Synthesis of Ge2NiS4 clusters and the thermal transformation to a Ge4Ni6S12 cluster

Article abstract of DOI:10.1021/ic702379y

The reaction of Ni(dppe)Cl₂ and syn-[DmpGe(SLi)(μ-S) ₂Ge(SLi)Dmp] prepared in situ from syn-[DmpGe(SH)(μ-S) ₂Ge(SH)Dmp] (1) and n-BuLi (2 equiv) afforded the Ge ₂NiS₄ cluster, [DmpGe(μ-S)]₂(μ-S) ₂Ni(dppe) (2) (Dmp = 2,6-dimesitylphenyl). The nickel in 2 assumes a slightly distorted square planar geometry. However, another Ge ₂NiS₄ cluster, [DmpGe(μ-S)]₂(μ-S) ₂Ni(PPh₃)₂ (3) obtained from a similar reaction with Ni(PPh₃)₂Cl₂, contains the nickel in a tetrahedron. When 3 was heated to 120°C in toluene, a novel Ge ₄Ni₆S₁₂ cluster [DmpGe(μ-S) ₃]₄Ni₆ (5) was obtained. In cluster 5, six nickels form an octahedron with the nickels occupying its vertexes, and four DmpGeS₃ units cap half of the trigonal faces.

Full text of DOI:10.1021/ic702379y

Inorg. Chem. 2008, 47, 1901-1903
Synthesis of Ge2NiS4 Clusters and the Thermal Transformation to a
Ge4Ni6S12 Cluster
Tsuyoshi Matsumoto, Yosuke Matsui, Mikinao Ito, and Kazuyuki Tatsumi*
Department of Chemistry, Graduate School of Science, and Research Center for Materials
Science, Nagoya UniVersity, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
Received December 12, 2007
Scheme 1
The reaction of Ni(dppe)Cl2 and syn-[DmpGe(SLi)(µ-
S)2Ge(SLi)Dmp] prepared in situ from syn-[DmpGe(SH)(µ-
S)2Ge(SH)Dmp] (1) and n-BuLi (2 equiv) afforded the Ge2NiS4
cluster, [DmpGe(µ-S)]2(µ-S)2Ni(dppe) (2) (Dmp ) 2,6-dimesi-
tylphenyl). The nickel in 2 assumes a slightly distorted square
planar geometry. However, another Ge2NiS4 cluster, [DmpGe(µ-
S)]2(µ-S)2Ni(PPh3)2 (3) obtained from a similar reaction with
Ni(PPh3)2Cl2, contains the nickel in a tetrahedron. When 3 was
heated to 120 °C in toluene, a novel Ge4Ni6S12 cluster [DmpGe(µ-
S)3]4Ni6 (5) was obtained. In cluster 5, six nickels form an
of Ge2PdS4 clusters.4 Herein we report the synthesis of Ge/
Ni/S clusters using 1, which have different structural
properties from the Pd analogues.
octahedron with the nickels occupying its vertexes, and four
DmpGeS3 units cap half of the trigonal faces.
The reaction of Ni(dppe)Cl2 and [DmpGe(SLi)(µ-
S)2Ge(SLi)Dmp] prepared in situ from 1 and 2 equiv of
n-BuLi in THF afforded the Ge2NiS4 cluster, [DmpGe(µ-
S)]2(µ-S)2Ni(dppe) (2), in 71% yield as brown crystals
Metal chalcogenido clusters have attracted attention be-
cause of their versatile reactivities in relation to metalloen-
zymes1 and industrial catalysts of hydrodesulfurization.2 We
have been especially interested in heteropolynuclear com-
plexes composed of germanium and transition metals,
anticipating their cooperation in reactions. Indeed, in our
studies on S/S and S/O bridged heterodinuclear Ge-Ru
complexes, the interaction of Ge and Ru was suggested in
their structural changes upon alkylation and protonation of
at the µ-S and µ-O.3 Recently, we have synthesized a new
1
(Scheme 1). The H NMR spectrum of 2 is in accordance
with the structure, and the sharpness of the signals indicates
its diamagnetism. X-Ray structural analysis reveals that the
nickel sits in a slightly distorted square plane composed of
the two germanethiolato sulfurs and dppe as shown in Figure
1.5 The planar geometry about the nickel is incarnated in
the sum of the bond angles around the Ni, 362.6°, which
includes a large bite angle at S(3)-Ni(1)-S(4) (Table 1).
