Au-O interactions and others in triphenylphosphinegold(I) sulfanylpropenoates with diverse structures

Article abstract of DOI:10.1039/b307192h

We investigated the reactions of triphenylphosphinegold(I) chloride in ethanol or methanol with the 3-(2-aryl)-2-sulfanylpropenoic acids H₂xspa [x = f, t, p; f = 3-(2-furyl)-, t = 3-(2-thienyl)-, p = 3-phenyl-; spa = 2-sulfanylpropenoato] in 1 : 1 and 2 : 1 mole ratios, and the reactions of diisopropylamine with the 1 : 1 complexes. Compounds of types [Au(PPh₃)(Hxspa)], [HQ][Au(PPh₃)(xspa)] (HQ = diisopropylammonium) and [(AuPPh₃)₂(xspa)] were isolated and characterized by IR, Raman and FAB mass spectrometry and by ¹H, ¹³C and ³¹P NMR spectroscopy. The structures of (Htspa)₂·Me₂CO and of the complexes [Au(PPh₃)(Hfspa)] (1), [HQ][Au(PPh₃)(pspa)] (6), [(AuPPh₃)₂(fspa)] (7), [(AuPPh₃)₂(tspa)]·2MeOH (8·2MeOH) and [(AuPPh₃)₂pspa]·2MeOH (9·2MeOH) were determined by X-ray diffractometry; those of the Au complexes exhibit π-stacking, hydrogen bonding and Au-Au and Au-O interactions as well as the expected Au-S and Au-P bonds.

Full text of DOI:10.1039/b307192h

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Au–O Interactions and others in triphenylphosphinegold(I)
sulfanylpropenoates with diverse structures
Elena Barreiro,a José S. Casas,a María D. Couce,b Agustín Sánchez,a José Sordo,*a
José M. Varelaa and Ezequiel M. Vázquez-Lópezb
a Departamento de Química Inorgánica, Facultade de Farmacia,
Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain.
E-mail: qijsordo@usc.es
b Departamento de Química Inorgánica, Facultade de Ciencias, Universidade de Vigo,
36200 Vigo, Galicia, Spain
Received 24th June 2003, Accepted 17th September 2003
First published as an Advance Article on the web 7th October 2003
We investigated the reactions of triphenylphosphinegold() chloride in ethanol or methanol with the
3-(2-aryl)-2-sulfanylpropenoic acids H2xspa [x = f, t, p; f = 3-(2-furyl)-, t = 3-(2-thienyl)-, p = 3-phenyl-;
spa = 2-sulfanylpropenoato] in 1 : 1 and 2 : 1 mole ratios, and the reactions of diisopropylamine with the
1 : 1 complexes. Compounds of types [Au(PPh3)(Hxspa)], [HQ][Au(PPh3)(xspa)] (HQ = diisopropylammonium)
and [(AuPPh3)2(xspa)] were isolated and characterized by IR, Raman and FAB mass spectrometry and by
1H, 13C and 31P NMR spectroscopy. The structures of (Htspa)2ؒMe2CO and of the complexes [Au(PPh3)(Hfspa)] (1),
[HQ][Au(PPh3)(pspa)] (6), [(AuPPh3)2(fspa)] (7), [(AuPPh3)2(tspa)]ؒ2MeOH (8ؒ2MeOH) and [(AuPPh3)2pspa]ؒ
2MeOH (9ؒ2MeOH) were determined by X-ray diffractometry; those of the Au complexes exhibit π-stacking,
hydrogen bonding and Au–Au and Au–O interactions as well as the expected Au–S and Au–P bonds.
the tetrafluoroborates of the cationic complexes [(AuPPh3)2-
Introduction
SCH2C(O)OAu(PPh3)]ϩ and [(AuPPh3)2SC6H4CO2H]ϩ.10
Well-known for their antiarthritic properties, Au() complexes
Here we describe the products of the reactions of Au(PPh3)Cl
in 1 : 1 and 2 : 1 mole ratios with the arylsulfanylpropenoic
[AuLX] that contain both thiolate and phosphine ligands have
also attracted interest as potential antitumour agents.1 Since the
acids depicted in Scheme 1, and of the reactions of the 1 : 1
susceptibility of the thiolate to replacement by biological
complexes so prepared with diisopropylamine. The aryl groups
ligands is presumed to modulate the biological activity of these
R in Scheme 1 were chosen both on account of the possibility
compounds,2 it is attractive to explore the activities of members
of this family in which the S–Au bond has been stabilized
by endowing the thiolate ligand with other groups that are
also capable of binding to the metal. In particular, Au ؒ ؒ ؒ O
interactions may be sought by using sulfanylcarboxylates.
Although no significant Au ؒ ؒ ؒ O interactions have been found
when sulfanylalkanoates or sulfanyl benzoates have been used
of their engaging in intermolecular interactions, and because
of their likely influence on the hydrophilicity and lipophilicity
of the complexes prepared, which are of great importance for
drug action.1,2 Five of the new complexes {[Au(PPh3)(Hfspa)]
(1), [HQ][Au(PPh3)(pspa)] (6) ([HQ] = diisopropylammonium),
[(AuPPh3)2(fspa)] (7), [(AuPPh3)2(tspa)]ؒ2MeOH (8ؒ2MeOH)
and [(AuPPh3)2(pspa)]ؒ2MeOH (9ؒ2MeOH)} were isolated as
(at least when the phosphine ligand is triphenylphosphine),2b,3–6
single crystals, the structures of which, elucidated by X-ray
the observation7 that in triorganotin() complexes of arylsulf-
crystallography, were found to feature π-stacking, hydrogen
anylpropenoates the Sn–O distances are shorter than in a
bonding, Au–Au and Au–O interactions as well as Au–S and
related sulfanylethanoate complex has suggested to us that
Au–P bonds. We also describe the crystal structure of (Htspa)2ؒ
Au–O interactions might be found in Au(PPh3) complexes of
Me2CO, which was isolated in an attempt to crystallize H2tspa
arylsulfanylpropenoates.
from acetone in air.
