μ-Biphenyl-2,2′-dithiolato-′K 2S:S′-bis[(triphenylphosphine-KP)gold(I)]

Article abstract of DOI:10.1107/S0108270104016099

The solid-state structures of [Au₂(C₁₂H ₈S₂)(C₁₈H ₁₅p)₂], (I), was analyzed. The compound (I) was formed by reaction of ClAuPPh₃ and 1,1'-biphenyl-2,2'-dithiol in the presence of trimethylbenzylammonium chloride and K₂CO₃ in a tetrahydrofuran/methanol solution. The typical p-Au and S-Au bond lengths were observed for gold(I)-phosphine-thiolate complexes. It was observed that the intramolecular Au...Au distance precluded a typical gold-gold bonding interaction, which occured when the distance between two Au^I atoms was at or slightly below the sum of the van der Walls radii.

Full text of DOI:10.1107/S0108270104016099

metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
tri-p-tolylphosphine, an aurophilicity-based one-dimensional
array is formed (Ehlich et al., 2002). The 1,10-biphenyl-4,40-
dithiol ligand has also been used to form SAMs (self-assem-
bled monolayers) on gold surfaces (de Boer et al., 2003). An
examination of structures containing biphenyl with sulfur
attached at the 2- and 20-positions shows no structure
containing gold coordinated to the 1,10-biphenyl-2,20-dithiol
ligand (Cambridge Structural Database, Version 5.25 of
November 2003; Allen, 2002).
ISSN 0108-2701
l-Biphenyl-2,20-dithiolato-j2S:S0-
bis[(triphenylphosphine-jP)gold(I)]
Scott A. Larkin,a Jeanette A. Krause Bauer,b V. E.
Konoplev,c Victor P. Dyadchenko,c Dmitrii A.
Lemenovskii,c Mitchell R. M. Brucea* and Alice E. Brucea*
aDepartment of Chemistry, University of Maine, Orono, ME 04469-5706, USA,
bDepartment of Chemistry, University of Cincinnati, OH 45221-0172, USA, and
cDepartment of Chemistry, M. V. Lomonosov Moscow State University, Leninskiye
Gory, Moscow 119992, Russia Federation
Correspondence e-mail: abruce@maine.edu
Accordingly, we now report the solid-state structure of the
title complex, (I), which contains one discrete dinuclear
monomer (Fig. 1). The PÐAu and SÐAu bond lengths are
typical for gold(I)±phosphine±thiolate complexes. The intra-
Received 22 April 2004
Accepted 1 July 2004
Online 11 August 2004
Ê
molecular AuÁ Á ÁAu distance [3.9064 (3) A] precludes a typical
The reaction of ClAuPPh3 and 1,10-biphenyl-2,20-dithiol in the
presence of trimethylbenzylammonium chloride and K2CO3 in
a tetrahydrofuran/methanol solution gives the title complex,
[Au2(C12H8S2)(C18H15P)2]. The molecule contains PÐAuÐS
units which `cross' with torsion angles of ꢀ90ꢁ [PÐAuÐAuÐ
P = 86.23 (5)ꢁ and SÐAuÐAuÐS = 95.62 (5)ꢁ]. The intra-
and intermolecular AuÁ Á ÁAu distances [3.9064 (3) and
gold±gold bonding interaction, which occurs when the
distance between two AuI atoms is at or slightly below the sum
Ê
of the van der Waals radii (3.32 A; Bondi, 1964). The crossed
arrangement of the PÐAuÐS units exhibits a PÐAuÐAuÐP
torsion angle of 86.23 (5)ꢁ (Table 1). The phenyl rings of the
biphenyldithiolate moiety are twisted out of the plane with
respect to each other, forming a C12ÐC7ÐC6ÐC1 dihedral
angle of 119.4 (6)ꢁ.
Ê
6.3797 (5) A, respectively] are outside the range for typical
AuÁ Á ÁAu interactions. However, the Au atoms appear to be
drawn together, leading to a signi®cant bending of the PÐ
AuÐS angles [170.24 (5) and 169.52 (5)ꢁ].
