiv), the crude product was puriﬁed via column chromatography

4 3

N-(4-tert-Butylphenyl)bis(6-(10-hexyl-10H-phenothiazin-3-yl)-

benzo[b]-thieno)[2,3-b:3′,2′-e][1,4]thiazine (10k). According to GP

with 3-bromo-10-hexyl-10H-phenothiazine (9k) (544 mg, 1.50

mmol, 3.00 equiv), the crude product was puriﬁed via column

chromatography (eluent: n-hexane/THF = 5/1 + 2% NEt ) to give

compound 10k as a brown solid (272 mg, 0.270 mmol, 54%), Mp

(eluent: n-hexane/dichloromethane = 2/1 + 2% NEt

) to give

compound 12b as a yellow solid (283 mg, 0.315 mmol, 63%), Mp

40−141 °C (dec.), R : 0.31 (n-hexane/THF = 5/1). H NMR (300

197−198 °C (dec.), R

MHz, THF-d ) δ 1.35 (s, 9 H), 3.73 (s, 12 H), 6.74−6.87 (m, 9 H),

6.91−7.07 (m, 10 H), 7.07−7.16 (m, 4 H), 7.49 (d, J = 8.6 Hz, 2 H),

: 0.14 (n-hexane/THF = 5:1). H NMR (300

MHz, THF-d ) δ 0.81−0.94 (m, 6 H), 1.31 (tt, J = 5.4, 2.4 Hz, 8 H),

.41 (s, 9 H), 1.43−1.53 (m, 4 H), 1.75−1.87 (m, 4 H), 3.91 (t, J =

.0 Hz, 4 H), 6.81−7.03 (m, 6 H), 7.04−7.18 (m, 4 H), 7.34 (d, J =

7.56 (d, J = 8.7 Hz, 2 H). C{ H} NMR (75 MHz, THF) δ 31.8

(CH3), 35.7 (Cquat), 55.7 (CH3), 115.6 (CH), 120.5 (CH), 121.5

(CH), 126.9 (CH), 127.1 (CH), 128.0 (CH), 128.6 (CH), 142.4

(Cquat), 146.4 (Cquat), 153.1 (Cquat), 157.1 (Cquat). MS (EI): 898

.3 Hz, 2 H), 7.43 (d, J = 8.0 Hz, 4 H), 7.55−7.70 (m, 6 H), 7.83 (d, J

1.6 Hz, 2 H). ¹³C{ H} NMR (75 MHz, THF-d ) δ 14.5 (CH ),

3.7 (CH ), 27.6 (CH ), 28.0 (CH ), 31.8 (CH ), 32.6 (CH ), 35.8

2 2 2 3 2

(

C_q_u_a_t), 48.1 (CH ), 99.7 (C_q_u_a_t), 116.5 (CH), 116.7 (CH), 120.3

([ C53 CH47

] , 14), 897 ([C54

] , 28), 750

CH), 120.3 (CH), 123.2 (CH), 124.8 (CH), 125.7 (C_q_u_a_t), 126.3

CH), 126.6 (CH), 128.2 (CH), 128.3 (CH), 129.1 (CH), 135.4

C_q_u_a_t), 136.0 (C_q_u_a_t), 136.2 (C_q_u_a_t), 136.4 (C_q_u_a_t), 141.2 (C_q_u_a_t),

([C54

([C40

([C30

O] , 15), 539 (16), 538 ([C40

44N] , 40), 537

43N] , 44), 523 (10), 522 (13), 509 (19), 508

O S ] , 55), 507 (12), 493 (20), 449 (12), 393 (16), 378

3 3

42.7 (C ), 145.6 (C ), 146.3 (C_q_u_a_t), 153.9 (C_q_u_a_t). MS (EI):

006 ([ C C H N S ] , 1), 1005 ([C H N S ] , 1), 564 (14),

63 (38), 562 (100), 491 (10), 479 (13), 478 (35), 477 (69), 448

16), 447 (58), 376 (16), 363 (18), 362 (41), 344 (12), 331 (13),

(11), 375 (12), 254 (10), 247 (24), 246 (14), 240 (13), 239 (11),

quat

25 (12), 207 (10), 191 (43), 177 (14), 176 ([C H N S ] , 100),

62 59

3 5

3 2 3 3

59 (12), 149 (17), 148 (37), 144 (38), 136 (16), 135 (11), 134

−

(40), 117 (12), 116 (28), 115 (14), 106 (12), 77 (11). IR: ν

[cm ]

