Dithiocarbamate Ligands as Building-Blocks in the Coordination Chemistry of Gold

Article abstract of DOI:10.1021/ic971600a

The monodentate dithiocarbamate complexes [Au₂(S₂CNR₂)₂{μ-(PPh ₂)₂C=CH₂}] (R = Me (1), Et (2), Bz. (3)) are obtained by reaction of [Au₂CI₂{PPh₂)₂=CH₂}] with NaS₂CNR₂. The free sulfur atoms in complex 2 can subsequently be used to coordinate a third metal center, giving the trinuclear derivatives [Au₂M(μ-S₂CNEt₂)₂-{μ(PPh ₂)₂C-CH₂}]X (X = CIO₄, M = Au (5), Ag (6); X = PF₆, M = Cu (7)). The dinuclear tricoordinate gold(I) complexes [Au₂(μ-S₂CNEt₂){μ-(PPh₂) ₂C=CH₂}₂]CIO₄ (8) and [Au₂(μ-S₂CNEt₂){μ-(PPh₂) ₂C=CH₂}(PPh₃)₂]-CIO₄ (9) are obtained by reaction of [Au₂(μ-S₂CNEt₂){μ-(PPh₂) ₂C=CH₂}₂](CIO₄ (4) with (PPh₂)₂C=CH₂ or PPh₃. The former is also obtained by reaction of [Au₂{μ(PPh₂)₂C=CH₂} ₂](CIO₄)₂ with sodium N,N-diethyldithiocarbamate (1:1). The crystal structures of complexes 2 and 8 are established by X-ray crystallography.

Full text of DOI:10.1021/ic971600a

5532
Inorg. Chem. 1998, 37, 5532-5536
Dithiocarbamate Ligands as Building-Blocks in the Coordination Chemistry of Gold
Eduardo J. Ferna´ndez, Jose´ M. Lo´pez-de-Luzuriaga, Miguel Monge, and Elena Olmos
Departamento de Qu´ımica, Universidad de La Rioja, Obispo Bustamante 3, E-26001 Logron˜o, Spain
M. Concepcio´n Gimeno and Antonio Laguna*
Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n, Universidad de
Zaragoza-CSIC, E-50009 Zaragoza, Spain
Peter G. Jones
Institu¨t fu¨r Anorganische und Analytische Chemie der Technischen Universita¨t, Postfach 3329, D-38023
Braunschweig, Germany
ReceiVed December 26, 1997
The monodentate dithiocarbamate complexes [Au2(S2CNR2)2{µ-(PPh2)2CdCH2}] (R ) Me (1), Et (2), Bz (3))
are obtained by reaction of [Au2Cl2{µ-(PPh2)2CdCH2}] with NaS2CNR2. The free sulfur atoms in complex 2
can subsequently be used to coordinate a third metal center, giving the trinuclear derivatives [Au2M(µ-S2CNEt2)2-
{µ-(PPh2)2CdCH2}]X (X ) ClO4, M ) Au (5), Ag (6); X ) PF6, M ) Cu (7)). The dinuclear tricoordinate
gold(I) complexes [Au2(µ-S2CNEt2){µ-(PPh2)2CdCH2}2]ClO4 (8) and [Au2(µ-S2CNEt2){µ-(PPh2)2CdCH2}(PPh3)2]-
ClO4 (9) are obtained by reaction of [Au2(µ-S2CNEt2){µ-(PPh2)2CdCH2}]ClO4 (4) with (PPh2)2CdCH2 or PPh3.
The former is also obtained by reaction of [Au2{µ-(PPh2)2CdCH2}2](ClO4)2 with sodium N,N-diethyldithiocar-
bamate (1:1). The crystal structures of complexes 2 and 8 are established by X-ray crystallography.
Introduction
derivatives tend to be more interesting because their structures
often involve short intra- and intermolecular gold-gold dis-
tances.
In the past few years there has been increasing interest in
the synthesis of gold(I) derivatives containing sulfur and/or
phosphorus donor ligands.1 Among the former, dithiocarbamate
complexes have extensively been studied in view of their
applications as vulcanization accelerators, flotation agents,
fungicides, and pesticides;2 their antimicrobial activity has been
reported,3 and they have been used to combat metal poisoning.4
As far as we are aware, only one type of gold(I) compound
containing monodentate dithiocarbamate, [Au(S2CNEt2)(PR3)],
has been reported.8 In the majority of dithiocarbamate gold
complexes the ligand is bidentate, bridging two gold centers
and forming diauracycles of the types [Au2(µ-S2CNR2)2]5g,9 and
[Au2(µ-S2CNR2)(µ-L-L)] (L-L ) diylide5d or diphosphine5f).
