Seven-coordinate thiophene-3-acetonitrile complexes of tungsten(II). Crystal structures of [WI2(CO)3{NCCH2(3-C4H3S)} 2] and [WI2(CO)3{NCCH2(3-C4H3S)} (AsPh3)]

Article abstract of DOI:10.1016/S0022-328X(98)00491-4

Reaction of [WI₂(CO)₃(NCMe)₂] with 2 equivalents of thiophene-3-acetonitrile {NCCH₂(3-C₄H₃S)} gave the crystallographically characterised complex [WI₂(CO)₃{NCCH₂(3-C₄H₃S)} ₂] (1). The structure of 1 can be described as a distorted capped octahedron with a carbonyl group in the capping position, two carbonyl groups and an iodide in the capped face and two acetonitrile ligands and an iodide in the uncapped face. Treatment of the seven-coordinate complex [WI₂(CO)₃(NCMe)₂] with an equimolar amount of L {L=AsPh₃ (2) or PPh₃ (3)} followed an in situ reaction with by one equivalent of thiophene-3-acetonitrile afforded the mixed ligand complexes [WI₂(CO)₃{NCCH₂(3-C₄H₃S)} L] {2 (crystallographically characterised) and 3}. The structure of 2 also has a capped octahedral geometry, again having a carbonyl ligand in the unique capping position.

Full text of DOI:10.1016/S0022-328X(98)00491-4

Journal of Organometallic Chemistry 560 (1998) 191–196
Seven-coordinate thiophene-3-acetonitrile complexes of tungsten(II).
Crystal structures of [WI2(CO)3{NCCH2(3-C4H3S)}2] and
[WI2(CO)3{NCCH2(3-C4H3S)}(AsPh3)]
Paul K. Baker a,*, Michael G.B. Drew b, Margaret M. Meehan a, Emma E. Parker a,
Allan E. Underhill a
a Department of Chemistry, Uni6ersity of Wales, Bangor, Gwynedd, LL57 2UW, UK
b Department of Chemistry, Uni6ersity of Reading, Whiteknights, Reading, RG6 6AD, UK
Received 12 December 1997
Abstract
Reaction of [WI2(CO)3(NCMe)2] with 2 equivalents of thiophene-3-acetonitrile {NCCH2(3-C4H3S)} gave the crystallographi-
cally characterised complex [WI2(CO)3{NCCH2(3-C4H3S)}2] (1). The structure of 1 can be described as a distorted capped
octahedron with a carbonyl group in the capping position, two carbonyl groups and an iodide in the capped face and two
acetonitrile ligands and an iodide in the uncapped face. Treatment of the seven-coordinate complex [WI2(CO)3(NCMe)2] with an
equimolar amount of L {L=AsPh3 (2) or PPh3 (3)} followed an in situ reaction with by one equivalent of thiophene-3-acetonitrile
afforded the mixed ligand complexes [WI2(CO)3{NCCH2(3-C4H3S)}L] {2 (crystallographically characterised) and 3}. The
structure of 2 also has a capped octahedral geometry, again having a carbonyl ligand in the unique capping position. © 1998
Elsevier Science S.A. All rights reserved.
Keywords: Tungsten(II); Seven-coordinate; Thiophene-3-acetonitrile; Crystal structure
1. Introduction
and structure of the first seven-coordinate thiophene-3-
acetonitrile tungsten complex [WI2(CO)3{NCCH2(3-
C4H3S)}2], and the preparation and characterisation of
the new tungsten mixed ligand complexes [WI2-
(CO)3{NCCH2(3-C4H3S)}L] {L=AsPh3 (crystallo-
graphically characterised) and PPh3}.
Polythiophenes and their derivatives have received
considerable attention over the years [1–6], mainly due
to their properties as linear conducting polymers. We
have previously described [7], the synthesis of the
alkyne thiophene-3-acetonitrile complexes [WI2(CO)-
{NCCH2(3-C4H3S)}(p2-RC2R)2] {R=Me (crystallo-
graphically characterised) or Ph} and [WI(CO)-
{NCCH2(3 - C4H3S)}{Ph2P(CH2)PPh2}(p2 - MeC2Me)]-
[BF4].
Hitherto, no seven-coordinate complexes of molybde-
num(II) or tungsten(II) containing thiophene function-
alised nitrile groups have been reported. In order to
extend our work in this area we describe the synthesis
2. Results and discussion
The starting material, [WI2(CO)3(NCMe)2] was pre-
pared by reaction of fac-[W(CO)3(NCMe)3] (prepared
in situ) with an equimolar amount of I2 at 0°C as
previously reported [8]. Treatment of [WI2(CO)3-
(NCMe)2] with 2 equivalents of thiophene-3-acetonitrile
in CH2Cl2 at r.t. gave the acetonitrile exchanged
product [WI2(CO)3{NCCH2(3-C4H3S)}2] (1) in 89%
yield. Complex 1 has been characterised by elemental
* Corresponding author.
0022-328X/98/$19.00 © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00491-4