Structures containing biphenyl with sulfur attached at the 2-
and 20-positions reveal a wide range (2±116ꢁ) of absolute
torsion angles between the phenyl rings (C2ÐC1ÐC10ÐC20
referenced to biphenyl). Some generalizations can be made by
grouping these structures into subsets. In one subset, which
Comment
Interest in gold chemistry has increased exponentially in
recent years to include diverse topics such as catalysis (Grisel
et al., 2002), liquid crystals (Jana et al., 2002), antiviral activity
(Dinger & Henderson, 1998) and novel luminescence (Lee &
Eisenberg, 2003; Mohamed et al., 2003; Yam et al., 2003;
White-Morris et al., 2003). An important factor fueling this
growth involves gold±gold interactions, which, at about
1
30 kJ mol (Schmidbaur et al., 1988; Narayanaswamy et al.,
1993; Harwell et al., 1996), have been increasingly used to
engineer speci®c molecular properties. Gold±sulfur complexes
have been of special interest because soft sulfur ligands
are predicted to promote gold±gold interactions (Pyykko
et al., 1994). Dithiol ligands, such as 1,10-biphenyl-4,40-dithiol
or 1,10-biphenyl-2,20-dithiol, are interesting because of their
potential to facilitate the formation of gold arrays. Phosphine±
gold±dithiolate complexes utilizing 1,10-biphenyl-4,40-dithiol
provide examples of how steric factors in¯uence the formation
of such solid-state gold arrays. When the phosphine is tri-
cyclohexylphosphine, there are no discernible sub-van der
Waals contacts between Au atoms, but when the phosphine is
Figure 1
A view of the molecular structure of (I), with the atomic numbering
scheme. Displacement ellipsoids are shown at the 50% probability level
and H atoms have been omitted for clarity. [PÐAuÐS = 170.24 (5) and
ꢁ
Ê
Ê
169.52 (5) , Au1Á Á ÁAu2 = 3.9064 (3) A, S1Á Á ÁS2 = 5.186 (2) A and P1Á Á Á
Ê
P2 = 5.529 (2) A.]
m440 # 2004 International Union of Crystallography
DOI: 10.1107/S0108270104016099
Acta Cryst. (2004). C60, m440±m442

metal-organic compounds
Table 1
Selected geometric parameters (A, ).
comprises more than half the structures, the biphenyl rings are
relatively ¯at, with torsion angles of 2±38ꢁ. These structures
are constrained by virtue of a direct bond between S atoms
(i.e. disul®de), or by a single S, O or Se atom bridging between
the 6- and 60-positions of the biphenyl rings. Another subset of
structures contains metal chelates (M = Mo, Ni, Pd, Rh, Ti, Cu
and Ru), with torsion angles of 59±87ꢁ. If there are bulky
groups opposite the S atoms, i.e. in the 6- and 60-positions, the
torsion angles between the phenyl rings tend to be ꢀ90ꢁ.
Finally, there are a few structures that contain bulky groups
bonded to the S atoms (e.g. sulfonates), and the torsion angle
can be as high as 116ꢁ. Complex (I) appears to fall into this last
category. The (triphenylphosphine)gold units coordinated to
sulfur are very bulky, and the torsion angle between the
phenyl rings opens up to 119ꢁ in order to minimize inter-
actions between the triphenylphosphine rings. Inspection of
(I) also reveals that the Au atoms appear to be drawn
together, leading to a signi®cant bending of the PÐAuÐS
angles [170.24 (5) and 169.52 (5)ꢁ]. However, as noted
above, the long distance between the Au atoms precludes a
typical gold±gold bonding interaction. Comparison with
other structures shows that signi®cant bending is observed
when short gold±gold, gold±metal or gold±heteroatom
interactions are present [e.g. AuÐAu (Davila et al., 1993;
Crespo et al., 1997), AuÐIr (Rio et al., 2001), AuÐOs (Leung
et al., 1998), AuÐN (Vincert et al., 2001; Wilton-Ely et al.,
2002) and AuÐS (Wilton-Ely et al., 2001; Kuz'mina et al.,
1993)]. These observations suggest the possibility that auro-