Dinuclear gold(I) complexes have also attracted considerable
recent attention,1b,10 and most of them display metal-metal
interactions with gold-gold distances shorter than the double
A large number of dithiocarbamate gold(I),5 gold(III),3b,5a,e,6
and gold(II)7 complexes have been prepared, although gold(I)
(1) (a) Puddephat, R. J. The Chemistry of Gold; Elsevier: Amsterdam,
1978. (b) Schmidbaur, H. Organogold Compounds, Gmelin Handbuch
der Anorganische Chemie; Springer-Verlag: Berlin, 1980.
(2) (a) Coucouvanis, D. Prog. Inorg. Chem. 1970, 11, 233. (b) Thorn, G.
D.; Ludwig, R. A. The Dithiocarbamates and Related Compounds;
Elsevier: Amsterdam, 1962; pp 169-207 and 224-277.
(6) (a) Beckett, M. A.; Crook, J. E.; Greenwood, N. N.; Kennedy, J. D.
J. Chem. Soc., Dalton Trans. 1984, 1427. (b) Uso´n, R.; Laguna, A.;
Laguna, M.; Castilla, M. L. J. Organomet. Chem. 1987, 336, 453. (c)
Murray. H. H.; Garzo´n, G.; Raptis, R. G.; Mazany, A. M.; Porter, L.
C.; Fackler, J. P., Jr. Inorg. Chem. 1988, 27, 836. (d) Parish, R. V.;
Howe, B. P.; Wright, J. P.; Mack, J.; Pritchard, R. G.; Buckley, R.
G.; Elsome, A. M.; Fricker, S. P. Inorg. Chem. 1996, 35, 1659. (e)
Bonnardel, P. A.; Parish, R. V.; Pritchard, R. G. J. Chem. Soc., Dalton
Trans. 1996, 3185.
(7) (a) Calabro, D. C.; Harrison, B. A.; Palmer, G. T.; Moguel, M. K.;
Rebbert, R. L.; Burmeister; J. L. Inorg. Chem. 1981, 20, 4311. (b)
Bardaj´ı, M.; Blasco, A.; Jime´nez, J.; Jones, P. G.; Laguna, A.; Laguna,
M.; Mercha´n, F. Inorg. Chim. Acta 1994, 223, 55. (c) Bardaj´ı, M.;
Gimeno, M. C.; Jones, P. G.; Laguna, A.; Laguna, M. Organometallics
1994, 13, 3415.
(8) Wijnhoven, J. G.; Bosman, W. J. P. H.; Beurskens, P. T. J. Cryst.
Mol. Struct. 1972, 2, 7.
(9) (a) A° kerstro¨m, S. ArkiV. Kemi 1959, 14, 387. (b) Jennische, P.;
Anacker-Eickhoff, H.; Wahlberg, A. Acta Crystallogr., Sect. A 1975,
31, 5143.
(10) (a) Uso´n, R.; Laguna, A. Coord. Chem. ReV. 1986, 70, 1. (b) Jones,
P. G. Gold Bull. 1981, 14, 102; (c) 1981, 14, 159; (d) 1983, 16, 114;
(e) 1986, 19, 46.
(3) (a) Thorn, G. D.; Ludwig, R. A. The Dithiocarbamates and Related
Compounds; Elsevier: Amsterdam, 1962; pp 207-224. (b) Criado,
J. J.; Lo´pez-Arias, J. A.; Macias, B.; Ferna´ndez-Lago, L. R.; Salas, J.
M. Inorg. Chim. Acta 1992, 193, 229, and references therein.
(4) (a) Sundermann, F. W. Ann. Clin. Lab. Sci. 1981, 11, 1. (b) Caruso,
F.; Chan, M. L.; Rossi, M. Inorg. Chem. 1997, 36, 3609.
(5) (a) Coucouvanis, D. Prog. Inorg. Chem. 1979, 26, 301, and references
therein. (b) Khan, M. N. I.; King, C.; Heinrich, D. D.; Fackler, J. P.,
Jr.; Porter, L. C. Inorg. Chem. 1989, 28, 2150. (c) Heinrich, D. D.;
Wang, J.; Fackler, J. P., Jr. Acta Crystallogr., Sect. C 1990, 46, 1444,
and references therein. (d) Bardaj´ı, M.; Conelly, N. G.; Gimeno, M.
C.; Jime´nez, J.; Jones, P. G.; Laguna, A.; Laguna, M. J. Chem. Soc.,
Dalton Trans. 1994, 1163. (e) Bardaj´ı, M.; Laguna, A.; Laguna, M.;
Mercha´n, F. Inorg. Chim. Acta 1994, 215, 215. (f) Bardaj´ı, M.; Laguna,
A.; Laguna, M. J. Chem. Soc., Dalton Trans. 1995, 1255. (g) Blaauw,
H. J. A.; Nivard, R. J. F.; Van der Kerk, G. J. M. J. Organomet. Chem.
1964, 2, 236.