In the solid state, many [AuLX] compounds are known
to aggregate through intermolecular Au ؒ ؒ ؒ Au or Au ؒ ؒ ؒ S
interactions, but if L or X has additional bonding capabilities,
as in the case of triphenylphosphinegold() sulfanylcarboxyl-
ates, hydrogen bonding, van der Waals forces and/or other
interactions can broaden the range of possible structures
considerably.3 In [Au(PPh3)(SCH(Me)CO2H)]2b and [Au(PPh3)-
(SCMe2CO2H)],4 in which the gold atom is coordinated to the S
and P atoms in an essentially linear P–Au–S unit, a hydrogen
bond between the carboxyl group and a neighbouring molecule
gives rise to a dimer. In [Au(PPh3)(SCH2CO2H)]4 an Au ؒ ؒ ؒ S
Scheme 1
interaction between neighbouring molecules and a hydrogen
Experimental
bond between CO2H groups together give rise to a polymeric
network. [Au(PPh3)(6-Hmna)]2b (6-H2mna = 6-sulfanylnicotinic
acid) has a polymeric network based on π–π stacking and
hydrogen bonding. We hypothesized that the use of sulfanyl-
propenoates might lead to a variety of structures which, given
the possibility of deprotonation of both the sulfanyl and carb-
oxyl groups,7,8 might include interesting dinuclear complexes
with Au–Au bonds.9 The only previous report of plurinuclear
Au()-phosphine complexes of sulfanylcarboxylates concerned
Material and methods
The 3-(2-aryl)-2-sulfanylpropenoic acids H2fspa, H2tspa and
H2pspa were prepared11 by condensation of the appropriate
aldehyde with rhodanine, subsequent hydrolysis in an alkaline
medium and acidification with aqueous HCl. Triphenylphos-
phinegold() chloride (Aldrich) and diisopropylamine (Merck)
were used as supplied.
D a l t o n T r a n s . , 2 0 0 3 , 4 7 5 4 – 4 7 6 1
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 3
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Elemental analyses, melting points and IR, Raman and mass
spectra (the data characterizing the metallated MS peaks were
calculated for the isotope 197Au) were obtained as in ref. 8.
NMR spectra (1H in dmso-d6 and 13C in dmso-d6 or chloro-
form) were recorded at room temperature on a Bruker AMX 300
operating at 300.14 and 75.40 MHz, respectively, using 5 mm
o.d. tubes; chemical shifts are reported relative to TMS using
δ(OH); 1254m, ν(C–O); 1481m, 1437vs, ν(Ph3P). NMR
(DMSO-d6): H, δ 12.60 (s, 1H, C(1)OH), 7.51 (s, 1H, C(3)H),
8.10 (d, 2H, C(5)Ho) 7.36 (t, 2H, C(6)Hm), 7.22 (m, 1H, C(7)Hp),
7.60 (m, 15H, H(PPh3)); 13C, δ 171.1 C(1), 127.8 C(2), 136.5
C(3), 134.4 C(4), 130.3 C(5), 127.6 C(6), 128.6 C(7); 31P{1H},
δ 35.3 (s).
1
1
the solvent signal as reference (δ H = 2.50 ppm; δ 13C = 39.5
[HQ][Au(PPh3)(fspa)] (4). [Au(PPh3)(Hfspa)] (0.090 g, 14.3
mmol), diisopropylamine (0.020 cm3), ethanol (15 cm3), light
brown solid. Yield: 48%. Mp 176 ЊC. Anal. Found: C 50.7, H
4.8, S 4.3, N 2.0. Calc. for C31H35O3SPAuN: C 51.0, H 4.8, S
4.4, N 1.9%. MS (FAB): the main metalated signals are at m/z
1409 (30%), [(AuPPh3)3S]ϩ; 1087 (27), [(AuPPh3)2(fspa)]ϩ; 729
(5), [M]ϩ 721 (11), [(PPh3)2Au]ϩ; 628 (44), [Au(PPh3)(fspa)]ϩ;
and 459 (100), [(PPh3)Au]ϩ. IR and Raman (R) (cmϪ1): 1614s,
ν(NH2ϩ); 1572s, 1581vs (R), νa(CO2); 1340vs, νs(CO2); 1481s,
1436s, 1481s (R), ν(PPh3). NMR (DMSO-d6): 1H, δ 7.43 (s, 1H,
C(3)H), 7.23 (d, 1H, C(5)H) 6.53 (m, 1H, C(6)H) 7.59 (d, 1H,
C(7)H), 7.55 (m, 15H, H (Ph3)), 1.12 (d, 12H, CH3 [HQ]), 3.18
(m, 2H, CH [HQ]), 8.30 (s, 2H, NH2ϩ [HQ]); 13C, δ 171.2 C(1),
119.1 C(2), 128.7 C(3), 154.1 C(4), 111.8 C(5), 110.5 C(6), 141.0
C(7), 45.6 CH [HQ], 19.7 CH3 [HQ]; 31P{1H}, δ 36.16 (s).
ppm). 31P NMR spectra were recorded in chloroform at 202.46
MHz on a Bruker AMX 500 spectrometer using 5 mm o.d.
tubes and are reported relative to external neat H3PO4 (85%).
Synthesis
The complexes of type [Au(PPh3)(Hxspa)] (x = f, t, p) were
prepared by adding Au(PPh3)Cl in 1 : 1 mole ratio to a solution
of the appropriate sulfanylcarboxylic acid and KOH in ethanol.
After stirring at room temperature for 1 h, the ethanol was
evaporated under vacuum and the solid formed was washed
with water and dried in vacuo.
The complexes [HQ][Au(PPh3)(xspa)] (HQ = diisopropyl-
ammonium) were prepared by adding diisopropylamine to a
solution of the appropriate 1 : 1 complex in ethanol. After
stirring at room temperature for 24 h the ethanol was evapor-
ated and the solid formed was dried in vacuo.
The complexes of type [(AuPPh3)2(xspa)] were prepared by
adding Au(PPh3)Cl in 2 : 1 mole ratio to a solution of the
appropriate sulfanylcarboxylic acid and NaOH in methanol,
or by adding Au(PPh3)Cl and NaOH to a solution of the
appropriate 1 : 1 complex in methanol. After stirring and reflux-
ing for 1 h, the methanol was evaporated and the solid formed
was washed with water and dried in vacuo.
[HQ][Au(PPh3)(tspa)] (5). [Au(PPh3)(Htspa)] (0.210 g, 32.0
mmol), diisopropylamine (0.046 cm3), ethanol (30 cm3), light
brown solid. Yield 55%. Mp 160 ЊC. Anal. Found: C 49.3, H
4.4, S 7.9, N 1.6. Calc. for C31H35O2S2PAuN: C 49.9, H 4.7, S
8.6, N 1.9%. MS (FAB): the main metalated signals are at m/z
1409 (3%), [(AuPPh3)3S]ϩ; 1103 (4), [(AuPPh3)2(tspa)]ϩ; 721
(11), [(PPh3)2Au]ϩ; 644 (1), [Au(PPh3)(Htspa)]ϩ; and 459 (20),
[(PPh3)Au]ϩ. IR (cmϪ1): 1610s, ν(NH2ϩ); 1560s, νa(CO2); 1330vs,
1
νs(CO2); 1478s, 1436vs, ν(PPh3). NMR (DMSO-d6): H, δ 7.89
(s, 1H, C(3)H), 7.30 (d, 1H, C(5)H) 7.08 (t, 1H, C(6)H), 7.65 (d,
1H, C(7)H), 7.56 (m, 15H, H (Ph3)), 1.16 (d, 12H, CH3 [HQ]),
[Au(PPh3)(Hfspa)] (1). H2fspa (0.034 g, 2.0 mmol), Au(PPh3)-
Cl (0.100 g, 2.0 mmol), ethanol (8 cm3), KOH (0.011 g, 2.0
mmol), H2O (2 cm3), light brown solid. Yield: 83%. Mp 171 ЊC.
