Reactions of nickelocene with phenyl- and methyllithium in the presence of bis(trimethylsilyl)acetylene

Article abstract of DOI:10.1016/S0020-1693(03)00012-4

Results of the reactions of nickelocene with phenyl- and methyllithium in the presence of bis(trimethylsilyl)acetylene have been reported. It was found that in the reaction of nickelocene with phenyllithium and bis(trimethylsilyl) acetylene three products

Full text of DOI:10.1016/S0020-1693(03)00012-4

Inorganica Chimica Acta 350 (2003) 520ꢀ526
/
www.elsevier.com/locate/ica
Reactions of nickelocene with phenyl- and methyllithium in the
presence of bis(trimethylsilyl)acetylene
Stanis law Pasynkiewicz a,*, Antoni Pietrzykowski a, Ewa Oledzka a,
˛
Barbara Kryza-Niemiec a, Janusz Lipkowski b, Romana Anulewicz-Ostrowska c
a Faculty of Chemistry, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland
b Institute of Physical Chemistry of the Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
c Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
Received 5 August 2002; accepted 12 December 2002
Dedicated to Professor Pierre Braunstein in recognition of his outstanding contributions to organometallic chemistry
Abstract
Results of the reactions of nickelocene with phenyl- and methyllithium in the presence of bis(trimethylsilyl)acetylene have been
reported. It was found that in the reaction of nickelocene with phenyllithium and bis(trimethylsilyl)acetylene three products were
formed: di(cyclopentadienylnickel) complex with bis(trimethylsilyl)acetylene (NiCp)2(mꢀ
tadienylnickel) complex with phenyl(trimethylsilyl)acetylene (NiCp)2(mꢀ CSiMe3) (2) and tetra(cyclopentadienylnickel)
h2ꢀh2-PhCꢀ
complex with 1,4-bis(trimethylsilyl)-1,3-butadiyne (NiCp)4(m,mꢀ CꢁCꢀCSiMe3) (3). Phenyl(trimethylsily-
h2ꢀh2ꢀh2ꢀh2-Me3SiCꢀ
l)acetylene and 1,4-bis(trimethylsilyl)-1,3-butadiyne were the products of coupling and cross-coupling of {CpNiPh} and {CpNiCꢀ
/
h2ꢀ
/
h2-Me3SiCꢀ
/CSiMe3) (1); di(cyclopen-
/
/
/
/
/
/
/
/
/
/
/
CSiMe3} formed as intermediate products of the reactions. All products were characterized by spectroscopic methods and crystal
and molecular structures of compounds 1 and 3 were determined by single crystal X-ray measurements.
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Nickel; Nickelocene; Alkynes; Butadiynes; Crystal structures
1. Introduction
We have previously found that nickelocene reacts
with methyllithium and diphenylacetylene forming
many di-, tri- and tetranickel compounds [1ꢀ3]. The
/
first step of the reaction of nickelocene with methyl-
lithium is the formation of unstable 16-electron species
{CpNiCH3} (Eq. (1)).
ð2Þ
NiCp2 ꢁLiCH3 0 fCpNiCH3gꢁLiCp
(1)
Methyl(cyclopentadienyl)nickel reacts in many direc-
tions. In the presence in alkynes it forms stable
di(cyclopentadienylnickel) complexes [4ꢀ
nickelacyclopentadienyl ring (Eq. (2)).
/12] or unstable
The species formed in the reaction (2) react further
forming many isolated and fully characterized cyclo-
pentadienylnickel compounds.
In this paper we present results of the reaction of
nickelocene with phenyl- and methyllithium in the
presence of di(trimethylsilyl)acetylene.
* Corresponding author. Tel.: ꢁ
5462.
E-mail address: pasyn@ch.pw.edu.pl (S. Pasynkiewicz).
/
48-22-660 7971; fax: ꢁ48-22-660
/
0020-1693/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0020-1693(03)00012-4

S. Pasynkiewicz et al. / Inorganica Chimica Acta 350 (2003) 520ꢀ
/526
521
2. Experimental
The next brownꢀ
toluene in C6H14. The compound was identified as
(NiCp)4(Me3SiCꢀCꢁCꢀCSiMe3) (3) (yield 5%). It was
/
green band was eluted using 25%
2.1. Reagents and general techniques
/
/
/
identified on the basis of its EIMS (70 eV) m/e
calculated for 58Ni (relative intensity, %): 686 (Mꢁ,
60%), 498 (100%), 246 (30%), 188 (60%), 123 (20%), 73
(60%), 58 (40%); H NMR (C6D6), d (ppm): 5.07 (s,
20H, Cp), 0.45 (s, 18H, CH3); 13C NMR (C6D6) d
All reactions were carried out in an atmosphere of dry
argon or nitrogen using Schlenk tube techniques.
