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Synthesis and Electronic Communication in Dumbbell-shapedPhenothiazine Dyads Bridged by Heterocycles

Full Name,a Full Namea,b and Thomas J. J. Mllera*

Received (in XXX, XXX) 1st January 2007, Accepted 1st January 2007

First published on the web 1st January 2007DOI: 10.1039/b000000x

The symmetrical dumbbell-shaped phenothiazine dyads 9, 12 and 13 show intense electronical

coupling between the redox-active phenothiazine units revealed from the cyclovoltammetric

spectra and DFT calculations. Futhermore, we have shown that the fluorescence emmision of

derivatives 9 and 10 can be switched off by the addition of TFA and on by neutralization.

Introduction

Phenothiazines belong to an important class of tricyclic

nitrogen-sulfur heterocycles,1 with a broad spectrum of

pharmacological activity.2 Most interestingly, phenothiazines

are also able to cleave DNA upon photochemical induction.3

As a consequence of a low oxidation potential, they readily

form stable radical cations and some of their physiological

activity can be attributed to this circumstance.4 Furthermore,

the radical cations give rise to a fingerprint of characteristic,

deep-colored absorptions.5 Thus, phenothiazine derivatives

have become important spectroscopic probes in molecular and

supramolecular arrangements for photoinduced electron

transfer (PET) studies6 and as motifs in organic materials.7

The prospect of integrating strongly coupled redox fragments

like phenothiazines into conjugated chains could constitute a

so far unknown class of redox addressable molecular wires, in

particular, for a redox manipulation of single molecules with

nanoscopic scanning techniques.8,9

As part of our program tosynthesize and investigate phenothiazinyl based molecular

wires,10-12 we have communicated syntheses, structures, and

first cyclic voltammetry measurements of directly linked

phenothiazinyl dyads, triads and up to heptades11 that can be

regarded as models for polymer-based coupled electrophores.

Recently, we reported studies on the correlation of the folding

angle of phenothiazines and the electronic properties by

introducing several sterically demanding aromatic substituents

in the 10-position.12 Here, we present the synthesis and

electronic studies on heterocyclic bridged, dumbbell-shaped

phenothiazine dyads with tunable redox and in some cases,

fluorescence properties.

Results and discussion

Syntheses

Generally, there are two well-described methods in literature

for the amination of (hetero)arenes: The Ullmann-coupling, 13

where overstoichiometric amounts of a copper-salt as

mediator are needed and the palladium-catalyzed Buchwald-

Hartwig reaction.14 Recently, Buchwald also described a

catalytical, palladium-free protocol of the Ullmann-coupling.15

In our synthetic approach, the coupling of 10H-phenothiazine

(1) with dibromo (hetero)arenes (2-7) was accomplished using

3 mol% of Pd2(dba)3.dba as palladium source, 5 mol% of

PHtBu3BF4 as ligand, NaOtBu as base and 1,4-dioxane as

solvent.16 After refluxing the reaction mixture over night, the

syntheses furnished in the desired coupling products 8-13 in

moderate to good yields (Scheme 1).

N N

SS

S

SBr Br

N N

SS

OOBr Br

NN

N

N

S

S

NN

Br

cond., 30 %

Br

cond., 35 %

12

115

6

7

N

S

H

NS

N

nhex nhex

NN N

SS

8

9

NN

NS

S10

1

N BrBr

NBr

Br

cond., 59 %

cond., 50 %

cond., 73 %

nhex

nhex

BrBr

4

3

2

Scheme 1 Synthesis of dumbbell-shaped phenothiazine dyads 8-13

(reaction conditions: dibromoarene 2-7 (1 eq.), 10H-phenothiazine 1

(2.2 eq), 0.03 eq Pd2(dba)3.dba, 0.05 eq PHtBu3BF4, 2.3 eq NaO

tBu, dry

1,4-dioxane, reflux, 19 h).

This journal is The Royal Society of Chemistry [year] Journal Name , [year], [vol] , 0000 | 1

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The structures ofN,N-bridged phenothiazine dyads 8-13 were

unambiguously assigned by 1H and 13C NMR, UV/vis, and IR

spectroscopy, by mass spectrometry and by correct

combustion analyses. (Eigentlich war es das schon zu den

Synthesen, falls Du einen Vorschlag bzgl. eines wichtiges

Aspekts oder zum Fllen hast, dann kann ich dies gerne

ausfhren).

DFT-Caculations

To determine the structure-properties relationship we carried

out calculations on the DFT level of theory (B3LYP/6-

31+G(d,p)). Herein, we used the gaussian software package.17

After the optimization of the structures of 3,6-pyridazine- (11)

and 2,5-thiophene- (13) bridged phenothiazine dyads we

focussed on the electron density distribution in the frontier

orbitals HOMO and LUMO.

In case of the thiophene bridged phenothiazine dyad 13 we

obtained an almost C2v-symmetrical structure in the geometry

optimization (Figure 1). The phenothiazine moieties both

show a tilt angle in its butterfly structure of 43.0.