Anal. Found: C 48.1, H 3.2, S 5.0. Calc. for C25H21O3SPAu: C
47.8, H 3.0, S 5.1%. MS (FAB): the main metalated signals are
at m/z 1409 (10%), [(AuPPh3)3S]ϩ 1087 (82), [(AuPPh3)2(fspa)]ϩ;
721 (17), [(PPh3)2Au]ϩ; 628 (58), [M]ϩ; and 459 (100),
ϩ
2.23 (m, 2H, CH [HQ]), 8.31 (s, 2H, NH2 [HQ]); 13C, δ 172.3
C(1), 127.3 C(2), 134.8 C(3), 143.5 C(4), 133.4 C(5), 127.3 C(6),
131.2 C(7), 46.5 CH [HQ], 20.1 CH3[HQ]; 31P{1H}, δ 35.27 (s).
[HQ][Au(PPh3)(pspa)] (6). [Au(PPh3)(Hpspa)] (0.100 g, 15.0
mmol), diisopropylamine (0.022 cm3), ethanol (15 cm3), white
solid. Yield: 55%. Mp 85 ЊC. Anal. Found: C 53.3, H 5.0, S 4.6,
N 1.7. Calc. for C33H37O2SPAuN: C 53.0, H 5.0, S 4.3, N 1.9%.
MS (FAB): the main metalated signals are at m/z 1409 (10%),
[(AuPPh3)3S]ϩ; 1097 (59), [(AuPPh3)2(ppa)]ϩ; 740 (3), [M]ϩ; 721
(34), [(PPh3)2Au]ϩ; 638 (16), [Au(PPh3)(Hpspa)]ϩ; and 459
(100), [(PPh3)Au]ϩ. IR and Raman (R) (cmϪ1): 1593s, ν(NH2ϩ);
1552s, 1558vs (R), νa(CO2); 1336s, νs(CO2); 1480s, 1437vs,
ν(PPh3). NMR (DMSO-d6): 1H, δ 7.52 (s, 1H, C(3)H), 8.00 (d,
2H, C(5)Ho) 7.29 (t, 2H, C(6)Hm), 7.15 (m, 1H, C(7)Hp), 7.55
(m, 15H, H (PPh3)), 1.12 (d, 12H, CH3 [HQ]), 3.18 (m (over-
[(PPh3)Au]ϩ. IR (cmϪ1): 1659vs, ν(C᎐O); 1435s, δ(OH); 1276m,
᎐
ν(C–O); 1475m, 1435s, ν(PPh3). NMR (DMSO-d6): 1H, δ 12.70
(s, br 1H, C(1)OH), 7.57 (s, 1H, C(3)H), 7.53 (d, 1H, C(5)H)
6.63 (t, 1H, C(6)H) 7.72 (d, 1H, C(7)H), 7.60 (m, 15H, H (Ph3));
13C, δ 170.1 C(1), 123.4 C(2), 128.8 C(3), 152.4 C(4), 113.9 C(5),
112.2 C(6), 142.9 C(7); 31P{1H}, δ 35.6 (s). Single crystals were
grown by slow evaporation of a solution in acetone.
[Au(PPh3)(Htspa)]ؒH2O (2ؒH2O). H2tspa (0.034 g, 2.0
mmol), Au(PPh3)Cl (0.100 g, 2.0 mmol), ethanol (8 cm3), KOH
(0.011 g, 2.0 mmol), H2O (2 cm3), light brown solid. Yield: 89%.
Mp 165 ЊC. Anal. Found: C 45.8, H 3.1, S 10.2. Calc. for
C25H22O3S2PAu: C 45.3, H 3.3, S 9.7%. MS (FAB): the main
metalated signals are at m/z 1409 (1%), [(AuPPh3)3S]ϩ; 1103 (1),
[(AuPPh3)2(tspa)]ϩ; 721 (1), [(PPh3)2Au]ϩ; 644 (5), [M]ϩ; and 459
ϩ
lapping), 2H, CH [HQ]), not observed (NH2 [HQ]); 13C,
δ 171.8 C(1), 127.6 C(2), 137.9 C(3), 136.9 C(4), 130.3 C(5),
126.5 C(6), 128.9 C(7), 46.3 CH [HQ], 20.3 CH3 [HQ]; 31P{1H},
δ 35.74 (s). Single crystals were grown by slow evaporation of
acetone.
(10), [(PPh3)Au]ϩ. IR (cmϪ1): 1656vs, ν(C᎐O); 1436s, δ(OH);
[(AuPPh3)2(fspa)]ؒH2O (7ؒH2O). H2fspa (0.026 g, 1.5 mmol),
Au(PPh3)Cl (0.150 g, 3.0 mmol), methanol (12 cm3), NaOH
(0.012 g, 3.0 mmol), H2O (3 cm3), light brown solid. Yield: 64%.
Mp 120 ЊC. Anal. Found: C 45.9, H 3.1, S 2.8. Calc. for
C43H36O4SP2Au2: C 46.7, H 3.1, S 2.9%. MS (FAB): the main
metalated signals are at m/z 1409 (9%), [(AuPPh3)3S]ϩ; 1087
(100), [M]ϩ; 721 (71), [(PPh3)2Au]ϩ; 627 (5), [Au(PPh3)-
(Hfspa)]ϩ; and 459 (94), [(PPh3)Au]ϩ. IR and Raman (R)
(cmϪ1): 1581m, 1585m (R), νas(COO); 1478m, 1478m (R),
᎐
1
1276s, ν(C–O); 1480m, 1436s, ν(PPh3). NMR (DMSO-d6): H,
δ 12.68 (s, br, 1H, C(1)OH), 7.98 (s, 1H, C(3)H), 7.45 (d, 1H,
C(5)H) 7.13 (t, 1H, C(6)H), 7.59 (d, 1H, C(7)H), 7.56 (m, 15H,
H (Ph3)); 13C, δ 170.1 C(1), 126.2 C(2), 131.6 C(3), 140.86 C(4),
131.5 C(5), 128.7 C(6), 130.2 C(7); 31P{1H}, δ 36.2 (s).
[Au(PPh3)(Hpspa)] (3). H2pspa (0.036 g, 2.0 mmol), Au-
(PPh3)Cl (0.100 g 2.0 mmol), ethanol (8 cm3), KOH (0.011 g,
2.0 mmol), H2O (2 cm3), light yellow solid. Yield: 84%. Mp
160 ЊC. Anal. Found: C 50.4, H 3.8, S 5.2. Calc. for C27H22O2-
SPAu: C 50.8, H 3.5, S 5.0%. MS (FAB): the main metalated
signals are at m/z 1409 (11%), [(AuPPh3)3S]ϩ; 1097 (82),
[(AuPPh3)2(pspa)]ϩ; 721 (34), [(PPh3)2Au]ϩ; 638 (12), [M]ϩ; and
1
1436s, ν(Ph3P). NMR (DMSO-d6): H, δ 7.44 (s, 1H, C(3)H),
7.20 (d, 1H, C(5)H) 6.51 (t, 1H, C(6)H) 7.58 (d, 1H, C(7)H),
7.55 (m, 30H, H (Ph3)); 13C, δ 171.2 C(1), 118.7 C(2), 128.7
C(3), 154.4 C(4), 111.8 C(5), 110.5 C(6), 140.6 C(7); 31P{1H},
δ 32.0 (s). Single crystals of [(AuPPh3)2(fspa)] (7) were grown by
slow evaporation of a methanolic solution.
