Bithienylsilanes: Unexpected structure and reactivity

Article abstract of DOI:10.1016/S0022-328X(00)00340-5

5-(2,2′-Bithienyl)hydrosilanes were prepared by reaction of bithienyl lithium with chlorodimethylsilane, dichloromethylsilane and trichlorosilane. It was shown that 5-(2,2′-bithienyl)dimethylsilane possesses higher reactivity in the hydrosilylation reaction of monosubstituted acetylene derivatives compared with (2-thienyl)dimethylsilane. The elongation of the π-conjugated chain leads to increasing selectivity of the hydrosilylation reaction. An unusual structure for bis[5-(2,2′-bithienyl)]methylsilane has been established by X-ray analysis.

Full text of DOI:10.1016/S0022-328X(00)00340-5

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 610 (2000) 8–15
Bithienylsilanes: unexpected structure and reactivity
Edmunds Lukevics, Victoria Ryabova, Pavel Arsenyan, Sergey Belyakov, Juris Popelis,
Olga Pudova *
Lat6ian Institute of Organic Synthesis, Aizkraukles 21, Riga, LV-1006, Lat6ia
Received 19 April 2000; received in revised form 26 May 2000
Abstract
5-(2,2%-Bithienyl)hydrosilanes were prepared by reaction of bithienyl lithium with chlorodimethylsilane, dichloromethylsilane
and trichlorosilane. It was shown that 5-(2,2%-bithienyl)dimethylsilane possesses higher reactivity in the hydrosilylation reaction of
monosubstituted acetylene derivatives compared with (2-thienyl)dimethylsilane. The elongation of the p-conjugated chain leads to
increasing selectivity of the hydrosilylation reaction. An unusual structure for bis[5-(2,2%-bithienyl)]methylsilane has been
established by X-ray analysis. © 2000 Elsevier Science S.A. All rights reserved.
Keywords: Bithiophene; Silane; Hydrosilylation; Coupling; X-ray determination
of silanylenes and p-electron heterocyclic moieties rep-
resents an area of current active interest [3]. The un-
usual electrical and optical properties are generally
attributed to the delocalization of electrons through
silylene moieties. The introduction of the reactive func-
tional groups to the silicon atom gave possibilities for
simple and easy construction of hyperbranched polysi-
lylthiophenes [4].
In the present report we describe the synthesis of
bithienylhydrosilanes, which according to X-ray crystal-
lographic study have unprecedented molecular struc-
ture. By virtue of the reactive Si–H bond present in
these compounds, various bithiophenes and thus oligo-
thiophene derivatives can be prepared.
1. Introduction
During the last decade the number of p-conjugated
oligomers and polymers investigated as advanced mate-
rials for electronic and optical applications has in-
creased rapidly. Thiophene-based oligomers belong to
one of the most carefully studied types of materials and
have received a great deal of attention for both funda-
mental and practical reasons. In view of their interest-
ing electrochemical, electronic and optical abilities [1]
these compounds are studied for non-linear optical
properties, electrical semiconducting properties in the
doped state, neutral electronic properties in thin film
applications such as active layers in field-effect transis-
tors and in electroluminescent devices [2]. Recent syn-
thesis of linear silyl-containing thiophene-based
materials possessing a regular alternating arrangement
2. Results and discussion
In previous investigations, we found that thienylhy-
drosilanes are more active [5] in the hydrosilylation of
allylamines, allylsilanes, vinylsilanes and different acet-
ylene derivatives than the corresponding phenylhydrosi-
lanes. To study the influence of the p-conjugated chain
elongation on reactivity of hydrosilanes we synthesized
bithienylhydrosilanes (1–3) bearing one, two or three
bithienyl groups at the silicon atom. These compounds
were prepared by coupling of bithienyl lithium with
chlorodimethylsilane, dichloromethylsilane and tri-
Scheme 1.
* Corresponding author. Fax: +371-7550-338.
E-mail address: olga@osi.lv (O. Pudova).
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00340-5

E. Luke6ics et al. / Journal of Organometallic Chemistry 610 (2000) 8–15
9
lane 1 is 72:28 (Scheme 2). The hydrosilylation of
methyl propiolate by silane 1 gives almost the same
isomer mixture (73:27) (Table 1). Comparing (2-
thienyl)dimethylsilane and 5-(2,2%-bithienyl)dimethyl-
silane (1) in hydrosilylation reactions it may be con-
cluded that elongation of the p-conjugated chain results
in a considerable increase in reactivity. For example,
the hydrosilylation of N-propargylamines with (2-
thienyl)dimethylsilane carried out at 20°C for 180 days
or at 50°C for 6 h yields traces of products. Only by
raising the temperature to 200°C were higher yields
(50–80%) achieved. Contrarily, the addition of 5-(2,2%-
bithienyl)dimethylsilane (1) to the triple CꢀC bond of
acetylene derivatives in the presence of Speier’s catalyst
occurs easily at room temperature and proceeds
exothermally. As a rule the hydrosilylation was com-
pleted during 0.5 h to give the hydrosilylation products
with almost quantitative yields. It should be noted that
the regioselectivity of the reaction rises with the elonga-
tion of the p-conjugated chain. The single exception is
the reaction of phenylacetylene hydrosilylation. Both in
the case of (2-thienyl)dimethylsilane and 5-(2,2%-
bithienyl)dimethylsilane (1) the isomeric ratio of prod-
ucts remains the same.