Futhermore, the one can see in both phenothiazine units anintra-configurat ion, which is typical for N-aryl

phenothiazines.18 Due to this symmetry, the calculated HOMO

(Figure 1, bottom) is localized on both phenothiazine

moieties, while the LUMO (Figure 1, middle) is localized on

the central thiophene. This gives a realistic distribution, since

the phenothiazine units are regarded as strong electron donors

while the thiophene moiety serves as an acceptor.

Fig. 1 DFT calculated frontier orbitals, HOMO (bottom) and LUMO (top)

of theN,N-thiophene bridged phenothiazine 13.

We also performed calculat ions with 10,10-

biphenothiazinyl-3,6-pyridazine (11) and also obtained a C2v-

symmetrical structure as the energy minimum. The tilt angles

of both phenothiazine units valued 32.1 in our calculation

and were signifficantly different to the ones of the thiophene

derivative 13. We assume this smaller tilt angle of 11 to the

electron-deficient character of the pyridazine bridge. Here, we

also found the intra-configuration of both phenothiazines to

be the most stable one. However, looking at the calculated

frontier orbitals of11 we found a completely diffrent electrondistribution (Figure 2) in comparison with the thiophene

derivative 13. While the LUMO (Figure 2, top) of 11 is

located mostly at the pyrazidine moiety, the HOMO (Figure 2,

bottom) is distributed over the whole molecule; in the case of

13 one could observe a distict seperation between HOMO and

LUMO due to electron-rich and electron-deficient units in the

molecule.

Fig. 2 DFT calculated HOMO (bottom) and LUMO (top) of the

phenothiazine dyad 11 containing a pyridazine spacer.

Electronic properties

The electronical properties of the dumbbell-shapedphenothiazine dyads 8-13 were determined by absorption and

emission spectroscopy and by cyclic voltammetry (Table 1).

Optical spectroscopy studies (UV/vis and fluorescence

spectra) of systems 8-10 and 11-12 display weak fluorescence

with emission of blue-green light and large Stokes shifts

(960010600 cm-1). The pyridazine bridged phenothiazine

derivative 11 does not display any emission properties.

As shown by comparison with the spectra of 10H-

phenothiazine (1) the same absorbtion spectra maxima appear

in the spectra of the dyads indicating that the donor

(phenothiazine) and acceptor (pyridine, pyridazine, furane,

thiophene or fluorene) -systems are essentially electronically

2 | Journal Name , [year], [vol] , 0000 This journal is The Royal Society of Chemistry [year]

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decoupled in the electronic ground state. The absorption

spectra of dyads 8-13 are very similar and show a significant

band at around 303-333 nm, a second intense absorption at

around 252- 259 nm and in the case of 8, 9 and 10 a third

intense absorption at 280 nm, 288 nm, and 283 nm,

respectively.

Table 1 Selected (absorption and emission spectra, cyclic voltammetry)

electronic properties of dumbbell-shaped phenothiazine dyads 8-13

Compound Absorptionmax,abs[nm]a

Emissionmax,abs

[nm]a

Stokes shift[cm-1]

E00/+1

[mV]bE0

+1/+2

[mV]b

8 259, 280,308

477, 506

(sh.)

11500 761 -

9 288, 251,

333

516, 552

(sh.)

10600 891 1276

10 253, 283,309

517, 556(sh.)

13000 736 1132

11 253, 303 - - 851 1155c

12 252, 304 443, 503(sh.)

10300 608 954

13 256, 311 444, 512

(sh.)

9600 640 1072

a Recorded in CH2Cl2.b Recorded in CH2Cl2, 20 C, v = 100 mV/s,

electrolyte: nBu4N+ PF6

-, Pt working electrode, Pt counter electrode,

Ag/AgCl reference electrode. c Irreversible oxidation.

The emission spectra of the dyads 8-13 are broad at range

from 443-517 nm. The dyads with pyridinyl acceptor show the

lowest energy emission and very similar maxima either at 517

nm (10) or at 516 nm (9). The compounds with a electron rich

spacer (furane derivative 12, thiophene derivative 13) present

a very similar maximum of emission at 443 and 444 nm, and

reveal an increase in energy emission comparative with the

electron poorspacer (pyridine). Concomitantly, the Stokes

shift is significantly increased from dyad 13 (9600 cm-1) to the

dyad 10 (13000 cm-1) and can be attributed to significant

geometrical changes upon excitation from a highly nonplanar

ground state to a largely planarized excited state.19 Hence, an

electronic communication could be responsible for the

coupling of donor and acceptor in the exited state.

