Dithiophosphinates of gold (I); oxidative addition of Cl2 to a neutral, dinuclear gold(I) dithiophosphinate complex, and X-ray crystal structures of [AuS2P(C2H5)2]2, [AuS2PPh2]2, Au2(CH2)2PMe2(S2PPh 2)

Article abstract of DOI:10.1139/v01-019

The formation and characterization of dinuclear gold(I) dialkyl- and diaryl-dithiophosphinate complexes of the type [AuS₂PR₂]₂ are described. The complexes are readily prepared from the reaction between a chloro-gold(I) starting material and the corresponding dithiophosphinate salt. The structures of the complexes show both the absence (R = Et, 1) and presence (R = Ph, 2a) of intermolecular Au···Au interactions as confirmed by X-ray crystallographic study in the solid state. Reaction between [AuS₂PPh₂]₂ and [Au(CH₂)₂PMe₂]₂ in CH₂Cl₂ solution leads to a ligand transfer reaction to form the hetero-bridged complex [Au₂{(CH₂)₂PMe₂}{S ₂PPh₂}] (3a) in high yield. Additionally, the latter complex reacts with Cl₂ to form the oxidative addition product [Au₂Cl₂{(CH₂)₂PMe₂}{S ₂PPh₂}] (4), the first gold(II) complex with a S-P-S bridging moiety. The X-ray crystal structure of both 3a and 4 exhibit rare boat conformations in the solid state, and 4 has a formal Au(II) - Au(II) single bond of 2.5611(5) A. Reaction between [AuS₂PPh₂]₂ and dppm (dppm = Ph₂PCH₂PPh₂) leads to a sparsely soluble three-coordinate dinuclear gold(I) complex with the molecular formula [Au₂{dppm}{S₂PR₂}₂]_n (n = 1 or ∞) (5).

Full text of DOI:10.1139/v01-019

896
Dithiophosphinates of gold (I); oxidative addition
of Cl2 to a neutral, dinuclear gold(I)
dithiophosphinate complex, and X-ray crystal
structures of [AuS2P(C2H5)2]2, [AuS2PPh2]2,
Au2(CH2)2PMe2(S2PPh2), and
Au2Cl2[(CH2)2PMe2][S2PPh2]
Werner E. van Zyl, José M. López-de-Luzuriaga, John P. Fackler, Jr., and
Richard J. Staples
Abstract: The formation and characterization of dinuclear gold(I) dialkyl- and diaryl-dithiophosphinate complexes of
the type [AuS2PR2]2 are described. The complexes are readily prepared from the reaction between a chloro–gold(I)
starting material and the corresponding dithiophosphinate salt. The structures of the complexes show both the absence
(R = Et, 1) and presence (R = Ph, 2a) of intermolecular Au···Au interactions as confirmed by X-ray crystallographic
study in the solid state. Reaction between [AuS2PPh2]2 and [Au(CH2)2PMe2]2 in CH2Cl2 solution leads to a ligand
transfer reaction to form the hetero-bridged complex [Au2{(CH2)2PMe2}{S2PPh2}] (3a) in high yield. Additionally, the
latter complex reacts with Cl2 to form the oxidative addition product [Au2Cl2{(CH2)2PMe2}{S2PPh2}] (4), the first
gold(II) complex with a S-P-S bridging moiety. The X-ray crystal structure of both 3a and 4 exhibit rare boat confor-
mations in the solid state, and 4 has a formal Au(II)—Au(II) single bond of 2.5611(5) Å. Reaction between
[AuS2PPh2]2 and dppm (dppm = Ph2PCH2PPh2) leads to a sparsely soluble three-coordinate dinuclear gold(I) complex
with the molecular formula [Au2{dppm}{S2PR2}2]n (n = 1 or ∞) (5).
Key words: dithiophosphinates, ylide, dithiols, gold–gold bond.
Résumé : On décrit la préparation et la caractérisation de complexes dinucléaires de dialkyl- et diaryldithiophosphina-
tes d’or(I), du type [AuS2PR2]2. Les complexes se forment facilement par réaction d’un produit de départ contenant du
chloro-or(I) avec le sel de dithiophosphinate correspondant. Les structures des complexes montrent dans un cas
l’absence (R = Et, 1) et dans l’autre la présence (R = Ph, 2a) d’interactions Au···Au intermoléculaires qui ont été
confirmées par une étude cristallographique par diffraction des rayons X à l’état solide. La réaction entre le
[AuS2PPh2]2 et le [Au(CH2)2PMe2]2, en solution dans le CH2Cl2, donne lieu à une réaction de transfert de ligand qui
conduit à la formation, avec un rendement élevé, du complexe hétéroponté [Au2{(CH2)2PMe2}{S2PPh2}], 3a. De plus,
ce dernier complexe réagit avec le Cl2 pour former le produit d’addition oxydante [Au2Cl2{(CH2)2PMe2}{S2PPh2}], 4,
le premier complexe d’or(II) comportant un pont S-P-S. Les structures de diffraction des rayons X des produits 3a et 4
montrent toutes les deux la présence de conformations bateaux, rares à l’état solide; de plus, le produit 4 comporte
aussi une liaison simple Au(II)—Au(II) de 2,5611(5)Å. La réaction du [AuS2PPh2]2 avec le dppm (dppm =
Ph2PCH2PPh2) conduit à la formation d’un complexe d’or(I) dinucléaire, tricoordiné et à peine soluble de formule mo-
léculaire [Au2{dppm]{S2PR2}2]n (n = 1 ou ∞), 5.
Mots clés : dithiophosphinates, ylure, dithiols, liaison or–or.
[Traduit par la Rédaction] van Zyl et al. 903
Received August 16, 2000. Published on the NRC Research Press Web at http://canjchem.nrc.ca site on July 19, 2001.
Best wishes to Professor Brian James on this occasion of his 65th birthday anniversary.
W.E. van Zyl, and J.P. Fackler, Jr.1 Department of Chemistry and Laboratory for Molecular Structure and Bonding, Texas A&M
University, P.O. Box 30012, College Station, TX 77842-3012, U.S.A.
J.M. López-de-Luzuriaga. Departamento de Química, Universidad de La Rioja, Obispo Bustamante 3, E-26001 Logroño, Spain.
R.J. Staples. Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, U.S.A.
1Corresponding author (telephone: (979) 845-2835; fax: (979) 845-2373; e-mail: Fackler@mail.chem.tamu.edu).
Can. J. Chem. 79: 896–903 (2001)
© 2001 NRC Canada
DOI: 10.1139/cjc-79-5/6-896

