Stereoselective synthesis and luminescence properties of novel trans-regular N-alkylcarbazolylene-silylene-vinylene polymers

Article abstract of DOI:10.1016/j.jorganchem.2013.11.022

Novel trans-stereoregular silylene-carbazolylene-vinylene derivatives (13-15) were synthesized via silylative coupling reaction of 3,6-bis(dimethylvinylsilyl)-N-alkylcarbazole (7-9) catalyzed by ruthenium-hydride complex RuHCl(CO)(PCy₃)₂ (1). All products were isolated, fully characterized by spectroscopic methods and GPC analyses and their absorption and fluorescence properties were determined.

Full text of DOI:10.1016/j.jorganchem.2013.11.022

Journal of Organometallic Chemistry 750 (2014) 150e161
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Stereoselective synthesis and luminescence properties of novel
trans-regular N-alkylcarbazolyleneesilyleneevinylene polymers
Monika Ludwiczak a, Mariusz Majchrzak a, Ma1gorzata Bayda b, Bronis1aw Marciniak a,
,b,
Maciej Kubicki a, Bogdan Marciniec a
*
a
ꢀ
Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznan, Poland
Center of Advanced Technologies, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznan, Poland
b
ꢀ
a r t i c l e i n f o
a b s t r a c t
Article history:
Novel trans-stereoregular silyleneecarbazolyleneevinylene derivatives (13e15) were synthesized via
silylative coupling reaction of 3,6-bis(dimethylvinylsilyl)-N-alkylcarbazole (7e9) catalyzed by ruthenium
ehydride complex RuHCl(CO)(PCy3)2 (1). All products were isolated, fully characterized by spectroscopic
methods and GPC analyses and their absorption and fluorescence properties were determined.
Ó 2013 Elsevier B.V. All rights reserved.
Received 23 July 2013
Received in revised form
18 November 2013
Accepted 19 November 2013
Keywords:
Conjugated polymers
Ruthenium
Carbazole
Polycondensation
Silylative coupling
Silicon
1. Introduction
6- or 2- and 7-positions leading to poly(3,6-carbazole)s and poly
(2,7-carbazoles)s derivatives respectively.
Rapid development of advanced technologies observed in the
last decades has stimulated the search for new materials with
strictly defined physicochemical properties. From among the new
materials the conjugated polymers have attracted much attention
recently because of their prospective applications. They are very
good candidates for modern light sources (organic and polymer
light-emitting diodes OLED and PLED) [1], field effect transistors
(FET) [2], organic solar cell [3] or electrochromic displays [4].
Among a variety of polymeric structures such as poly(p-phenylene)
s, poly(p-phenylenevinylene)s, polythiophenes or polycarbazoles
the latter are particularly interesting because of the carbazole unit
they comprise [5]. The starting material, carbazole, is very cheap
and fully aromatic which ensures its chemical and environmental
stability. Moreover, the nitrogen atom can be easily substituted
with many functional groups which allows the regulation of
physico-chemical properties of the materials. Wide application
opportunities are open due to a possibility of substitution at 3- and
The introduction of silicon atoms into p-conjugated systems
improves their solubility and processability because of increased
flexibility. Molecular as well as macromolecular compounds con-
taining silyleneearylene (including silyleneecarbazolylene) frag-
ments can be synthesized via Wurtz polycondensation [1b,6,7],
Grignard reagents [7], as well as catalyzed by transition metals
reactions as Sonogashira [7,8], Suzuki [3a,9] and Suzuki/Miyaura
[10] coupling or Heck condensation [11].
A popular way to obtain vinyleneesilyleneehetarylene de-
rivatives is hydrosilylation reaction catalyzed by platinum and
rhodium complexes, but whilst it allows high yields it often leads to
many isomers [1g,6a,12].
Silylative coupling reaction of vinylsilanes in the presence of
ruthenium or rhodium complexes containing (or generating)
metalehydrogen ([M]eH) and metalesilicon ([M]eSi) bond seems
to be the optional, convenient and effective way to obtain this type
of compounds. The silylative coupling (SC) reaction proceeds
through cleavage of the ]CeSi bond of vinyl-substituted silicon
compounds and the activation of the ]CeH bond of the second
vinylsilane molecule [13,14] (Scheme 1).
* Corresponding author. Faculty of Chemistry, Adam Mickiewicz University,
The non-metallocarbene mechanism of this reaction involving
-silyl elimination and insertion of a C]C double bond into the
resulting [M]eSi bond has been previously reported [14] and can be
ꢀ
Umultowska 89b, 61-614 Poznan, Poland. Tel.: þ48 618291366.
b
E-mail
addresses:
marcinb@amu.edu.pl,
marcinb@main.amu.edu.pl
(B. Marciniec).
0022-328X/$ e see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2013.11.022