According with cyclic voltametry two reversible anodic

oxidations can be found for the dyads 9, 10, 12 and 13 (Figure

3). In comparison with 10H-phenothiazine (E00/+1= 624 mV)

the first reversible one electron oxidations are shifted

annodically, except for the furane bridged derivative 12 which

is shifted slightly cathodically (E00/+1= 608 mV). The anodical

shift values up to 270 mV in case of the 2,6-pyridine bridged

9 (E00/+1= 891 mV). The second oxidation occurs at a higher

potential, where the highest oxidation potential was observed

for the second redox step of9 (E0+1/+2= 1276 mV). This can be

interpreted as a strong electronic coupling between the

phenothiazinyl units as a consequence of an extended

delocalization of the initially formed radical cation. Since the

2,5-pyridine bridged dyad 10 is not symmetrical at all, it is not

surprisingly that two reversible oxidation processes are

observed. The first one (E00/+1= 736 mV) can be assigned to

the more electron-rich phenothiazine moiety located at the 2-

position of the central pyridine unit. The other phenothiazine,

connected at the electron-deficient 5-position of pyridine is

oxidized in a second redox step, occuring at E00/+1= 1132 mV.

The great difference of both oxidation processes (E= 396

mV) is assumed to be caused by an electronic coupling of

both phenothiazine units in the stage of the in-situ formed

mono radical cation of10, which is widely delocalized.

1,6 1,4 1,2 1,0 0,8 0,6 0,4 0,2 0,0

-6

-4

-2

0

2

I

[A]

U[V]

U[V]

Fig. 3 Cyclic voltommogram of13, recorded in CH2Cl2.

Most remarkable is cyclovoltammogram of 11 (Figure 4)

which shows a separation of two anodic oxidations by morethen 300 mV and just a single reversible process. This

behavior can be explained through the simultaneous one

electron oxidation each at both phenothiazine units at the frist

redox potential ofE00/+1= 851 mV. The second oxidation can

be assigned to the irreversible formation of the diradical

phenothiazinyl species, presumably in both phenothiazine

units. The voltammogram of 8 with a 2,7-fluorene spacer

reveals only one single reversible oxidation potential with

perfect Nernstian behavior. In comparison to the symmetric

phenothiazine dyads 9, 12 and 13, the phenothiazine units in

the symmetric pyridazine bridged (11) and the 2,7-fluorene

bridged (8) derivatives seem to be electronically decoupled.

This is in good agreement with the presented data obtainedfrom the DFT calculations, where no separation of the frontier

orbitals could be observed in case of11. On the other hand, a

clearly separation of HOMO and LUMO was found while

calculating the symmetrical, thiophene bridged phenothiazine

dyad 13.

1,4 1,2 1,0 0,8 0,6 0,4 0,2 0,0

-2,5

-2,0

-1,5

-1,0

-0,5

0,0

0,5

1,0

I[A]

U[V]

Fig. 4 Cyclic voltommogram of11, recorded in CH2Cl2.

Since the phenothazine dyads 9 and 10 contain of a basic

pyridine moiety, titration studies monitored by fluorescence

spectroscopy were performed with trifluoroacetic acid (TFA)


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in methylene chloride (Figure 5). Generally, the protonation

of phenothiazine derivatives leads to the formation of radical

cations.1,20 As we recently reported,10d titration studies of

phenothiazines with TFA in methylene chloride are possible

and reproducable. Both compounds 9 and 10 show similar

behaviour after the addition of increasing amounts of TFA.

The neutral compounds 9 and 10 display an emission at 517

nm and 516 nm, respectively. After the addition of 0.1 eq 5eq of TFA the emission is quenched in both cases. We assume

that first the pyridine units are protonated, leading to a species

with a very low band gap, as the LUMO is stabilized by

protonation. This species are nonfluorescent as there

apparently are effective paths available for non-radiative

excited-state deactivation, in line with energy gap law. 21 Upon

further addition of TFA, the phenothiazine units are likewise

protonated, stabilizing the HOMO.

350 400 450 500 550 600

0

50

100

150

200

250

300

350

PLintensity[a.u.]

Wavelength [nm]

0 eq0.1eq

0.2eq

0.3eq

0.5eq

1eq

2eq

3eq

5eq

Fig. 5 Emission spectra of9 in presence of increasing amounts of TFA.

However, this process is reversible, since the neutralization

of the acidic sample with a base led back to the original

fluorescence signal .This marks out that both pyridine bridged

phenothiazines 9 and 10 possess tuneable fluorescence

properties upon protonation/deprotonation besides the

observed electronic communication between the phenothazine

moieties.

While plotting the intensity of the fluorescence signal at

517 nm of9 versus the added equivalents of TFA one obtains

a exponential graph (Figure 6). (Hier knnte man dieses

Phnomen noch etwas diskutieren, wenn man eine log

Auftragung whlt, bekommt man eine recht gute Gerade miteinem fir von r = 0.98211).

0 1 2 3 4 5

0,0

0,2

0,4

0,6

0,8

1,0

PLInt.at

517nm[

a.u.]

Eq. of TFA

Fig. 6 Fluorescence signal of 9 at 517 nm plotted vs. the added

equivalents of TFA.