Bis(trimethylsilyl)acetylene and lithium trimethylsilyla-
cetylide (0.5 M solution in THF) were purchased from
Aldrich. Methyl- and phenyllithium were prepared by
conventional methods. Solvents were dried by conven-
1
(ppm): 101.57 (Cꢁ
/
C), 96.92 (Cꢁ/Si), 87.45 (Cp), 1.86
(CH3). Black crystals, suitable for X-ray analysis, were
obtained from a mixture of C6H14 with few drops of
CH2Cl2.
1
tional methods. H and 13C NMR spectra were mea-
sured on Varian Mercury 400 MHz instruments. Mass
spectra were recorded on AMD-604 and AMD M-40
mass spectrometers.
2.3. Reaction of nickelocene with methyllithium in the
presence of bis(trimethylsilyl)acetylene
2.2. Reactions of nickelocene with phenyllithium in the
presence of bis(trimethylsilyl)acetylene
A solution of methyllithium in Et2O (4.6 cm3, 7.18
mmol) was added within 1 h at ꢂ
/
55ꢀ65 8C to a solution
/
A solution of 0.92 g of NiCp2 (4.8 mmol) and 1.1 cm3
of bis(trimethylsilyl)acetylene (4.8 mmol) in 50 cm3 THF
of NiCp2 1.23 g (6.53 mmol) and bis(trimethylsilyl)ace-
tylene 1.5 cm3 (6.53 mmol) in 70 cm3 of THF. The
mixture was stirred at this temperature for the next
hour, and then it was allowed to warm up slowly to r.t.
The reaction mixture changed colour from green to
was cooled to ꢂ
THF (5.5 cm3, 5.3 mmol) was then added drop by drop
within 1 h (temperature was maintained at ꢂ55ꢀ
50 8C). The mixture was stirred at this temperature
/
55 8C. A solution of phenyllithium in
/
/
ꢂ
/
brownꢀgreen. Stirring was continued overnight. The
/
for the next hour and then it was allowed to warm up
slowly to room temperature (r.t.). Stirring was contin-
ued overnight. The volatile substances were removed
solution was concentrated, and then 10 cm3 of THF and
50 cm3 of C6H14 were added, it was hydrolyzed with 60
cm3 of deoxygenated water. The organic layer was
separated and dried, the solvents were evaporated, the
3
under reduced pressure, 10 cm of THF and 40 cm3 of
C6H14 were added and the products were hydrolyzed
with 40 cm3 of the deoxygenated water. The organic
layer was separated and dried, then solvents were
residue was re-dissolved in tolueneꢀ
chromatographed on Al2O3 (deactivated with 5% of
water) using C6H14 and C6H14ꢀtoluene as eluents. A
small amount of green NiCp2 (eluent C6H14) was eluted.
The next green band containing (NiCp)2(Me3SiCꢀ
CSiMe3) (1) (yield 25%) was collected (eluent 5% toluene
in C6H14). The third fraction was also collected (C6H14ꢀ
toluene 1:6), solvents were evaporated yielding a green
solid identified as (NiCp)2(Me3SiCꢀCꢁCꢀCSiMe3) (4)
(yield 10%). H NMR (C6D6), d (ppm): 5.14 (s, 10H,
Cp), 0.28ꢀ
0.14 (s, 18H, CH3); 13C NMR (C6D6) d
(ppm): 102.93 (SiꢁCꢁNi), 102.74 (NiꢁCꢁC), 99.21
/
C6H14 mixture and
/
evaporated, then residue was re-dissolved in tolueneꢀ
C6H14 mixture and chromatographed on Al2O3 (deacti-
vated with 5% of water) using C6H14ꢀtoluene mixture as
/
/
/
eluent. Organic product, eluted with hexane before the
first organometallic band, was identified as biphenyl by
means of GC/MS analysis: m/e (relative intensity) 154
(Mꢁ, 100%), 76 (13.8%).
/
/
/
/
1
A small amount of green NiCp2 (eluent C6H14) was
/
eluted.
The
next
green
band
containing
/
/
/
/
(NiCp)2(Me3SiCꢀ
/
CSiMe3) (1) was collected (yield
(ꢁ
/
Cꢂ
/
C), 87.72 (Cp), 0.86 (Cꢁ
/
Si); EIMS (EI, 70 eV)
53%; eluent 10% toluene in C6H14). It was characterized
1
m/e calculated for 58Ni (relative intensity, %): 440 (Mꢁ,
100%), 246 (67%), 188 (13%), 123 (7%), 73 (10%), 58
by H, 13C NMR and EIMS. The results were in good
agreement with those published in Refs. [11,13]. Green
crystals, suitable for X-ray measurements, were ob-
tained by re-crystallization from MeOH.
(2%). The next brownꢀ
/
green band containing
CSiMe3) (3) was collected
(NiCp)4(Me3SiCꢀ
/
Cꢁ
/
Cꢀ
/
(yield 8%; eluent 30% toluene in C6H14).