Scheme 2.
chlorosilane, respectively (Scheme 1). To prevent the
substitution of the Si–H bond by bithienyl group the
reaction was carried out at −78°C. In such conditions
the yields of compounds 1–3 achieved 71–80%.
It has been shown that in the presence of chloropla-
tinic acid (H2PtCl6·6H2O) 5-(2,2%-bithienyl)dimethyl-
silane (1) reacts exothermally with 3,3-dimethyl-1-bu-
tyne, trimethylsilylacetylene, 3-diethylaminoprop-1-yne,
phenylacetylene and methyl propiolate. In the case of
3,3-dimethylbut-1-yne and 3-diethylamino-1-propyne
the hydrosilylation proceeds regioselectively and
stereospecifically to give solely b-trans-products 4 (R=
t-Bu) or 6 (R=Et2NCH2), respectively. The replace-
ment of the tert-butyl group by trimethylsilyl in the
acetylene derivative leads to an insignificant decrease in
regioselectivity and formation of the b-trans- and a
isomers, the b-trans-product 5 (R=Me3Si) being pre-
dominant (96:4). The ratio of the b-trans-/a products
formed in the reaction of phenylacetylene with hydrosi-
These compounds can be successfully used for syn-
thesis of oligothiophene derivatives. For example, b-
(E)-[5-(2,2%-bithienyl)dimethylsilyl]-R-ethylenes 4 and 5
were lithiated by BuLi into the 5%-position of the bithio-
phene heterocycle. Subsequent oxidative coupling of the
lithium derivatives [6] by the action of anhydrous CuCl2
yields quaterthiophenes 7 (R=t-Bu) and 8 (R=
Me3Si), containing silylvinyl terminal groups (Scheme
3).
The unusually high activity of 5-(2,2%-bithienyl)-
dimethylsilane (1) induced us to study physicochemical
Table 1
Hydrosilylation of acetylenes RCꢀCH with 5-(2,2%-bithienyl)dimethylsilane (1) (20°C, 1 h, catalyst H2PtCl6·6H2O) and 1H-NMR data for the
mixture of isomers
Compound (R) Yield (%) b-(E)-/a isomer ratio (GC l (1H)-NMR (ppm)
and 1H-NMR data)
R
SiMe HCꢁCH
ꢁCH2
Bithiophene
ring protons
Me3C (4)
80
92
85
100/0
96/4
1.12
0.48
5.68 (J=20.46 Hz)
7.1–7.28
6.25 (J=20.46 Hz)
7.08 (J=21.8 Hz)
7.20 (J=21.8 Hz)
5.73 (J=18.1 Hz)
5.93 (J=18.1 Hz)
Me3Si (5)
0.09
0.16
0.4
0.41
6.73 (J=5.6 Hz) 7.0–7.25
Et2NCH2 (6)
100/0
0.62 (t, J=7.8 Hz) 0.3
2.04 (q, J=7.8 Hz)
2.80 (d, J=5.2 Hz)
6.88–7.16
COOMe
Ph
88
81
73/27
72/28
3.76
3.78
7.19–7.25
0.48
6.27 (J=20.4 Hz)
7.02 (J=20.4 Hz)
6.58 (J=18.8 Hz)
7.08 (J=18.8 Hz)
6.12 (J=2.1 Hz) 6.95–7.26
6.78 (J=2.1 Hz)
5.56 (J=2.8 Hz) 6.97–7.30
6.01 (J=2.8 Hz)
0.54
0.41
0.49

10
E. Luke6ics et al. / Journal of Organometallic Chemistry 610 (2000) 8–15
Scheme 3.
Fig. 1. Molecular structure of hydrosilane 2.