Conclusions

In conclusion, we have presented the synthesis and electronic

properties of dumbbell-shaped phenothiazine dyads. The

introduction of the heterocyclic bridge was easy accomplished

by the Buchwald-Hartwig aryl amination. The symmetrical

systems 9, 12 and 13 show intense electronical coupling

between the redox-active phenothiazine units as shown from

the cyclovoltammetric spectra and DFT calculations.

Futhermore, we have shown that the fluorescence emmision of

derivatives 9 and 10 in CH2Cl2 can be switched off by the

addition of TFA and on by neutralizing the sample solution.

The presented phenothiazine derivatives represent a new class

of tunable molecules, switchable by redox processes and by

the pH value in case of 9 and 10. Futher studies with more

emission harvesting phenothiazine derivatives are currently

underway.

Experimantal

General considerations

Reagents, catalysts and ligands were purchased reagent grade

and used without further purification. The used solvents were

dried and distilled according to standard procedures.22 2,5-

Dibromofurane23 (6) and 9,9-dihexyl-2,7-dibromofluorene24

(2) were prepared according to literature. Column

chromatography: silica gel 60, mesh 70-230. TLC: silica gel

plates.

1

H and

13

C NMR spectra: CD2Cl2, (locked to Me4Si).The assignments of quaternary C, CH, CH2 and CH3 have been

made by using DEPT spectra. Elemental analyses were carried

out in the Microanalytical Laboratories, Institut fr

Pharmazeutische Chemie, Heinrich-Heine University,

Dsseldorf, Germany.

Fluorescence measurements (Perkin-Elmer LS-55) were

performed in dry and degassed CH2Cl2 at room temperature.

To avoid re-absorption and re-emission effects the

concentrations were strictly kept below 1 M. The solutions

were irradiated at approximately 10 nm less in energy than the

longest wave length absorption maximum.

Electrochemistry: Cyclic voltammetry experiments (EG &


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G potentiostatic instrumentation) were performed under argon

in dry and degassed CH2Cl2 at room temperature and at scan

rates of 100, 250, 500, and 1000 mVs1. The electrolyte was

Bu4NPF6 (0.025 M). The working electrode was a 1 mm

platinum disk, the counter-electrode was a platinum wire, and

the reference electrode was a Ag/AgCl electrode. The

potentials were corrected to the internal standard of Fc/Fc+ in

CH2Cl2 (E00/+1= 450 mV).25

General procedure (GP)

Under inert conditions anhydrous 10H-phenothiazine 1 (2.2

eq), bromo derivatives 2-7 (1 eq), Pd2(dba)3.dba (0.03eq.),

PHtBuF4 (0.05 eq.), NaOtBu (2.3 eq.) and anhydrous 1,4-

dioxane were placed in a pressure tube. The reaction mixture

was stirred at 101 C for 19 h. After cooling to r.t., the

solution was diluted with deionized water, saturated Na2SO3

solution and methylene chloride. The aqueous phase was

extracted with small portions of methylene chloride, the

combined organic phases were dried with anhydrous MgSO4

and the solvents were removed in vacuo. The residue was

chromatographed on silica gel (hexane) to furnish theproducts 8-13 as solids or resins.

3,6-[10,10]Biphenothiazinyl-9,9-dihexyl-9H-fluorene (8)

This compound was synthesized according to GP and after

purification by flash-chromatography on silica gel (hexane) 8

(800 mg, 73 %) was obtained as a colourless resin. Mp. 227

C. Rf (hexane/acetone 10:1): 0.511H NMR (CD2Cl2, 500

MHz): 0.76 (t, J= 7.0 Hz, 6H), 1.07 (m, 16H), 2.04 (t, J=

8.3 Hz, 4H), 6.27 (dd, J= 1.5 Hz, J= 8.0 Hz, 4H), 6.84 (m,

8H), 7.03 (dd, J= 2.0 Hz, J= 7.3 Hz, 4H), 7.39 (dd, J= 1.5

Hz, J= 8.0 Hz, 2H), 7.44 (d, J = 1.5 Hz, 2H), 8.02 (d, J= 8

Hz, 2H). 13C NMR (CD2Cl2, 125 MHz): 13.4 (CH3), 22.0

(CH2), 23.6 (CH2), 29.1 (CH2), 31.2 (CH2), 39.8 (CH2), 55.5(Cquat.), 115.4 (CH), 119.3 (Cquat.), 121.8 (CH), 122.1 (CH.),

125.6 (CH), 126.2 (CH), 126.5 (CH), 129.4 (CH), 139.7

(Cquat.), 140.0 (Cquat.), 144.1 (Cquat.), 153.7 (Cquat.). IR (KBr) =

2953, 2925, 2853, 1592, 1483, 1461, 1442, 1305, 1259, 1237,

1121, 1043, 924, 825, 744, 673, 613, 546 cm -1. UV/Vis: max

( ) = 259 (164700), 280 (49600), 308 (35200). MS (MALDI)

m/z: 728.234 (M+). Anal. calcd. f. C49H48N2S2: C 80.72, H

6.64, N 3.84, found: C 80.72, H 6.79, N 3.82.