M. Ludwiczak et al. / Journal of Organometallic Chemistry 750 (2014) 150e161
151
Scheme 1. General scheme of silylative coupling reaction.
generalized for dimerization of divinyl-substituted silanes [15a,16],
siloxane [16], silazanes [17] and bis(vinylsilyl)alkanes [18] leading
to competitive linear oligomerization.
We have also presented the synthesis of polymers and co-
polymers containing aryleneesilyleneevinylene and arylenee
silyleneevinyleneephenyleneevinylene units, respectively, with
well-defined structures [19e22] (Scheme 2).
Nevertheless, to the best of our knowledge, no examples of a
method for the synthesis of silyl-carbazole conjugated compounds
have been described yet. Herein, we report a good efficient protocol
for the synthesis of novel trans-stereoregular carbazolyleneesily-
20 ꢁC; 4 g column packed with silica gel). UVeVis spectra were
recorded on Cary 5000 using 1 cm rectangular cell. Fluorescence
measurements were performed on a Perkin Elmer LS 50B spec-
trofluorimeter (lexc ¼ 310 nm, range: 280e750 nm, excitation slit:
5 nm, emission slit: 5 nm, single scans). Carbazole in cyclohexane
(deoxygenated solution, FFL ¼ 0.38) [24] was used as a reference to
determine fluorescence quantum yields. Fluorescence lifetime
measurements were carried out using a time-correlated single-
photon counting technique (nanosecond system from IBH Consul-
tants, Model 5000) using a photodiode laser 295 nm and a
photodiode 338 nm as the excitation sources. Fluorescence decays
were monitored at the maxima of the fluorescence.
leneevinylene
p-conjugated materials, their spectroscopic, ab-
sorption and luminescence characterization.
X-ray Crystallography. Diffraction data were collected at room
temperature by the
u-scan technique on an Agilent Technologies
four-circle diffractometers: for (4) Xcalibur with Eos CCD-detector,
2. Experimental section
ꢁ
using MoKa radiation source (
l
¼ 0.7107 A), and for (5) SuperNova,
ꢁ
with Atlas detector and microfocus CuKa X-ray tube (
l
¼ 1.5418 A).
2.1. General considerations
The data were corrected for Lorentz-polarization as well as for
absorption effects [25]. The structures were solved with SIR92 [26]
and refined with the full-matrix least-squares procedure on F2 by
SHELXL-2013 [27]. All non-hydrogen atoms were refined aniso-
tropically. The hydrogen atoms were placed geometrically, in
idealized positions, and refined as rigid groups with their Uiso’s as
1.2 times Ueq of the appropriate carrier atom. In the crystal struc-
ture of 5, the methyl groups of the isopropyl group are disordered
over two positions, with the site occupations of 68 and 32%.
The chemical reagents were obtained from the following
sources: hexane, pentane, toluene, diethyl ether, tetrahydrofuran
(THF), dimethylformamid (DMF), acetone were purchased from
Fluka, CDCl3, from Dr Glaser A. G. Basel, carbazole from Alfa Aesar,
styrene, 1,2-dibromoethane, ethanol, methanol, isopropyl bro-
mide, n-hexyl bromide, benzyl bromide, tetrabutylammonium
bromide, N-bromosuccinimide (NBS), magnesium sulfate, calcium
hydride, sodium hydride, potassium hydroxide from Aldrich and
chlorodimethylvinylsilane from Gelest. The solvents were distilled
(tetrahydrofuran, toluene and diethyl ether from sodium and
hexane from calcium hydride) under argon and stored over mo-
1H NMR (300 MHz), 13C NMR (75 MHz), 29Si NMR (60 MHz) and
DEPT (45, 60 and 135) spectra were recorded on a Varian XL
300 MHz spectrometer in CDCl3 solution. Chemical shifts are re-
ported in
d (ppm) with reference to the residue solvent (CDCl3)
peak for 1H, 13C and to TMS for 29Si. Analytical gas chromatographic
(GC) analyses were performed on a Varian Star 3400CX with a DB-5
fused silica capillary column (30 m ꢀ 0.15 nm) and TCD. Mass
spectra of the organic and organometallic molecular products were
obtained by GCMS analysis (Varian Saturn 2100T, equipped with a
BD-5 capillary column (30 m) and an ion trap detector. High-
resolution mass spectroscopic (HRMS) analyses were performed
on an AMD-402 mass spectrometer. Gel permeation chromatog-
raphy (GPC) analyses were performed using an Agilent HPLC sys-
tem equipped with UV absorbance detector and RI detector
(analysis conditions: mobile phase e THF; flow rate 0.80 mL/min;
temperature 20 ꢁC; injection volume e 17
mL). The number-average
molecular weight (Mn), weight-average molecular weight (Mw) and
polydispersity index (PDI) were determined by polystyrene stan-
dard calibration curve. Thin-layer chromatography (TLC) was made
ꢁ
lecular sieves type 4 A. Solvents for photophysical measurements,
on plates coated with 250 mm thick silica gel (Aldrich and Merck),
cyclohexane and dichloromethane (for spectroscopy, Merck)
were used as received. 3,6-dibromo-N-alkylcarbazoles were dried
and degassed and 1,4-divinylbenzene as well as chlorodimethyl
vinylsilane were purified by ‘bulb-to-bulb’ distillation and
stored under argon. All the syntheses of monomers, macromo-
lecular compounds and catalytic tests were carried out under
an inert argon atmosphere. Ruthenium complex [RuHCl(-