(

−

840 (w), 3038 (w), 2953 (w), 2899 (w), 2866 (w), 2828 (w), 2359

30 (16), 238 (10), 134 (11), 78 (12), IR: ν [cm ] 2951 (w), 2924

(

w), 1595 (w), 1541 (w), 1501 (s), 1460 (s), 1441 (m), 1420 (m),

406 (w), 1339 (w), 1302 (w), 1271 (m), 1236 (s), 1173 (m), 1152

w), 1126 (w), 1105 (m), 1059 (m), 1030 (m), 999 (w), 959 (m),

16 (w), 837 (w), 806 (m), 779 (m), 644 (m), 633 (w). Anal. Calcd

for C H N O S (897.3): C 72.21, H 5.27, N 4.68, S 10.71. Found:

(

w), 2852 (w), 1355 (w), 1598 (w), 1556 (w), 1537 (w), 1504 (m),

452 (s), 1413 (w), 361 (w), 1332 (w), 1311 (w), 1247 (m), 1234

m), 1193 (w), 1161 (w), 1132 (w), 1105 (w), 1070 (w), 1039 (w),

(

018 (w), 954 (w), 866 (w), 846 (w), 804 (m), 785 (w), 744 (m),

25 (w), 705 (w), 680 (w), 653 (w), 603 (w). Anal. Calcd for

54 47

4 3

C 71.92, H 5.15, N 4.50, S 10.74.

C H N S (1006.5): C 73.99, H 5.91, N 4.18, S 15.93. Found: C

3 5

N-(4-tert-Butylphenyl)bis(6-(10H-phenothiazin-10-yl)benzo[b]-

thieno)[2,3-b:3′,2′-e][1,4]thiazine (12c). According to GP 3 with an

enhanced reaction time of 48 h using 10H-phenothiazine (11c) (249

mg, 1.25 mmol, 2.50 equiv), the crude product was puriﬁed via

column chromatography (eluent: n-hexane/dichloromethane = 2/1 +

3.77, H 5.94, N 4.04, S 16.11.

General Procedure (GP 3) for the Synthesis of 3,9-Bis(di(hetero)-

arylamino Substituted anti-anti Bis[1]benzothieno[1,4]thiazines

tube with a magnetic stir bar was placed PdCl (4.43 mg, 25 μmol,

2. In a ﬂame-dried and nitrogen ﬂushed 10 mL screw cap Schlenk

.00 mol %), dppf (13.9 mg, 25 μmol, 5.00 mol %), and dry toluene

2% NEt

) to give compound 12c as a bright orange solid (376 mg,

: 0.29 (n-hexane/THF = 5:1).