192
P.K. Baker et al. / Journal of Organometallic Chemistry 560 (1998) 191–196
Table 1
Physical and analytical data for the complexes [WI2(CO)3{NCCH2(3-C4H3S)}2] and [WI2(CO)3{NCCH2(3-C4H3S)}L] (L=AsPh3 or PPh3)
No.
Complex
Colour
Yield (%)
Analytical data (found (calcd.))
C
H
N
1
2
3
[WI2(CO)3{NCCH2(3-C4H3S)}2]
Red/Brown
Yellow
89
78
93
23.4
(23.4)
34.0
(34.1)
35.6
1.3
(1.3)
2.2
(2.1)
2.3
3.4
(3.6)
1.5
(1.5)
1.7
[WI2(CO)3{NCCH2(3-C4H3S)}(AsPh3)]
[WI2(CO)3{NCCH2(3-C4H3S)}(PPh3)]
Yellow
(35.7)
(2.2)
(1.5)
the free ligand. The 1H-NMR spectrum of 1 shows
three resonances in the region of 7.05–7.38 ppm due
to the protons in the thiophene ring. Ha and Hb are
next to a sulfur atom and therefore are shifted
downfield. The signal at l=7.38 ppm is (Hb) is a
doublet of doublets with a coupling constant of J=
4.98 Hz due to Hc and a coupling constant of J=
3.0 Hz due to Ha. The resonance at l=7.28 ppm
can be assigned to Ha and is an apparent singlet. A
doublet with J=2.95 Hz would be expected because
of its long range coupling to Hb. Hc is a doublet
with J=4.89 Hz and is coupled to Hb. The protons
from the thiophene CH2 group appear as a singlet at
4.2 ppm.
analysis (C, H and N) (Table 1), IR (Table 2) and
1H-NMR spectroscopy (Table 3), and also by X-ray
crystallography. Complex 1 is very soluble in CH2Cl2
and moderately soluble in CHCl3, but only slightly
soluble in diethyl ether. The complex is air-sensitive in
both the solid state and in solution, however it can be
stored in the solid state under nitrogen for several days.
The IR spectrum of 1 shows carbonyl bands at 2030
cm−1 (strong) and 1950 cm−1 (broad), which is typical
of other bis(nitrile) complexes of the type [MI2
(CO)3(NCR)2] [8,9]. There is also a weak nitrile band at
2291cm−1 and w(C–S) bands at 1067(m) and 1024(m)
cm−1
.
Single crystals of 1 were grown from a CH2Cl2/
CHCl3 (90:10) mixture at r.t.. The molecular struc-
ture of 1 is shown in Fig. 1, together with the
atomic numbering scheme. The dimensions in the co-
ordination sphere for 1 are given in Table 5. The
metal is bonded to three carbonyl groups, two ace-
tonitrile ligands and two iodides. The geometry of
the metal environment can be considered to be a
capped octahedron with one carbonyl C(100) in the
capping position, two others C(200) and C(300) to-
gether with I(2) in the capped face and the two ace-
tonitrile groups N(11), N(21) together with I(3), in
the uncapped face. The bonds to the three carbonyl
The r.t. 13C{1H}-NMR spectrum (CDCl3, 25°C)
shows two carbonyl resonances at l=218.26 and
200.32 ppm with an intensity ratio of 1:2. In view of
Table 2
IR data (cm−1 a
) for complexes 1–3
Complex w(CꢀN) cm−1
w(CꢀO) cm−1
w(C–S) cm−1
1
2
3
2291w
2288w
2290w
2030s, 1950br
2035s, 1958s, 1909m 1160w, 1072w
2022s, 1957s, 1912m 1085m
1067m, 1024m
˚
groups are equivalent at 1.98(1), 1.98(1), 1.99(1) A,
but the iodide in the capped face offers a longer
a Spectra recorded in CHCl3 as thin films between NaCl plates; br,
broad; m, medium; s, strong; w, weak.
˚
bond {W(1)–I(2) 2.863(1) A} than the iodide in the
˚
uncapped face {W(1)–I(3) 2.824(1) A}. The structure
is thus very similar to those found for other
[WI2(CO)3(NCR)2] structures e.g. [WI2(CO)3(NCMe)2]
Table 3
1H-NMR data (l, J in Hz) for complexes 1–3
[10],
[WI2(CO)3(NCEt)2]
[10],
and
[WI2(C-
Complex 1H-NMR (l) ppm
O)3(NCPh)2] [11]. These also have capped octahedral
structures with the iodide atoms occupying trans
sites, one in the capped face and one in the un-
capped face.
The labelling scheme for the protons of the thio-
phene is given in Fig. 2. The thiophene-3-acetonitrile
proton resonances are shifted downfield compared to
1
7.38 (dd, 2Hb, JH–H=4.98 Hz, 2.95 Hz), 7.28(2Ha,
apparent singlet), 7.05(d, 2Hc, JH–H=4.89Hz),
4.2(s, 2H, CH2
7.6–7.1 (brm, 18H, P
7.6–7.1 (brm, 18H, P
6 )
2
3
6
6
h+C4H3
6
S), 3.7(s, 2H, CH2
6
)
)
h+C4H3
6
S), 3.7(s, 2H, CH2
6
a Spectra recorded in CDCl3 (+25oC) and referenced to SiMe4.