The third light-green band was eluted with 13%
toluene in C6H14 (yield 10%). It was identified as a
2.4. Reaction of nickelocene with lithium
(trimethylsilyl)acetylide
dinickel compound (NiCp)2(Me3SiCꢀ
/
CPh) (2) based on
its H, 13C NMR and mass spectra. H NMR (acetone-
d6), d (ppm): 7.25ꢀ7.58 (m, 5H, Ph), 5.25 (s, 10H, Cp),
0.33 (s, 9H, CH3); 13C NMR (acetone-d6) d (ppm):
139.61ꢀ128.0 (Ph), 112.34 (CꢁPh), 96.02 (CꢁSi), 87.79
1
1
/
A solution of 1.61 g of NiCp2 (8.5 mmol) in 50 cm3
THF was cooled to ꢂ55 8C. A solution of lithium
/
/
/
/
(trimethylsilyl)acetylide (0.5 M inTHF; 16.5 cm3, 9.4
mmol) was then added within 1 h (temperature was
(Cp), 1.15 (CH3); EIMS (EI, 70 eV) m/e calculated for
58Ni (relative intensity, %): 420 (Mꢁ, 30%), 246 (100%),
188 (60%), 123 (25%).
maintained at ꢂ
/
55ꢀ
/
ꢂ50 8C). The mixture was stirred
/
at this temperature for the next hour, and then it was

522
S. Pasynkiewicz et al. / Inorganica Chimica Acta 350 (2003) 520ꢀ526
/
allowed to warm up slowly to r.t. Stirring was continued
overnight. The volatile substances were removed under
3
reduced pressure, 30 cm of toluene and 20 cm3 of
C6H14 were added and the products were hydrolyzed
with 50 cm3 of the deoxygenated water. The organic
layer was separated and dried, then solvents were
evaporated, a residue was re-dissolved in tolueneꢀ
C6H14 mixture and chromatographed on Al2O3 (deacti-
vated with 5% of water) using C6H14ꢀtoluene mixture as
eluent. The following compounds were isolated and
characterized: NiCp2*a small amount in the first green
band eluted with C6H14; (NiCp)2(Me3SiCꢀCꢁCꢀ
CSiMe3) (4)*the second green band eluted with 10%
toluene in C6H14 (yield 30%); (NiCp)4(Me3SiCꢀCꢁCꢀ
CSiMe3) (3)*the third band eluted as brownꢀgreen
/
/
/
/
/
/
/
/
/
/
/
/
chromatographic band using 50% toluene in C6H14
(yield 45%).
Fig. 1. The ORTEP drawing of 1 with atom numbering scheme. The
displacement ellipsoids are drawn at the 30% probability level.
2.5. Crystal structure determination
Single crystals of 1 and 3 suitable for X-ray diffraction
studies were placed in a thin-walled capillary (Linde-
mann glass) in a nitrogen atmosphere, plugged with
grease and flame sealed.
direct methods using SHELXS-97 [14]. Full-matrix least-
squares refinement method against F2 values was carried
out using the SHELXL-97 [15] program. All hydrogen
atoms were placed in calculated positions and refined
using a riding model. Crystallographic symmetry of 3
clearly indicates that the molecules are not related by
symmetry; the unit cell being triclinic and containing
twelve molecules of the complex. Search for higher
symmetry failed at the early stage of structure solution
and it became evident at the further stages that there are
some significant differences in molecular conformation
between some of the six molecules. Thermal disorder,
illustrated by ORTEP plots, is different as well. And,
although ‘chemical’ differences (in terms of bond lengths
and angles) are very small and mostly insignificant in
statistical terms, the six complex molecules are slightly
different molecular species from the structural view-
point. Atom numbering system has been kept the same
All measurements of the crystal of 1 were performed
on a Kuma KM4CCD k-axis diffractometer with
graphite-monochromated MoKa radiation. The crystal
was positioned at 65 mm from the KM4CCD camera.
256 frames were measured at 1.88 intervals with a
counting time of 15 s. The data were corrected for Lp.
No absorption correction was applied. Data reduction
and analysis were carried out with the Kuma Diffraction
(Wroclaw) programs. The structure was solved by direct
methods using SHELXS-97 [14] and refined using
SHELXL-97 [15]. The refinement was based on F2 for
all reflections except those with very negative F2.
Weighted R factors wR and all goodness-of-fit S values
are based on F2. Conventional R factors are based on F
with F set to zero for negative F2. The Fo2ꢀ2s(Fo2)
/
in all six independent molecules, i.e., Ni1Aꢁ
distance corresponds, e.g., to Ni1DꢁC1D and Ni1Gꢁ
C1G, etc.
/C1A
criterion was used only for calculating R factors and is
not relevant to the choice of reflections for the refine-
ment. The R factors based on F2 are about twice as large
as those based on F. All hydrogen atoms were located
from a differential map and refined isotropically.
Scattering factors were taken from Tables 6.1.1.4 and
4.2.4.2 in Ref. [16]. The crystal structure of 1 is
presented in Fig. 1. The crystal data, data collection
and refinement parameters for the compound are given
in Table 1. Selected bond lengths and bond angles are
presented in Tables 2 and 3.