CO)(PCy3)2] (1) was prepared according to the literature procedure
[23].
and column chromatography was conducted with silica gel 60 (70e
230 mesh, Fluka). Gel chromatography analyses were performed
using a flash Reveleris system equipped with two UV absorbance
detectors and ELSD detector (analysis conditions: mobile phase e
dichloromethane/hexane 1:9; flow rate 2 mL/min; temperature
2.2. Syntheses of organic compounds
2.2.1. 3,6-Dibromocarbazole (3)
A solution of NBS (42.72 g, 0.24 mol) in 200 mL DMF was added
slowly to a suspension of carbazole (20 g, 0.12 mol) in dichloro-
methane (1.2 L). The reaction mixture was stirred at room
Scheme 2. Silylative coupling polycondensation (SCP) of bis(dimethylvinylsilyl)aryle-
nesin the presence of ruthenium complex.

152
M. Ludwiczak et al. / Journal of Organometallic Chemistry 750 (2014) 150e161
temperature and the progress of the reaction was controlled by
GCMS analysis. Then the solution was washed with water
(3 ꢀ 200 mL), the organic layer was dried under magnesium sulfate
and filtered. The solvent was evaporated and the residue was dis-
solved in acetone (100 mL) and precipitated with hexane (600 mL).
3,6-dibromocarbazole was filtered and dried under vacuum to
afford 35 g (yield 90%) of product.
Br
2
Br
7
5
6
3
4
9
N
1
8
H
1H NMR (300 MHz, CDCl3):
(d, 2H, JHH ¼ 8.6 Hz, H2), 8.13 (d, 2H, JHH ¼ 1.9 Hz, H4), 10.37 (s, 1H,
H9). 13C NMR (75 HMz, CDCl3):
112.2 (C1), 112.6 (C3), 123.3 (C4),
124.1 (Ci, NeC]Ce), 129þ.3 (C2), 138.3 (Ci, NeC]Ce). MS (EI): m/z
(rel. intensity e %): 327ꢂ (49), 325 (100), 326 (20), 246 (16), 165
(28), 138 (11), 83 (11).
d
7.31 (d, 2H, JHH ¼ 8.6 Hz, H1), 7.52
d
2.2.3. 3,6-Dibromo-N-isopropylcarbazole (5)
This compound was prepared using the same reaction condi-
tions as described above, but isopropyl bromide was used instead to
produce a white solid in 77% yield.
2.2.2. 3,6-Dibromo-N-hexylcarbazole (4)
Hexyl bromide (1.45 mL, 15.7 mmol), tetrabutylammonium
bromide (0.16 g, 0.5 mmol) and potassium hydroxide (0.83 g,
14.8 mmol) were added to a solution of 3,6-dibromocarbazole
ꢁ
(6.18 g, 9.2 mol) in acetone (previously dried under 3 A sieves).
The reaction mixture was stirred for 3 h and refluxed. Progress of
the reaction was controlled by GCMS analysis. Then the mixture
was cooled to room temperature and the solvent was evaporated.
The residue was dissolved in diethyl ether (100 mL), filtered and
washed with water (3 ꢀ 10 mL). The organic layer was dried under
magnesium sulfate and filtered. Then the solvent was evaporated
and the residue was stirred with pentane (100 mL) for 1 h, filtered
and dried under vacuum. 6.1 g (yield 78%) of 3,6-dibromo-N-hex-
ylcarbazole was obtained as white solid. The product was crystal-
lized by dissolving in small amount of hot hexane and left to cool at
room temperature.
1H NMR (300 MHz, CDCl3):
d
1.68 (d, 6H, JHH ¼ 7 Hz, H2 ), 4.91
0
0
(sept, 1H, JHH ¼ 7.0 Hz, H1 ), 7.42 (d, 2H, JHH ¼ 8.8 Hz, H2), 7.53 (d, 2H,
JHH ¼ 8.8 Hz, H1), 8.14 (d, 2H, JHH ¼ 1.9 Hz, H4). 13C NMR (75 MHz,
0 0
d 20.8 (C2 ), 47.1 (C1 ), 111.6 (C1), 111.8 (C3), 123.2 (C4), 123.9
CDCl3):
(Ci, NeC]Ce), 128.7 (C2), 138.3 (Ci, NeC]Ce). MS (EI): m/z (rel.
intensity e %): 367ꢂþ (61), 353 (18), 352 (100), 350 (39), 273 (33),
272 (12), 191 (8), 164 (25), 138 (8), 87 (8). Crystal Data: C15H13Br2N;
ꢁ
formula weight Mr ¼ 367.08; orthorhombic; Pbca; a ¼ 16.8746(3) A,
3
ꢁ
ꢁ
ꢁ
b ¼ 8.3695(2) A, c ¼ 20.3155(3) A, V ¼ 2869,20(10) A , Z ¼ 8,
dx ¼ 1.70 g cmꢃ3
,
l
¼ 1.54178 A (CuKa),
m
¼ 7.01 mmꢃ1; reflections:
ꢁ
collected 13,528, unique 2929 (Rint ¼ 2.65%), with I > 2
s(I) 2359;
ꢁꢃ3
R ¼ 5.26%, wR2 ¼ 15.81%, S ¼ 1.11, max/min Dr: 1.11/ꢃ0.68e A
.
Perspective view of the molecule 5 is presented below. Thermal
ellipsoids are drawn at the 33% probability level, hydrogen atoms
are represented by spheres of arbitrary radii. Only one possible
position for disordered C15 and C16 atoms is shown.
1H NMR (300 MHz, CDCl3):
d
0.86 (t, 3H, JHH ¼ 7.0 Hz, H6 ), 1.21e
0
0
0
0
0
1.38 (m, 6H, H3 , H4 , H5 ), 1.81 (quint, 2H, JHH ¼ 7.3 Hz, H2 ) 4.24 (t,
0
2H, JHH ¼ 7.2 Hz, H1 ), 7.27 (d, 2H, JHH ¼ 8.7 Hz, H2), 7.55 (d, 2H,
JHH ¼ 8.7 Hz, H1), 8.14 (d, 2H, JHH ¼ 1.9 Hz, H4). 13C NMR (75 MHz,
0 0 0 0
d 13.9 (C6 ), 22.5 (C5’), 26.9 (C3 ), 28.8 (C2 ), 31.5 (C4 ), 43.3
CDCl3):
0
(C1 ),110.4 (C1),111.9 (C3),123.2 (C4), 123.4 (Ci, NeC]Ce), 129.0 (C2),
139.3 (Ci, NeC]Ce). MS (EI): m/z (rel. intensity e %): 411ꢂþ (31), 409
(58), 408 (9), 341 (10), 340 (53), 338 (100), 337 (34), 258 (20), 152
(10). Crystal Data: C18H19Br2N; formula weight Mr ¼ 409.16;
ꢁ
ꢁ
orthorhombic; Pca21;
a
¼
20.3019(16) A,
b
¼
4.5582(4) A,
c ¼ 18.4012(18) A, V ¼ 1702.8(3) A , Z ¼ 4, dx ¼ 1.60 g cmꢃ3
,
3
ꢁ
ꢁ
ꢁ
l
¼ 0.71073 A (MoKa),
m
¼ 4.75 mmꢃ1; reflections: collected 27,069,
unique 3018 (Rint ¼ 10.58%), with I > 2 (I) 1827; R ¼ 6.43%,
s
ꢁꢃ3
wR2 ¼ 13.82%, S ¼ 1.03, max/min Dr: 0.79/ꢃ0.33e A . Perspective
view of the molecule 4 is presented below. Thermal ellipsoids are
drawn at the 50% probability level, hydrogen atoms are represented
by spheres of arbitrary radii.