P.K. Baker et al. / Journal of Organometallic Chemistry 560 (1998) 191–196
193
Fig. 1. The structure of [WI2(CO)3{NCCH2(3-C4H3S)}2] (1), together with the atomic numbering scheme. Ellipsoids shown at 30% probability.
capped face is made up of two iodide groups and
the acetonitrile group. Thus in 2 the iodides are mu-
tually cis while in 1 they are trans. Clearly, this is
due to the bulk of the triphenylarsine ligand which
preferentially takes up a position in the capped face.
The bond lengths are W(1)–C(100) 1.90(2), W(1)–
Colton and Kevekordes [12] correlation of the solid
state and solution state structures of seven-coordinate
halocarbonyl complexes of molybdenum(II) and
yungsten(II), it is likely the resonance at 218.26 is
due to the unique capping carbonyl {C(100) in Fig.
1} and the resonance at 200.32 ppm can be ascribed
to the equivalent octahedral carbonyl groups.
Reaction of [WI2(CO)3(NCMe)2] with one equiva-
lent of L (L=AsPh3 or PPh3) in CH2Cl2 at r.t.
gives [WI2(CO)3(NCMe)L] [13], which when reacted
in situ with an equimolar amount of thiophene-3-
acetonitrile afforded the new complexes [WI2
(CO)3{NCCH2(3-C4H3S)}L] (2 and 3) which were
fully characterised (Tables 1–3). Complexes 2 and
˚
C(200), W(1)–C(300) 2.02(2), 2.00(2) A; W(1)–As(1)
2.655(2) and W(1)–N(11) 2.204(15) with W(1)–I(3)
˚
and W(1)–I(2) 2.846(1) and 2.860(1) A, respectively.
We are currently investigating the electropolymeri-
sation of [WI2(CO){NCCH2(3-C4H3S)}(p2-RC2R)2]
(R=Me or Ph) [7], and [WI2(CO)3{NCCH2(3-
C4H3S)}2] (1).
3
are considerably less soluble than complex 1
3. Experimental details
which indicates they will be less soluble for electro-
polymerisation studies. They are more stable than
complex 1 in both solution and the solid state.
All reactions described in this paper were carried out
under a dinitrogen atmosphere using standard Schlenk
line techniques. The complex [WI2(CO)3(NCMe)2] [8]
and [WI2(CO)3(NCMe)L] (L=AsPh3 or PPh3) [13]
Single crystals of 2 (L=AsPh3) were grown from
a CDCl3 solution at room temperature. The molecu-
lar structure of 2 is shown in Fig. 3, together with
the atomic numbering scheme. The dimensions in the
coordination sphere for 2 are given in Table 5. The
structure of 2 also shows a capped octahedral struc-
ture, but here the metal atom is bonded to three
carbonyls, an acetonitrile group, the triphenylarsine
ligand and two iodide ions. The capping atom is
again a carbonyl group C(100) with the capped face
made up of the other two carbonyl groups C(200)
and C(300) and also the triphenylarsine. The un-
Fig. 2. 1H-NMR numbering scheme for the thiophene-3-acetonitrile
ligand, NCCH2(3-C4H3S).