10, 10-Biphenothiazinyl-2,6-pyridine (9)



(1.72 g, 59 %) was obtained as a colorless solid. Mp.138 C.Rf (hexane/acetone 5:1): 0.45.

1H NMR (CD2Cl2, 500 MHz):

6.33 (d, J = 8.0 Hz, 2H), 7.21 (m, 9H), 7.39 (dd, J = 1.5

Hz,J= 7.5 Hz, 4H), 7.46 (dd,J= 2.0 Hz,J= 8.0 Hz, 4H). 13C

NMR (CD2Cl2, 125 MHz): 100.9 (CH), 125.2 (CH), 126.7

(CH), 127.6 (CH), 127.7 (CH), 133.1 (Cquat.), 138.5 (CH),

141.0 (Cquat.), 155.2 (Cquat.). IR (KBr) = 1594, 1575, 1476,

1429, 1345, 1301, 1254, 1194, 1169,1124, 1087, 1033, 940,

861, 778, 752, 731, 695, 659, 635, 612, 546, 523 cm-1.

UV/Vis: max () = 251 (39000),288 (10900), 333 (17600).

MS (EI+) m/z (%): 475 (5, Mn+2), 474 (15, Mn+1), 473.0 (30,

M+), 274 (20), 242 (35), 198 (100), 154 (23), 127 (8). Anal.

calcd. f. C29H19N3S2: C 73.54, H 4.04, N 8.87, found: C 73.31,

H 3.86, N 8.82.

10, 10-Biphenothiazinyl-2,5-pyridine (10)



(1.07g, 50 %) was obtained as a colourless solid. Mp. 220 C.

Rf (hexane/acetone 5:1): 0.50.1

H NMR (CD2Cl2, 500 MHz): 6.29 (dd,J= 1.5 Hz, J= 8.0 Hz, 2H), 6.82 (dt, dJ= 1.5 Hz,tJ= 7.5 Hz, 2H), 6.88 (dt, dJ= 1.5 Hz, tJ= 7.5 Hz, 2H), 7.01

(dd, J= 1.5 Hz, J= 7.5 Hz, 2H), 7.09 (m, 1H), 7.23 (dt, dJ=

1.0 Hz, J = 7.5 Hz, 2H), 7.37 (dt, dJ = 1.5 Hz, tJ = 7.5 Hz,

2H), 7.48 (m, 3H), 7.75 (dd, J= 1.0 Hz, J= 8.0 Hz 2H), 8.18

(m, 1H). 13C NMR (CD2Cl2, 125 MHz): 109.8 (CH), 115.7

(CH), 120.1 (Cquat.), 122.3 (CH.), 125.8 (CH), 126.4 (CH),

126.6 (CH), 126.7 (CH), 127.4 (CH), 127.9 (CH), 130.0

(Cquat), 133.3 (Cquat), 140.0 (CH), 140.4 (Cquat), 144.0 (Cquat),

149.5 (CH), 155.1 (Cquat). IR (KBr) = 1602, 1584,

1551,1475, 1460, 1440, 1385, 1307, 1259, 1233, 1127, 1082,

1044, 824, 746, 621, 540 cm -1. UV/Vis: max ( ) = 253

(107800), 283 (26400), 309 (26900).MS (MALDI) m/z:472.941 (M+).Anal. calcd. f. C29H19N3S2

.0.2 CH2Cl2: C 71.49,

H 3.99, N 8.57, found: C 71.47, H 4.30, N 8.38.

10, 10-Biphenothiazinyl-3,6-pyridazine (11)



(346 mg, 35 %) was obtained as a yellow resin. Mp. 231 C.

Rf(hexane/acetone 5:1): 0.321H NMR (CD2Cl2, 500 MHz):

7.04 (s, 2H), 7.16 (dt, dJ= 1.0 Hz, tJ= 7.5 Hz, 4H), 7.27 (dt,dJ= 1.0 Hz,J= 7.5 Hz, 4H), 7.37 (dd, J= 1.5 Hz, J= 7.5 Hz,

4H), 7.52 (dd, J= 1.0 Hz, J= 7.5 Hz, 4H). 13C NMR (CD2Cl2,

125 MHz): 120.1 (CH), 124.8 (CH), 125.3 (CH), 126.8

(CH), 127.5 (CH), 130.8 (Cquat.), 140.8 (Cquat.), 154.9 (Cquat.).IR (KBr) = 2967, 2371, 2345, 1774, 1725, 1655, 1627, 1578,

1533, 1509,1478, 1460, 1417, 1364, 1314, 1259, 1233, 1084,

1027, 947, 825, 803, 754, 695, 665, 623, 546 cm -1. UV/Vis:

max ( ) = 253 (25600), 303 (10400). MS (MALDI) m/z:

474.9 (M+).Anal. calcd. f. C28H18N4S2.0.3 CH2Cl2: C 69.45, H

3.79, N 11.51, found: C 69.40, H 4.22, N 11.24.