459 (100), [(PPh3)Au]ϩ. IR (cmϪ1): 1663s, ν(C᎐O); 1437vs,
᎐
D a l t o n T r a n s . , 2 0 0 3 , 4 7 5 4 – 4 7 6 1
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Scheme 2
[(AuPPh3)2(tspa)] (8). H2tspa (0.026 g, 1.5 mmol), Au(PPh3)-
Cl (0.150 g, 3.0 mmol), methanol (12 cm3), NaOH (0.012 g,
3.0 mmol), H2O (3 cm3), golden solid. Yield: 74%. Mp 105 ЊC.
Anal. Found: C 46.5, H 3.4, S 5.6. Calc. for C43H34O2S2P2Au2:
C 46.0, H 3.2, S 5.7%. MS (FAB): the main metalated signals
are at m/z 1409 (1%), [(AuPPh3)3S]ϩ; 1103 (43), [M]ϩ; 721 (69),
[(PPh3)2Au]ϩ; 644 (2), [Au(PPh3)(Htspa)]ϩ; and 459 (100),
[(PPh3)Au]ϩ. IR (cmϪ1): 1571m, νas(COO); 1478w, 1434m,
ν(Ph3P). NMR (DMSO-d6): 1H, δ 8.18 (s, 1H, C(3)H), 7.47 (d,
1H, C(5)H), 7.18 (t, 1H, C(6)H), 7.70 (d, 1H, C(7)H), 7.43 (m,
30H, H (Ph3)); 13C, δ 168.4 C(1), 126.6 C(2), 134.3 C(3), 140.5
C(4), 132.1 C(5), 126.4 C(6), 131.5 C(7); 31P{1H}, δ 32.6 (s).
Single crystals of [(AuPPh3)2(tspa)]ؒ2MeOH (8ؒ2MeOH) were
grown by slow evaporation of a methanolic solution.
lated15 positions, except for those of the carboxylate groups in
(Htspa)2ؒMe2CO, 1 and 6, the NH2 group in 6, and the alcohol
molecules in 8ؒ2MeOH and 9ؒ2MeOH, which were located and
refined isotropically or fixed (6).
CCDC reference numbers 212119–212124.
See http://www.rsc.org/suppdata/dt/b3/b307192h/ for crystal-
lographic data in CIF or other electronic format.
Results and discussion
The 1 : 1 complexes [Au(PPh3)(Hxspa)] (x = f, t, p) were
prepared by adding Au(PPh3)Cl to a solution of the appropriate
sulfanylcarboxylic acid and KOH in ethanol. Reaction of these
1 : 1 complexes with diisopropylamine afforded compounds
[HQ][Au(PPh3)(xspa)]. The 2 : 1 complexes [(AuPPh3)2(xspa)]
were prepared by adding a solution of Au(PPh3)Cl in 2 : 1 mole
ratio to a solution of the appropriate acid and NaOH in meth-
anol, or by adding Au(PPh3)Cl to a 1 : 1 complex (Scheme 2).
The FABϩ mass spectra of these complexes show the [M]ϩ
peak and other fragments that, as in similar systems,3 are
indicative of the cleavage of the Au–S and Au–P bonds.
[(AuPPh3)2(pspa)]ؒ2MeOH (9ؒ2MeOH). H2pspa (0.045 g, 2.5
mmol), Au(PPh3)Cl (0.250 g, 5.0 mmol), methanol (20 cm3),
NaOH (0.020 g, 5.0 mmol), H2O (5 cm3), light yellow solid.
Yield: 83%. Mp 130 ЊC. Anal. Found: C 48.3, H 3.7, S 2.6. Calc.
for C47H44O4SP2Au2: C 48.6, H 3.8, S 2.8%. MS (FAB): the
main metalated signals are at m/z 1409 (6%), [(AuPPh3)3S]ϩ;
1097 (24), [M]ϩ; 721 (68), [(PPh3)2Au]ϩ; and 459 (100),
[(PPh3)Au]ϩ. IR and Raman (R) (cmϪ1): 1581s, 1585s (R),
νas(COO); 1480m, 1436s, ν(Ph3P). NMR (DMSO-d6): 1H, δ 7.50
(s, 1H, C(3)H), 8.00 (d, 2H,C(5)Ho), 7.30 (t, 2H, C(6)Hm) 7.10
(m, 1H, C(7)Hp), 7.55 (m, 30H, H(PPh3)); 13C, δ 170.9 C(1),
127.4 C(2), 141.2 C(3), 138.9 C(4), 130.0 C(5), 125.1 C(6),
128.1 C(7); 31P{1H}, δ 31.6 (s); 30.9 (s) (at low temperature).
Single crystals were grown by slow evaporation of a methanolic
solution.
(Htspa)2ؒMe2CO
Single crystals obtained by slow evaporation of an acetone
solution of H2tspa were composed of (Htspa)2 dimers formed
by oxidation of the acid. (Htspa)2ؒMe2CO crystallized in the
unusual monoclinic space group P2/n. The asymmetric unit
contains two crystallographically independent half-molecules
that by rotation around the two-fold axis generate two dimeric
molecules (hereinafter denoted molecules A and B) which are
associated by hydrogen bonds as shown in Fig. 1. The main
bond lengths and angles in A and B are listed in Table 2.
Crystallography
X-Ray data collection and reduction. Single crystals of
(Htspa)2ؒMe2CO, [Au(PPh3)(Hfspa)] (1), [HQ][Au(PPh3)(pspa)]
(6), [(AuPPh3)2(fspa)] (7), [(AuPPh3)2(tspa)]ؒ2MeOH (8ؒ
2MeOH) and [(AuPPh3)2(pspa)]ؒ2MeOH (9ؒ2MeOH) were
mounted on glass fibres for data collection in a Bruker Smart
CCD automatic diffractometer at 293 K using Mo-Kα
radiation (λ = 0.71073 Å). Table 1 summarizes the crystal data,
experimental details and refinement results. Corrections for
Lorentz effects, polarization12 and absorption13 were made.