(

1 mL) and heated to 80 °C for 30 min. To the catalyst solution was

0.449 mmol, 90%), Mp 287−288 °C, R

added 8a (301 mg, 0.500 mmol, 1.00 equiv), the amine 11 (1.25

H NMR (500 MHz, THF-d

) δ 1.40 (s, 9 H), 6.20 (dd, J = 8.0, 1.4

mmol, 2.50 equivs), sodium-tert-butoxide (240 mg, 2.50 mmol, 5.00

equiv), and HP( Bu )BF (14.5 mg, 50.0 μmol, 10.0 mol %), and the

reaction mixture was heated to 100 °C for 24 h. After cooling to room

temperature, water was added, the mixture was diluted with

dichloromethane, and the phases were separated. The aqueous

phase was extracted with dichloromethane (3 × 20 mL), and the

combined organic phases were washed with brine and dried

Hz, 4 H), 6.73−6.83 (m, 8 H), 6.96 (dd, J = 7.3, J = 1.8 Hz, 4 H),

7.45 (dd, J = 8.4, J = 1.9 Hz, 2 H), 7.57−7.65 (m, 4 H), 7.66−7.70

4 13 1

(m, 2 H), 7.72 (d, J = 1.9 Hz, 2 H). C{ H} NMR (126 MHz,

THF) δ 31.7 (CH ), 35.8 (Cquat), 100.0 (Cquat), 117.1 (CH), 121.3

(Cquat), 122.1 (CH), 123.4 (CH), 125.7 (CH), 127.5 (CH), 127.7

(CH), 128.6 (CH), 129.1 (CH), 129.5 (CH), 136.3 (Cquat), 137.1

(Cquat), 137.5 (Cquat), 141.0 (Cquat), 144.2 (Cquat), 145.7 (Cquat),

(

anhydrous magnesium sulfate). The crude product was adsorbed

154.5 (Cquat). MS (EI): 840 ([ C

] , 13), 839

on Celite and puriﬁed by column chromatography under a nitrogen

([ C C49

] , 23), 838 ([C50

] , 42), 704 (15), 690

atmosphere.

(18), 640 (17), 508 (19), 507 (23), 506 (14), 478 (21), 419 (1), 308

13 12

N-(4-tert-Butylphenyl)bis(6-(N,N-diphenylamino)benzo[b]-

thieno)[2,3-b:3′,2′-e][1,4]thiazine (12a). According to GP 3 with

diphenylamine (11a) (212 mg, 1.25 mmol, 2.50 equiv), the crude

product was puriﬁed via column chromatography (eluent: n-hexane/

(12), 200 ([ C

NS] , 13), 199 ([ C C11

H NS] , 60),198

([C H NS] , 100), 171 (3), 167 (33), 166 (24), 54 (19), 127 (10),

−

105 (15), 77 (11). IR: ν [cm ] 3053 (w), 2985 (w), 2958 (w), 2900

(w), 2866 (w), 2823 (w), 1712 (w), 2587 (w), 1548 (w), 1508 (m),

1483 (m), 1460 (s), 1440 (s), 1404 (m), 1363 (w), 1352 (w), 1305

(m), 1280 (m), 1257 (m), 1236 (m), 1186 (w), 1159 (w), 1126 (w),

1105 (w), 1082 (m), 1056 (m), 1043 (m), 1018 (w), 995 (w), 9630

dichloromethane = 2/1 + 2% NEt ) to give compound 12a as a

yellow solid (351 mg, 0.451 mmol, 90%), Mp 329−330 °C, R : 0.20

(n-hexane/THF = 5:1). H NMR (300 MHz, THF-d ) δ 1.36 (s, 9

012

J. Org. Chem. 2021, 86, 8000−8014

The Journal of Organic Chemistry

(3) Chen, D.; Su, S.-J.; Cao, Y. Nitrogen heterocycle-containing

Article

(

w), 921 (m), 879 (w), 842 (w), 810 (w), 771 (w), 740 (s), 707 (m),

materials for highly efficient phosphorescent OLEDs with low

operating voltage. J. Mater. Chem. C 2014, 2, 9565−9578.

63 (m), 634 (m). Anal. Calcd for C H N S (838.2): C 71.65, H

50 35 3 5

.21, N 5.01, S 19.13. Found: C 71.38, H 4.43, N 4.74, S 18.96.

(

4) Salunke, J. K.; Sonar, P.; Wong, F.-L.; Roy, V. A. L.; Lee, C. S.;

ASSOCIATED CONTENT

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Heterocyclic Compounds: Synthesis, Physical Properties and OLED

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Accession Codes

CCDC 2054531 contains the supplementary crystallographic

data for this paper. These data can be obtained free of charge

via www.ccdc.cam.ac.uk/data_request/cif, or by emailing

data_request@ccdc.cam.ac.uk, or by contacting The Cam-

bridge Crystallographic Data Centre, 12 Union Road,

Cambridge CB2 1EZ, UK; fax: +44 1223 336033.

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AUTHOR INFORMATION

Corresponding Author

■

Thomas J. J. Mu

Makromolekulare Chemie, Heinrich-Heine-Universität

Dusseldorf, D-40225 Du sseldorf, Germany; orcid.org/

000-0001-9809-724X; Email: ThomasJJ.Mueller@hhu.de

ller − Institut fur Organische Chemie und

(

654−3665.

10) Farchioni, R.; Grosso, G. Organic Electronic Materials:

Conjugated Polymers and Low Molecular Weight Organic Solids;

Springer Science & Business Media, 2013; Vol. 41.