/
/
The crystal structure of 3 is presented in Fig. 2.The
crystal data, data collection and refinement parameters
for the compound are given in Table 1. Tables 4 and 5
present the observed bond lengths and bond angles.
3. Results and discussion
Crystal data for 3 were collected with subsequent 8
and v scans on a Nonius KappaCCD diffractometer
with graphite monochromated Mo Ka radiation, using
diffractometer control program ‘Collect’ [17]. Unit cell
parameters and data reduction were processed with
Denzo and Scalepak [18]. The structure was solved by
Reactions of nickelocene with phenyl- or methyl-
lithium and bis(trimethylsilyl)acetylene were carried out
at molar ratios of reactants NiCp2:LiR:Me3SiCꢀ
CSiMe3ꢃ1:1:1.1 in THF. The reactants were mixed
together at about ꢂ50 8C, and the reaction mixture was
then allowed to warm up to room temperature and
/
/
/

S. Pasynkiewicz et al. / Inorganica Chimica Acta 350 (2003) 520ꢀ
/526
523
Table 1
Crystal data and structure refinement for 1 and 3
Table 2
Selected bond lengths (A) in 1 *
˚
1
3
Ni(1)ꢁ
Ni(1)ꢁ
Ni(1)ꢁ
Ni(1)ꢁ
Ni(1)ꢁ
Ni(1)ꢁ
Ni(1)ꢁ
Ni(1)ꢁ
Ni(2)ꢁ
Ni(2)ꢁ
Ni(2)ꢁ
Ni(2)ꢁ
Ni(2)ꢁ
Ni(2)ꢁ
Ni(2)ꢁ
Si(1)ꢁ
Si(1)ꢁ
Si(1)ꢁ
/
C(1)
C(2)
1.911(11)
1.988(12)
2.058(16)
2.046(18)
2.086(13)
2.101(16)
2.163(17)
2.341(2)
Si(1)ꢁ
Si(2)ꢁ
Si(2)ꢁ
Si(2)ꢁ
Si(2)ꢁ
C(1)ꢁ
C(9)ꢁ
C(9)ꢁ
C(10)ꢁ
C(11)ꢁ
C(12)ꢁ
C(14)ꢁ
C(14)ꢁ
C(15)ꢁ
C(16)ꢁ
C(17)ꢁ
Ni(1)ꢁ
Ni(2)ꢁ
/
C(1)
C(2)
C(7)
C(6)
C(8)
1.846(11)
1.715(13)
1.804(17)
1.820(15)
1.83(2)
1.410(14)
1.38(2)
1.40(2)
1.42(3)
1.33(3)
1.35(2)
1.25(3)
1.41(3)
1.33(4)
1.34(4)
1.30(4)
1.736
/
/
Empirical formula
Formula weight
Temperature (K)
Crystal system
C
418.00
18H28Ni2Si2
C30H38Ni4Si2
689.62
150(2)
/
C(10)
C(12)
C(9)
/
/
/
293(2)
monoclinic
/
/
triclinic
¯
P1
/
C(13)
C(11)
Ni(2)
C(1)
/
C(2)
Space group, number P21/n
˚
/
/
/
C(10)
C(13)
a (A)
˚
9.264(2)
15.934(1)
16.937(2)
18.827(2)
91.06(2)
90.58(2)
115.00(2)
4603.2(6)
6
/
/
b (A)
15.862(3)
14.863(3)
90
/
1.912(10)
2.005(11)
2.04(2)
/
C(11)
C(12)
C(13)
C(15)
C(18)
C(16)
C(17)
C(18)
˚
c (A)
/
C(2)
/
a (8)
b (8)
/
C(17)
C(15)
C(18)
C(14)
C(16)
/
93.55(3)
90
/
2.062(19)
2.078(19)
2.076(16)
2.09(2)
/
g (8)
/
/
3
V (A )
˚
2179.9(8)
4
/
/
Z
/
/
Dcalc (g cmꢂ1
Absorption coeffi-
)
1.274
1.832
1.493
2.512
/
C(3)
C(4)
C(5)
1.851(14)
1.831(15)
1.840(16)
/
/
/Cp
cient (mmꢂ1
F(000)
)
/
/Cp
1.735
880
2148
Crystal size (mm)
0.4ꢄ
Mo Ka (lꢃ
mator
3.60ꢀ21.00
95h 54, ꢂ
k 515, ꢂ145
Reflections collected 7128
/
0.3ꢄ
/
0.2
0.25ꢄ
/
0.22ꢄ
/
0.14
* Estimated standard deviations in parentheses.