10.1021/ic971600a CCC: $15.00 © 1998 American Chemical Society
Published on Web 09/24/1998

Dithiocarbamate in the Coordination Chemistry of Au
Inorganic Chemistry, Vol. 37, No. 21, 1998 5533
van der Waals radius of gold.10a These have been attributed to
correlation and relativistic effects11 that may be significant in
medical applications or contribute to useful optical properties.12
Our current interest is focused on the synthesis of dinuclear
Table 1. Details of Data Collection and Structure Refinement for
the Complexes 2 and 8
2
8‚1/4CH2Cl2
C36H42Au2N2P2S4 C57.25H54.50Au2Cl1.50NO4P4S2
yellow tablet yellow tablet
chem formula
cryst habit
cryst size/ mm
cryst system
space group
a/Å
-
gold complexes with monodentate S2CNR2 ligands; the free
sulfur donor atom of these derivatives can be used to further
coordinate other metallic fragments in order to prepare het-
eropolynuclear compounds, in which Au-M interactions could
be present.
0.50 × 0.20 × 0.02 0.4 × 0.4 × 0.1
orthorhombic
Pbcn
13.532(4)
12.889(4)
21.439(6)
triclinic
P1h
14.940(2)
18.489(3)
20.504(3)
90.271(10)
94.119(6)
91.028(10)
5648.0(14)
4
b/Å
c/Å
Experimental Section
R/deg
â/deg
Reagents. Dialkyldithiocarbamate sodium salts were purchased from
Aldrich. The compounds [AuCl(tht)],13 [Au(tht)2]ClO4,14 (PPh2)2Cd
CH2,15 [Au2Cl2{µ-(PPh2)2CdCH2}],16 and [Au2{µ-(PPh2)2CdCH2}2]-
γ/deg
U/Å3
3739(2)
4
Z
17
(ClO4)2 were prepared by literature methods.
Dc/Mg m-3
M
1.931
1086.83
2096
1.712
1455.63
2850
Caution! Perchlorate salts with organic cations may be explosive.
General Procedure. Infrared spectra were recorded in the range
4000-200 cm-1 on a Perkin-Elmer 883 spectrophotometer and on a
Perkin-Elmer FT-IR Spectrum 1000 spectrophotometer using Nujol
mulls between polyethylene sheets. Conductivities were measured in
ca. 5 × 10-4 M acetone solutions with a Jenway 4010 conductimeter.
C, H, N analyses were carried out with a Perkin-Elmer 240C
microanalyzer. Mass spectra were recorded on a VG Autospec using
the LSIMS techniques and nitrobenzyl alcohol as matrix and on a
HP59987 A Electrospray. 1H and 31P NMR spectra were recorded on
a Bruker ARX 300 in CDCl3 solutions. Chemical shifts are quoted
relative to SiMe4 (1H, external) and H3PO4 (85%) (31P, external).
Synthesis of [Au2(S2CNR2)2{µ-(PPh2)2CdCH2}] (R ) Me (1), Et
(2), Bz (3)). To a dichloromethane solution (20 mL) of [Au2Cl2-
{(PPh2)2CdCH2}] (0.2 mmol, 0.17 g) under N2 was added NaS2CNR2
[0.4 mmol; 0.07 g (R ) Me), 0.10 g (R ) Et), 0.12 g (R ) Bz)], and
the solution immediately became yellow. The reaction mixture was
stirred for 2 h, generating a white solid (NaCl), which was separated
by filtration. The filtrate was evaporated to ca. 5 mL, and addition of
diethyl ether (20 mL) led to precipitation of complexes 1-3 as yellow
solids. Yield: 71 (1), 86 (2), 43% (3). Mass spectra: [M]+ at m/z )
1030 (43, 1), 1086 (2, 2), 1334 (20, 3). Anal. Calcd for C32H34-
Au2N2P2S4 (1): C, 37.29; H, 3.32; N, 2.72. Found: C, 37.79; H, 3.64;
N, 2.63. C36H42Au2N2P2S4 (2): C, 39.8; H, 3.9: N, 2.6. Found: C,
39.78; H, 4.43; N, 2.67. C56H50Au2N2P2S4 (3): C, 50.37; H, 3.77; N,
2.09. Found: C, 49.74; H, 3.47; N, 1.93. 31P{1H} NMR (CDCl3): δ
(1) 36.8 (s); (2) 37.0 (s); (3) 36.4 (s). 1H NMR (CDCl3): δ (1) 7.74-
7.33 (m, 20H, Ph), 6.22 [“t”, 2H, N(HP) 25.3 Hz, CdCH2], 3.47 (s,
12H, CH3); (2) 7.74-7.31 (m, 20H, Ph), 6.22 [“t”, 2H, N(HP) 25.4
F(000)
T/°C
-100
-100
2θmax/deg
µ(MoKR)/mm-1
transmission
no. of reflns measd 3227
no. of unique reflns 3208
50
50
8.17
0.459-0.879
5.49
0.541-1.0
21 361
19 836
0.035
0.044
0.086
1301
1146
0.849
2.22
Rint
0.049
Ra(F, F > 4σ(F)) 0.045
wRb(F2, all refl)
no. of params
no. of restraints
Sc
0.098
209
279
0.811
1.14
max. ∆F/e Å-3
a R(F) ) ∑||Fo| - |Fc||/∑|Fo|. b wR(F2) ) [∑{w(Fo - Fc2)2}/
2
∑{w(Fo )2}]0.5; w-1 ) σ2(Fo ) + (aP)2 + bP, where P ) [Fo2 + 2Fc2]/
2
2
3 and a and b are constants adjusted by the program. c S ) [∑{w(Fo
2
- Fc2)2}/(n - p)]0.5, where n is the number of data and p the number
of parameters.