M. Ludwiczak et al. / Journal of Organometallic Chemistry 750 (2014) 150e161
153
2.2.4. 3,6-Dibromo-N-benzylcarbazole (6)
2.3. Syntheses of organosilicon compounds
This compound was prepared using the same reaction condi-
tions as described for 4, but benzyl bromide was used instead. Also
dichloromethane was used instead of diethyl ether during isolation
procedure to produce a white solid in 84% yield.
2.3.1. 3,6-Bis(dimethylvinylsilyl)-N-hexylcarbazole (7)
A solution of 3,6-dibromo-N-hexylcarbazole (8.99 mmol) in
4 mL of THF was added slowly dropwise to a suspension of Mg
(1.1 g, 3.00 mmol, whose surface was activated by use of 1,2-
dibromoethane, 0.1 mL) and chlorodimethylvinylsilane (1.14 mL,
8.39 mmol) in 6 mL of THF (the mixture was lightly warmed, 20e
30 ꢁC). After the addition was completed, the reaction mixture was
refluxed and the progress of the reaction was controlled by GC
analysis. The mixture was cooled to room temperature, the solvent
was evaporated and the product was extracted with hexane/water
solvents. The organic layer was dried under magnesium sulfate and
filtered. The solvent was evaporated and the residue was separated
with silica gel column (hexane/CH2Cl2 ¼ 4:1, Rf ¼ 0.4). Light yellow
liquid mixture consisted of 3,6-bis(dimethylvinylsilyl)-N-hex-
ylcarbazole (82%), 3-(dimethylvinylsilyl)-N-hexylcarbazole (10%)
and 1,3,6-tris(dimethylvinylsilyl)-N-hexylcarbazole (8%) was
obtained.
1H NMR (300 MHz, CDCl3):
0 0
d 5.47 (s, 2H, H7 ), 7.06 (m, 2H, H2 ),
0
0
7.23e7.30 (m, 3H, H3 , H4 ), 7.25 (d, 2H, JHH ¼ 8.4 Hz, H2), 7.52 (d, 2H,
JHH ¼ 8.6 Hz, H1), 8.18 (d, 2H, JHH ¼ 1.5 Hz, H4). 13C NMR (75 MHz,
0
CDCl3):
d
46.8 (C7 2), 110.6 (C1), 112.5 (C3), 123.3 (C4), 123.6 (Ci, Ne
0
0
0
C]C), 126.21 (C2 ), 127.8 (C4’), 128.9 (C3 ), 129.3 (C2), 136.18 (C1 ),
139.55 (Ci, NeC]C). MS (EI): m/z (rel. intensity e %): 417ꢂþ (18), 415
(37), 164 (13), 91 (100), 65 (22).
2.2.5. N-Isopropylcarbazole (10)
This compound was prepared using the same reaction condi-
tions as for 4, but isopropyl bromide and carbazole was used
instead to produce a white solid in 85% yield.
1H NMR (300 MHz, CDCl3):
d 0.50 (s, SieCH3), 0.90 (t, 3H,
0
0
0
JHH ¼ 7.0 Hz, H6’), 1.23e1.43 (m, 6H, H3 , H4 , H5 ), 1.87 (quint, 2H,
0
0
JHH ¼ 7.2 Hz, H2 ), 4.32 (t, 2H, JHH ¼ 7.2 Hz, H1 ), 5.85 (dd, 2H,
JHH ¼ 3.9, 20.2 Hz, SieCH]CH2), 6.13 (dd, 2H, JHH ¼ 3.9, 14.6 Hz,
SieCH]CH2), 6.45 (dd, 2H, JHH ¼ 14.6, 20.2 Hz, SieCH]CH2), 7.27
(t, 1H, H7 from C22H29NSi), 7.46 (t, 1H, JHH ¼ 7.0 Hz, H6 from
C
22H29NSi), 7.45 (d, 2H, JHH ¼ 8.1 Hz, H2), 7.64 (d, 2H, JHH ¼ 8.2 Hz,
1H NMR (300 MHz, CDCl3):
d
1.73 (d, 6H, JHH ¼ 7.1 Hz, H2 ), 5.02
0
H1), 8.18 (t, 1H, JHH ¼ 7.7 Hz, H5 from C22H29NSi), 8.30 (d, 1H,
0
(sept, 1H, JHH ¼ 7.0 Hz, H1 ), 7.24 (t, 2H, H3), 7.46 (d, 2H, JHH ¼ 8.8 Hz,
JHH ¼ 1.9 Hz, H4 from C22H29NSi), 8.33 (d, 2H, JHH ¼ 1.8 Hz, H4). 13
C
H2), 7.55 (d, 2H, JHH ¼ 8.2 Hz, H1), 8.14 (d, 2H, JHH ¼ 7.9 Hz, H4). 13
C
0
0
NMR (75 MHz, CDCl3):
d
ꢃ2.4 (SieCH3), 14.0 (C6 ), 22.5 (C5 ), 26.9
0
0
NMR (75 MHz, CDCl3): d 20.8 (C2 ), 46.6 (C1 ), 109.9 (C1), 118.49 (C3),
0
0
0
0
(C3 ), 28.9 (C2 ), 31.6 (C3 ), 43.0 (C1 ), 108.3 (C1), 108.6 (C1 from
120.3 (C4), 123.3 (Ci, NeC]Ce), 125.3 (C2), 139.4 (Ci, NeC]Ce). MS
(EI): m/z (rel. intensity e %): 209ꢂþ (50), 194 (100), 167 (16), 139 (7).
C
22H29NSi), 118.9 (C8 from C22H29NSi), 120.3 (C6 from C22H29NSi),
122.7 (C3), 125.5 (C7 from C22H29NSi), 126.1 (C4), 126.50 (Ci, NeC]
Ce from C22H29NSi), 126.6 (C5 from C22H29NSi, 126.7 (Ci, NeC]Ce
), 131.0 (C2), 132.5 (SieCH]CH2), 138.9 (SieCH]CH2), 140.4 (Ci, Ne
C]Ce from CeCH]CHeCSi]CHe), 141.1 (Ci, NeC]Ce). 29Si NMR
2.2.6. 3-Bromo-N-isopropylcarbazole (11)
This compound was prepared using the same reaction condi-
tions as for 3, but N-isopropylcarbazole and NBS (1:1) were used
instead to produce a white solid in 92% yield.
(60 MHz, CDCl3):
d
ꢃ10.55 (for C22H29NSi), ꢃ10.50 (for
C26H37NSi2). MS (EI): m/z (rel. intensity
e
%): 3,6-
bis(dimethylvinylsilyl)-N-hexylcarbazole: 420ꢂþ (36), 419 (100),
406 (5), 360 (19), 349 (43), 335 (11), 334 (22), 85 (9), 59 (12); 3-
(dimethylvinylsilyl)-N-hexylcarbazole: 336ꢂþ (23), 335 (84), 320
(38), 267 (6), 266 (25), 265 (100), 206 (7), 114 (4), 85 (3), 59 (6);
1,3,6-tris(dimethylvinylsilyl)-N-hexylcarbazole: 506ꢂþ (7), 505
(24), 504 (48), 503 (100), 432 (26), 419 (32), 405 (69), 347 (6), 307
(11), 114 (7), 85 (28), 73 (7), 59 (27).
1H NMR (300 MHz, CDCl3):
d
1.7 (d, 6H, JHH ¼ 6.8 Hz, H2 ), 4.96
2.3.2. 3,6-Bis(dimethylvinylsilyl)-N-isopropylcarbazole (8)
0
0
(sept, 1H, JHH ¼ 7.0 Hz, H1 ), 7.24 (t, 1H, H6), 7.41 (d, 1H, JHH ¼ 7.8 Hz,
H2), 7.51 (m, 3H, H1, H7, H8), 8.06 (d, 1H, JHH ¼ 7.7 Hz, H5), 8.22 (s, 1H,
This compound was prepared using the same reaction condi-
tions as described above, but 3,6-dibromo-N-isopropylcarbazole
was used instead to produce 1.11 g of mixture consisted of 3,6-
bis(dimethylvinylsilyl)-N-isopropylcarbazole (76%), 3-(dimethylvi-
H4). 13C NMR (75 HMz, CDCl3):
d 20.8 (C2 ), 46.9 (C1 ),110.2 (C1),111.4
0 0
(C5), 119.0 (C8), 120.3 (C6), 122.2 (Ci-Br), 123.0 (C7), 125.1 (Ci, NeC]
Ce), 126.1 (C4), 127.93 (C2), 138.0 (Ci, NeC]Ce), 139.7 (Ci, NeC]Ce
). MS (EI): m/z (rel. intensity e %): 287ꢂþ (40), 274 (100), 193 (15),
254 (4), 193 (21), 166 (9), 139 (7), 63 (3).
nylsilyl)-N-isopropylcarbazole
(17%)
and
1,3,6-
tris(dimethylvinylsilyl)-N-isopropylcarbazole (7%) was obtained as
colorless liquid.