˚
Radiation
/
0.71073 A), graphite monochro-
m range (8)
Index ranges
/
2.16ꢀ
05h 5
14 k 514, ꢂ
8006
8006, Rint
Full-matrix least-squares on F2
/
19.78
15, ꢂ
175
Table 3
Selected bond angles (8) in 1 *
ꢂ/
/
/
/
155
/
/
/
/
165
/
/
/
/
l 5
/
/
/
/l 5
/17
C(1)ꢁ
C(1)ꢁ
C(2)ꢁ
C(1)ꢁ
C(1)ꢁ
C(2)ꢁ
C(4)ꢁ
C(2)ꢁ
C(2)ꢁ
C(7)ꢁ
C(2)ꢁ
C(2)ꢁ
/
Ni(1)ꢁ
Ni(1)ꢁ
Ni(1)ꢁ
Ni(2)ꢁ
Ni(2)ꢁ
Ni(2)ꢁ
Si(1)ꢁ
Si(2)ꢁ
Si(2)ꢁ
Si(2)ꢁ
Si(2)ꢁ
C(1)ꢁ
/
C(2)
42.3(4)
52.3(3)
54.5(3)
C(2)ꢁ
Si(1)ꢁ
C(2)ꢁC(1)ꢁ
Si(1)ꢁC(1)ꢁ
Ni(1)ꢁC(1)ꢁ
C(1)ꢁC(2)ꢁ
C(1)ꢁC(2)ꢁ
Si(2)ꢁC(2)ꢁ
C(1)ꢁC(2)ꢁ
Si(2)ꢁC(2)ꢁ
Ni(1)ꢁC(2)ꢁ
/
C(1)ꢁ
/
Ni(1)
71.7(6)
Unique data
Refinement method
2321, Rint
ꢃ/
0.0996
ꢃ/0.0000
/
/
Ni(2)
Ni(2)
C(2)
/
C(1)ꢁ
/
Ni(1)
130.5(6)
72.5(6)
132.0(6)
75.5(4)
152.0(9)
65.9(6)
132.1(6)
65.4(6)
135.3(5)
71.8(4)
/
/
/
/
Ni(2)
Data/restraints/para- 2321/0/227
meters
8006/0/974
/
/
42.1(4)
52.2(3)
/
/
Ni(2)
Ni(2)
/
/
Ni(1)
Ni(1)
/
/
Final R indices [I ꢀ
/
/
/
53.8(3)
/
/
Si(2)
2s(I)]
R1; wR2
/
/
C(1)
C(7)
C(6)
C(6)
C(8)
108.4(7)
109.1(8)
109.1(8)
109.2(12)
109.4(9)
146.3(9)
/
/
Ni(1)
b
0.0885; 0.1767
0.0482; 0.1287
/
/
/
/
Ni(1)
R indices (all data)
b
R1; wR2
Goodness-of-fit on
F2 a
/
/
/
/
Ni(2)
0.1197; 0.1971
1.055
0.0627; 0.1353
1.132
/
/
/
/
Ni(2)
Ni(2)
/
/
/
/
/
/
Si(1)
Largest difference
˚
peak and hole (e A
0.657/ꢂ
/
0.654
0.583/ ꢂ
/0.628
ꢂ3
)
* Estimated standard deviations in parentheses.
c
Weights a, b
0.0500; 21.1989
0.0694; 13.0071
a
Goodness-of-fitꢃ
/
Sꢃ
jFcjj/ajFoj, wR2ꢃ
1/[s2(Fo2)ꢁ(aP)2ꢁ
bP], where Pꢃ
/
{a[w(Fo2ꢂ
{a[w(Fo2ꢂ
[2Fc2ꢁ
/
Fc2)2]/(nꢂ
Fc2)2]/a[w(Fo2)2]}1/2
max(Fo2, 0)]/3.
/
p)}1/2
.
means of EI MS, 1H and 13C NMR. Crystal and
molecular structure of compounds 1 and 3 were
determined by single crystal X-ray analysis.
b
c
R1ꢃ
/
ajjFojꢂ
/
/
/
.
wꢃ
/
/
/
/
/
The compound 1 crystallizes in monoclinic crystal
system with four molecules in the unit cell. A compar-
ison of crystallographic data of 1 with other structurally
characterized complexes of acetylenes with di(cyclopen-
stirred overnight. The mixture was hydrolyzed with
deoxygenated water and the organic layer was separated
by column chromatography on neutral alumina deacti-
vated with 5% of water, using hexaneꢀ
/
toluene mixture
tadienylnickel) [5ꢀ7,9,10] leads to the conclusion that
/
as an eluent.
bulky trimethylsilyl group have a substantial influence
The reaction of nickelocene with phenyllithium and
bis(trimethylsilyl) acetylene leads to the formation of
three nickel complexes: di(cyclopentadienylnickel)com-
on distances and angles in the molecule. Although the
˚
Ni distance (2.341 A) is almost identical as in the
Niꢁ
/
˚
other complexes (2.33ꢀ
are much longer in 1. Niꢁ
/
2.34 A), the Niꢁ
Cac distances in 1 are not
equal (1.911 and 1.988 A for Ni(1) and 1.912 and 2.005
/
Cac and Cacꢁ
/
Cac
plex with bis(trimethylsilyl)acetylene (NiCp)2(mꢀ
h2ꢀ h2ꢀh2ꢀ
Me3SiCꢀCSiMe3) (1); (NiCp)2(mꢀ PhCꢀ
CSiMe3) (2) and tetra(cyclopentadienylnickel) complex
with 1,4-bis(trimethylsilyl)-1,3-butadiyne (NiCp)4(m,mꢀ
CSiMe3) (3). Biphenyl
/
h2ꢀ
/
/
/
˚
/
/
/
/
/
˚
A for Ni(2), respectively) what indicates that CpNiꢁ
/
/
NiCp moiety is located perpendicularly to CacꢁCac
bond, but closer to one of the acetylenic carbon atoms.