3.1; N, 1.35. Found: C, 35.46; H, 3.19; N, 1.34. 31P{1H} NMR
(CDCl3): δ 41.0 (s). 1H NMR (CDCl3): δ 7.68-7.43 (m, 20H, Ph),
6.46 [“t”, 2H, N(HP) 26.3 Hz, CdCH2], 3.97 (m, 8H, CH2), 1.39 (m,
12H, CH3).
Synthesis of [Au2M(µ-S2CNEt2)2{µ-(PPh2)2CdCH2}]X (X ) ClO4,
M ) Au (5), Ag (6); X ) PF6, M ) Cu (7)). To a dichloromethane
(5, 6) or acetonitrile (7) solution of 2 (0.2 mmol, 0.28 g) was added
[Au(tht)2]ClO4 (0.2 mmol, 0.09 g) (5), AgClO4 (0.2 mmol, 0.04 g) (6),
or [Cu(NCCH3)4]PF6 (0.2 mmol, 0.07 g) (7). The resulting suspension
was stirred for 0.5 h and then filtered. The filtrate was concentrated
to ca. 5 mL, and addition of diethyl ether (20 mL) led to the precipitation
of complexes 5-7 as yellow solids. Yield: 86 (5), 64 (6), 61% (7).
Anal. Calcd for C36H42Au3ClN2O4P2S4 (5): C, 31.25; H, 3.05; N, 2.0.
Found: C, 30.95; H, 3.15; N, 2.0. C36H42AgAu2ClN2O4P2S4 (6): C,
33.4; H, 3.25; N, 2.15. Found: C, 33.85; H, 3.0; N, 2.0. C36H42Au2-
CuF6N2P3S4 (7): C, 33.35; H, 3.25; N, 2.15. Found: C, 33.35; H,
3.15; N, 1.9. 31P{1H} NMR (CDCl3): δ (5) 41.3 (s), (6) 40.3 (s), (7)
41.0 (s). 1H NMR (CDCl3): δ (5) 7.65-7.45 (m, 20H, Ph), 6.48 [“t”,
2H, N(HP) 26.5 Hz, CdCH2], 3.98 (m, 4H, CH2), 3.84 (m, 4H, CH2),
1.40 (m, 6H, CH3), 1.34 (m, 6H, CH3); (6) 7.64-7.42 (m, 20H, Ph),
6.43 [“t”, 2H, N(HP) 26.1 Hz, CdCH2], 3.96 (m, 8H, CH2), 1.39 (m,
12H, CH3); (7) 7.64-7.43 (m, 20H, Ph), 6.43 [“t”, 2H, N(HP) 26.3
Hz, CdCH2], 3.98 (m, 8H, CH2), 1.39 (m, 12H, CH3).
3
Hz, CdCH2], 3.89 (q, 8H, CH2), 1.31 [t, 12H, J(HH) 6.6 Hz, CH3];
(3) 7.76-7.27 (m, 40H, Ph), 6.23 [“t”, 2H, N(HP) 25.0 Hz, CdCH2],
5.08 (s, 8H, CH2).
Synthesis of [Au2(µ-S2CNEt2){µ-(PPh2)2CdCH2}]ClO4 (4). To
a dichloromethane solution of [Au2{(PPh2)2CdCH2}2](ClO4)2 (0.2
mmol, 0.28 g) was added [Au2(S2CNEt2)2] (0.2 mmol, 0.14 g). The
resulting mixture was stirred for 1 h to obtain a yellow solution, which
was evaporated to ca. 5 mL. Diethyl ether (20 mL) was then added to
precipitate a yellow solid. Yield: 66%. Mass spectra: [M]+ at m/z
) 938 (100). Anal. Calcd for C31H32Au2ClNO4P2S2: C, 35.87; H,
(11) (a) Schmidbaur, H. Gold Bull. 1990, 23, 11. (b) Li, J.; Pyykko¨, P.
Chem. Phys. Lett. 1992, 197, 586. (c) Kaltsoyannis, N. J. Chem. Soc.,
Dalton Trans. 1997, 1. (d) Pyykko¨, P. Chem. ReV. 1997, 97, 597.
(12) (a) Sadler, P. J.; Sue, R. E. Metal-Based Drugs 1994, 1, 107. (b) Wang,
S.; Garzo´n, G.; King, C.; Wang, J.-C.; Fackler, J. P., Jr. Inorg. Chem.