154
M. Ludwiczak et al. / Journal of Organometallic Chemistry 750 (2014) 150e161
1H NMR (300 MHz, CDCl3):
d
0
0.53 (s, SieCH3), 5.52 (s, 2H, H7 ),
5.69-6.48 (m, SieCH]CH2, from C23H23NSi), 5.89 (dd, 2H, JHH ¼ 3.9,
20.3 Hz, SieCH]CH2), 6.17 (dd, 2H, JHH ¼ 3.9, 14.7 Hz, SieCH]CH2),
6.48 (dd, 2H, JHH ¼ 14.7, 20.3 Hz, SieCH]CH2), 7.20 (d, 2H,
0
JHH ¼ 8.1 Hz, H2 ), 7.24 (m, 1H, H7 from C23H23NSi), 7.26e7.33 (m,
3H, H3’), 7.43 (m, 1H, H6 from C23H23NSi) 7.43 (d, 2H, JHH ¼ 8.2 Hz,
H2), 7.61 (m, 1H, H8 from C23H23NSi), 7.64 (d, 2H, JHH ¼ 8.2 Hz, H1),
8.24 (tryplet, 1H, JHH ¼ 7.8 Hz, H5 from C23H23NSi), 8.38 (d, 1H,
JHH ¼ 2.1 Hz, H4 from C23H23NSi), 8.40 (d, 2H, JHH ¼ 1.9 Hz, H4). 13
C
0
NMR (75 MHz, CDCl3):
d
ꢃ2.4 (SieCH3), 46.5 (C7 ), 108.6 (C2), 108.9
(C1 from C23H23NSi), 119.4 (C8 from C23H23NSi), 120.3 (C6 from
23H23NSi), 122.81 (C3), 125.8 (C7 from C23H23NSi), 126.1 (C4), 126.4
1H NMR (300 MHz, CDCl3):
d
0.48 (s, SieCH3), 1.72 (d, 6H,
C
0
JHH ¼ 7.0 Hz, H2’), 5.02 (sept, 1H, JHH ¼ 7.0 Hz, H1 ), 5.83 (dd, 2H,
JHH ¼ 3.9, 20.2 Hz, SieCH]CH2), 6.12 (dd, 2H, JHH ¼ 3.9, 14.6 Hz, Sie
CH]CH2), 6.43 (dd, 2H, JHH ¼ 14.6, 20.2 Hz, SieCH]CH2), 7.24 (t,
1H, JHH ¼ 7.0 Hz, H7 from C22H29NSi), 7.47 (t, 1H, JHH ¼ 7.0 Hz, H6
from C22H29NSi), 7.55 (d, 2H, JHH ¼ 8.6 Hz, H2), 7.61 (d, 2H,
JHH ¼ 8.2 Hz, H1), 8.17 (t, 1H, JHH ¼ 7.6 Hz, H5 from C22H29NSi), 8.30
(d, 1H, JHH ¼ 1.9 Hz, H4 from C22H29NSi), 8.32 (d, 2H, JHH ¼ 1.8 Hz,
(Ci, NeC]Ce), 126.41 (-C6H5), 127.45 (ꢃC6H5), 128.7 (ꢃC6H5), 131.3
(C2), 132.5 (SieCH]CH2), 137.0 (Ci, ꢃC6H5), 138.8 (SieCH]CH2),
141.4 (Ci, NeC]Cꢃ). 29Si NMR (60 MHz, CDCl3):
d
ꢃ10.46 (for
C
23H23NSi), ꢃ10.41 (for C27H31NSi2). MS (EI): m/z (rel. intensity e
%): 3,6-bis(dimethylvinylsilyl)-N-benzylcarbazole: 425ꢂþ (100), 424
(70), 410 (47), 341 (19), 335 (17), 91 (45), 59 (44). 3-(dimethylvi-
nylsilyl)-N-benzylcarbazole: 342ꢂþ (33), 341 (100), 326 (70), 300
(16), 250 (26), 91 (64), 59 (5). 1,3,6-tris(dimethylvinylsilyl)-N-ben-
zylcarbazole: 510ꢂþ (38), 509 (100), 424 (35), 318 (28), 208 (18), 91
(34), 65 (34).
H4). 13C NMR (75 MHz, CDCl3):
d
ꢃ2.4 (SieCH3), 20.8 (C2 ), 46.6 (C1 ),
0
0
109.7 (C1), 109.9 (C1 from C22H29NSi), 118.1 (C8 from C22H29NSi),
120.3 (C6 from C22H29NSi), 123.1 (C3), 125.3 (C7 from C22H29NSi),
126.1 (C4), 126.2 (Ci, NeC]Ce), 130.7 (C2), 132.5 (SieCH]CH2),
138.9 (SieCH]CH2), 140.1 (Ci, NeC]Ce). 29Si NMR (60 MHz,
2.3.4. 3-(dimethylvinylsilyl)-N-isopropylcarbazole (12)
CDCl3):
m/z (rel. intensity
d
ꢃ10.63 (for C19H23NSi), ꢃ10.57 (for C23H31NSi2). MS (EI):
This compound was prepared using the same reaction condi-
tions as described for 7, but 3-bromo-N-isopropylcarbazole was
used instead to produce 1.2 g of colorless liquid (75%).
e
%): 3,6-bis(dimethylvinylsilyl)-N-iso-
propylcarbazole: 377ꢂþ (60), 364 (15), 363 (37), 362 (100), 319 (6),
292 (23), 276 (6), 85 (23), 59 (36); 3-(dimethylvinylsilyl)-N-iso-
propylca-rbazole: 249ꢂþ (9), 293 (36), 278 (100), 252 (16), 85 (23),
59 (17); 1,3,6-tris(dimethylvinylsilyl)-N-isopropylcarbazole: 463ꢂþ
(17), 462 (38), 461 (100), 446 (60), 420 (12), 418 (32), 377 (16), 376
(37), 334 (22), 320 (6), 276 (6), 85 (41), 59 (60).
2.3.2.1. 3,6-Bis(dimethylvinylsilyl)-N-isopropylcarbazole (8b) e after
flash chromatography. 1H NMR (300 MHz, CDCl3):
d
0.48 (s, Sie
0
0
CH3), 1.72 (d, 6H, JHH ¼ 7.0 Hz, H2 ), 5.02 (sept, 1H, JHH ¼ 7.0 Hz, H1 ),
5.83 (dd, 2H, JHH ¼ 3.9, 20.2 Hz, SieCH]CH2), 6.12 (dd, 2H,
JHH ¼ 3.9, 14.6 Hz, SieCH]CH2), 6.43 (dd, 2H, JHH ¼ 14.6, 20.2 Hz,
SieCH]CH2), 7.55 (d, 2H, JHH ¼ 8.6 Hz, H2), 7.61 (d, 2H, JHH ¼ 8.2 Hz,
1H NMR (300 MHz, CDCl3):
d
0.46 (s, SieCH3), 1.72 (d, 6H,
H1), 8.32 (d, 2H, JHH ¼ 1.8 Hz, H4). 13C NMR (75 MHz, CDCl3):
ꢃ2.4
d
0
0
JHH ¼ 7.0 Hz, H2 ), 5.02 (sept, 1H, JHH ¼ 7.0 Hz, H1 ), 5.83 (dd, 1H,
JHH ¼ 3.7, 20.2 Hz, SieCH]CH2), 6.11 (dd, 1H, JHH ¼ 3.7, 14.6 Hz,
SieCH]CH2), 6.41 (dd, 1H, JHH ¼ 14.6, 20.2 Hz, SieCH]CH2), 7.24
(t, 1H, H7), 7.45 (t, 1H, H6), 7.54 (d, 1H, H8), 7.56 (t, 1H, H2), 7.60 (d,
1H, JHH ¼ 8.2 Hz, H1), 8.15 (t, 1H, H5), 8.30 (s, 1H, H4). 13C NMR
0
0
(SieCH3), 20.8 (C2 ), 46.6 (C1 ), 109.7 (C1), 123.1 (C3), 126.1 (C4), 126.2
(Ci, NeC]Ce), 130.7 (C2), 132.5 (SieCH]CH2), 138.9 (SieCH]CH2),
140.1 (Ci NeC]Ce). 29Si NMR (60 MHz, CDCl3):
d
ꢃ10.60 MS (EI):
m/z (rel. intensity
e
%): 3,6-bis(dimethylvinylsilyl)-N-iso-
propylcarbazole: 377ꢂþ (60), 364 (15), 363 (37), 362 (100), 319 (6),
292 (23), 276 (6), 85 (23), 59 (36).
0
0
(75 MHz, CDCl3):
d
ꢃ2.4 (SieCH3), 20.8 (C2 ), 46.6 (C1 ), 109.7 (C1)
109.9 (C5), 118.5 (C8), 120.3 (C6), 123.3 (C3), 125.3 (C7), 126.1 (C4),
126.3 (Ci, NeC]Ce), 130.7 (C2), 132.5 (SieCH]CH2), 138.9 (Sie
CH]CH2), 139.4 (Ci, NeC]C-), 140.1 (Ci, NeC]C-). 29Si NMR
2.3.3. 3,6-Bis(dimethylvinylsilyl)-N-benzylcarbazole (9)
This compound was prepared using the same reaction condi-
tions as described for 7, but 3,6-dibromo-N-benzylcarbazole was
used instead to produce 5.3 g of light yellow liquid mixture con-
sisted of 3,6-bis(dimethylvinylsilyl)-N-benzylcarbazole (76%), 3-
(60 MHz, CDCl3):
d
ꢃ10.63 (for C19H23NSi), ꢃ10.64 (for C23H31NSi2).
MS (EI): m/z (rel. intensity e %): 3-(dimethylvinylsilyl)-N-iso-
propylcarbazole: 294ꢂþ (9), 293 (36), 278 (100), 252 (16), 85 (23),
59 (17).
(dimethylvinylsilyl)-N-benzylcarbazole
(22%)
and
1,3,6-
tris(dimethylvinylsilyl)-N-benzylcarbazole (2%).
2.4. A typical procedure for catalytic examination
The syntheses were carried out in dried and evacuated (vacuum/
argon) 5 mL glass ampoule-reactors equipped with a magnetic
stirring bar under argon atmosphere. The reaction mixture con-
tained toluene (the amount depended on total concentration:
0.25e1 M), dimethylvinylsilylhetarylene (0.5 mmol), rutheniume
hydride complex [RuHCl(CO)(PCy3)2] (1) (0.5% mole2% mol). The
system was heated in an oil bath at 80 ꢁC for 72 h and then 1H NMR
analysis was performed (NMR spectra were measured at room
temperature in CDCl3 solution).