van Zyl et al.
897
Scheme 1.
S
P
S
P
Ph
Ph
S
S
Ph
Ph
2 [Au(THT)Cl]
Cl
Cl
Au
Au
S
S
Au
Au
S
S
Ph
Ph
Ph
P
P
S
P
S
P
Ph
Ph
Ph
S
S
Ph
Ph
1
dium salt of the ligand, Na[S2PEt2], and shows a solution H
Introduction
3
2
NMR with JP,H larger than JP,H. The analog [AuS2PPh2]2
was obtained by a direct synthesis and its structure redeter-
mined. A ligand transfer reaction with an ylide has led to a
new, mixed ligand ylide–dithiophosphinate product, which
The chemistry of gold–sulfur compounds finds significant
application ranging from surface science (1) to medicine (2).
The use of gold(I) dithiophosphates as sensitizers in photo-
graphic films is well established (3). Recently the lumines-
cent properties of gold(I) dithiocarbamates and related
materials has been suggested for possible use as
photosensors (4). The organophosphor-1,1-dithiolato class of
compounds (which includes the dithiophosphinates) have
found widespread use as anti-oxidant additives in the oil and
petroleum industry (5), insecticide derivatives (6), and metal
ore extraction reagents (7). Although the dithiophosphinic
acids, R2P(S)SH, have been known for more than a century
(8), gold(I) complexes of these ligands have not been studied
extensively. In 1968, Kuchen et al. (9) reported the first ex-
amples of gold(I) dithiophosphinate complexes. The com-
plexes were obtained by reduction of gold(III) and required
the separation of several by-products. Dinuclearity was sug-
gested for the majority of these compounds based on
osmometric molecular weight determinations in chloroform.
Further research remained dormant until 1995 when Siasios
and Tiekink (10) reported the structure of [AuS2PPh2]2 as
the first diaryldithiophosphinate complex of gold. The com-
like
the
previously
studied
and
bis(ylide),
mixed
methy-
ligand
lene-thiophosphinate
dithiocarbamate–bis(ylide) products (12), form stable Au(II)
derivatives upon oxidation with halogens.
Results and discussion
Preparative methods
The
reaction
between
[Au(tht)Cl]
(tht=
tetrahydrothiophene) and Na[S2PEt2]·2H2O in THF (molar
ratio 1:1) leads to the cyclic dinuclear complex [AuS2PEt2]2
(1). Following extraction of the product into CH2Cl2 solution
and filtration through anhydrous MgSO4 to remove water
and NH4Cl, complex 1 was isolated in >70% yield.
Different synthetic methodologies were investigated for
the complex [AuS2PPh2]2 (2a). Although 2a and its analog
[AuS2P(C6H4-p-Me)2]2 (2b) were isolated in a manner simi-
lar to 1, the yield for 2a was only ~50% because of the prod-
uct’s sparse solubility in organic solvents, which hampered
an efficient separation from by-products. Significantly im-
proved yields (>75%) were obtained by extraction with wa-
ter (in which 2a remained stable) to remove NH4Cl (from
the ammonium salt of the ligand and the [Au(tht)Cl] and to
obtain the product as a yellow paste, which was dried by
consecutively washing with methanol and ether. A third
method to prepare 2a was discovered by accident in a reac-
tion shown in Scheme 1. In hot benzene the disulfide
Ph2P(S)S-SP(S)Ph2 was reduced by cleavage of the S–S bond,
in the presence of [(tht)Au(I)Cl], to form the dinuclear com-
plex 2a in ~30% isolable yield. Organic by-products were
not identified. Unlike the low thermal stability of the acid
Ph2P(S)SH, which decomposes through rapid elimination of
hydrogen sulfide (11), the gold complex 2a appears to have
remarkable thermal stability. It was recovered nearly quanti-
tatively from a boiling benzene solution exposed to air for
3 days.
plex was obtained as
non-reproducible synthesis, and the structure was deter-
mined in the wrong space group, I4.
The first systematic study of gold(I) dithiophosphinate
complexes was reported by Schmidbaur and co-workers
(11). The main focus of their study was to use
dithiophosphinic acid anions [R2PS2]– as potential bidentate
ligands to form efficient clustering centers for gold(I) cat-
a
decomposition product,
a
ions,
as
exemplified
by
complexes
such
as
[Ph2P{SAu(PR3)}2]+ and Me2P(S)SAuPR3.
As part of our ongoing studies of sulfur compounds of the
Group 11 elements, the chemistry of the complexes of
dithio-phosphorus ligands, [AuS2PR2]2, sulfur analogs of the
bis(ylide) complexes (for reviews of this chemistry see,
ref. 12), is reported in this study. These materials show both
the absence (R = Et) and the presence (R = Ph) of weak
intermolecular Au···Au interactions in the solid state. The
compound [AuS2PEt2]2 was readily prepared from the so-
© 2001 NRC Canada