The structures were solved by Patterson (9) or direct methods
[(Htspa)2ؒMe2CO, 1, 6, 7 and 8ؒ2MeOH].13 The acetone mole-
cule of (Htspa)2ؒMe2CO was disordered, as was one of the
methanol molecules in both 8ؒ2MeOH and 9ؒ2MeOH. For
(Htspa)2ؒMe2CO and 8ؒ2MeOH we were unable to find a
statistical model for the disorder, and the program SQUEEZE14
was therefore used to correct the reflection data for diffuse
scattering. In 9ؒ2MeOH the disorder was accounted for by
a model with the methyl group in two positions with equal
occupancy factors (50%). In 8ؒ2MeOH the phenyl groups were
refined as rigid hexagons with C–C distances of 1.39 Å. Other-
wise, most non-hydrogen atoms were treated using anisotropic
temperature parameters in the last cycle of the refinement; the
exceptions being O2M and the disordered methyl carbons of
9ؒ2MeOH (C2A and C2B), which were refined isotropically.
Hydrogen atoms were refined as riders at geometrically calcu-
Fig. 1 Crystal structure of (Htspa)2ؒMe2CO, showing the numbering
scheme.
In each molecule, the two Htspa units are linked by a
disulfide bridge with an unexceptional S–S distance (2.070(2)
and 2.069(2) Å in molecules A and B, respectively; the sum of
the covalent radii of two sulfur atoms is 2.04 Å).16 The Htspa
units are essentially planar, with Z configuration about the
C(12)–C(13) bond and the thiophene sulfur atom cis to the
sulfanyl sulfur; the angle between their mean planes is 9.7(3)Њ in
A and 16.9(2)Њ in B.
Molecules A and B are associated by hydrogen bonds
between their carboxylic acid groups, and the geometric param-
eters of these bonds [0.77(4), 1.87(4), 2.630(4) Å, 170(6)Њ for
O(11)–H(11) ؒ ؒ ؒ O(22); 0.82(4), 1.82(4), 2.635(4) Å, 173(5)Њ for
D a l t o n T r a n s . , 2 0 0 3 , 4 7 5 4 – 4 7 6 1
4756

Table 1 Crystal data for (Htspa)2ؒMe2CO, [Au(PPh3)(Hfspa)] (1), [HQ][Au(PPh3)(pspa)] (6), [(AuPPh3)2fspa] (7), [(AuPPh3)2tspa]ؒ2MeOH (8ؒ2MeOH) and [(AuPPh3)2pspa]ؒ2MeOH (9ؒ2MeOH)
Compound
(Htspa)2ؒMe2CO
[Au(PPh3)(Hfspa)] (1)
[HQ][Au(PPh3)(pspa)] (6)
[(AuPPh3)2fspa] (7)
[(AuPPh3)2tspa]ؒ2MeOH (8ؒ2MeOH)
[(AuPPh3)2pspa]ؒ2MeOH (9ؒ2MeOH)
Empirical formula
Mr
C17H16O5S4
428.54
C25H20AuO3PS
628.41
C33H37AuNO2PS
739.63
C43H34Au2O3P2S
1086.64
C45H42Au2O4P2S2
1166.78
C47H44Au2O4P2S
1160.76
T/K
Crystal system
Space group
293(2)
Monoclinic
P2/n
293(2)
Monoclinic
P21/n
293(2)
Monoclinic
P21/n
293(2)
Monoclinic
P21/c
293(2)
Monoclinic
P21/c
293(2)
Monoclinic
P21/c
a/Å
b/Å
c/Å
7.3669(7)
17.7955(17)
14.8798(15)
96.630(2)
1937.7(3)
4
11.2143(16)
27.397(4)
15.353(2)
91.373(3)
4715.6(12)
8
9.8237(12)
13.9493(17)
23.244(3)
101.027(3)
3126.4(6)
4
9.8209(8)
17.8496(15)
22.7002(19)
92.495(2)
3975.6(6)
4
21.106(3)
13.354(2)
16.268(2)
111.560(3)
4264.4(11)
4
21.6565(12)
13.3177(7)
16.1638(9)
110.8850(10)
4356.8(4)
4
β/Њ
U/Å3
Z
Dc/Mg mϪ3
1.469
0.515
1.770
6.419
1.571
4.853
1.815
7.543
1.817
7.087
1.770
6.890
µ/mmϪ1
Crystal size /mm
θ Range for data collection /Њ
Index ranges
0.24 × 0.14 × 0.12
1.79–28.05
Ϫ9 to 9,
Ϫ23 to 22,
Ϫ19 to 11
10907
0.18 × 0.10 × 0.9
1.49–28.02
Ϫ13 to 14,
Ϫ33 to 36,
Ϫ19 to 20
24394
0.22 × 0.14 × 0.08
1.71–28.05
Ϫ12 to 12
Ϫ18 to 14
Ϫ24 to 30
16614
0.47 × 0.30 × 0.15
1.45–28.11
Ϫ7 to 12
Ϫ23 to 23
Ϫ29 to 30
22785
0.06 × 0.06 × 0.05
1.84–28.05
Ϫ26 to 27
Ϫ17 to 17,
Ϫ21 to 16
21094
0.25 × 0.22 × 0.10
1.83–28.02
Ϫ24 to 28,
Ϫ10 to 17,
Ϫ21 to 20
24708
Reflections collected
.
Unique reflections (Rint
Final R1, wR2 [I > 2σ(I )]
Final R1, wR2 (all data)
)
4453 (0.0576)
0.0576, 0.1228
0.1732, 0.1459
10287 (0.0944)
0.0566, 0.0743
0.2698, 0.1083
6895 (0.1080)
0.0471, 0.0580
0.2273, 0.0814
9005 (0.0924)
0.0590, 0.1365
0.1160, 0.1511
9146 (0.1183)
0.0625, 0.1477
0.2542, 0.1821
9848 (0.0945)
0.0457,0.0908
0.0882, 0.0992

View Article Online
Table 2 Bond lengths (Å) and angles (Њ) in (Htspa)2ؒMe2CO
Molecule A
Molecule B
S(11)–C(12)
S(11)–S(11)#1
S(12)–C(17)
S(12)–C(14)
O(11)–C(11)
O(12)–C(11)
C(11)–C(12)
C(12)–C(13)
C(13)–C(14)
1.774(4)
S(21)–C(22)
S(21)–S(21)#
S(22)–C(27)
S(22)–C(24)
O(21)–C(21)
O(22)–C(21)
C(21)–C(22)
C(22)–C(23)
C(23)–C(24)
1.767(4)
2.069(2)
1.717(5)
1.717(4)
1.329(4)
1.215(4)
1.456(5)
1.346(5)
1.445(5)
2.070(2)
1.711(5)
1.723(4)
1.320(5)
1.214(4)
1.458(5)
1.353(5)
1.422(5)
C(12)–S(11)–S(11)#1
O(12)–C(11)–O(11)
O(12)–C(11)–C(12)
O(11)–C(11)–C(12)
C(13)–C(12)–C(11)
C(13)–C(12)–S(11)
C(11)–C(12)–S(11)
C(12)–C(13)–C(14)
C(15)–C(14)–C(13)
103.11(13)
122.4(4)
123.3(4)
114.3(4)
121.0(4)
122.7(3)
116.2(3)
132.2(4)
122.9(4)
C(22)–S(21)–S(21)#1
O(22)–C(21)–O(21)
O(22)–C(21)–C(22)
O(21)–C(21)–C(22)
C(23)–C(22)–C(21)
C(23)–C(22)–S(21)
C(21)–C(22)–S(21)
C(22)–C(23)–C(24)
C(25)–C(24)–C(23)
102.62(13)
122.0(4)
123.6(4)
114.4(4)
121.5(4)
122.2(3)
116.2(3)
131.8(4)
122.5(4)
Symmetry operation: #1 Ϫx ϩ 3/2, y, Ϫz ϩ 3/2.