M. Ludwiczak et al. / Journal of Organometallic Chemistry 750 (2014) 150e161
155
2.5. A general procedure for silylative coupling polycondensation
(SCP)
1H NMR (300 MHz, CDCl3):
d
0.46 (s, 12H, SieCH3), 1.65 (d, Ne
0
0
H2 ), 4.95e4.97 (m, 1H, H1 ), 6.95 (s, 2H, Si-HC]CHeSi), 7.50 (d, 2H,
H2), 7.58 (d, 2H, H1), 8.30 (d, 2H, H4). 13C NMR (75 MHz, CDCl3):
0
0
Reagents and solvent were dried and deoxygenated, the syn-
d
ꢃ2.3 (SieCH3), 20.8 (C2 ), 46.6 (C1 ), 109.6 (C1), 109.9 (CI), 118.6
theses were carried out under argon atmosphere. A mixture of
monomer (7, 8 or 9), rutheniumehydride complex [RuHCl(-
CO)(PCy3)2] (1) and toluene were placed in 5e10 mL glass reactor
equipped with magnetic stirring bar and condenser connected to a
bubbler. Molar ratio of reagents were [ViSi]:[RueH] ¼ 1:0.01, con-
centration of solution was 1 M. The reaction mixture was stirred
and heated at 80 ꢁC under argon flow for 72 h.
(CVIII), 120.3 (CVI), 123.1 (C3), 125.3 (CVII), 126.1 (C4), 126.8 (Ci, NeC]
Ce), 130.9 (C2), 140.0 (Ci, NeC]Ce), 150.8 (Si-HC]CHeSi). 29Si
NMR (60 MHz, CDCl3):
d
ꢃ11.47, ꢃ11.41. GPC analysis: Mw ¼ 5464
[g*molꢃ1], Mn ¼ 3002 [g*molꢃ1], PDI (Mw/Mn) ¼ 1.82, n ¼ 9. The
compound was isolated as white powder, yield 77%.
2.7.3. Poly[dimethylsilylene-(3,6-N-isopropylcarbazolylene)-
dimethyl-silylene-(E)-vinylene](14b)
2.6. Isolation procedure of macromolecular compounds
After the reaction was completed, the solvent was evaporated
under vacuum. The product was dissolved in THF, purified by
repeated precipitation from methanol, filtered and dried under
vacuum. The isolated yields were as follows: 47e80% depending of
substrates.
2.7. Analytical data of macromolecular compounds
2.7.1. Poly[dimethylsilylene-(3,6-N-hexylcarbazolylene)-dimethyl-sil
ylene-(E)-vinylene] (13)
1H NMR (300 MHz, CDCl3):
d
0.46 (s, 12H, SieCH3), 1.65 (d, H2 ),
0
0
4.95e4.97 (m, 1H, H1 ), 6.95 (s, 2H, Si-HC]CHeSi), 7.50 (d, 2H, H2),
7.58 (d, 2H, H1), 8.30 (d, 2H, H4). 13C NMR (75 MHz, CDCl3):
d
ꢃ2.3
0
(SieCH3), 20.8 (C2’), 46.6 (C1 ), 109.6 (C1), 123.1 (C3), 126.1 (C4), 126.8
(Ci, NeC]Ce), 130.9 (C2), 140.0 (Ci, NeC]Ce), 150.8 (Si-HC]CHe
Si). 29Si NMR (60 MHz, CDCl3):
d
ꢃ11.43. GPC analysis: Mw ¼ 8155
[g*mol-1], Mn ¼ 4910 [g*mol-1], PDI (Mw/Mn) ¼ 1.66, n ¼ 15. The
compound was isolated as white powder, yield 80%.
2.7.4. Poly[dimethylsilylene-(3,6-N-benzylcarbazolylene)-
dimethyl-silylenee(E)evinylene] (15)
1H NMR (300 MHz, CDCl3):
d
0.46 (s, SieCH3), 0.90 (m, 3H, H6 ),
0
0
0
0
0
0
1.26-1.40 (m, 6H, H3 , H4 , H5 ),1.71e1.95 (m, 2H, H2 ), 4.26 (m, 2H, H1 ,
5.79 (dd, 2H, JHH ¼ 39, 20.3 Hz, SieCH]CH2), 6.08 (dd, 2H, JHH ¼ 4.0,
14.6 Hz, SieCH]CH2), 6.40 (dd, 2H, JHH ¼ 14.7, 20.3 Hz, SieCH]CH2),
6.95 (s, SieCH]CHeSi), 7.40 (d, 2H, JHH ¼ 7.6 Hz, H2), 7.60 (d, 2H,
JHH ¼ 8.0 Hz, H1), 8.08 (t,1H, HV), 8.28 (d,1H, HIV), 8.30 (d, 2H, H4). 13
C
0
0
NMR (75 MHz, CDCl3):
d
ꢃ2.3 (SieCH3),14.0 (C6 ), 22.5 (C5 ), 26.9 (C3’),
0
0
28.9 (C2 ), 31.6 (C4 ), 43.0 (C1’), 108.3 (C1), 108.6 (CI), 118.8 (CVIII), 120.3
(CVI),122.7 (C3),125.5 (CV),126.1 (CVII),126.2 (C4),126.7 (Ci, NIx-C]C-),
127.0 (Ci, NeC]C-), 130.9 (C2), 132.5 (SieCH]CH2), 138.9 (SieCH]
CH2), 141.1 (Ci, NeC]Ce),150.8 (SieCH]CHeSi). 29Si NMR (60 MHz,
CDCl3):
d
ꢃ12.49 (for C22H29NSi), ꢃ11.15 (for C26H37NSi2). GPC anal-
ysis: Mw ¼ 3685 [g*molꢃ1], Mn ¼ 1956 [g*molꢃ1], PDI (Mw/Mn) ¼ 1.85,
n ¼ 8. The compound was isolated as white powder, yield 47%.
1H NMR (300 MHz, CDCl3):
d
0.46 (s, SieCH3), 5.50 (s, 2H, H7 ),
0
2.7.2. Poly[dimethylsilylene-(3,6-N-isopropylcarbazolylene)-
dimethylesilylenee(E)evinylene] (14a)
5.83 (trace, dd, 2H, SieCH]CH2), 6.08 (trace, dd, 2H, SieCH]CH2),
6.40 (trace, dd, 2H, SieCH]CH2), 6.97 (SieCH]CHeSi), 7.17 (d, 2H,