and structural features of bithienylhydrosilanes. As is
clear from Table 2, the increase in the number of
heterocyclic substituents at the silicon atom is accompa-
nied by a bathochromic shift in UV–vis spectra from
311 nm for hydrosilane 1 to 325 nm for hydrosilane 3
and an increase of the wSi–H bond frequency in IR
spectra. The low field shift of the Si–H protons from
4.56 to 5.80 ppm and the shielding effect of the silicon
angles in molecule 2. Comparison of the structural data
available for unsubstituted [7], 5-monosubstituted [8],
series of 5,5%- [9], 3,3%- [10], 4,4%- [11], 3,4%-disubstituted
[12] and more substituted [13] 2,2%-bithiophenes with
the results obtained for bithienylhydrosilane 2 clearly
indicates an unprecedented type of conjugation in the
last compound. Four thiophene heterocycles A, B, A%
and B% are planar within error limits. The rings A and
B are coplanar; cycles A% and B% are slightly twisted
(3.2(4)°), both bithienyl fragments adopt transoid orien-
tation. According to 1H and 13C-NMR data for hy-
drosilane (2) in CDCl3 two bithienyl substituents of this
compound are quite identical, however, in the solid
state these two groups are different (Scheme 4). One
bithienyl group (cycles A% and B%) has the usual struc-
ture which was found in most of the studied bithio-
phenes. Simultaneously the second bithienyl fragment
(cycles A and B) represents a stable mesomeric form of
semiquinoid type characterized by a true double CꢁC
1
atom were detected in H and 29Si-NMR spectra. The
same tendencies were observed in spectra of 2-thienyl-
hydrosilanes. The similarity of physicochemical proper-
ties and considerable difference of reactivity were a
reason to study the molecular structure of bithienylhy-
drosilanes. Crystals of hydrosilane 2 suitable for X-ray
analysis were obtained by crystallization from hexane.
2.1. Molecular structure of
bis[5-(2,2%-bithienyl)]methylsilane (2)
,
bond C(5)–C(22) between two heterocycles (1.387 A)
The molecular structure of hydrosilane 2 is shown in
Fig. 1. Table 3 gives the values of bond lengths and
,
and C(23)–C(24) (1.254 A) in the terminal thiophene
Table 2
Spectroscopic characterization of 2-thienyl-5e and 5-(2,2%-bithienyl)hydrosilanes 1–3

E. Luke6ics et al. / Journal of Organometallic Chemistry 610 (2000) 8–15
11
Table 3
,
ring B, contrary to C(5%)–C(22%) of 1.604 A and C(23%)–
,
Bond lengths (A) and angles (°) for molecule 2
,
C(24%) of 1.563 A in the A%B% bithienyl substituent.
The stereoscopic view of the molecular arrangement
in the crystal of hydrosilane 2 is shown in Fig. 2. The
crystal structure is characterized by the herringbone
molecular packing motif typical for planar bithio-
phenes. The shortest intermolecular contacts are 3.668
Crystal state
Calculated value
1.713
S(1)–C(2)
S(1%)–C(2%)
S(1)–C(5)
S(1%)–C(5%)
S(21)–C(22)
S(21%)–C(22%)
S(21)–C(25)
S(21%)–C(25%)
Si(1)–C(2)
Si(1)–C(2%)
Si(1)–C(1)
C(2)–C(3)
C(2%)–C(3%)
C(3)–C(4)
C(3%)–C(4%)
C(4)–C(5)
C(4%)–C(5%)
C(5)–C(22)
C(5%)–C(22%)
C(22)–C(23)
C(22%)–C(23%)
C(23)–C(24)
C(23%)–C(24%)
C(24)–C(25)
C(24%)–C(25%)
1.672(14)
1.779(15)
1.786(14)
1.668(15)
1.657(14)
1.801(15)
1.682(15)
1.697(16)
1.845(13)
1.898(14)
1.846(10)
1.437(21)
1.301(22)
1.370(21)
1.413(22)
1.363(22)
1.352(25)
1.387(23)
1.604(24)
1.436(22)
1.323(23)
1.254(22)
1.563(23)
1.435(24)
1.210(25)
1.738
,
,
A (C···C) and 3.813 A (C···S). The polar axis of symme-
try along the z direction occurs in the structure, there-
fore according to [14] the crystal symmetry of
hydrosilane 2 may promote pyroelectric and piezoelec-
tric effects. However, the semiconductor properties
complicate the investigations of these effects.
1.744
1.719
1.842
1.892
1.370
1.433
1.375
1.444
1.381
1.435
1.374
2.2. Theoretical calculations
To compare the structure of isolated hydrosilane
molecule 2 with results obtained by X-ray diffraction in
the solid state, molecular orbital (MO) calculations of
the electronic structure in the ground state have been
carried out. The computations were fulfilled in MNDO
PM3 approximation [15] of the self-consistent field
theory. The calculated bond lengths and angles ob-
tained by full optimization of geometrical parameters
are also given in Table 3. Isolated molecule 2 is charac-
terized by Cs symmetry, therefore the symmetrically
equivalent geometrical parameters are not shown in
Table 3. As follows from Table 3 the geometry of the
isolated molecule is near to standard; the strongly
planar five-membered cycles A and B are mutually
coplanar.
For interpretation of the calculations the electronic
structures of thiophene (T) and 2,2%-bithiophene (TT)
molecules were also calculated. Fig. 3 shows the scheme
of HOMO and LUMO level displacement for T, TT
and hydrosilane 2. It should be noted that in the series
of T, TT and 2 the HOMO and LUMO energies are
converged as in the case of unsaturated hydrocarbons.
Thus, the calculations show the possibility of semicon-
ductor properties for compound 2. Fig. 3 also illus-
trates the orbital structure of HOMO and LUMO for
molecule 2. It can be noticed that HOMO increases the
orders of C(2)–C(3), C(4)–C(5), C(22)–C(23), C(24)–
C(25) bonds and, consequently, shortens these bonds.