This structure compares well with that of the palladium
analogue which we have reported recently.4
dinuclear
mercaptogermane
syn-[DmpGe(SH)(µ-
S)2Ge(SH)Dmp] (1) as a building unit for germanium-
A similar Ge2NiS4 cluster, [DmpGe(µ-S)]2(µ-S)2Ni(PPh3)2
(3), results from the reaction with Ni(PPh3)2Cl2 as green
crystals. Here the Ni(II) center resides in a tetrahedral
geometry as shown in Figure 2, and the geometry with its
associated paramagnetism is compatible with the broad
containing metal clusters, and it was applied for the synthesis
* To whom correspondence should be addressed. E-mail:
i45100a@nucc.cc.nagoya-u.ac.jp.
(1) (a) Transition Metal Sulfur Chemistry, Biological and Industrial
Significance; Steifel, E. I., Matsumoto K., Eds.; American Chemical
Society:Washington,DC,1996.(b)TransitionMetalSulphidessChemistry
and Catalysis; Weber, Th., Prons, R., van Santen, R. A., Eds.; Kluwer
Academic Publishers: Dordrecht, The Netherlands, 1998.
1
signals observed in the H NMR spectrum.
The Ge2NiS4 core has C2V local symmetry, and the C2 axis
passes through the Ni(1) and the midpoint of Ge(1) and
Ge(2). Because of the greater steric congestion derived from
the bulk of PPh3 ligands, the nickel in 3 assumes a tetrahedral
geometry, which is allowed by the flexible dithiadigermet-
(2) (a) Topsøe, H.; Clausen, B. S.; Massoth, F. E. Hydrotreating Catalysis:
Science and Technology; Springer-Verlag: Berlin, 1996. (b) Kabe, T.;
Ishihara, A.; Qian, W. Hydrodesulfurization and Hydrodenitrogena-
tion: Chemistry and Engineering; Kondasa-Wiley-VCH: Tokyo, 1999.
(3) (a) Matsumoto, T.; Nakaya, Y.; Itakura, N.; Tatsumi, K. J. Am. Chem.
Soc. In press. (b) Matsumoto, T.; Nakaya, Y.; Tatsumi, K. Angew.
Chem., Int. Ed. In press. (c) Matsumoto, T.; Nakaya, Y.; Tatsumi, K.
Organometallics 2006, 25, 4835.
(4) Matsumoto, T.; Matsui, Y.; Ito, M.; Tatsumi, K. Chem. Asian J. In
press.
10.1021/ic702379y CCC: $40.75  2008 American Chemical Society
Inorganic Chemistry, Vol. 47, No. 6, 2008 1901
Published on Web 02/13/2008

COMMUNICATION
coordinates to the Ni in 3 at the two germanethiolato sulfurs,
it coordinates to the Pd in 4 at the three sulfurs including a
µ-sulfide of the Ge2S2 quadrangle, in addition to the two
thiolate sulfurs, to form a highly distorted square planar
geometry at the Pd. These results are understandable because
Ni has a rather small energy difference between its square
planar and tetrahedral geometries and are in agreement with
the common findings that the palladium(II) favors a square-
planar coordination environment, while the coordination
environment in the complexes of nickel(II) is much more
variable.6
When cluster 3 was heated to 110 °C for 12 h, a slow color
change from green to dark brown was observed. Separation of
the crude products by preparative gel permeation chromatog-
raphy (GPC) gave a major fraction at a significantly short
retention time compared with that of 1, indicating the unex-
pected formation of large clusters.7 The recrystallization of this
fraction from CH2Cl2/EtOH afforded the novel Ge4Ni6S12 cluster
[DmpGe(µ-S)3]4Ni6 (5) as brown crystals in 53% yield.8 As
shown in Figure 3, the cluster is composed of six square planar
Ni2+ and four tetrahedral [DmpGeS3]3- units. The six nickels
form an octahedron as shown by the dotted line with the nickels
occupying its vertexes, and the four DmpGeS3 units cap half
of the trigonal faces. The intramolecular Ni–Ni distances ranging
from 3.078(2) to 3.184(2) do not indicate their significant
interactions. The mean values of Ni–S and Ge–S distances are
Figure 1. Molecular structure of 2. All hydrogen atoms are excluded for
clarity.