/
h2ꢀ
/
h2ꢀ
/
h2ꢀ
/
h2-Me3SiCꢀ
/
Cꢁ
/
Cꢀ
/
was also formed as the result of coupling of two phenyl
groups. All the above compounds were characterized by
This was not observed for other reported complexes,
where CpNiꢁ/NiCp moieties were symmetrically located

524
S. Pasynkiewicz et al. / Inorganica Chimica Acta 350 (2003) 520ꢀ526
/
Fig. 2. The ORTEP drawing of 3 with atom numbering scheme (one of six molecules in the unit cell). The displacement ellipsoids are drawn at the 50%
probability level.
Table 4
Selected bond lengths (A) in 3 *
Table 5
Selected bond angles (8) in 3 *
˚
Ni1Eꢁ
Ni1Eꢁ
Ni1Eꢁ
Ni1Eꢁ
Ni1Eꢁ
Ni1Eꢁ
Ni1Eꢁ
Ni1Eꢁ
Ni2Eꢁ
Ni2Eꢁ
Ni2Eꢁ
Ni2Eꢁ
Ni2Eꢁ
Ni2Eꢁ
Ni2Eꢁ
Si1EꢁC2E
C1EꢁC2E
/
C1E
C2E
C5E
C6E
C4E
C7E
C3E
Ni2E
C1E
C2E
C9E
C11E
C10E
C12E
C8E
1.902(19)
1.930(16)
2.100(16)
2.108(18)
2.104(12)
2.103(22)
2.132(19)
2.359(5)
C1Eꢁ
Ni1Gꢁ
Ni1Gꢁ
Ni1Gꢁ
Ni1Gꢁ
Ni1Gꢁ
Ni1Gꢁ
Ni1Gꢁ
Ni1Gꢁ
Ni2Gꢁ
Ni2Gꢁ
Si1Gꢁ
C1GꢁC2G
Ni1Eꢁ
Ni2Eꢁ
Ni1Gꢁ
Ni1Gꢁ
/
C1G
1.460(17)
1.907(18)
1.931(16)
2.106(16)
2.118(14)
2.114(19)
2.118(20)
2.128(18)
2.369(2)
1.904(21)
1.943(15)
1.838(23)
1.348(17)
1.735
C1Eꢁ
C1Eꢁ
C2Eꢁ
C1Eꢁ
C1Eꢁ
C2Eꢁ
C2Eꢁ
C2Eꢁ
C1Gꢁ
C2EꢁC1Eꢁ
Ni1EꢁC1Eꢁ
C1EꢁC2Eꢁ
C1EꢁC2Eꢁ
Si1EꢁC2Eꢁ
C1EꢁC2Eꢁ
Si1EꢁC2Eꢁ
Ni2EꢁC2Eꢁ
/
Ni1Eꢁ
Ni1Eꢁ
Ni1Eꢁ
Ni2Eꢁ
Ni2Eꢁ
Ni2Eꢁ
/
C2E
41.1(4) C1Gꢁ
51.6(3) C2Gꢁ
52.5(4) C1Gꢁ
41.1(4) C1Gꢁ
51.7(3) C2Gꢁ
52.3(3) C2Gꢁ
143.5(9) C2Gꢁ
70.6(6) C1EꢁC1Gꢁ
130.2(7) C2GꢁC1Gꢁ
70.9(6) C1EꢁC1GꢁNi1G
76.8(4) Ni2GꢁC1GꢁNi1G
145.1(7) C1GꢁC2Gꢁ
68.0(1) C1GꢁC2Gꢁ
133.7(5) Si1GꢁC2Gꢁ
68.3(6) C1GꢁC2GꢁNi2G
135.9(5) Si1GꢁC2GꢁNi2G
75.3(4) Ni1GꢁC2GꢁNi2G
/
Ni1Gꢁ
Ni1Gꢁ
Ni2Gꢁ
Ni2Gꢁ
Ni2Gꢁ
/
Ni2G
Ni2G
C2G
51.5(3)
52.5(3)
41.0(4)
51.6(4)
52.1(3)
144.9(9)
71.1(6)
132.0(7)
70.4(6)
133.5(7)
76.9(4)
147.0(8)
68.5(5)
135.3(5)
67.9(6)
132.2(5)
75.4(4)
/
/
C1G
C2G
C4G
C3G
C6G
C5G
C7G
Ni2G
C1G
C2G
/
/
Ni2E
Ni2E
C2E
/
/
/
/
/
/
/
/
/
/
/
/
/
/Ni1G
/
/
/
/
Ni1E
Ni1E
/
/Ni1G
/
/
/
/
/
C1Gꢁ
/
C1E
/
/
/
C1Eꢁ
C1Eꢁ
C1Eꢁ
Ni2E
Ni2E
/
C1G
/
C1Gꢁ
/
Ni2G
/
/
/
/Ni1E
/
/
Ni2G
Ni1G
/
1.898(19)
1.934(15)
2.072(15)
2.092(16)
2.109(22)
2.118(23)
2.140(19)
1.832(22)
1.346(17)
/
/
/Ni1E
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/C2G
/
/Si1E
/
/Si1G
/
/
/
/Ni2E
/
/Ni1G
/
/Cp
/
/
Ni2E
/
/Ni1G
/
/Cp
1.752
/
/Ni1E
/
/
/
/Cp
1.737
1.735
/
/
Ni1E
Ni1E
/
/
/
/Cp
/
/
/
/
* Estimated standard deviations in parentheses.