At the same time, HOMO decreases the orders of
C(3)–C(4), C(5)–C(22), C(23)–C(24) bonds and pro-
motes their lengthening. On the contrary, LUMO in-
creases the orders of the latter bonds and decreases the
orders of the former. For molecule 2 in crystal form the
calculated highest occupied MO can be approximately
C(2)–S(1)–C(5)
95.7(8)
90.7(8)
97.0(8)
92.3
91.6
C(5%)–S(1%)–C(2%)
C(22)–S(21)–C(25)
C(25%)–S(21%)–C(22%)
C(2)–Si(1)–C(1)
C(1)–Si(1)–C(2%)
C(2)–Si(1)–C(2%)
C(3%)–C(2%)–S(1%)
C(3)–C(2)–Si(1)
C(3%)–C(2%)–Si(1)
C(3)–C(2)–Si(1)
S(1)–C(2)–Si(1)
S(1%)–C(2%)–Si(1)
C(4)–C(3)–C(2)
C(2%)–C(3%)–C(4%)
C(5)–C(4)–C(3)
82.5(10)
110.2(9)
104.7(9)
114.8(4)
107.9(11)
109.0(12)
123.3(11)
132.0(12)
128.5(9)
118.7(9)
113.7(12)
115.9(15)
116.8(13)
110.2(16)
131.5(14)
129.3(15)
105.7(15)
113.6(11)
122.7(12)
116.9(9)
129.3(13)
129.2(13)
123.7(10)
110.3(12)
120.5(12)
107.0(11)
113.9(15)
101.8(13)
117.5(17)
112.8(18)
104.5(13)
122.4(17)
109.5
114.5
111.7
126.5
121.7
112.8
112.8
125.5
110.3
124.2
126.1
123.3
110.6
112.9
112.5
112.3
C(5%)–C(4%)–C(3%)
C(4)–C(5)–C(22)
C(4%)–C(5%)–C(22%)
C(4)–C(5)–S(1)
C(4%)–C(5%)–S(1%)
C(22)–C(5)–S(1)
C(22%)–C(5%)–S(1%)
C(5)–C(22)–C(23)
C(23%)–C(22%)–C(5%)
C(5)–C(22)–S(21)
C(5%)–C(22%)–S(21%)
C(23%)–C(22%)–S(21%)
C(23)–C(22)–S(21)
C(24)–C(23)–C(22)
C(22%)–C(23%)–C(24%)
C(23)–C(24)–C(25)
C(25%)–C(24%)–C(23%)
C(24)–C(25)–S(21)
C(24%)–C(25%)–S(21%)
written as c(€HOMO+€LUMO), where €
and
HOMO
€
are HOMO and LUMO of molecule TT and c
LUMO
is a normalizing coefficient, and moreover, €
is
HOMO
localized on A%, B% cycles, whilst €
is on A and B
LUMO
cycles.

12
E. Luke6ics et al. / Journal of Organometallic Chemistry 610 (2000) 8–15
Scheme 4.
The calculated heat of formation for isolated
molecule 2 is 4.66 eV (107.4 kcal mol−1). Since the
molecular geometry in crystal 2 differs from optimal,
the energy of the molecule increases and the calculated
heat of formation in the solid state is 12.76 eV (294.1
kcal mol−1). According to the calculation, the dipole
moment value for isolated molecule 2 is 0.63 D. How-
ever, the value (1.70 D) and direction of the dipole
moment for the molecule of hydrosilane 2 in crystal
form differ from those found for the isolated state. The
increase in the dipole moment stabilizes the crystal
structure by means of electrostatic interactions. If the
multipole contributions are neglected, the electrostatic
term of crystal lattice energy is proportional to Kv2,
where v is the dipole moment and the coefficient K
depends on lattice type. The space group for crystals 2
is Pna21; for this lattice type the value K is maximal
and equal to 2.57. Thus, it may be expected that the
increase in molecular energy in crystals of hydrosilane 2
will be compensated for a gain of lattice energy.
Fig. 3. The HOMO and LUMO levels for thiophene 2 (a), bithio-
phene (b) and bithienylsilane (c).
SCF method of MO theory using the PM3 approxima-
tion [15] for valence electrons. The geometrical parame-
ters were optimized. Equilibrium geometries on
potential surfaces are located by the Davidson–
Fletcher–Powell algorithm [16]. The initial geometrical
parameters for the calculations were taken from X-ray
structure analysis data.
For X-ray crystal structure analysis a four-circle sin-
gle-crystal Sintex P21 diffractometer with graphite-
3. Experimental
,
monochromated Mo–Ka (u=0.71069 A) radiation was
used for intensity data collection. Reflection intensities
The quantum chemical calculations of electronic
structure for the studied systems were performed by the
were collected at room temperature using the q/2q scan
Fig. 2. Stereoview of packing of hydrosilane 2.