philicity, even at these long distances, may in¯uence the solid-
state structure. In recent work, Pyykko and co-workers
(Pyykko & Tamm, 1998; Pyykko, 2004) estimated the auro-
philic energy as a function of the AuÁ Á ÁAu distance, and at
ꢁ
Ê
Au1ÐP1
Au1ÐS1
Au2ÐP2
Au2ÐS2
P1ÐC19
P1ÐC25
2.2605 (14)
2.3020 (13)
2.2565 (13)
2.3024 (13)
1.804 (6)
P1ÐC13
P2ÐC31
P2ÐC43
P2ÐC37
S1ÐC1
1.823 (5)
1.806 (5)
1.819 (5)
1.823 (5)
1.777 (5)
1.779 (5)
1.820 (5)
S2ÐC12
P1ÐAu1ÐS1
P2ÐAu2ÐS2
170.24 (5)
169.52 (5)
C1ÐS1ÐAu1
C12ÐS2ÐAu2
111.05 (17)
107.15 (17)
S1ÐAu1ÐAu2ÐS2
95.62 (5)
P1ÐAu1ÐAu2ÐP2
86.23 (5)
Data collection
Bruker SMART 1K CCD
diffractometer
! scans
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
Tmin = 0.319, Tmax = 0.756
10 002 independent re¯ections
6889 re¯ections with I > 2ꢄ(I)
Rint = 0.066
ꢂmax = 28.3ꢁ
h = 26 ! 26
k = 13 ! 13
42 287 measured re¯ections
l = 26 ! 25
Re®nement
Re®nement on F2
R[F2 > 2ꢄ(F2)] = 0.037
wR(F2) = 0.071
S = 1.00
10002 re¯ections
w = 1/[ꢄ2(F2o) + (0.026P)2
+ 4.627P]
where P = (F2o + 2Fo2)/3
(Á/ꢄ)max = 0.002
3
Ê
Áꢅmax = 1.00 e A
3
Ê
0.92 e A
Extinction correction: SHELXL97
488 parameters
H-atom parameters constrained
Áꢅmin
=
Extinction coef®cient: 0.00011 (3)
Ê
H atoms were positioned geometrically (CÐH = 0.95 A) and
treated as riding, with Uiso(H) values of 1.2Ueq(C). The ®nal differ-
ence map was featureless, the highest residual electron-density peaks
Ê
being approximately 0.9 A from the Au atoms.
Ê
3.9 A, a gold±gold interaction is estimated to be around
3 kJ mol 1. This is about one-tenth of the strength of a typical
strong gold±gold interaction. Other weak interactions, such as
CÐHÁ Á ÁF, which are estimated to be signi®cantly weaker than
a typical OÁ Á ÁH hydrogen bond, have been shown to be
important features for stabilizing crystal structures (Howard et
al., 1996; Thalladi et al., 1998; Lee et al., 2000).
Data collection: SMART (Bruker, 1997); cell re®nement: SAINT
(Bruker, 1997); data reduction: SAINT; program(s) used to solve
structure: SHELXTL (Siemens, 1994); program(s) used to re®ne
structure: SHELXTL; molecular graphics: SHELXTL; software used
to prepare material for publication: SHELXTL.
The authors acknowledge support from both the NSF,
International Programs (grant No. CHE-98-10077), and the
Russian Foundation for Basic Research (grant Nos. 00-03-
32840 and 03-03-32716). Data were collected through the Ohio
Crystallographic Consortium, funded by the Ohio Board of
Regents 1995 Investment Fund (grant No. CAP-075), located
at the University of Toledo Instrumentation Center in A&S,
Toledo, OH 43606, USA.
Experimental
Complex (I) was synthesized by reaction of ClAuPPh3 (910 mg,
1.84 mmol) and 1,10-biphenyl-2,20-dithiol (200 mg, 0.92 mmol) in the
presence of trimethylbenzylammonium chloride (68 mg, 0.36 mmol)
and K2CO3 (500 mg, 3.62 mmol) in a tetrahydrofuran/methanol
solution. Crystals suitable for X-ray analysis were grown from Et2O/
CH2Cl2 and were obtained as colorless plates.
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: FR1487). Services for accessing these data are
described at the back of the journal.
Crystal data
[Au2(C12H8S2)(C18H15P)2]
Mr = 1134.78
Monoclinic, P21=c
Mo Kꢁ radiation
Cell parameters from 6392
re¯ections
References
ꢂ = 2.5±28.3ꢁ
Ê
Ê
a = 20.0310 (4) A
1
b = 10.2199 (2) A
ꢃ = 7.40 mm
T = 150 (2) K
Allen, F. H. (2002). Acta Cryst. B58, 380±388.
Ê
c = 20.0399 (3) A
Boer, B. de, Meng, H., Perepichka, D., Zheng, J., Frank, M., Chabal, Y. & Boa,
Z. (2003). Langmuir, 19, 4272±4284.
Bondi, A. (1964). J. Phys. Chem. 68, 441±451.
Bruker (1997). SAINT (Version 5.A06) and SMART (Version 5.051). Bruker
AXS Inc., Madison, Wisconsin, USA.