Table
3
Selected interatomic distances (Å) and angles (Њ) in
[Au(PPh3)(Hfspa)] (1)
O(21)–H(21) ؒ ؒ ؒ O(12)] are in keeping with the C–O bond
lengths in each carboxyl group being in the normal ranges
(1.21–1.25 Å for C᎐O, and 1.31–1.35 Å for C–OH).17
᎐
(a) Au environment
[Au(PPh3)(Hxspa)]
Au(1)–P(1)
Au(1)–S(1)
Au(1)–O(11)
Au(2)–P(2)
Au(2)–S(2)
Au(2)–O(22)
2.255(3)
P(1)–Au(1)–S(1)
P(1)–Au(1)–O(11)
S(1)–Au(1)–O(11)
P(2)–Au(2)–S(2)
P(2)–Au(2)–O(22)
S(2)–Au(2)–O(22)
176.89(14)
114.1(2)
67.9(2)
174.83
115.3(2)
67.8(2)
2.301(3)
3.022(10)
2.258(4)
2.320(4)
3.011(10)
The asymmetric unit of the crystal of [Au(PPh3)(Hfspa)] (1)
contains two molecules with slightly different parameters that
are connected by hydrogen bonds between the CO2H groups
and by a weak π-stacking interaction between two PPh3 phenyl
rings. Fig. 2 shows both these molecules, and their most
significant structural parameters are listed in Table 3.
(b) Hfspa
S(1)–C(12)
1.738(12)
1.270(14)
1.244(16)
1.451(17)
1.351(14)
1.404(16)
O(12)–C(11)–O(11)
O(12)–C(11)–C(12)
O(11)–C(11)–C(12)
C(13)–C(12)–C(11)
C(13)–C(12)–S(1)
C(11)–C(12)–S(1)
C(12)–C(13)–C(14)
O(22)–C(21)–O(21)
O(22)–C(21)–C(22)
O(21)–C(21)–C(22)
C(23)–C(22)–C(21)
C(23)–C(22)–S(2)
C(21)–C(22)–S(2)
C(22)–C(23)–C(24)
119.5(15)
123.3(14)
116.8(16)
113.7(13)
123.0(11)
123.0(11)
128.1(14)
118.6(15)
123.4(15)
118.0(15)
116.5(13)
123.3(11)
120.0(11)
128.6(15)
O(11)–C(11)
O(12)–C(11)
C(11)–C(12)
C(12)–C(13)
C(13)–C(14)
S(2)–C(22)
1.726(13)
1.279(14)
1.239(14)
1.427(17)
1.371(16)
1.445(19)
O(21)–C(21)
O(22)–C(21)
C(21)–C(22)
C(22)–C(23)
C(23)–C(24)
Ϫ166.0Њ and 16.1Њ, respectively. The C–S bond lengths are close
to those found in (Htspa)2ؒMe2CO and in complexes of similar
ligands,7,8 and are also close to the theoretical length of a
single C–S bond, 1.81 Å.19 In both molecules the Hfspa
moiety exhibits Z configuration about the C(12)–C(13) [or
C(22)–C(23)] bond, and the O atom of the furan ring is trans to
the S atom.
The hydrogen bond parameters [0.84, 1.78, 2.603(14) Å, 168Њ
for O(11)–H(11) ؒ ؒ ؒ O(22); 0.83, 1.79, 2.601(15) Å, 166Њ for
O(21)–H(21) ؒ ؒ ؒ O(12)] are in keeping with the C–O bond
lengths in each CO2H group being closer to each other than in
(Htspa)2ؒMe2CO.
The existence of a weak π-stacking interaction between the
rings [C(231) ؒ ؒ ؒ C(236)] and [C(121) ؒ ؒ ؒ C(126)] is supported
by the distance between their centres [3.829(5) Å] and by the
shortest interatomic distance between them [C(236) ؒ ؒ ؒ C(125)
3.539(19) Å].
Comparison of the structures of the triphenylphosphine-
gold() sulfanylcarboxylates that have now been characterized
by X-ray diffraction {1, [Au(PPh3)(SCH2CO2H)],4 [Au(PPh3)-
Fig. 2 Interaction by hydrogen bonding and weak π-stacking between
the two molecules in the asymmetric unit of [Au(PPh3)(Hfspa)] (1)
(hydrogen atoms, except those involved in hydrogen bonds, are omitted
for clarity).
In both molecules the Au atom is coordinated to S and P
atoms in an almost linear arrangement (P(1)–Au(1)–S(1)
176.89(14)Њ; P(2)–Au(2)–S(2) 174.83Њ). The Au(1)–O(11) and
Au(2)–O(22) distances [3.022(10) and 3.011(10) Å, respectively]
are less than the sum of the van der Walls radii of Au and
O (3.20 Å)16 and thus suggest a weak interaction that may
be responsible for the slight deviation from linearity of the
P–Au–S angle. The Au–S and Au–P bond lengths are close to
the values found in other compounds with an S–Au–P
fragment.18
Although the main parameters of the Hfspa moiety are
similar in the two molecules, they differ slightly as regards the
planarity of their C(S)–COO fragments, the O(12)–C(11)–
C(12)–S(1) and O(22)–C(21)–C(22)–S(2) torsion angles being
D a l t o n T r a n s . , 2 0 0 3 , 4 7 5 4 – 4 7 6 1
4758

View Article Online
(SCH(Me)CO2H],2b [Au(PPh3)(SCMe2CO2H)],4 [Au(PPh3)-
(4-SC6H4CO2H)],3 [Au(PPh3)(2-SC6H4CO2H)]5,6 and [Au-
(PPh3)(6-Hmna)]2b} shows that they have similar Au–S and
Au–P bond lengths but exhibit considerable variety as regards
their intermolecular interactions, as was emphasized in the
Introduction. Compound 1 is the first in which the stability of a
dimeric structure created by carboxyl–carboxyl hydrogen bonds
appears to be reinforced by π-stacking.
