metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
requirements of the P atom. The CuÐS1 distance of
Ê
Ê
2.274 (1) A is shorter than the CuÐS2 distance of 2.307 (1) A,
consistent with signi®cant thiolate character in the former
bond. This conclusion is supported by comparing relevant
geometric parameters in the complex with those in uncoor-
dinated [Cy2P(S)C(S)N(H)Ph] (Siasios & Tiekink, 1994).
Thus, the respective S1ÐC1 and C1ÐN1 distances in the
ISSN 0108-2701
Bis[N-phenyl(dicyclohexylthiophos-
phinoyl)thiomethanamido-S,S0]-
copper(II)
Ê
complex of 1.726 (3) and 1.272 (4) A are signi®cantly longer
Ê
and shorter than 1.624 (2) and 1.317 (3) A, as found in the
uncoordinated ligand. In contrast, the P1ÐC1 distances are
Ê
equal within experimental error, i.e. 1.834 (3) cf. 1.846 (3) A.
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Nevertheless, the P1 S2 distance of 1.999 (1) A is elongated
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compared with 1.9495 (9) A in the free ligand. The lack of
E. Horn,a,b K. Kurosawab and E. R. T. Tiekinkc*
aTsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki 305-
8577, Japan, bDepartment of Chemistry, Rikkyo University, Nishi-Ikebukuro, Tokyo
171-8501, Japan, and cDepartment of Chemistry, The University of Adelaide,
Adelaide 5005, Australia
planarity in the ®ve-membered ring, mentioned above,
precludes extensive delocalization of ꢀ-electron density over
these atoms.
Ê
The shortest non-H intermolecular contact of 3.614 (6) A
occurs between C17 and C18i [symmetry code: (i) x,
Correspondence e-mail: edward.tiekink@adelaide.edu.au
1
z]. These arise from the partial overlap of two phenyl
y,
Received 27 July 2000
1
Accepted 22 August 2000
rings; however, there is no evidence for extensive ꢀ-stacking in
the lattice. There are no close intermolecular interactions
involving the Cu centres that might be expected for complexes
of this type. An examination of the crystal structure reveals
that symmetry-related cyclohexyl groups occupy positions
above and below the Cu coordination plane preventing close
associations.
The ligands in [Cu(C19H27NPS2)2] adopt an S,S0-chelation
mode leading to an S4 donor set which de®nes a square-planar
geometry about the Cu atom, which lies on an inversion centre.
Comment
The S,S0-chelation mode of the ligand found in the present
structure has two precedents in the literature, namely in
octahedral [Mn{Ph2P(S)C(S) NPh}(CO)4] (Antoniadis et al.,
1982) and square-planar [Ni{Ph2P(S)C(S) NPh}2] (Siasios &
Tiekink, 1996b). In contrast, an S,N-chelation mode is found
in the structure of [CpMn{Ph2P(S)C(S) NPh}(CO)2] (Am-
brosius et al., 1984). Similar ±CuÐSÐCÐPÐS± ®ve-
membered rings as seen in the title structure have been
observed in the structures of {[(PhSCH2)3P S]CuX}2 (X = Cl
and Br) and {[(PhSCH2)3P S](CuI)2}2 (Fuchs et al., 1997),
but these involve sp3 rather than sp2 C atoms. Finally, square-
planar CuS4 geometries are known in related dithiocarbamate,
Phosphine ligands of the type R2PC(S)N(H)R0 (R, R0 = alkyl,
aryl) are known to adopt a variety of coordination modes
involving one or more of the P, S and N donor atoms (Siasios
& Tiekink, 1996a). Oxidation of the P centre, leading to
ligands of the general formula R2P(Y)C(S)N(H)R0 (Y = O, S
or Se), gives rise to different coordination possibilities. Anti-
arthritic activity has been displayed by gold complexes of the
phosphine ligands (Whitehouse et al., 1998) and in this
context, Cu complexes of these species have been investi-
gated. The crystal structure of one of these, (I), is reported
herein.
The molecular structure is shown in Fig. 1 and selected
geometric parameters are collected in Table 1. The Cu atom is
located on a centre of symmetry and exists in a distorted
square-planar coordination geometry de®ned by an S4 donor
set. The greatest deviation from ideal geometry is manifested
in the chelate angle of 95.85 (4)ꢀ. The [Cy2P(S)C(S) NPh]
monoanion (Cy is cyclohexyl) coordinates via the thioamide-
S1 and phosphinoyl-S2 atoms, forming a ®ve-membered
CuÐSÐCÐPÐS ring. There is signi®cant puckering in the
ring as seen in the CuÐS2ÐP1ÐC1 and S1ÐC1ÐP1ÐS2
torsion angles of 23.2 (1) and 23.8 (2)ꢀ, respectively. This
feature of the structure may be traced to the tetrahedral
Figure 1
The molecular structure and crystallographic numbering scheme for (I).
Displacement ellipsoids are shown at the 35% probability level (Johnson,
1976).
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Acta Cryst. (2000). C56, 1319±1320
# 2000 International Union of Crystallography Printed in Great Britain ± all rights reserved 1319
Horn