1989, 28, 4623. (c) Narayanaswamy, R.; Young, M. A.; Parkhurst,
E.; Ouellette, M.; Kerr, M. E.; Ho, D. M.; Elder, R. C.; Bruce, A. E.;
Bruce, M. R. M. Inorg. Chem. 1993, 32, 2506. (d) Tang, S. S.; Chang
C.-P.; Lin, I. J. B.; Liou, L.-S.; Wang, J.-C. Inorg. Chem. 1997, 36,
2294.
(13) Uso´n, R.; Laguna, A.; Laguna, M. Inorg. Synth. 1989, 26, 85.
(14) Uso´n, R.; Laguna, A.; Laguna, M.; Jime´nez, J.; Go´mez, M. P.; Sainz,
A.; Jones, P. G. J. Chem. Soc., Dalton Trans. 1990, 3457.
(15) Colquhoun, J.; McFarlane, W. J. Chem. Soc., Dalton Trans. 1982,
1915.
Synthesis of [Au2(µ-S2CNEt2){µ-(PPh2)2CdCH2}2]ClO4 (8). (a)
To a dichloromethane (20 mL) solution of 4 (0.2 mmol, 0.21 g) was
added (PPh2)2CdCH2 (0.2 mmol, 0.08 g). After stirring for 2 h the
initially pale yellow solution became intensely yellow. The reaction
mixture was evaporated to ca. 5 mL, and addition of diethyl ether (20
mL) gave complex 8 as a yellow solid. Yield: 65%. (b) This complex
can be also obtained by addition of NaS2CNEt2 (0.2 mmol, 0.05 g) to
a dichloromethane (20 mL) suspension of [Au2{(PPh2)2CdCH2}2]-
(ClO4)2 (0.2 mmol, 0.14 g). After 5 min the solution became yellow.
(16) Schmidbaur, H.; Herr, R.; Mu¨ller, G.; Riede, J. Organometallics 1985,
4, 1208.

5534 Inorganic Chemistry, Vol. 37, No. 21, 1998
Ferna´ndez et al.
Scheme 1 (i) 2 [AuCl(tht)]; (ii) 2 NaS2CNR2; (iii) [Au(tht)2]ClO4; (iv) [Au2(µ-S2CNEt2)2]; (v) [Au(tht)2]ClO4 or AgClO4; (vi)
[Cu(MeCN)4]PF6; (vii) (PPh2)2CdCH2; (viii) NaS2CNEt2; (ix) 2 PPh3
F
The reaction mixture was stirred for 2 h, generating a white solid
(NaClO4), which was separated by filtration. The filtrate was evapo-
rated to ca. 5 mL, and addition of diethyl ether (20 mL) led to
precipitation of complex 8. Yield: 56%. Mass spectra: [M]+ at m/z
) 1334 (2). Electrospray: [M + H]+ at m/z ) 1335 (5). Anal. Calcd
for C57H54Au2ClNO4P4S2: C, 47.75; H, 3.8; N, 0.95. Found: C, 47.2;
H, 3.75; N, 0.9. 31P{1H} NMR (CDCl3): δ 40.1 (s). 1H NMR
(CDCl3): δ 7.43-7.26 (m, 40H, Ph), 6.42 [“q”, 2H, N(HP) 11.7 Hz,
CdCH2], 4.13 (m, 8H, CH2), 1.38 (m, 12H, CH3).
Results and Discussion
Our first objective was the synthesis of gold(I) complexes
with monodentate dithiocarbamate. Thus, the treatment of the
dinuclear complex [Au2Cl2{µ-(PPh2)2CdCH2}] with 2 equiv
of N,N-dialkyldithiocarbamate (alkyl ) methyl, ethyl, benzyl),
as illustrated in Scheme 1, results in the formation of three new
derivatives [Au2(S2CNR2)2{µ-(PPh2)2CdCH2}] (R ) Me (1),
Et (2), Bz (3)) that should contain monodentate dithiocarbamate.
Their elemental analyses and physical and spectroscopic
properties are in accordance with the proposed stoichiometry.
The molar conductivities of these products in acetone solution
(ΛM ) 2 (1), 4 (2), 3 (3) Ω-1 cm2 mol-1) rule out an ionic
formulation. Usually, the IR spectra of complexes with a
bidentate dithiocarbamate ligand show the ν(CdN) stretching
absorption above 1485 cm-1, whereas in compounds with the
ligand possessing a monodentate coordination it appears below
1485 cm-1. In complexes 1-3 it is found at 1463 (1), 1472
(2), and 1469 (3) cm-1, also indicating a monodentate coordina-
tion by the sulfur donor ligand.19
Synthesis of [Au2(µ-S2CNEt2){µ-(PPh2)2CdCH2}(PPh3)2]ClO4 (9).