Authors

Henning R. V. Berens − Institut fu

Makromolekulare Chemie, Heinrich-Heine-Universität

Dusseldorf, D-40225 Dusseldorf, Germany

Kausar Mohammad − Institut fur Organische Chemie und

Makromolekulare Chemie, Heinrich-Heine-Universität

Dusseldorf, D-40225 Dusseldorf, Germany

Guido J. Reiss − Institut fur Anorganische Chemie und

Strukturchemie, Heinrich-Heine-Universität Dusseldorf, D-

0225 Dusseldorf, Germany

(11) Huang, T.-H.; Lin, J. T.; Chen, L.-Y.; Lin, Y.-T.; Wu, C.-C.

r Organische Chemie und

Dipolar Dibenzothiophene S,S-Dioxide Derivatives Containing

Diarylamine: Materials for Single-Layer Organic Light-Emitting

Devices. Adv. Mater. 2006, 18, 602−606.

(12) He, Z.; Kan, C.-W.; Ho, C.-L.; Wong, W.-Y.; Chui, C.-H.;

Tong, K.-L.; So, S.-K.; Lee, T.-H.; Leung, L. M.; Lin, Z. Light-emitting

dyes derived from bifunctional chromophores of diarylamine and

oxadiazole: Synthesis, crystal structure, photophysics and electro-

luminescence. Dyes Pigm. 2011, 88, 333−343.

(13) Zhang, J.; Li, H.-B.; Sun, S.-L.; Geng, Y.; Wu, Y.; Su, Z.-M.

Density functional theory characterization and design of high-

performance diarylamine-fluorene dyes with different π spacers for

dye-sensitized solar cells. J. Mater. Chem. 2012, 22, 568−576.

Complete contact information is available at:

https://pubs.acs.org/10.1021/acs.joc.1c00397

(

14) Jeux, V.; Segut, O.; Demeter, D.; Aléveque, O.; Leriche, P.;

Notes

Roncali, J. Push −Pull Triphenylamine Chromophore Syntheses and

The authors declare no competing ﬁnancial interest.

Optoelectronic Characterizations. ChemPlusChem 2015, 80, 697 −703.

(15) Cho, S.; Hwang, N.; Lee, S. E.; Kim, Y. K.; Yoon, S. S. Highly

ACKNOWLEDGMENTS

Efficient Blue Organic Light-Emitting Diodes Based on Diarylamine-

Substituted Pyrene Derivatives. J. Nanosci. Nanotechnol. 2019, 19,

■

The authors cordially thank the Deutsche Forschungsgemein-

schaft (Grant Mu 1088/9-1) and the Fonds der Chemischen

Industrie for ﬁnancial support. Computational support and the

infrastructure was provided by the “Centre for Information and

Media Technology” (ZIM) at the University of Du

Germany). The authors furthermore thank B. Sc. Marc

16) Fungo, F.; Jenekhe, S. A.; Bard, A. J. Plastic Electrochromic

056−1060.

Devices: Electrochemical Characterization and Device Properties of a

Phenothiazine-Phenylquinoline Donor −Acceptor Polymer. Chem.

Mater. 2003, 15, 1264−1272.

sseldorf

(

(17) Meyer, T.; Ogermann, D.; Pankrath, A.; Kleinermanns, K.;

Teunnissen for the experimental assistance.

Muller, T. J. J. Phenothiazinyl rhodanylidene merocyanines for dye-

sensitized solar cells. J. Org. Chem. 2012, 77, 3704−3715.

(18) Seo, Y.-H.; Lee, W.-H.; Park, J.-H.; Bae, C.; Hong, Y.; Park, J.-

W.; Kang, I.-N. Side-chain effects on phenothiazine-based donor −

acceptor copolymer properties in organic photovoltaic devices. J.

Polym. Sci., Part A: Polym. Chem. 2012, 50, 649−658.

DEDICATION

■

Dedicated to Prof. Dr. Wolfgang Kaim on the occasion of his

0th birthday.

(19) Salunke, J. K.; Wong, F. L.; Feron, K.; Manzhos, S.; Lo, M. F.;

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014