E. Luke6ics et al. / Journal of Organometallic Chemistry 610 (2000) 8–15
13
technique. Multisolution direct method package
SHELX-86 [17] was used for solution of the structure.
SHELXL-93 programs [18] were used for the refinement
calculations. Other crystallographic, measurement and
refinement data for hydrosilane 2 are listed in Table 4.
580B spectrometer. GC analysis was performed on a
Varian 3700 instrument equipped with flame-ionizing
detector using a capillary column 5 m×0.53 mm,
df=2.65 m, HP-1. The carrier gas was nitrogen. The
melting points were determined on a digital melting
point analyser (Fisher), the results are given without
correction.
3.1. General considerations and materials
All reactions were performed under an atmosphere of
dry argon, all solvents used in reactions were dried by
standard procedures. The following reagents were ob-
tained from commercial sources and used without fur-
ther purification: 2-bromothiophene, n-BuLi (hexane
solution, 2.5 M), chlorodimethylsilane, dichloromethyl-
silane, trichlorosilane, trimethylsilylacetylene, 3,3-
dimethylbut-1-yne, phenylacetylene, methyl propiolate,
3-diethylaminoprop-1-yne. 2,2%-Bithiophene was pre-
pared by catalytic coupling of 2-thienylmagnesium bro-
mide with 2-bromothiophene. Column chromatography
was carried out using 60-200 mesh silica gel from
Acros.
3.2. Synthesis of bithienylsilanes (1–3)
A solution of 2.5 M n-BuLi in hexane (4 ml) was
added dropwise to a solution of 2,2%-bithiophene (1.66
g, 0.01 mol) dissolved in 40 ml of dry ether at −40°C.
After 1 h corresponding chlorosilane was quickly added
at −78°C and the mixture was stirred for 2 h at room
temperature. Then the reaction mixture was hydrolyzed
and extracted with CH2Cl2, the organic layer dried over
MgSO4 and evaporated. In the case of dimethyl[5-(2,2%-
bithienyl)]silane (1) the residue was distilled. Hydrosi-
lanes 2 and 3 were chromatographed on silica gel using
petroleum ether as eluent.
1
The H-, 13C- and 29Si-NMR spectra were recorded
on a Varian Mercury 200 spectrometer at 200.06, 50.31
and 39.74 MHz correspondingly at 303 K. The chemi-
cal shifts are given relative to TMS from solvent
(CDCl3) signal (lH=7.25). Mass spectra were recorded
on a Hewlett Packard apparatus (70 eV). UV–vis spec-
tra were obtained on a Hitachi UV spectrometer U
3200. IR-spectra were recorded with a Perkin–Elmer
3.2.1. 5-(2,2%-Bithienyl)dimethylsilane (1)
B.p. 110°C, 2 mmHg. Yield 80%. MS: m/e 224
1
(M +). H-NMR (200 MHz, CDCl3, ppm): 0.65 (6H,
’
s), 4.88–4.95 (1H, m), 7.42–7.58 (5H, m, arom). 13C-
NMR (50.31 MHz, CDCl3, ppm): −1.87, 124.9, 125.3,
125.5, 126.1, 128.8, 136.9, 138.2, 144.1. 29Si-NMR
(39.74 MHz, CDCl3, ppm): −23.3. Anal. Calc. for
C10H12SiS2: C, 53.52; H, 10.07; S, 28.58. Found: C,
53.50; H, 10.12; S, 28.91%.
Table 4
Crystal data, measurement conditions and refinement results for
compound 2
3.2.2. Bis[5-(2,2%-bithienyl)]methylsilane (2)
M.p. 93°C. Yield 75%. MS: m/e 374 (M +). 1H-
’
NMR (200 MHz, CDCl3, ppm): 0.73 (3H, s), 5.15–5.24
(1H, m), 6.97–7.31 (10H, m, arom). 13C-NMR (50.31
MHz, CDCl3, ppm): −2.0, 125.2, 125.5, 125.7, 126.2,
128.8, 137.9, 138.4, 145.2. 29Si-NMR (39.74 MHz,
CDCl3, ppm): −32.0. Anal. Calc. for C17H14SiS4: C,
54.50; H, 3.77; S, 34.23. Found: C, 54.50; H, 3.72; S,
34.71%.
Molecular weight Mr
Crystal size (mm3)
Crystal system
Space group
Cell parameters:
374.61
0.20×0.20×0.25
Orthorhombic
Pna21
,
a (A)
9.848(2)
5.759(1)
31.017(5)
1759.3(6)
4
,
b (A)
,
c (A)
3
,
Unit cell volume V (A )
Molecular multiplicity Z
3.2.3. Tris[5-(2,2%-bithienyl)]silane (3)
F(000)
776
0.601
M.p. 104°C. Yield 71%. 1H-NMR (200 MHz, CDCl3,
ppm): 5.80 (1H, s, JSi–H=220.1 Hz), 7.00 (1H, dd,
J=0.2 Hz, J=0.8 Hz), 7.2–7.24 (2H, m), 7.28 (1H, d,
J=3.6 Hz), 7.39 (1H, d, J=3.6 Hz). 13C-NMR (50.31
MHz, CDCl3, ppm): 125.5, 126.0, 126.2, 128.9, 130.9,
137.7, 139.9, 146.3. 29Si-NMR (39.74 MHz, CDCl3,
ppm): −41.6 Hz. Anal. Calc. for C24H16SiS6: C, 54.92;
H, 3.07; S, 36.66. Found: C, 54.87; H, 3.15; S, 36.42%.