The IR and Raman spectra of [Au(PPh3)(Hfspa)] do not
show the ν(SH) band located at 2568 cmϪ1 in the spectrum of
H2fspa, and the vibrations of the CO2H group are slightly
shifted from their positions in the latter spectrum [1673,
Table
4
Selected interatomic distances (Å) and angles (Њ) in
[HQ][Au(PPh3)(pspa)] (6)
(a) Au environment
Au–P
Au–S
Au–O(2)
Au–O(1)
2.262(3)
2.297(3)
3.392(6)
3.715(5)
P–Au–S
176.07(10)
107.94(13)
73.61(13)
121.73(13)
61.69(12)
P–Au–O(2)
S–Au–O(2)
P–Au–O(1)
S–Au–O(1)
(b) pspa
O(1)–C(1)
O(2)–C(1)
C(1)–C(2)
C(2)–C(3)
C(3)–C(4)
S–C(2)
1.246(9)
1.271(9)
1.507(12)
1.314(12)
1.499(13)
1.746(10)
O(1)–C(1)–O(2)
O(1)–C(1)–C(2)
O(2)–C(1)–C(2)
C(3)–C(2)–C(1)
C(1)–C(2)–S
125.4(10)
119.7(9)
114.8(9)
122.3(10)
115.3(8)
131.3(11)
ν(C᎐O); 1417, δ(OH); 1266, ν(C–O)]. Both findings are in
᎐
keeping with the S-coordination and CO2H group hydrogen
bonding shown by the X-ray study. Similar alterations were
found in the spectra of compounds 2ؒH2O and 3, suggesting
that the three 1 : 1 adducts have similar solid state structures.
Since the ligands rapidly decompose in dmso-d6, 1H, 13C and
31P NMR data (see Experimental section) were obtained from
freshly prepared concentrated solutions. No decomposition of
any of the gold complexes was detected under the conditions
used. Assignment of the signals was based on HMQC and
HMBC experiments and on previous data.7,8 The broad signal
at about 13 ppm in the 1H NMR spectra of the ligands persists
in the complexes, in keeping with the non-deprotonation of the
CO2H group, and the shift of the C(3)H signal to higher field
(from 7.60, 8.18 and 7.73 ppm for H2fspa, H2tspa and H2pspa,
respectively) is in keeping with the S-coordination found in the
C(2)–C(3)–C(4)
ligand and by the triphenylphosphine P atom, and these two
bonds are practically collinear. In the Au environment the main
difference with respect to 1 is the absence of an Au ؒ ؒ ؒ O
interaction, the Au–O distances (3.392(6) and 3.715(5) Å) both
being greater than the sum of the van der Waals radii of Au and
O (3.20 Å).16 The absence of this interaction is probably due to
the plane of the carboxylate group in the pspa moiety (which
adopts E configuration about the C(2)–C(3) bond) being
almost orthogonal to the S–C(2)–C(1) plane [76.8(3)Њ] (Fig. 3),
whereas in 1 the practically planar C(S)–COOH fragment
allows weak Au–O interaction.
Hydrogen bonds between the O1 atoms of two anions and
the nitrogens of two [HQ]ϩ cations [N–H(0A) ؒ ؒ ؒ O1 = 0.90,
1.82, 2.699(10) Å, 166Њ and N–H(0B) ؒ ؒ ؒ O1#1 = 0.90, 1.92,
2.759(9) Å, 154, #1 = Ϫx ϩ 2, Ϫ y ϩ 2, z] create centro-
symmetric dimers. The parameters of the hydrogen bonds and
CO groups involved are very similar to those of an arrangement
of this kind found by us in [HQ][SnPh3(pspa)].7 However, in the
tin compound the pspa fragment is quasi-planar, enabling a
short Sn–O interaction (2.383(2) Å). Both the soft character of
the Au atom and steric factors may be responsible for the COO
rotation that, as noted above, appears to prevent an analogous
interaction in 6.
solid state.7,8 This coordination mode is corroborated by the 13
C
data: the C(3) signal shifts to higher field (from 132.0, 141.2 and
145.6 ppm in H2fspa, H2tspa and H2pspa), and the C(1) signal
to lower field (from 166.4, 166.6 and 167.1 in H2fspa, H2tspa
and H2pspa). All three complexes have a 31P{1H} NMR signal
at about 36 ppm, close to those of other triphenylphosphine
complexes with S–Au–P fragments.2b,3
[HQ][Au(PPh3)(xspa)]
The X-ray study of [HQ][Au(PPh3)(pspa)] (6) shows the crystal
to consist of diisopropylammonium cations and [Au(PPh3)-
(pspa)] anions. Fig. 3 shows an ORTEP plot of the centro-
symmetric dimers created by hydrogen bonding between the
diisopropylammonium cation and the carboxylate group;
significant distances and angles are listed in Table 4. The Au
atom is coordinated by the S atom of the dideprotonated pspa
Comparison of the IR and Raman spectra of [HQ][Au(PPh3)-
(pspa)] with those of H2pspa shows the disappearance of the
ν(SH) band located at 2567 cmϪ1 in the spectrum of the free
acid, and the replacement of the CO2H bands at 1670 cmϪ1
[ν(C᎐O)], 1416 cmϪ1 [δ(OH)] and 1266 cmϪ1 [ν(C᎐O)] by bands
᎐
᎐
typical of a carboxylate group. The slight difference between
the positions of these bands and their positions in the IR spec-
trum of the sodium salt {1574 cmϪ1 [ν(CO)as] and 1383 cmϪ1
[ν(CO)sym]} may be due to the hydrogen bonds present in the
complex. A similar pattern was found in this region of the
spectra of [HQ][Au(PPh3)(tspa)] and [HQ][Au(PPh3)(fspa)],
suggesting that all three compounds have the same structure in
the solid state.
The 1H NMR spectra of these compounds show a shift of the
C(3)H signal to higher field, which suggests the persistence of
the S–Au bond in solution, and the disappearance of the broad
signal located at about 13 ppm in the spectrum of the free acid,
which shows that the CO2H group remains deprotonated.
The shift of the C(3) signal in the 13C NMR spectra confirms
S-coordination, while the position of the C(1) signal suggests
the persistence in solution of the N–H ؒ ؒ ؒ O bond found in the
solid state, being closer to positions associated with a mono-
dentate carboxylate group20 than to its position in the spectra
of the corresponding sodium salts in D2O (175.7, 176.0 and
174.8 ppm for H2fspa, H2tspa and H2pspa, respectively). The
positions of the C(1) signal in mixtures of the free acid and
diisopropylamine in 1 : 2 mole ratio are 167.2, 168.5 and 170.9
ppm for H2fspa, H2tspa and H2pspa, respectively.
Fig. 3 Crystal structure of [HQ][Au(PPh3)(pspa)] (6), showing the
hydrogen bonding between the diisopropylammonium cation and the
carboxylate group (symmetry code Ј=Ϫxϩ2, Ϫyϩ2, z) Hydrogen
atoms, except those involved in hydrogen bonds, are omitted for clarity.