ꢀ = 96.303 (2)ꢁ
V = 4077.67 (13) A
Plate, colorless
0.20 Â 0.10 Â 0.04 mm
3
Ê
Z = 4
Dx = 1.848 Mg m
3
ꢂ
Acta Cryst. (2004). C60, m440±m442
Scott A. Larkin et al.
[Au2(C12H8S2)(C18H15P)2] m441

metal-organic compounds
Crespo, O., Gimeno, M., Jones, P., Ahrens, B. & Laguna, A. (1997). Inorg.
Chem. 36, 495±500.
Davila, R., Elduque, A., Grant, T., Staples, R. & Fackler, J. Jr (1993). Inorg.
Chem. 32, 1749±1755.
Dinger, M. & Henderson, W. (1998). J. Organomet. Chem. 560, 233±243.
Ehlich, H., Schier, A. & Schmidbaur, H. (2002). Inorg. Chem. 41, 3721±3727.
Grisel, R., Weststrate, K., Gluhoi, A. & Nieuwenhuys, B. (2002). Gold Bull. 35,
39±45.
Harwell, D., Mortimer, M., Knobbler, N., Anet, F. & Hawthorne, M. (1996). J.
Am. Chem. Soc. 118, 2679±2685.
Howard, J., Hoy, V., O'Hagen, D. & Smith, G. (1996). Tetrahedron, 52, 12613±
12622.
Jana, N., Gearheart, L., Obare, S., Johnson, C., Edler, K., Mann, S. & Murphy,
C. (2002). J. Mater. Chem. 12, 2909±2912.
Kuz'mina, L., Smyslova, E. & Grandberg, K. (1993). Zh. Neorg. Khim. 38,
1009±1011.
Pyykko, P. (2004). Private communication.
Pyykko, P., Li, J. & Runeberg, N. (1994). Chem. Phys. Lett. 218, 133±
138.
Pyykko, P. & Tamm, T. (1998). Organometallics, 17, 4842±4852.
Rio, I., Terroba, R., Cerrada, E., Hursthouse, M., Laguna, M., Light, M. &
Ruiz, A. (2001). Eur. J. Inorg. Chem. pp. 2013±2019.
È
Schmidbaur, H., Graf, W. & Muller, G. (1988). Angew. Chem. Int. Ed. Engl. 27,
417±419.
Sheldrick, G. M. (1996). SADABS. University of Gottingen, Germany.
È
Siemens (1994). SHELXTL. Version 5.03. Siemens Analytical X-ray
Instruments Inc., Madison, Wisconsin, USA.
Thalladi, V., Weiss, H., Blaser, D., Boese, R., Nangia, A. & Desiraju, G. (1998).
J. Am. Chem. Soc. 120, 8702±8710.
Vincert, B., Clarke, D., Smyth, D., de Vos, D. & Tiekink, E. (2001). Met. Based
Drugs, 8, 79±84.
White-Morris, R., Olmstead, M. & Balch, A. (2003). J. Am. Chem. Soc. 125,
1033±1040.
Wilton-Ely, J., Schier, A., Mitzel, N., Nogai, S. & Schmidbaur, H. (2002). J.
Organomet. Chem. 643, 313±323.
Wilton-Ely, J., Schier, A., Mitzel, N. & Schmidbaur, H. (2001). J. Chem. Soc.
Dalton Trans. pp. 1058±1062.
Lee, H., Knobler, C. & Hawthorne, M. (2000). Chem. Commun. pp. 2485±2486.
Lee, Y. & Eisenberg, R. (2003). J. Am. Chem. Soc. 125, 7778±7779.
Leung, Q., Chim, J. & Wong, W. (1998). Inorg. Chem. 37, 6382±6384.
Mohamed, A., Lopez-de-Luzuriaga, J. & Fackler, J. Jr (2003). J. Cluster Sci. 14,
61±70.
Narayanaswamy, R., Young, M., Parkhurst, E., Ouellette, M., Kerr, M., Ho, D.,
Elder, R., Bruce, A. & Bruce, M. (1993). Inorg. Chem. 32, 2506±2517.
Yam, V., Cheung, K., Yip, S. & Cheung, K. (2003). J. Organomet. Chem. 681,
196±209.
ꢂ
m442 Scott A. Larkin et al.
[Au2(C12H8S2)(C18H15P)2]
Acta Cryst. (2004). C60, m440±m442