10, 10-Biphenothiazinyl-2,5-furane (12)



(800 mg, 30 %) was obtained as an orange resin. Mp. 200 C.


6.59 (s, 2H), 6.78 (d, J= 8 Hz, 4H), 6.95 (t, J= 7.5 Hz, 4H),7.09 (t, J = 7.5 Hz, 4H), 7.13 (d, J = 8.0 Hz, 4H). 13C NMR

(CD2Cl2, 125 MHz): 108.2 (CH), 116.3 (CH), 122.1 (Cquat.),

123.4 (CH.), 126.5 (CH), 126.8 (CH), 142.7 (Cquat.), 144.8

(Cquat.). IR (KBr) = 1615, 1589, 1568, 1462, 1443, 1300,

1253, 1234, 1169, 1126, 1085, 1039, 986, 916, 825, 746, 718,

677, 661 cm-1. UV/Vis: max ( ) = 252 (80700), 304 (8200).

MS (EI+) m/z (%): 464 (10, Mn+2), 463 (21, Mn+1) 462.0 (48,

M), 236 (100), 198 (100), 154 (21). Anal. calcd. f.

C28H18N2OS2.0.1CH2Cl2: C 71.64, H 3.89, N 5.95, found: C

71.63, H 3.83, N 5.79.

10, 10-Biphenothiazinyl-2,5-thiophene (13)


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(250 mg, 52 %) was obtained as a yellow solid. Mp. 215 C.


6.91 (d, J = 8.5 Hz, 4H), 6.95 (d, J = 7.5 Hz, 4H), 7.06 (m,

2H), 7.10 (m, 8H). 13C NMR (CD2Cl2, 125 MHz): 116.9

(CH), 121.8 (Cquat.), 123.3 (CH.), 126.4 (CH), 126.5 (CH),

126.9 (CH), 141.7 (Cquat.), 143.3 (Cquat.). IR (KBr) = 3439,3067, 1589, 1556, 1461, 1442, 1302, 1251, 1234, 1198, 1168,

1128, 1042, 915, 814, 750, 712, 659, 631, 562 cm-1. UV/Vis:

max ( ) = 256 (46300), 311 (5100). MS (EI+) m/z (%): 480

(17, Mn+2), 479 (20, Mn+1),478.0 (50, M), 279 (3), 247 (10),

198 ( M-278, 100), 154 (3), 127 (4). Anal. calcd. f.

C28H18N2S3.0.25 CH2Cl2: C 67.88, H 3.73, N 5.60, found: C

67.78, H 3.87, N 5.43.

Acknowlegments

The support of this work by the Deutsche

Forschungsgemeinschaft DFG (Priority program 1181), the

Deutscher Akademischer Austauschdienst DAAD (scholarshipfor L. N. P.), and by the Fonds der Chemischen Industrie is

gratefully acknowledged. The authors also cordially thank

Dr. Stefan Beutner for valuable discussions and the

BASF AG for the generous donation of chemicals.

Notes and references

a Institut fr Organische Chemie und Makromolekulare Chemie,

Heinrich-Heine-Universitt Dsseldorf, Universittsstr. 1, 40225

Dsseldorf, Germany. Fax: +4902118114324; E-mail:

[email protected] Babes-Bolyai University Cluj-Napoca, Faculty of Chemistry and

Chemical Engineering, Arany Janos Str. no.11, Cluj-Napoca, 400428

Romania

Electronic Supplementary Information (ESI) available: Detailedexperimental procedures, and copies of 1H and 13C NMR spectra of

compounds 813; cyclovoltammetric and flourescence spectra of 8-13;

atomic coordinates of the calculated structures of 11 and 13.See

DOI: 10.1039/b000000x/

Footnotes should appear here. These might include comments relevant

to but not central to the matter under discussion, limited experimental and

spectral data, and crystallographic data.

1 M. Sainsbury in Comprehensive Heterocyclic Chemistry, Vol. 3; A.

R. Katritzky, C. W. Rees, Eds.; Pergamon: Oxford, 1984, pp. 995.

2 (a) F. Mietzsch, Angew. Chem. 1954, 66, 363. (b) M. Ionescu, H.

Mantsch, Adv. Heterocycl. Chem. 1967, 8, 83. (c) C. Bodea, I.

Silberg, Adv. Heterocycl. Chem. 1968, 9, 321. (d) L. Valzelli, S.

Garattini, in Principles of Psychopharmacology; W. G. Clark, Ed.;

Academic Press: 1970, 255. (e) C. O. Okafor, Heterocycles 1977, 7,

391. (f) Z. Eckstein, T. Urbanski, Adv. Heterocycl. Chem. 1978, 23,

1. (g) J. Szabo, Chem. Heterocycl. Compd. USSR (Engl. Trans.)