To a dichloromethane solution of 4 (0.2 mmol, 0.21 g) was added PPh3
(0.4 mmol, 0.11 g). After stirring for 2 h the initial pale yellow solution
turned to bright yellow. The reaction mixture was evaporated to ca. 5
mL, and addition of diethyl ether (20 mL) gave complex 9 as a yellow
solid. Yield: 56%. Mass spectra, m/z: 1200 (7), [M - PPh3]+; 938
(100), [M - 2PPh3]+; 1067 (50), [M - vdpp]+. Anal. Calcd for
C67H62Au2ClNO4P4S2: C, 51.50; H, 3.99; N, 0.89. Found: C, 50.98;
H, 3.58; N, 0.89. 31P{1H} NMR (CDCl3): δ 39.8 (s), 36.5 (m, PPh3).
1H NMR (CDCl3): δ 7.95-7.38 (m, 50H, Ph), 6.46 (m, 2H, CdCH2),
3.79 (m, 4H, CH2), 1.19 (m, 6H, CH3).
Crystal Structure Determinations. Crystals were mounted in inert
oil on glass fibers. Data were collected using monochromated Mo KR
radiation (λ ) 0.710 73 Å). A Siemens P4 difractometer with an LT-2
low-temperature attachment was used (scan type ω). Cell constants
were refined from setting angles of ca. 60 reflections in the 2θ range
7-23°. Absorption corrections were applied on the basis of Ψ-scans.
Structures were solved by the heavy atom method and refined
anisotropically on F2 (program SHELXL-93).18 Hydrogen atoms were
included using a riding model. To improve refinement stability, a range
of restraints to local ring symmetry and light atom displacement
parameters were employed. Special refinement details for complex 8:
the dichloromethane molecule is disordered over a center of symmetry,
and its carbon atom was not located. The composition is thus one
molecule of complex to 1/4 molecule of dichloromethane. Further
details are given in Table 1.
The molecular structure of complex 2 has been confirmed
by X-ray structure analysis (Figure 1). Selected bond lengths
and angles are presented in Table 2. The molecule displays
crystallographic 2-fold symmetry, the 2-fold axis passing along
the double bond C(1)-C(2). The coordination of the gold atoms
is almost linear, with a P-Au-S(2) angle of 174.43(12)°. The
very dissimilar Au-S distances, Au-S(2) 2.319(4) and Au-
S(1) 2.969(4) Å, show that the dithiocarbamate ligands are
essentially monodentate. However, the longer distance may
represent a weak contact between the gold and the second sulfur
atom; cf. complexes such as [AuII (µ-CH2PPh2CH2)2(S2-
2
CNR2)2],7b in which the bonded distances are 2.439, 2.431(2)
Å and the nonbonded Au-S distances 3.313, 3.306 Å in two
independent molecules, and [Au(S2CNEt2)(PPh3)]8 with 2.338
(17) Ferna´ndez, E. J.; Gimeno, M. C.; Jones, P. G.; Laguna, A.; Lo´pez-
de-Luzuriaga, J. M.; Olmos, M. E. Chem. Ber. 1997, 130, 1513.
(18) Sheldrick, G. M. SHELXL-93, a program for crystal structure refine-
ment; University of Go¨ttingen: Germany, 1993.
(19) Nakamoto, K. Infrared and Raman Spectra of Inorganic and Coor-
dination Compounds; Wiley & Sons: New York, 1986; p 346.

Dithiocarbamate in the Coordination Chemistry of Au
Inorganic Chemistry, Vol. 37, No. 21, 1998 5535
Table 3. Selected Bond Lengths [Å] and Angles [deg] for 8
Au(1)-P(3)
Au(1)-S(1)
Au(2)-P(2)
Au(2)-S(2)
S(1)-C(5)
Au(1′)-P(3′)
Au(1′)-S(1′)
Au(2′)-P(2′)
Au(2′)-S(2′)
2.306(2)
2.554(2)
2.309(2)
2.664(2)
1.727(8)
2.309(2)
2.662(3)
2.313(2)
2.608(2)
Au(1)-P(1)
Au(1)-Au(2)
Au(2)-P(4)
P(3)-C(51)
S(2)-C(5)
Au(1′)-P(1′)
Au(1′)-Au(2′)
Au(2′)-P(4′)
2.351(2)
2.9019(6)
2.339(2)
1.818(8)
1.746(8)
2.339(2)
2.9002(6)
2.365(2)
P(3)-Au(1)-P(1)
P(1)-Au(1)-S(1)
P(1)-Au(1)-Au(2)
P(2)-Au(2)-P(4)
P(4)-Au(2)-S(2)
P(4)-Au(2)-Au(1)
C(5)-S(1)-Au(1)
P(3′)-Au(1′)-P(1′)
P(1′)-Au(1′)-S(1′)
143.19(8) P(3)-Au(1)-S(1)
98.99(8) P(3)-Au(1)-Au(2)
85.89(5) S(1)-Au(1)-Au(2)
149.09(8) P(2)-Au(2)-S(2)
96.49(8) P(2)-Au(2)-Au(1)
90.28(6) S(2)-Au(2)-Au(1)
106.1(3) C(5)-S(2)-Au(2)
147.08(8) P(3′)-Au(1′)-S(1′)
117.56(8)
93.99(5)
96.14(6)
114.41(8)
96.28(6)
77.14(5)
113.1(3)
119.71(8)
Figure 1. Molecular structure of complex 2. Radii are arbitrary. Only
the asymmetric unit is numbered.