* Estimated standard deviations in parentheses.
groups. Although the crystal structure is of poor quality
(R1ꢃ0.0885) and the bond lengths and angles cannot be
above Cacꢁ
1.88 to 1.91 A. This was not also observed for
monodentate complex (Ph3P)2Ni(Me3SiCꢀCSiMe3)
Cac (1.410 A) is longer than in other
/
Cac bond with equal Niꢁ
/
C distances from
/
˚
discussed in details, the general trends are as expected.
The compound 3 is the example of tetranuclear nickel
diyne complex in which every two nickel atoms are
/
˚
[19]. The Cacꢁ
complexes (1.34ꢀ
range between double and single Cꢁ
CꢁC bond should cause a decreasing of the values of the
SiꢁCacꢁCac angles. Although the ethynyl ligand in 1 is
as expected cis-bent, the SiꢁCacꢁCac angles (146.3 and
152.08) are larger than in other complexes (140ꢀ1488).
/
˚
˚
bridged by Cꢀ
C bond in h2,h2-bridging mode. This is a
/
/
1.36 A). The value 1.410 A is in the
/C bond. The longer
rare example of structurally characterized of this type
nickel complexes. The only other one was reported in
Ref. [20]. Four carbon atoms of the diyne are almost
/
/
/
/
/
coplanar (torsion angle Cꢁ
Ni distances (2.359 and 2.369 A) are close to those
reported for the dinickelꢀalkyne complexes in the
bridging mode [5ꢀ7,9,10], but much shorter than in
/
Cꢁ
/
Cꢁ
/
C is 178.88). The Niꢁ
/
˚
/
This is probably due to a steric rather than electronic
reason and caused by a repulsion of bulky trimethylsilyl
/
/

S. Pasynkiewicz et al. / Inorganica Chimica Acta 350 (2003) 520ꢀ
/526
525
˚
bridging diyne complexes (2.655 and 2.687 A) [20,21].
species {CpNiPh} and {CpNiCꢀ
/
CSiMe3} (Eq. (5)).
˚
C distance of 1.919 A is very close to
those reported for 1,4-bis(trimethylsilyl)-1,3-butadiyne
The average Niꢁ
/
complexes with Ni(0) in the h2,h2-bridging mode [21]
and is slightly longer than those (1.901 [21] and 1.909 A
[22]) in the monodentate mode. In contrary the average
ð5Þ
˚
Niꢁ
/
C distance in the h2,h2-bridging mode is shorter
than that of complexes of other diynes (from 1.947 to
These species readily undergo coupling reactions due
to the lack of easily accessible a- and b-hydrogen atoms
[28] (Eqs. (6) and (7)).
˚
1.988 A) [20,23,24]. The Niꢁ
/
C distances between the
nickel atom and the inside carbon atoms of the diyne are
shorter than those between the nickel atom and the
outside carbon atoms (Niꢁ
1.931, 1.898, 1.934, 1.904, 1.943 A; see the Table 4 to
check which NiꢁC distance correspond to which Niꢁ
/
Cac: 1.902, 1.930, 1.907,
fCpNiPhg 0 fCpNiꢁNiCpgꢁPhꢁPh
(6)
(7)
˚
/
/C
fCpNiꢁCꢀCꢁSiMe3g
0 fCpNiꢁNiCpgꢁMe3SiꢁCꢀCꢁCꢀCꢁSiMe3
bond). This phenomenon was observed also for other
nickel complexes with trimethylsilyl derivatives of diyne
[21,22] and nonsymmetrically substituted alkynes [25] in
both: bridging and monodentate modes, and was
probably due to steric reasons. The influence of the
Me3Si group on the complexation of alkynes was
described and discussed due to steric as well as electronic
reasons [8,25,26].
The formation of Me3SiCꢀ
/
Cꢁ
/
Cꢀ/CSiMe3 by coupling
by the two alkynyls at Ni was described in Ref. [29].