Absorption coefficient v (mm−1
)
Data collection
2qmax (°)
H
K
L
Number of measured independent reflections
Number of observed reflections (I\2|(I))
Refinement data
R factor
Goodness of fit
50
0–11
0–6
0–36
1587
896
0.0554
0.952
0.083
214
3.3. Hydrosilylation of acetylene deri6ati6es
(Z/|)max
Number of parameters
Flack’s x parameter
A mixture of hydrosilane (0.01 mol), alkyne (0.01
mol) and 10−4 M% of Speier’s catalyst was stirred for
0.0(3)

14
E. Luke6ics et al. / Journal of Organometallic Chemistry 610 (2000) 8–15
0.5–1 h in a Wheaton vial at room temperature.
Processes were controlled by GC. Products were
purified using column chromatography.
3.4.1. 5,5¨-bis[(E)-tert-Butylethenyldimethylsilyl]-
2,2%:5%,2¦:5¦,2§-quaterthiophene (7)
M.p. 142–143°C (from EtOH). Yield 70%. MS: m/e
611 (M +). 1H-NMR (200 MHz, CDCl3, ppm): 0.38
’
3.3.1. i-(E)-[5-(2,2%-bithienyl)dimethylsilyl]-tert-
butylethylene (4)
(12H, s), 1.03 (18H, s), 5.62 (2H, d, J=18 Hz), 6.18 (2H,
d, J=18 Hz), 7.05–7.25 (8H, m, arom). 13C-NMR
(50.31 MHz, CDCl3, ppm): −1.2, 29.0, 35.3, 119.8,
124.2, 124.9, 135.3, 135.9, 136.4, 139.4, 142.3, 160.2. 29Si-
NMR (39.74 MHz, CDCl3, ppm): −14.2. Anal. Calc.
for C32H42S4Si2: C, 62.89; H, 6.93; S, 20.99. Found: C,
62.79; H, 6.98; S, 21.10%.
MS: m/e 306 (M +). 13C-NMR (50.31 MHz, CDCl3,
’
ppm): −0.4, 29.9, 36.6, 118.7, 125.0, 125.6, 126.0, 128.8,
136.7, 137.8, 138.2, 144.7, 163.6. 29Si-NMR (39.74 MHz,
CDCl3, ppm): −23.2. Anal. Calc. for C16H22S2Si: C,
62.69; H, 7.23; S, 20.92. Found: C, 62.72; H, 7.34; S,
21.07%.
3.4.2. 5,5§-bis[(i-(E)-Trimethylsilylethenyl)-
dimethylsilyl]2,2%:5%,2¦:5¦,2§-quaterthiophene (8)
3.3.2. i-(E)-[5-(2,2%-bithienyl)dimethylsilyl]-
trimethylsilylethylene (5)
1
M.p. 163–165°C (from EtOH). Yield 79%. H-NMR
MS: m/e 322 (M +). 13C-NMR (50.31 MHz, CDCl3,
’
(200 MHz, CDCl3, ppm): 0.08 (18H, s), 0.39 (12H, s),
6.71 (4H, d, J=22 Hz), 6.99–7.13 (4H, m, arom), 7.21–
7.25 (4H, m, arom). 13C-NMR (50.31 MHz, CDCl3,
ppm): −0.9, −0.7, 98.1, 124.7, 125.2, 125.4, 125.5,
126.0, 128.9, 136.9, 137.3, 139.3, 143.4, 147.4, 147.9,
154.8. 29Si-NMR (39.74 MHz, CDCl3, ppm): −7.0
(Me3Si), −15.4 (Me2Si). Anal. Calc. for C30H42S4Si4: C,
56.02; H, 6.58; S, 19.94. Found: C, 56.14; H, 6.68; S,
20.03%.
ppm): −0.9, −0.7, 124.7, 125.3, 126.0, 128.7, 136.4,
138.4, 143.3, 148.0, 150.8, 152.3, 154.7. 29Si-NMR (39.74
MHz, CDCl3, ppm): −4.3, −15.4. Anal. Calc. for
C15H22S2Si2: C, 55.78; H, 6.86; S, 19.86. Found: C, 55.72;
H, 6.84; S, 19.02%.