1979, 15, 291. (h) W. J. Albery, A. W. Foulds, K. J. Hall, A. R.

Hillman, R. G. Edgell, A. F. Orchard,Nature 1979, 282, 793.

3 (a) E. Nishiwaki, H. Nakagawa, M. Takasaki, T. Matsumoto, H.

Sakurai, M. Shibuya, Heterocycles 1990, 31, 1763. (b) J. Decuyper,

J. Piette, M. Lopez, M. P. Merville, A. Vorst, Biochem. Pharmacol.

1984, 33, 4025. (c) A. G. Motten, G. R. Buettner, C. F. Chignell,

Photochem. Photobiol. 1985, 42, 9. (d) H. Fujita, I. Matsuo, Chem.

Biol. Interac. 1988, 66, 27.

4 (a) I. Forrest, F. Forrest,Biochim. Biophys. Acta 1958, 29, 441. (b) Y.

Iida, Bull. Chem. Soc. Jpn. 1971, 44, 663. (c) J.-C. Moutet, G.

Reverdy,Nouv. J. Chim. 1983, 7, 105.

5 For UV/Vis and EPR spectra of 10-methylphenothiazine, see e.g.: (a)

H. J. Shine, E. E. Mach, J. Org. Chem. 1965, 30, 2130. (b) H. J.

Shine, D. R. Thompson, C. Veneziani, J. Heterocycl. Chem. 1967, 4,

517. (c) For cyclovoltammetric and spectroscopic data of

phenothiazine, see e.g.: L. A. Tinker, A. J. Bard, J. Am. Chem. Soc.

1979, 101, 2316. (d) B. Padusek, M. K. Kalinowski, Electrochim.

Acta 1983, 28, 639. (e) R. McIntyre, H. Gerischer,Ber. Bunsen Ges.

Phys. Chem. 1984, 88, 963.

6 (a) R. Duesing, G. Tapolsky, T. J. Meyer,J. Am. Chem. Soc. 1990,

112, 5378. (b) W. E. Jones Jr., P. Chen, T. J. Meyer, J. Am. Chem.

Soc. 1992, 114, 387. (c) A. M. Brun, A. Harriman, V. Heitz, J.-P.

Sauvage,J. Am. Chem. Soc. 1991, 113, 8657. (d) H. D. Burrows, T. J.

Kemp, M. J. Welburn, J. Chem. Soc., Perkin Trans. 2 1973, 969. (e)

J.-P. Collin, S. Guillerez, J.-P. Sauvage, J. Chem. Soc., Chem.

Commun. 1989, 776. (f) J. Daub, R. Engl, J. Kurzawa, S. E. Miller, S.

Schneider, A. Stockmann, M. R. Wasielewski, J. Phys. Chem. A

2001, 105, 5655.

7 (a) R. C. Wheland, J. L. Gillson, J. Am. Chem. Soc. 1976, 98, 3916.

(b) P. Berges, J. Kudnig, G. Klar, E. Sanchez-Martinez, R. Diaz-

Calleja, Synth. Met. 1992, 46, 207. (c) A. Knorr, J. Daub, Angew.

Chem., Int. Ed. Engl. 1995, 34, 2664. (d) H. Spreitzer, M. Scholz, G.

Gescheidt, J. Daub,Liebigs Ann. Chem. 1996, 2069. (e) H. Spreitzer,

J. Daub, Chem. Eur. J. 1996, 2, 1150.

8 (a) For applications of AFM and STM in chemistry, see e.g.: Various

authors Chem. Rev. 1997, 97, Issue 4. (b) For applications in

molecular electronics, see e.g.: J. P. Rabe, in An Introduction to

Molecular Electronics; M. C. Petty, M. R. Bryce, D. Bloor, Eds.;

Oxford University Press: New York, 1995, 261. (c) For nanoscalematerials see e.g.: Various authorsAcc. Chem. Res. 1999, 32, Issue 5.

9 For conductance of single molecules under STM conditions, see e.g.:

(a) L. A. Bumm, J. J. Arnold, M. T. Cygan, T. D. Dunbar, T. P.

Burgin, L. I. I. Jones, D. L. Allara, J. M. Tour, P. S. Weiss, Science

1996, 271, 1705. (b) W. B. Davis, W. A. Svec, M. A. Ratner, M. R.

Wasielewski,Nature 1998, 396, 60. (c) M. T. Cygan, T. D. Dunbar,

J. J. Arnold, L. A. Bumm, N. F. Shedlock, T. P. Burgin, L. I. I. Jones,

D. L. Allara, J. M. Tour, P. S. Weiss, J. Am. Chem. Soc. 1998, 120,

2721. (d) G. Leatherman, E. N. Durantini, D. Gust, T. A. Moore, A.