898
Can. J. Chem. Vol. 79, 2001
Fig. 1. Drawings of two reasonable structures for the complex [Au2{dppm}{S2PPh2}2]n where n = 1 (top) or n = ∞ (bottom) following
the reaction between 2a and dppm.
R
R
P
S
S
Au
S
Au
S
R
R
Ph P
2
P
PPh
P
2
S
S
dppm
R
R
Au
S
Au
S
CH2Cl2
P
R
S
R
S
R
R
R
R
P
P
S
S
PPh
PPh
2
2
Au
S
Au
Au
S
Au
S
S
P
P
R
R
R
R
Formation
of
the
oxidative
addition
product
Fig. 2. View of the molecular structure (50% thermal ellipsoids)
of complex 1 showing the atomic labeling scheme. Selected
bond lengths (Å) and angles (°): Au(1)···Au(1A) 3.1822(13),
Au(1)—S(1) 2.309(4), Au(1)—S(2) 2.310(4),
S(1)—P(1) 2.035(5), P(1)—C(1) 1.780(14) Å;
S(1)-Au(1)-S(2) 173.87(13), S(2)-Au(1)-Au(1A) 93.19(10),
P(1)-S(1)-Au(1) 100.4(2), S(2A)-P(1)-S(1) 115.0(2)°.
[Au2Cl2{(CH2)2PMe2}{S2PPh2}] (4) was accomplished with
Cl2 in a CH2Cl2 solution. Upon Cl2 addition the solution im-
mediately turns from colorless to orange. Interestingly, fol-
lowing work-up and isolation of 4, this solid product slowly
releases chlorine gas at 140–160°C. The material gradually
changes color from orange to colorless without additional
decomposition. The compound melts at ~205°C, which is in
the same range as the expected reductive elimination product
3a. The elimination of chlorine gas was determined in a sep-
arate experiment wherein a saturated starch – NaI solution
on filter paper was placed above -100 mg of 4 that was
heated. The chlorine released caused the filter paper to turn
purple as expected for iodine formation. This apparently re-
versible reductive elimination appears related to the revers-
ible
CH3Br
addition–elimination
observed
with
[Au(CH2)2PPh2]2 (12), but has not been observed previously
with halogens.
The gold(I) complex [Au2{dppm}{S2PPh2}2]n (n = 1 or ∞)
(5) is formed from the reaction between 2a and dppm
(dppm = Ph2PCH2PPh2) in CH2Cl2 in good yield. The com-
plex is sparingly soluble in organic solvents, a result which
hinders detailed spectroscopic investigation. However, based
on limited 1H NMR data and elemental analysis, two
three-coordinate gold(I) structures are consistent with the
available data. They are sketched in Fig. 1. Of these com-
pounds, precedence exists for the molecular adduct with
cationic complexes of dinuclear gold(I) dithiocarbamates,
[Au2(µ-S2CNEt2){µ-PPh2)2C=CH2}2]+, prepared and struc-
turally established by X-ray crystallography (14). The lim-
ited solubility of 5 precluded 31P{1H} NMR studies.
Complexes 3a and 3b were formed in good yield (~80%)
from the reaction between [AuS2PPh2] (2a) and [AuS2PEt2]
(1), respectively, with [Au(CH2)2PMe2]2 (molar ratio 1:1) in
a CH2Cl2 solution. The reaction was complete after 20 min.
Complexes 3a and 3b are the first reported dinuclear gold(I)
complexes with heterobridged phosphor-1,1-dithiolato moi-
eties and bis(ylide) bridging ligands and show some unique
structural features (vide infra). Laguna and co-workers (13)
previously reported heterobridged complexes with
dithiocarbamate S2CN(CH2Ph)−2, and xanthate S2COR–,
along with bis(ylide) ligands bridging the two gold(I) cen-
ters.
Solution H and 31P NMR studies
1
1
All the complexes reported were studied in solution by H
and 31P{1H} NMR spectroscopy, except 5. In several cases
© 2001 NRC Canada