3.3.3. i-(E)-[5-(2,2%-bithienyl)dimethylsilyl]-
diethylaminomethylethylene (6)
MS: m/e 335 (M +). 13C-NMR (50.31 MHz, CDCl3,
’
ppm): −0.3, 26.4, 31.4, 36.5, 117.5, 124.6, 125.2, 126.1,
128.8, 136.4, 137.5, 137.9, 145.6, 163.4. 29Si-NMR (39.74
MHz, CDCl3, ppm): −22.5. Anal. Calc. for C17H25-
NS2Si: N, 4.17; C, 60.84; H, 7.51; S, 19.11. Found: N,
4.15; C, 60.95; H, 7.43; S, 19.18%.
4. Supplementary material
Atomic coordinates and components of temperature
factor tensors have been deposited with the Cambridge
Crystallographic Data Centre, CCDC no. 136564.
Copies of this information may be obtained free of
charge from The Director, CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (Fax: +44-1223-336033; e-
mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
3.3.4. Isomeric mixture of i-trans and h-products
(R=COOMe)
MS: m/e 308 (M +). Anal. Calc. for C14H16O2S2Si: C,
’
54.51; H, 5.23; S, 20.79. Found: C, 54.55; H, 5.27; S,
19.87%.
3.3.5. Isomeric mixture of i-trans and h-products
(R=Ph)
Acknowledgements
MS: m/e 326 (M +). Anal. Calc. for C18H18S2Si: C,
’
66.21; H, 5.56; S, 19.64. Found: C, 66.26; H, 5.61; S,
19.55%.
We thank Laura Favaretto (I. Co. C.E.A., Consiglio
Nazionale Ricerche, Bologna, Italy) for assistance with
the mass spectroscopic measurements of quaterthio-
phenes.
3.4. Synthesis of quaterthiophenes 7 and 8
To a solution of 0.02 mol of 5-substituted 2,2%-bithio-
phene (4 or 5) in 30 ml of dry ether, 0.02 mol of n-BuLi
in hexane were added dropwise. After 1 h, the reaction
mixture was cooled to −30°C and CuCl2 (0.02 mol) was
added by portions. Then the solution was allowed to
warm to room temperature, and treated with 40 ml of
3M HCl. The mixture was extracted with CH2Cl2, the or-
ganic layer washed with brine, dried over MgSO4 and
evaporated. After evaporation the residue was washed
with ether recrystallized from ethanol to give corespond-
ing quaterthiophenes as bright yellow solids.
References
[1] (a) A. Kraft, A.C. Grimsdale, A.B. Holmes, Angew. Chem. Int.
Ed. Engl. 37 (1998) 402. (b) R.E. Martin, F. Diederich, Angew.
Chem. Int. Ed. Engl. 38 (1999) 1350. (c) J.M. Tour, Chem. Rev. 96
(1996) 537.
[2] (a) G. Schopf, G. Koßmehl, Polythiophenes — Electrically Con-
ductive Polymers, Springer-Verlag, Berlin, 1997. (b) R.
Hajlaoui, G. Horowitz, F. Garnier, A. Arce-Brouchet, L. Laigre,
A. El Kassmi, F. Demanze, F. Kouki, Adv. Mater. 9 (1997) 389.
(c) C. Arbizzani, A. Bongini, M. Mastragostino, A. Zanelli, G.

E. Luke6ics et al. / Journal of Organometallic Chemistry 610 (2000) 8–15
15
Barbarella, M. Zambianchi, Adv. Mater. 7 (1995) 571. (d) G.
Barbarella, P. Ostoja, P. Maccagnani, O. Pudova, L. Antolini,
D. Casarini, A. Bongini, Chem. Mater. 10 (1998) 3683. (e) H.E.
Katz, J.G. Laquindanum, A.J. Lovinger, Chem. Mater. 10
(1998) 633. (f) T. Noda, I. Imae, N. Noma, Y. Shirota, Adv.
Mater. 9 (1997) 239. (g) A. Adachi, J. Ohshita, A. Kunai, J.
Kido, K. Okita, Chem. Lett. (1998) 1233.
Mercier, L. Ricard, F. Mathey, Angew. Chem. Int. Ed. Engl. 29
(1990) 655.
[9] (a) C. Alema´n, E. Brillas, A.G. Davies, L. Fajari, D. Giro´, L.
Julia´, J.J. Pe´rez, J. Ruis, J. Org. Chem. 58 (1993) 3091. (a) A.
Lipka, H.G. von Schnering, Chem. Ber. 110 (1977) 1377. (c) H.
Muguruma, S. Hotta, I. Karube, Chem. Lett. (1996) 501. (d) M.
Kuroda, J. Nakayama, H. Hoshito, N. Furusho, S. Ohba,
Tetrahedron Lett. 35 (1994) 3957. (e) L.V. Panfilova, M.Yu.
Antipin, Yu.T. Struchkov, Yu.D. Churkin, A.E. Lipkin, Zh.
Strukt. Khim. 21 (2) (1980) 190.
[10] (a) M.J. Marsella, P.J. Carroll, T.M. Swager, J. Am. Chem. Soc.
117 (1995) 9832. (b) M.J. Marsella, R.J. Newland, P.J. Carroll,
T.M. Swager, J. Am. Chem. Soc. 117 (1995) 9842. T. Pilati, Acta
Crystallogr. Sect. C 51 (1995) 690. (d) M. Kozaki, S. Tanaka, Y.