(5) Crystal data for 2: C74H74Ge2NiP2S4; monoclinic; C2/c (No. 15); a )
30.814(3) Å, b ) 21.9372(16) Å, c ) 30.454(3) Å; ꢀ ) 127.5838(18)°,
V ) 16311(3) Å3; Z ) 8; T ) 193 K; λ ) 0.71073 Å; F(000) )
5632; µ ) 11.363 cm-1; Fcalcd ) 1.105 g cm-3; 91 233 reflections
(2θ < 55.0°), 18 666 unique (Rint ) 0.093); R1 ) 0.0860 (I > 2σ(I)),
wR2 ) 0.2642 (all data); GOF (on F2) ) 1.367. Crystal data for
Figure 2. Molecular structure of 3. All hydrogen atoms and the crystalline
solvent molecules are excluded for clarity.
j
3·1.5toluene: C94.5H92Ge2NiP2S4; triclinic; P1 (No. 2); a ) 14.0364(14)
Å, b ) 18.010(3) Å, c ) 18.085(3) Å; R ) 106.910(6)°, ꢀ )
107.7173(13)°, γ ) 95.117(2)°, V ) 4086.6(9) Å3; Z ) 2; T ) 193
K; λ ) 0.71073 Å; F(000) ) 1690; µ ) 11.459 cm-1; Fcalcd ) 1.318
g cm-3; 47 524 reflections (2θ < 55.0°), 18 477 unique (Rint ) 0.143);
R1 ) 0.0711 (I > 2σ(I)), wR2 ) 0.2050 (all data); GOF (on F2) )
0.959. Crystal data for 5·CH2Cl2: C97H100Cl2Ge4Ni6S12; monoclinic;
P21/n (No. 14); a ) 22.913(7) Å, b ) 16.604(4) Å, c ) 27.451(11)
Å; ꢀ ) 101.493(10)°, V ) 10234(6) Å3; Z ) 4; T ) 193 K; λ )
Table 1. Selected Bond Lengths (Å) and Angles (deg) for 2 and 3
2
3
Ge(1)–S(1)
Ge(1)–S(2)
Ge(2)–S(1)
Ge(2)–S(2)
Ge(1)–S(3)
Ge(2)-S(4)
Ni(1)–S(3)
Ni(1)–S(4)
Ni(1)–P(1)
Ni(1)–P(2)
S(3)· · ·S(4)
2.2424(13)
2.232(2)
2.245(2)
2.2342(13)
2.1808(13)
2.1884(11)
2.2226(15)
2.231(2)
2.2398(19)
2.2483(18)
2.258(2)
2.2559(18)
2.202(2)
0.71073 Å; F(000) ) 4816; µ ) 25.735 cm-1; Fcalcd ) 1.534 g cm-3
;
96 655 reflections (2θ < 55.0°), 23 294 unique (Rint ) 0.123); R1 )
0.1156 (I > 2σ(I)), wR2 ) 0.3044 (all data); GOF (on F2) ) 1.257.
The structure was solved by heavy-atom Patterson methods and
expanded using Fourier techniques. All calculations were performed
with a Rigaku/MSC CrystalStructure program package except for
refinement which was performed using SHELX-97 by full-matrix least
squares against F2. Anisotropic refinement was applied to all non-
hydrogen atoms. All the hydrogen atoms were put at calculated
positions, except for those of the disordered crystalline solvent
molecules, two toluenes for 3 and a dichloromethane for 5.
2.187(2)
2.2614(17)
2.2643(15)
2.340(2)
2.357(2)
4.079(2)
2.172(2)
2.1656(13)
3.633(2)
S(3)-Ni(1)-S(4)
S(3)-Ni(1)-P(1)
S(3)-Ni(1)-P(2)
S(4)-Ni(1)-P(1)
S(4)-Ni(1)-P(2)
P(1)-Ni(1)-P(2)
dihedrala
109.33(6)
128.66(8)
82.89(6)
162.71(9)
164.36(6)
82.86(6)
87.55(6)
140.6
109.75(7)
108.50(7)
103.03(6)
100.95(7)
103.09(8)
143.0
(6) Cotton, F. A.; Wilkinson, G.; Murillo, G. AdVanced Inorganic
Chemistry, 6th ed.; John Wiley & Sons: New York, 1999; pp 840–842..