156
M. Ludwiczak et al. / Journal of Organometallic Chemistry 750 (2014) 150e161
Scheme 3. Synthesis of 3,6-bis(dimethylvinylsilyl)-N-alkylcarbazole.
Scheme 4. Synthesis of poly[dimethylsilylene-(3,6-N-alkylcarbazolylene)-(E)-vinylene]s.
Fig. 1. 1H NMR spectra of poly[dimethylsilylene-(3,6-N-isopropylcarbazolylene)-dimethylsilylene-(E)-vinylene] (14a) in CDCl3 at 25 ꢁC.

M. Ludwiczak et al. / Journal of Organometallic Chemistry 750 (2014) 150e161
157
Fig. 2. 13C NMR spectra of poly[dimethylsilylene-(3,6-N-isopropylcarbazolylene)-dimethylsilylene-(E)-vinylene] (14a) in CDCl3 at 25 ꢁC.
141.3 (Ci, NeC]Ce), 150.8 (SieCH]CHeSi). 29Si NMR (60 MHz,
Table 1
CDCl3):
d
ꢃ11.40, ꢃ11.29. GPC analysis: Mw ¼ 5901 [g*molꢃ1],
The results of SCP for dimethylsilylene-(3,6-N-alkylcarbazolylene)-silylelene-(E)-
vinylene polymers.
Mn ¼ 3816 [g*molꢃ1], PDI (Mw/Mn) ¼ 1.55, n ¼ 8. The compound
Mw [g*molꢃ1
]
Mna [g*molꢃ1
]
PDIa
nb
a
Entry
Isolated yield (%)
was isolated as white powder, yield 75%.
15
14a
14b
75
77
80
5900
5500
8200
3800
3000
4900
1.6
1.8
1.7
8
9
15
3. Results and discussion
a
Mw, Mn and PDI determined by GPC using polymer standards e polystyrenes e
as references (THF as an eluent).
3.1. Materials synthesis and characterization
b
Calculated for main signals from GPC chromatogram.
The general synthetic routes of monomer synthesis and poly-
condensation are presented in Schemes 3 and 4 respectively. First,
N-bromosuccinimide (NBS) was used to brominate the 3,6-position
of carbazole to obtain 3,6-dibromocarbazole and then the nitrogen
atom was substituted with alkyl groups: hexyl, isopropyl and
benzyl. These two steps were carried out under air directly from
commercial available compounds and allowed obtaining the
JHH ¼ 8.0 Hz, H2’), 7.20e7.24 (m, 3H, H3’, H4’), 7.40 (d, 2H, H2), 7.56 (d,
2H, H1), 8.13 (t, 1H, HV), 8.31 (d, 1H, JHH ¼ 2.1 Hz, HIV), 8.34 (d, 2H,
JHH ¼ 1.9 Hz, H4). 13C NMR (75 MHz, CDCl3):
d
ꢃ2.3 (SieCH3), 46.5
0
(C7 ), 108.5 (C1), 108.9 (CI), 119.3 (CVII), 120.3 (CVI), 122.8 (Ci-Si), 125.8
0
(CVII), 126.4 (C4), 127.4 (Ci, NeC]Ce), 128.7 (C2), 131.3 (CI ), 132.5
(trace, SieCH]CH2), 137.05 (Ci, eC6H5), 138.8 (trace, SieCH]CH2)
Fig. 3. GPC chromatogram in THF of polymer 14a and 14b.

158
M. Ludwiczak et al. / Journal of Organometallic Chemistry 750 (2014) 150e161
Fig. 4. 1H NMR and 13C NMR spectra of poly[dimethylsilylene-(3,6-N-isopropylcarbazolylene)-dimethylsilylene-(E)-vinylene] (14b) in CDCl3 at 25 ꢁC.
predicted products with high yields. All synthesized 3,6-dibromo-
N-alkylcarbazoles were dried and kept under argon for the next
step. Most of the reactions proceeded selectively with very good
yield to form the respective carbazole derivatives. Additionally X-
ray analyses were performed for 4 and 5.
products. However, the undesirable compounds were obtained,
two by-products 3-(dimethylvinylsilyl)-N-alkylcarbazole (due to
partial debromination) and 1,3,6-tris(dimethylvinylsilyl)-N-alkyl-
carbazole were present. That is why next steps (polycondensation)
were carried out with above mentioned mixtures. As we have
previously reported, pentacoordinated ruthenium complexes are
the most effective in stereoselective SCP of bis(dimethylvinylsilyl)
arylenes and that is why [RuHCl(CO)(PCy3)2] (1) was chosen as a
catalyst for polycondensation of bis(dimethylvinylsilyl)-N-alkyl-
carbazoles. All reactions were carried out at 80 ꢁC under argon flow
for 72 h in toluene. Because of using a mixture of compounds as
starting material many possible products could be obtained, but
surprisingly the reaction led to the expected trans-regular poly
[dimethylsilylene-(3,6-N-alkylcarbazolylene)-(E)-vinylene]s
3,6-Bis(dimethylvinylsilyl)-N-hexylcarbazole (7), 3,6-bis(dime
thylvinylsilyl)-N-isopropylcarbazole
(8),
3,6-bis(dimethylviny
lsilyl)-N-benzylcarbazole (9) were prepared in ’one pot’ by well
known Grignard’s reaction under argon atmosphere. 3,6-dibromo-
N-alkylcarbazoles with magnesium in THF generated ‘in situ’
Grignard reagent, which immediately reacted with chlor-
odimethylvinylsilane. The initial studies (different temperatures,
amount of chlorosilane and different solvents) of the above
mentioned process allowed to minimize the formation of side
Fig. 5. Absorption, normalized fluorescence spectra (left figure) and fluorescence decays (right figure) of molecular compounds.

M. Ludwiczak et al. / Journal of Organometallic Chemistry 750 (2014) 150e161
159
Table 2
Absorption and fluorescence properties of compounds in CH2Cl2 (air-saturated solutions) at room temperature.
a
Compound
3
(
lAbs, max) [dm3 ꢀ molꢃ1 ꢀ cm]
lFL, max [nm]
FFL
sFL [ns]
kFb [nsꢃ1
]
N
H
27,500 (212)
39,200 (233)
21,800 (245)
11,800 (255)
19,000 (291)
2900 (307)
3800 (318)
3600 (331)
335
350
0.38c
0.23d
11.5
7.0
0.033
2ref
refin cyclohexane (reference solution)
N
H
14,100 (257)
16,100 (292)
3700 (320)
3100 (333)
339
354
0.18
6.7
0.027
2
N
23,600 (265)
14,900 (295)
3500 (332)
3900 (346)
352
369
0.18
6.2
0.029
10
Si
38,900 (241)
34,100 (269)
11,700 (298)
3300 (332)
3300 (347)
353
370
0.18
0.16
6.3
6.5
0.029
0.025
N
12
35,400 (243)
29,800 (273)
8700 (300)
2400 (322)
2600 (334)
1800 (347)
355
372
14a
25,700 (244)
23,900 (274)
5800 (300)
2000 (334)
1700 (347)
358
373
0.14
6.00
0.023
29,500 (243)
23,100 (272)
7200 (299)
2300 (330)
2100 (344)
369
0.10
5.8
0.017
Bold values signify the most important values of photochemical studies.
a
Molar absorption coefficients for homopolymers are calculated per mer.
b
c
ꢃ1
.
FL
kF was calculated using formula kF
Data taken from Refs. [24], deoxygenated solution.
¼
FFL
ꢀ
s
d
FFL ¼ 0.38 for oxygen-free solution of carbazole was used to determine fluorescence quantum yield for carbazole in cyclohexane in air-saturated solution (FFL ¼ 0.23). The
latter solution served as a secondary reference to determine fluorescence quantum yields of synthesized compounds.