Yamashita, J. Org. Chem. 59 (1994) 442. (e) J. Ohshita, M.
Nodono, T. Watanabe, Y. Ueno, A. Kunai, Y. Harima, K.
Yamashita, M. Ishikawa, J. Organomet. Chem. 553 (1998) 487.
(f) J. Ohshita, M. Nodono, H. Kai, T. Watanabe, A. Kunai, K.
Komaguchi, M. Shiotani, A. Adachi, K. Okita, Y. Harima, K.
Yamashita, M. Ishikawa, Organometallics 18 (1999) 1453.
[11] (a) G. Barbarella, M. Zambianchi, L. Antolini, U. Folli, F.
Goldoni, D. Iarossi, L. Schenetti, A. Bongini, J. Chem. Soc.
Perkin Trans. 2 (1995) 1869. (b) T. Mitsumori, K. Inoue, N.
Koga, H. Iwamura, J. Am. Chem. Soc. 117 (1995) 2467.
[12] L. Antolini, F. Goldoni, D. Iarossi, A. Mucci, L. Schenetti, J.
Chem. Soc. Perkin Trans. 1 (1997) 1957.
[3] (a) C. Moreau, F. Serin-Spirau, C. Biran, M. Bordeau, P.
Gerval, Organometallics 17 (1998) 2797. (b) J. Ohshita, M.
Nodono, T. Watanabe, Y. Ueno, A. Kunai, Y. Harima, K.
Yamashita, M. Ishikawa, J. Organomet. Chem. 553 (1998) 487.
(c) J. Hockemeyer, A. Castel, P. Rivie`re, J. Satge´, K.G. Ryder,
A. Drury, A.P. Davey, W.J. Blau, Appl. Organomet. Chem. 11
(1997) 513.
[4] (a) J. Nakayama, J.-S. Lin, Tetrahedron Lett. 38 (1997) 6043. (b)
J. Yao, D.Y. Son, Organometallics 18 (1999) 1736. (c) W. Uhlig,
Appl. Organomet. Chem. 13 (1999) 871.
[5] (a) E. Lukevics, S. Germane, N.P. Erchak, E.P. Popova, Khim.-
Farm. Zh. 12 (2) (1978) 67. (b) E. Lukevics, S. Germane, O.A.
Pudova, N.P. Erchak, Zh. Obshch. Khim. 13 (10) (1979) 52. (c)
E. Lukevics, R. Ya. Sturkovich, O.A. Pudova, J. Organomet.
Chem. 292 (1985) 151. (d) E. Lukevics, O. Pudova, R.
Sturkovich, A. Gaukhman, J. Organomet. Chem. 346 (1988) 297.
(e) E. Lukevics, M.A. Dzintara, N.P. Erchak, O.A. Pudova, V.F.
Matorykina, Yu.Yu. Popelis, Izv. Akad. Nauk, Ser. Khim.
(1984) 80.
[6] (a) G. Barbarella, O. Pudova, C. Arbizzani, M. Mastragostino,
A. Bongini, J. Org. Chem. 63 (1998) 1742. (b) G. Barbarella, L.
Favaretto, G. Sotgiu, M. Zambbianchi, L. Antolini, O. Pudova,
A. Bongini, J. Org. Chem. 63 (1998) 5497.
[13] (a) U. Dahlmann, C. Krieger, R. Neidlein, Eur. J. Org. Chem.
(1998) 525. (b) G. Engelmann, G. Kossmehl, S. Heinze, P.
Tschuncky, W. Jugelt, H.-P. Welzel, J. Chem. Soc. Perkin Trans.
2 (1998) 169.
[7] (a) P.A. Chaloner, S.R. Gunatunga, P.B. Hitchcock, Acta Crys-
tallogr. Sect. C 50 (1994) 1941. (b) M. Pelletier, F. Brisse, Acta
Crystallogr. Sect. C 50 (1994) 1942.
[14] L.D. Landau, E.M. Lifshitz, Theoretical Physics, vol. VIII,
Electrodynamics of Continuous Media, Nauka, Moscow, 1982,
p. 86.
[8] (a) S.P. Armes, P.A. Chaloner, P.B. Hitchcock, Acta Crystallogr.
Sect. C 50 (1994) 1945. (b) J. Wouters, I. Creuven, B. Norberg,
G. Edvard, F. Durant, A. van Aerschot, P. Herdewijn, Acta
Crystallogr. Sect. C 53 (1997) 892. (c) M.-O. von Bevierre, F.
[15] J.J.P. Stewart, J. Comput. Chem. 10 (1989) 209.
[16] R. Fletcher, M.J.D. Powell, Comput. J. 6 (1963) 163.
[17] G.M. Sheldrick, Acta Crystallogr. Sect. A 46 (1990) 467.
[18] G.M. Sheldrick, Crystallogr. Comput. 6 (1993) 110.
.