Cross coupling reaction also may occur resulting with
the formation of phenyl(trimethylsilyl)acetylene (Eq.
(8))
The reaction of nickelocene with methyllithium and
bis(trimethylsilyl)acetylene gave some different pro-
ducts. Compounds 1 and 3 were formed as in the
reaction with phenyllithium, but there was no analogous
fCpNiPhgꢁfCpNiꢁCꢀCꢁSiMe3g
0 fCpNiꢁNiCpgꢁPhꢁCꢀCꢁSiMe3
(8)
compound to 2, e.g. (NiCp)2(mꢀ
/
h2ꢀ
/
h2-CH3Cꢀ
/
CSiMe3).
The new product isolated form this reaction was
Reactions of bis(trimethylsilyl)acetylene and the pro-
ducts of reaction (7) and (8) with {(NiCp)2} species lead
to the formation of final products (Eq. (9)).
di(cyclopentadienylnickel)complex with bis(trimethylsi-
h2ꢀ
lyl)butadiyne
CSiMe3) (4).
(NiCp)2(mꢀ
/
/
h2-Me3SiCꢀ
/
Cꢁ
/
Cꢀ
/
We have previously shown that nickelocene reacts
with phenyl- or methyllithium in the presence of
diphenylacetylene or 2-butyne forming unstable nick-
elacyclopentadienyl species, which reacts further form-
ing a variety of organonickel compounds [1ꢀ/3] (Eq. (3)).
ð3Þ
ð9Þ
The reaction of phenyllithium with nickelocene and
bis(trimethylsilyl)acetylene differs from the reaction
with diphenylacetylene or 2-butyne. Bulky Si(CH3)3
substituents prevent acetylene units from a coupling
and the formation of nickelacyclopentadienyl ring. On
the other hand a similarity of trimethylsilyl group to
acidic hydrogen in acetylene [27] facilitates the reaction
of phenyllithium with bis(trimethylsilyl)acetylene and
the formation of lithiumacetylide (Eq. (4)).
The reaction of methyllithium with nickelocene and
bis(trimethylsilyl)acetylene proceeds differently that in
the case of phenyllithium. {(NiCp)2×
/
(CH3Cꢀ
/
CSi(CH3)3}, a compound analogues to 2, has not been
formed in this reaction. In contrary to {CpNiPh},
{CpNiCH3} does not undergoes coupling and cross-
coupling reactions but forms complex with Me3SiCꢀ
CSiMe3 [13], what decreases its reactivity and may
lead to the formation of {CpNiꢁCꢀCSiMe3} and
SiMe4. {CpNiꢁCꢀCSiMe3} reacts further according to
/
/
/
/
/
LiPhꢁMe3SiꢁCꢀCꢁSiMe3
the Eq. (7). {NiCp}2, formed in this reaction, reacts with
bis(trimethylsilyl)acetylene and bis(trimethylsilyl)buta-
diyne present in the reaction mixture forming final
products 1, 3 and 4 (Eqs. (10) and (11)).
0 LiꢁCꢀCꢁSiMe3 ꢁPhSiMe3
(4)
Therefore, nickelocene can simultaneously react with
phenyllithium and lithium acetylide forming unstable

526
S. Pasynkiewicz et al. / Inorganica Chimica Acta 350 (2003) 520ꢀ526
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ð10Þ
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formation of bis(trimethylsilyl)butadiyne (Eqs. (4), (5)
and (7)), we have prepared lithium(trimethylsilyl)acety-
lide and reacted it with nickelocene. Compounds 3 and 4
were formed in this reaction.
Lithium(trimethylsilyl)acetylide was prepared in the
reaction of methyllithium with bis(trimethylsilyl)acety-
lene (Eq. (12)).
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¨ ¨
[16] A.J.C. Wilson (Ed.), International Tables for Crystallography,
vol. C, Kluwer, Dordrecht, 1992.
LiMeꢁMe3SiꢁCꢀCꢁSiMe3 0 LiꢁCꢀCꢁSiMe3
(12)
[17] B.V. Nonius, ‘Collect’ data collection software, Delft 1998.
[18] Z. Otwinowski, W. Minor, in: C.W. Carter, Jr., R.M. Sweet
(Eds.), Processing of X-ray Diffraction Data Collected in
Oscillation Mode, Methods in Enzymology, vol. 276: Macro-
molecular Crystallography, part A, Academic Press, New York,
Lithium(trimethylsilyl)acetylide reacts with nickelo-
cene according to the reaction (5) forming unstable
cyclopentadienylnickel(trimethylsilyl)acetylide. The lat-
ter undergoes coupling with the formation of bis(tri-
methylsilyl)butadiyne and bis(cyclopentadienylnickel)
species according to the Eq. (7). These intermediate
products form final complexes 3 and 4 (Eq. (11)).
1997, pp. 307ꢀ326.
/
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Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC Nos. 198415 and 198416 for
compounds 1 and 3, respectively. Copies of this
information can be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge, CB2
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/
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