L. Moore, S. Stone, Z. Zhou, P. Rez, Y. Z. Liu, S. M. Lindsay, J.

Phys. Chem. B 1999, 103, 4006.

10 (a) T. J. J. Mller, Tetrahedron Lett. 1999, 40, 6563. (b) C. S.

Krmer, K. Zeitler, T. J. J. Mller, Org. Lett. 2000, 2, 3723. (c) C. S.

Krmer, T. J. J. Mller, Eur. J. Org. Chem. 2003, 3534. (d) M.

Hauck, J. Schnhaber, A. J. Zucchero, K. I. Hardcastle, T. J. J.

Mller, U. H. F. Bunz, J. Org. Chem. 2007, 72, 6714. A. W. Franz,L. N. Popa, T. J. J. Mller, Tetrahedron Lett. 2008, accepted.

11 (a) C. S. Krmer, K. Zeitler, T. J. J. Mller, Tetrahedron Lett. 2001,

42, 8619. (b) C. S. Krmer, T. J. Zimmermann, M. Sailer, T. J. J.

Mller, Synthesis 2002, 1163. (c) M. Sailer, M. Nonnenmacher, T.

Oeser, T. J. J. Mller,Eur. J. Org. Chem.2006, 423. (d) M. Sailer, A.

W. Franz, T. J. J. Mller, Chem. Eur. J. 2008, 14, 2602.

12 A. W. Franz, F. Rominger, T. J. J. Mller, J. Org. Chem. 2008, 73,

1795.

13 F. Ullmann,Ber. Dtsch. Chem. Ges. 1903, 36, 2382.

14 (a) A. S. Guram, R. A. Rennels, S. L. Buchwald,Angew. Chem. Int.

Ed. 1995, 34, 1348. (b) J. Louie, J. F. Hartwig, Tetrahedron Lett.

1995, 36, 3609. (c) For reviews see: J. F. Hartwig, in Handbook of

Organopalladium Chemistry for Organic Synthesis, E. Negishi, (Ed.)

Wiley-Interscience, New York, 2002, 1051. (d) A. R. Muci, S. L.

Buchwald, Top. Curr. Chem. 2002, 219, 131. (e) For an excellent

overview of modern aromatic carbon-nitrogen cross-coupling

reactions see: L. Jiang, S. L. Buchwald, in Metal-Catalyzed Cross-

Coupling Reactions, A. De Meijere, F. Diederich, (Eds.), 2nd Ed.

Wiley-VCH, 2004, 699, and references therein.

15 (a) F. Y. Kwong, S. L. Buchwald, Org. Lett. 2003, 5, 793. (b) L.

Jiang, G. E. Job, A. Klapars, S. L. Buchwald, Org. Lett. 2003, 5,

3667.

16 T. Okamoto, M. Kuratsu, M. Kozaki, K. Hirotsu, A. Ichimura, T.

Matsushita, K. Okada, Org. Lett. 2004, 6, 3493.

17 M. J. Frisch, et al. Gaussian 03, Revision C.03; Gaussian, Inc.,

Wallingford, CT, USA, 2004.

18 J.-P. Malrieu, B. Pullman, Theor. Chim. Acta 1964, 2, 293.

19 L. Yang, J.-K. Feng, A.-M. Ren,J. Org. Chem. 2005, 70, 5987.

20 (a) M. Stainsbury in Rodds Chemistry of Carbon Compounds 2nd

ed.; M. Stainsbury, Ed.; Elsevier: Amsterdam 1998, 4, 575. (b) R.


5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

105

110

115

120

125

130


7/7



McIntyre, H. Gerscher, Ber. Bunsen-Ges. Phys. Chem. 1984, 88, 963.

(d) R. M. Krishna, V. Kurshev, L. Kervan,Phys. Chem. Chem. Phys.

1999, 11, 2833.

21 C. Fahrni, L. C. Yang, D. G. VanDerveer, J. Am. Chem. Soc. 2003,

125, 3799.

22 H. G. O. Becker, W. Berger, G. Domschke, E. Fanghnel, J. Faust,

M. Fischer, F. Gentz, K. Gewald, R. Gluch, R. Mayer, K. Mller, D.

Pavel, H. Schmidt, K Schollberg, K. Schwetlick, E. Seiler, G.

Zeppenfeld, Organikum, 20th ed.; Johann Ambrosius Barth Verlag:

Heidelberg, Leipzig, 1996.

23 M. A. Keegstra, A. Klomp, Synthetic Commun 1990, 20, 3371.

24 R. Grisorio, P. Mastrorilli, C.F. Francesco Nobile, G. Romanazzi, G.

P. Suranna, E.W.Meijer, Tetrahedron Letters 2004, 45, 5367.

25 P. Zanello, in Ferrocenes, A. Togni, T. Hayashi, (Eds.), VCH,

Weinheim, New York, Basel, Cambridge, Tokyo, 1995, 317.


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