92.97(8) P(3′)-Au(1′)-Au(2′) 93.96(6)
Table 2. Selected Bond Lengths [Å] and Angles [deg] for 2a
P(1′)-Au(1′)-Au(2′) 88.83(6) S(1′)-Au(1′)-Au(2′) 91.33(6)
P(2′)-Au(2′)-P(4′)
P(4′)-Au(2′)-S(2′)
P(4′)-Au(2′)-Au(1′) 89.71(6) S(2′)-Au(2′)-Au(1′) 76.98(6)
C(5′)-S(1′)-Au(1′) 103.3(3) C(5′)-S(2′)-Au(2′) 107.5(3)
147.12(8) P(2′)-Au(2′)-S(2′)
119.38(8)
Au-P
2.234(3)
2.969(4)
1.815(11)
1.826(13)
1.765(13)
1.33(2)
Au-S(2)
Au-Au#1
P-C(21)
S(1)-C(3)
C(1)-C(2)
C(4)-C(5)
C(6)-N
2.319(4)
3.3429(12)
1.816(14)
1.658(13)
1.26(2)
1.47(2)
1.45(2)
93.40(8) P(2′)-Au(2′)-Au(1′) 95.02(6)
Au-S(1)
P-C(1)
P-C(11)
S(2)-C(3)
C(3)-N
C(4)-N
C(6)-C(7)
corresponding to the molecular ion at m/z ) 1283 (23, 5), 1195
(3, 6), and 1148 (13, 7).
The structural arrangement of the dithiocarbamate ligands
could produce intermetallic contacts in the Au2M. Unfortu-
nately, no suitable crystals for X-ray diffraction studies have
been obtained.
1.485(14)
1.50(2)
P-Au-S(2)
174.43(12)
66.42(11)
97.97(8)
104.3(6)
103.1(6)
118.0(5)
77.6(5)
122.7(6)
123.3(10)
118.8(8)
114.3(11)
P-Au-S(1)
117.79(12)
76.52(9)
130.89(9)
108.0(4)
111.4(5)
111.4(4)
96.7(4)
114.6(11)
117.9(9)
111.1(10)
S(2)-Au-S(1)
S(2)-Au-Au#1
C(1)-P-C(21)
C(21)-P-C(11)
C(21)-P-Au
C(3)-S(1)-Au
C(2)-C(1)-P
N-C(3)-S(1)
S(1)-C(3)-S(2)
N-C(6)-C(7)
P-Au-Au#1
S(1)-Au-Au#1
C(1)-P-C(11)
C(1)-P-Au
As is well-known, the structural chemistry of gold(I) is
characterized by its linear coordination. However, some
examples of tricoordinate gold(I) complexes have been de-
scribed,20 although there is only one dithiocarbamate derivative
reported to date.5b To increase the number of this type of
compound, we reacted [Au2{µ-(PPh2)2CdCH2}2](ClO4)2 with
NaS2CNEt2 (1:2) or [Au2(µ-S2CNEt2){µ-(PPh2)2CdCH2}]ClO4
(4) with (PPh2)2CdCH2 (1:1). The resulting complex (8)
displays two gold centers in a tricoordinate environment,
coordinated by one sulfur of the dithiocarbamate and two
phosphorus atoms, one from each diphosphine (see Scheme 1;
X-ray structure, see below). In a similar way, the reaction of
4 with PPh3 in a 1:2 molar ratio affords the new tricoordinate
species [Au2(µ-S2CNEt2){µ-(PPh2)2CdCH2}(PPh3)2]ClO4 (9).
In the IR spectra of complexes 8 and 9 the ν(CdN) stretching
band appears at 1480 (8) and 1481 (9) cm-1, lower than
previously reported values for this system,5b probably associated
with the tricoordination. Their molar conductivities in acetone
(ΛM ) 132 (8), 156 (9) Ω-1 cm2 mol-1) prove that the
dithiocarbamate ligands are coordinated to the gold centers rather
than being counterions. Moreover, the 31P{1H} spectrum of 9
shows two singlets at 39.8 and 36.5 ppm. No P-P coupling is
observed, whereas gold(I) linear compounds containing the unit
P-Au-PPh3 usually display AB systems.21
C(11)-P-Au
C(3)-S(2)-Au
P#1-C(1)-P
N-C(3)-S(2)
C(5)-C(4)-N
a Symmetry transformations used to generate equivalent atoms: #1,
-x+1, y, -z+1/2.
and 3.015 Å. The Au-Au distance is 3.3429(12) Å and is
longer than those found in other dinuclear gold(I) systems such
as [Au2{µ-(PPh2)2CdCH2}]Cl2 (2.977(1) Å),16 which has the
same phosphine ligand; the two P-Au-S moieties are twisted
with respect to each other by 59° (torsion angle Au-P‚‚‚P′-
Au′). As expected, the longer C-S bond involves the coordi-
nated S atom (C(3)-S(2) 1.765(13), C(3)-S(1) 1.658(13) Å).