D a l t o n T r a n s . , 2 0 0 3 , 4 7 5 4 – 4 7 6 1
4759

View Article Online
[(AuPPh3)2(xspa)]
Figs. 4–6 show the structures and numbering schemes of the
dinuclear gold complexes [(AuPPh3)2(fspa)] (7), [(AuPPh3)2-
tspa]ؒ2MeOH (8ؒ2MeOH) and [(AuPPh3)2pspa]ؒ2MeOH (9ؒ
2MeOH), and Table 5 lists their most significant structural
parameters.
Fig. 6 Structure of [(AuPPh3)2(pspa)]ؒ2MeOH (9ؒ2MeOH) (hydrogen
atoms, except those involved in hydrogen bonding, are omitted for
clarity).
Table 5 Selected interatomic distances (Å) and angles (Њ) in the di-
nuclear complexes 7, 8ؒ2MeOH and 9ؒ2MeOH
Fig. 4 Structure of [(AuPPh3)2(fspa)] (7) (hydrogen atoms are omitted
for clarity).
7
8ؒ2MeOH
9ؒ2MeOH
(a) Au environment
Au(1)–P(1)
Au(1)–S(1)
Au(1)–O(11)
Au(1)–Au(2)
Au(2)–P(2)
Au(2)–S(1)
2.248(3)
2.361(3)
2.499(9)
2.9617(6)
2.262(3)
2.344(3)
2.252(4)
2.365(5)
2.586(15)
3.0325(12)
2.265(4)
2.339(5)
2.2484(18)
2.3534(17)
2.637(6)
3.0344(4)
2.252(2)
2.329(2)
P(1)–Au(1)–S(1)
P(1)–Au(1)–O(11)
S(1)–Au(1)–O(11)
C(2)–S(1)–Au(1)
Au(2)–S(1)–Au(1)
C(1)–O(11)–Au(1)
P(2)–Au(2)–S(1)
C(2)–S(1)–Au(2)
164.58(10)
118.7(2)
76.5(2)
103.3(4)
78.02(8)
117.9(8)
171.34(11)
104.8(3)
162.112(17)
123.4(4)
73.6(4)
164.37(7)
122.61(12)
72.06(12)
105.2(2)
80.78(6)
116.2(5)
175.84(7)
102.8(3)
105.6(8)
80.27(16)
120.5(16)
175.53(19)
102.7(7)
(b) Ligand
S(1)–C(2)
O(11)–C(1)
O(12)–C(1)
C(1)–C(2)
C(2)–C(3)
C(3)–C(4)
1.767(11)
1.255(14)
1.238(14)
1.506(17)
1.362(15)
1.445(16)
1.73(2)
1.34(2)
1.21(3)
1.61(3)
1.32(2)
1.43(3)
1.758(8)
1.251(9)
1.225(10)
1.537(10)
1.357(10)
1.471(10)
Fig. 5 Structure of [(AuPPh3)2(tspa)]ؒ2MeOH (8ؒ2MeOH) (hydrogen
atoms, except those involved in hydrogen bonding, are omitted for
clarity).
The crystal of 8ؒ2MeOH is formed by [(AuPPh3)2(tspa)] and
two methanol molecules, one of which is disordered (see
Experimental section). The other one is linked by a hydrogen
bond to one of the oxygen atoms of the carboxylate group
[O(1M)–H(1M) ؒ ؒ ؒ O(11)#1: 0.82, 2.26, 2.76(2) Å, 119.7Њ; #1 =
x, y Ϫ 1, z] (Fig. 5). Compound 9 also crystallized with two
methanol molecules in the asymmetric unit, but in this case
both molecules are hydrogen-bonded to the carboxylate group,
the geometric parameters of O(1M)–H(1M) ؒ ؒ ؒ O(11) being
0.92(7), 1.83(8), 2.737(8) Å, 167Њ; and those of O(2M)–
H(2M) ؒ ؒ ؒ O(12) 0.84, 1.88, 2.723(15) Å, 177Њ] (Fig. 6).
O(12)–C(1)–O(11)
O(12)–C(1)–C(2)
O(11)–C(1)–C(2)
C(3)–C(2)–C(1)
C(3)–C(2)–S(1)
C(1)–C(2)–S(1)
C(2)–C(3)–C(4)
122.7(13)
119.5(12)
117.5(11)
118.3(10)
120.9(9)
120.5(8)
132.4(11)
131(2)
121(2)
108(2)
113.3(19)
124.0(18)
122.7(17)
131(2)
126.6(8)
118.6(7)
114.8(8)
118.3(8)
122.7(6)
119.0(6)
129.4(8)
Au(2)–S(1) and the S–Au–P angle is significantly narrower for
Au(1) than for Au(2).
As the figures show, the two gold atoms have different
coordination environments. Au(1) is strongly bound not only
to the thiolate S atom and to a P atom, but also to a carboxylate
O atom, the Au–O(11) distance [2.499(9)–2.637(6) Å] being
significantly shorter than both the sum of the van der Waals
radii (3.20 Å)16 and the weak bond in 1. This interaction
probably affects other structural parameters. Thus, whereas
the Au(1)–P(1) and Au(2)–P(2) bond lengths are similar and
close to the values found in 1 and 6, Au(1)–S(1) is longer than
In all three compounds the Au(1)–Au(2) distance [2.9617(6)–
3.0344(4)] is shorter than the sum of the van der Walls radii for
this metal (3.70 Å)16 and also shorter than the 3.107(1) Å found
in the dinuclear derivative of sulfanylbenzoic acid, in which the
carboxyl group is protonated and no significant Au–O inter-
action was found (Au ؒ ؒ ؒ O 3.079 Å),10 but it is similar to the
Au–Au distance in (µ2-3,4-toluenedithiolato)bis(triphenylphos-
phino)digold [3.096(2) Å], in which two different environments
of gold were observed (AuPS2 and AuPS).21
D a l t o n T r a n s . , 2 0 0 3 , 4 7 5 4 – 4 7 6 1
4760

View Article Online
Although as far as we know an environment like that of
Au(1) has not previously been reported, its coordination can be
compared with those found in gold() dithiolates.21,22 If Au–Au
interactions are ignored, these Au atoms have distorted trigonal
geometry with AuPSO or AuPS2 kernels. The S–Au–S angles of
dithiolates are close to 85Њ, whereas in 7–9ؒ2MeOH the S–Au–O
angles range from 72.10 to 76.5Њ. In dithiolates the two P–Au–S
angles are close to 160 and 115Њ, whereas in 7–9ؒ2MeOH the
P–Au(1)–S and P–Au(1)–O angles lie in the ranges 162–165 and
118–124Њ, respectively.
Acknowledgements
We thank the Directorates General for Regional Policies (EU)
and for Research (Spanish Ministry of Science and Tech-
nology) for financial support under ERDF programs (projects
BQU2002-04524-C02-01 and BQU2002-04524C02-02), and
the Xunta de Galicia, Spain, for support under projects
PGIDIT03PXIC20306PN and PGIDIT03PXIC30103PN.
References
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