194
P.K. Baker et al. / Journal of Organometallic Chemistry 560 (1998) 191–196
Fig. 3. The structure of [WI2(CO)3{NCCH2(3-C4H3S)}(AsPh3)] (2), together with the atomic numbering scheme. Ellipsoids shown at 30%
probability.
were prepared by the literature method. All chemicals
were purchased from commercial sources.
solution was filtered into a second Schlenk tube con-
taining thiophene-3-acetonitrile (0.31 g, 0.28cm3, 2.5
mmol) in 10 cm3 CH2Cl2 and the resulting solution
was stirred for 30 min. The solvent was removed in
vacuo to yield, the yellow complex [WI2(CO)3-
{NCCH2(3-C4H3S)}(AsPh3)] (2) (yield=1.85 g, 78%).
Suitable crystals for X-ray crystallography were grown
from a room temperature solution of 2 in CDCl3.
In a similar reaction of [WI2(CO)3(NCMe)2] with 1
equivalent of PPh3 for 1 min followed by an in situ
addition of 1 equivalent of NCCH2(3-C4H3S) in
CH2Cl2 affords [WI2(CO)3{NCCH2(3-C4H3S)}(PPh3)]
(3). For physical and analytical data see Table 1.
Elemental analyses for carbon, hydrogen and nitro-
gen were recorded on a Carlo–Erba Elemental Analy-
ser MOD1108 (using helium as a carrier gas). IR
spectra were recorded as thin films between NaCl
plates, on a Perkin Elmer 1600 FTIR spectrophoto-
1
meter. H- and 13C-NMR spectra were recorded on a
Bruker AC 250 MHz NMR spectrometer (all spectra
were referenced to SiMe4).
3.1. [WI2(CO)3{NCCH2(3-C4H3S)}2] (1)
To a solution of [WI2(CO)3(NCMe)2] (1.5 g, 1.7
mmol) in 30 cm3 of CH2Cl2 was added thiophene-3-
acetonitrile (0.41 g, 0.38 cm3, 3.31 mmol). The solu-
tion was stirred in a warm water bath for 90 min and
then for a further hour at r.t.. After this time the
mixture was filtered and the solvent removed in vacuo
to yield, the dark red-brown crystalline powder,
[WI2(CO)3{NCCH2(3-C4H3S)}2] (1) (yield=1.91 g,
89%). Suitable crystals for X-ray crystallography were
grown from a r.t. solution of 1 in CH2Cl2:CHCl3
(90:10).
3.3. X-ray crystallography
Crystals of 1 and 2 suitable for X-ray work were
prepared as described above.
3.3.1. Crystal data for 1 and 2
Crystal data and structure refinement details for 1
and 2 are given in Table 4.
3.3.2. Data collection and processing
Data for the two crystals were collected with Mo–
Kh radiation using the MARresearch Image Plate Sys-
tem. 95 frames were measured at 2° intervals with a
counting time of 2 min. Data analysis was carried out
with the XDS program [14]. Both structures were
solved using direct methods with the SHELX86 pro-
gram [15].
3.2. [WI2(CO)3{NCCH2(3-C4H3S)}(AsPh3)] (2)
To a solution of [WI2(CO)3(NCMe)2] (1.5 g, 2.5
mmol) in 15 cm3 CH2Cl2 was added AsPh3 (0.76 g,
2.5 mmol) with continuous stirring. After 3 min the