(7) Preparative GPC was performed on a LC-908 instrument (Japan
Analytical Industry, Co. Ltd) with a series of Jaigel 1H and 2H
columns, using chloroform as the eluent with 3.5 mL min-1. The
fraction containing 5 was observed at 45 min retention time, while 1
has a significantly longer 49 min retention time.
a Dihedral angles between planes Ge(1)-S(1)-S(2) and Ge(2)-S(1)-S(2).
(8) Synthesis of [DmpGe(µ-S)3]4Ni6 (5). A toluene solution of 3 (200
mg, 0.135 mmol) was heated for 12 h at 110 °C. The crude product
was separated by GPC (CHCl3, 3.5 mL/min) to give a fraction of 45
min retention time, which was further crystallized by EtOH/CH2Cl2
to give 5 (27 mg) as a red crystals. The yield calculated on the basis
of nickels is 53%.1H NMR (500 MHz, CDCl3): δ ) 7.47 (t, J ) 7.6
Hz, 4H, p-CH of Dmp), 6.98 (s, 16H, m-CH of Mes), 6.97 (d, J )
7.6 Hz, 8H, m-CH of Dmp), 2.27 (s, 24H, p-CH3 of Mes), 1.83 (s,
48H, o-CH3 of Mes). Elemental analysis calcd (%) for
C96H100Ge4Ni6S12: C, 50.55; H, 4.42; S, 16.87. Found: C, 49.98; H,
4.02; S, 16.90.
anedithiolate property. Indeed, the S(3)-Ni(1)-S(4) bond
angle for 3 becomes considerably larger than that for 2, and
the S(3) · · · S(4) distance of 3 is elongated accordingly by
0.45 Å from that of 2 (Table 1). Of note is the fact that the
structure of 3 is completely different from that of the Ge2PdS4
cluster 4 (Scheme 1) obtained from the analogous reaction
using Pd(PPh3)2Cl2. Whereas the dithiadigermetanedithiolate
1902 Inorganic Chemistry, Vol. 47, No. 6, 2008

COMMUNICATION
diamagnetic properties indicated by the 1H NMR spectra, which
show a set of sharp signals assignable to the Dmp group.
In summary, new Ge/Ni/S clusters, [DmpGe(µ-S)]2(µ-
S)2Ni(dppe) (2) and [DmpGe(µ-S)]2(µ-S)2Ni(PPh3)2 (3),
were synthesized using the syn-[DmpGe(SH)(µ-
S)2Ge(SH)Dmp] (1) as a germanium source. Thermal
transformation of 3 leads to a structurally unique Ge4Ni6S12
cluster [DmpGe(µ-S)3]4Ni6 (5). These results open a
synthetic route to variegated sulfido clusters composed
of germanium and transition metals.
Acknowledgment. This work was supported by Grant-
in-Aid for Scientific Research on Priority Areas (No.
18065013, “Chemistry of Concerto Catalysis”) from Ministry
of Education, Culture, Sports, Science and Technology,
Japan. We are grateful to Prof. Roger E. Cramer for
discussions and careful reading of the manuscript.
Figure 3. Molecular structure of 5 and its schematic structure. All hydrogen
atoms and the crystalline solvent molecule are excluded for clarity. Color
code: Ge, green; Ni, blue; S, yellow; C, gray.
2.249 Å (range 2.214(2) – 2.274(2) Å) and 2.222 Å (range
2.201(2) – 2.234(2) Å), which are ordinary values for those
bonds, respectively.9,10 The structure is consistent with the
Supporting Information Available: X-ray crystallographic data
in CIF format for complexes 2, 3, and 5 and the experimental
details. The material is available free of charge via the Internet at
http://pubs.acs.org.
(9) Meyer, F.; Kozlowski, H. In ComprehensiVe Coordination Chemistry
II; McCleverty, J. A., Meyer, T. J., Eds.; Elsevier: Amsterdam, 2004;
Vol. 6, pp 322–342..
(10) Baines, K. M.; Stibbs, W. G. Coord. Chem. ReV. 1995, 145, 157.
IC702379Y
Inorganic Chemistry, Vol. 47, No. 6, 2008 1903