160
M. Ludwiczak et al. / Journal of Organometallic Chemistry 750 (2014) 150e161
Fig. 6. Absorption, normalized fluorescence spectra (left figure) and fluorescence decays (right figure) of compound 12 and macromolecular materials 14e15.
mostly terminated with 3-(dimethylvinylsilyl)-N-alkylcarbazole.
All polymeric materials showed good solubility in organic solvents
as THF, CH2Cl2, CHCl3 so GPC analyses were performed.
reaction and confirmed trans-structure it is almost impossible to
obtain a cyclic compound. It is reasonable then to assume that the
structure of the polymer is linear. Main differences between ma-
terials obtained from mixture and pure compounds are shown in
GPC results (Table 1, Fig. 3), the increase of molecular weights and
decrease of polydispersity indexes, were observed.
Figs. 1 and 2 present 1H NMR and 13C NMR spectra of the ob-
tained
poly[dimethylsilylene-(3,6-N-isopropylcarbazolylene)-
dimethylsilylene-(E)-vinylene] (14a). As we have previously proved
[13d,20] only trans- and gem-isomers are expected as products of
dimethylvinylsilylarenes silylative coupling reaction. Fig. 1 shows
the presence of singlet (6.95 ppm) assigned to vinylene fragment.
Due to DEPT analyses we were able to confirm that obtained
product has trans-regular structure. 1H NMR spectrum shows no
signals expected from terminal vinyl groups and on 13C NMR
spectrum only the small signal (132.5 ppm) assigned to SieCH]
CH2 has been seen, which suggests almost total termination of the
polymer. That statement was also confirmed by presence of some
signals characteristic for 3-substituted-N-alkylcarbazole. Figs.1 and
2 show respectively signals charac0teristic for the proton H4’
3.2. Photophysical properties
Absorption and fluorescence spectra were recorded in air-
saturated dichloromethane at room temperature. On Fig. 5 refer-
ence solution of carbazole in cyclohexane (2ref) is presented for
comparison. Carbazole reveals a bathochromic shift with an in-
crease in the solvent polarity from cyclohexane to dichloromethane
(Fig. 5, panel A) indicating that the lowest excited singlet state has
pe
p* character. Substitution of an isopropyl group at the nitrogen
(10) shifts the absorption and fluorescence spectra to the red (Fig. 5,
panel B). Further modification with a dimethylsilylvinyl group at
position 3 (12) does not change the fluorescence profile signifi-
cantly (Fig. 5, panel C). Characteristic for 3-dimethylvinylsilyl-N-
isopropylcarbazole is its intense band in an absorption at 269 nm.
(Table 2)
0
0
(8.29 ppm) and carbons C6 , C7 , C8 (120.3, 125.3, 118.6 ppm).
Although not all expected signals of terminal fragment were
0
detected it is possible not to see them. Proton H6 should be seen at
about 7.45 ppm but it is near the signal H2 (7.5 ppm) which is wider
for the polymer than for a molecular0compounds. At 7.20 ppm and
0
8.10 ppm only traces of H7 and H5 were observed. Most of ex-
Fluorescence lifetimes for all compounds are in the range of 7.0
to 5.8 ns. Although the polymers have slightly lower fluorescence
quantum yields and fluorescence lifetimes, they have in general
very similar photophysical behavior to 3-dimethylvinylsilyl-N-iso-
propylcarbazole indicating that silicon acts as an insulating spacer
between monomeric units (Fig. 6). This is the reason that the length
of the investigated polymers does not affect their photophysical
properties, namely there is not much difference between polymer
14a, synthesized from a mixture of substrates, and polymer 14b,
synthesized from purified 3,6-bis(dimethylvinylsilyl)-carbazole.
Higher molar absorption coefficient and fluorescence quantum
yield for 14a comparing to 14b may be due to a presence of
remaining 3-dimethylvinylsilyl-N-isopropylcarbazole. Drawing any
conclusion about the influence of polymer termination on the
photophysical behavior is unjustified because of similarity between
compounds 10 and 12.
pected for 3-substituted-N-isopropylcarbazole carbon atoms were
difficult to detect because of their appearance at the same ppm
value as for 3,6-disubstituted-N-isopropylcarbazole.
According to the results, the polymeric material obtained con-
sisted of about 9 mers, which is directly connected with presence of
3-(dimethylvinylsilyl)-N-alkylcarbazole in the reaction mixture,
being responsible for polymer termination.
To improve results all efforts were directed towards better
separation of starting materials. The satisfying effect was obtained
for 3,6-bis(dimethylvinylsilyl)-N-isopropylcarbazole. Applying off-
lash chromatography allowed to increase purity of compound 8
from 76% to over 99%. Though small amount of pure compound was
obtained, it allowed to continue experiment. SC polymerization
was carried out in the same conditions as before and material 14b
was obtained. The NMR spectra (Fig. 4) were similar to materials
synthesized from mixture of dimethylvinylsilylcarbazoles and
proved linear structures of obtained polymer materials without
regard for purity of starting compounds. Characteristic signals for
(E)-vinylene fragments and as expected no traces of 3-substituted-
N-alkylcarbazole are seen. Although expected terminal vinyl groups
have not been detected it is related to the length of obtained ma-
terial. Polymer 14a consisted of about 9 mers and signals of its
terminal group (3-substituted-N-isopropylcarbazole) were difficult
to detect. Because of the mechanism of the silylative coupling
4. Conclusions
The novel trans-stereoregular carbazole oligomer derivatives
have been synthesized via highly chemoselective silylative
coupling reaction. Their spectroscopic and photophysical proper-
ties were characterized. Despite using compounds mixture in SC
reaction exclusively linear and of low polydispersity index poly-
meric materials were obtained and their low molecular weight was

M. Ludwiczak et al. / Journal of Organometallic Chemistry 750 (2014) 150e161
161
[5] J.-F. Morin, M. Leclerc, D. Ades, A. Siove, Macromol. Rapid Commun. 26 (2005)
761e778.
directly connected with the presence of 3-substituted-N-alkylcar-
bazole responsible for polymer termination. SC reaction of com-
pounds with purity over 99% increased molecular weight and
decreased PDI of obtained materials and additionally proved our
statement about their linear structures. The length of the polymers
does not change their photophysical properties.
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Acknowledgments
Authors thank Dr. Gordon L. Hug for his interest in photo-
physical part of this work.
Financial support from the National Science Centre
NN204265538 and UMO-2011/02/A/ST5/00472 (Maestro) is grate-
fully acknowledged.
Appendix A. Supplementary material
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