P.K. Baker et al. / Journal of Organometallic Chemistry 560 (1998) 191–196
195
Table 4
Crystal data and structure refinement for 1 and 2
Table 5
˚
Dimensions in the cooordination sphere of 1 and 2 (A, °)
Compound
1
2
Compound 1
W(1)–C(300)
W(1)–C(200)
W(1)–C(100)
W(1)–N(21)
1.978(12)
1.981(12)
1.988(13)
2.178(9)
Empirical formula
C15H10I2N2O3S2WC27H20AsI2NO3SW
Formula weight
Temperature (K)
Wavelength (A)
Crystal system
Space group
768.02
293 (2)
0.71073
Triclinic
P21/n
951.07
293 (2)
0.71073
Triclinic
P21/c
W(1)–N(11)
W(1)–I(3)
W(1)–I(2)
2.226(9)
2.8243(11)
2.8633(9)
˚
C(300)–W(1)–C(200)
C(300)–W(1)–C(100)
C(200)–W(1)–C(100)
C(300)–W(1)–N(21)
C(200)–W(1)–N(21)
C(100)–W(1)–N(21)
C(300)–W(1)–N(11)
C(200)–W(1)–N(11)
C(100)–W(1)–N(11)
N(21)–W(1)–N(11)
C(300)–W(1)–I(3)
C(200)–W(1)–I(3)
C(100)–W(1)–I(3)
N(21)–W(1)–I(3)
N(11)–W(1)–I(3)
C(300)–W(1)–I(2)
C(200)–W(1)–I(2)
C(100)–W(1)–I(2)
N(21)–W(1)–I(2)
N(11)–W(1)–I(2)
I(3)–W(1)–I(2)
103.7(5)
Unit cell dimensions
74.9(5)
72.4(5)
82.8(4)
158.6(4)
128.9(4)
160.3(5)
83.6(4)
124.7(4)
84.3(4)
77.7(4)
76.6(3)
131.8(4)
85.1(3)
86.5(2)
113.6(4)
117.1(3)
71.0(4)
77.2(3)
77.6(2)
157.2(3)
˚
a (A)
9.229 (9)
12.712 (11)
18.688 (18)
105.98 (1)
2108
8.529 (8)
20.824 (18)
16.977 (17)
102.90 (1)
2939
˚
b (A)
˚
c (A)
i (°)
3
˚
Volume (A )
Z
4
4
Dcalc (mg mm−3
)
2.420
8.623
2.149
7.247
Absorption coefficient
(mm−1
F(000)
)
1400
1768
Crystal size (mm)
q range for data collection
(°)
0.20×0.25×0.25 0.15×0.15×0.20
2.77–24.96
2.65–26.01
Index range
05h510
−155k515
−225l521
5492
3336 (0.0332)
3336/0/227
1.083
05h510
−255k525
−205l520
9720
5451 (0.0722)
5451/0/327
1.080
Reflections measured
Independent reflections (Rint
Data/restraints/parameters
Goodness-of-Fit on F2
Weighting scheme (a, b)a
Transmission factors
(max,min)
)
Compound 2
W(1)–C(100)
W(1)–C(300)
W(1)–C(200)
W(1)–N(11)
W(1)–As(1)
W(1)–I(3)
W(1)–I(2)
0.082, 13.755
1.00, 0.26
0.093, 64.46
1.00, 0.34
1.899(19)
2.000(16)
2.02(2)
2.204(15)
2.6552(17)
2.8465(14)
2.8596(11)
71.8(7)
Final R indices [I\2|(I)]
R1, wR2
0.0505, 0.1350
0.0765, 0.2011
R indices (all data) R1, wR2 0.0676, 0.1460
Largest diff. peak and hole 4.907, −1.434
0.1007, 0.2148
1.515, −1.959
−3
˚
(e A
)
C(100)–W(1)–C(300)
C(100)–W(1)–C(200)
C(300)–W(1)–C(200)
C(100)–W(1)–N(11)
C(300)–W(1)–N(11)
C(200)–W(1)–N(11)
C(100)–W(1)–As(1)
C(300)–W(1)–As(1)
C(200)–W(1)–As(1)
N(1)–W(1)–As(1)
C(100)–W(1)–I(3)
C(300)–W(1)–I(3)
C(200)–W(1)–I(3)
N(11)–W(1)–I(3)
As(1)–W(1)–I(3)
C(100)–W(1)–I(2)
C(300)–W(1)–I(2)
C(200)–W(1)–I(2)
N(11)–W(1)–I(2)
As(1)–W(1)–I(2)
I(3)–W(1)–I(2)
73.8(7)
a Weighting scheme, w=1/(|2(Fo2)+(aP)2+bP), where P=(F2o+
2F2c)/3.
107.1(7)
128.2(6)
82.8(5)
158.0(6)
72.0(5)
113.0(4)
113.9(6)
78.2(3)
129.2(5)
77.5(5)
78.0(6)
85.4(4)
158.81(5)
126.3(6)
161.4(5)
77.5(5)
3.3.3. Structure analysis and refinement
In both structures the non-hydrogen atoms were
refined with anisotropic thermal parameters. The hy-
drogen atoms were included in geometric positions and
given thermal parameters equivalent to 1.2 times those
of the atom to which they were attached. An empirical
absorption correction was made using the DIFABS
program [16]. Both structures were then refined on F2
using SHELXL [17]. All calculations were carried out
on a Silicon Graphics R4000 Workstation at the Uni-
versity of Reading.
87.2(3)
79.88(4)
86.15(4)
Acknowledgements
University of Reading for funds for the Image Plate
and we thank A.W. Johans for his assistance with the
crystallographic investigations.
M.M. Meehan and E.E. Parker thank the EPSRC for
research studentships. We thank the EPSRC and the

196
P.K. Baker et al. / Journal of Organometallic Chemistry 560 (1998) 191–196
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