The above-mentioned ionic species [Au2(µ-S2CNEt2){µ-
(PPh2)2CdCH2}]ClO4 (4) can also be prepared through a
metathesis reaction of [Au2{µ-(PPh2)2CdCH2}2](ClO4)2 and
[Au2(µ-S2CNEt2)2] (see Scheme 1). Its physical and spectro-
scopic properties are clearly different from those of 2: it is a
uni-univalent electrolyte in acetone solution (ΛM ) 142 Ω-1
cm2 mol-1) and its ν(CdN) band appears at 1501 cm-1 19
.
The crystal structure of complex 8 (Table 3) has been
established by X-ray diffraction; the asymmetric unit of complex
8 has two independent but closely similar molecules (A and
B), one of which is shown in Figure 2. Both molecules consist
of two gold atoms bridged by two diphosphines and one
dithiocarbamate ligand and presenting short intramolecular
gold-gold contacts of 2.9019(6) and 2.9002(6) Å. These
distances are longer than those found in dinuclear dithiocar-
bamate complexes such as [Au2(µ-S2CNR2)2] (2.76-2.8 Å),5c,9b,22
The free sulfur atoms of complex 2 can coordinate a metal
center by reaction with [Au(tht)2]ClO4, AgClO4, or [Cu-
(MeCN)4]PF6, affording trinuclear complexes 5-7, in which
the dithiocarbamate ligands bridge two different metal centers,
a situation that, as far as we are aware, is unprecedented (see
Scheme 1). Their elemental analyses and spectroscopic and
physical properties are in accordance with the proposed
formulation, and they are uni-univalent electrolytes in acetone
(ΛM ) 149 (5), 154 (6), 166 Ω-1 cm2 mol-1). In their IR
spectra, the ν(CdN) stretching band appears at 1494 (5), 1499
(6), and 1495 (7) cm-1, as expected for bidentate dithiocar-
bamate ligands. Their mass spectra (LSIMS+) display the peak
(20) Gimeno, M. C.; Laguna, A. Chem, ReV. 1997, 97, 511.
(21) Ferna´ndez, E. J.; Gimeno, M. C.; Jones, P. G.; Laguna, A.; Laguna,
M.; Olmos, E. J. Chem. Soc., Dalton Trans. 1994, 2891.

5536 Inorganic Chemistry, Vol. 37, No. 21, 1998
Ferna´ndez et al.
2.662(3) and 2.608(2) (molecule B) Å, are shorter than those
in [Au2(S2CNEt2)(dppm)2][BH3CN] (2.648(3) and 2.703(3) Å),
but longer than those in other three-coordinate complexes such
as [Au(SCN)(PPh3)2] (2.468(4) Å).23 The Au-P bond distances
lie in the range 2.306(2)-2.365(2) Å and are also typical of
three-coordinate complexes.
The gold atoms display a distorted trigonal planar geometry
with angles close to 143° (P-Au-P), 117°, and 100° (P-Au-
S); the distortion is less marked than in [Au2(S2CNEt2)-
(dppm)2][BH3CN], where the P-Au-P angle is 160°. The Au
atoms lie maximally 0.07 Å out of the respective PS2 planes,
and the interplanar angles are 6° and 11° in the two molecules.
The mutual rotations of the coordination planes are expressed
by the torsion angles P(1)-Au(1)-Au(2)-P(2) 14°, 15°; P(3)-
Au(1)-Au(2)-P(4) 21°, 15°; and S(1)-Au(1)-Au(2)-S(2)
36°, 41°.
Figure 2. Structure of one of the two independent cations of complex
8. H atoms are omitted for clarity.
Acknowledgment. We thank the Direccio´n General de
Ensen˜anza Superior (no. PB97 1010 CO2 02) and the Fonds
der Chemischen Industrie for financial support.
slightly longer than those in [Au2{µ-(CH2)2PPh2}(µ-S2CNEt2)]
(2.868(1) and 2.867(1) Å), but similar to those in the related
compound [Au2(S2CNEt2)(dppm)2][BH3CN] (2.949(1) Å).5b The
Au-S bond distances, 2.554(2) and 2.664(2) (molecule A) and
Supporting Information Available: Two X-ray crystallographic
files, in CIF format, are available on the Internet only. Access and
ordering information is given on any current masthead page.
(22) Hesse, R.; Jennische, P. Acta Chem. Scand. 1972, 26, 3855.
(23) Muir, J. A.; Muir, M. M.; Arias, S. Acta Crystallogr. Sect. B 1982,
38, 1318-1320.
IC971600A