van Zyl et al.
899
Fig. 3. View of the molecular structure (50% thermal ellipsoids)
of two adjacent units of the chain of complex 2a showing the
atom labeling scheme (determination 1). Atoms are shown as
thermal ellipsoid plots at the 50% probability level. Selected
bond lengths (Å) and angles (°): Au(1)—Au(1B) 2.9610(3),
Au(1)—Au(1A) 3.0859(3), Au(1)—S(1) 2.3112(10),
S(1)—P(1) 2.0265(11), P(1)—C(5) 1.817(6) Å;
S(1C)-Au(1)-S(1) 171.29(4), P(1)-S(1)-Au(1) 100.84(5),
C(1)-P(1)-C(5) 105.1(2), S(1)-P(1)-S(1A) 116.00(8)°.
P21/n with an inversion center between the two gold atoms.
The structure is shown in Fig. 2.
The structure of 2a was previously reported (10), but sev-
eral details raised suspicion causing us to further investigate
the material. A significant concern was the absence of an in-
version center (space group I4) for this molecularly symmet-
rical molecule. Other troublesome indicators were the
unequally sized thermal ellipsoids reported for gold atoms
(Z = 79) and large variations in the presumably equal Au—S
bond lengths which range from 2.23(2) to 2.38(2) Å. Fol-
lowing a rational synthesis (vide supra), high quality single
crystals of 2a were obtained, which allowed for successful
structure refinement in the tetragonal space group I4/m. Un-
like the methyl and ethyl derivatives which shows no
intermolecular Au···Au interactions, the phenyl derivative
shows short intermolecular Au···Au contacts of 2.9610(3) Å.
This structure was determined at room temperature also for
spectroscopic purposes. The results are statistically insignifi-
cant for the general structure but the intramolecular Au—Au
distance is about 1% longer, and the intramolecular Au—Au
distance about 1% shorter at room temperature than at –77°C.
The structure of 2a is shown in Fig. 3.
The complex 3a crystallizes in the space group P21/c with
no intermolecular Au···Au interactions. An unusual feature
of this structure is that the complex crystallizes in a boat
conformation. Few examples of this form apparently exist
for dimetallocycle Au(I) compounds (see Lin and
co-workers (17)) when compared with the common chair
conformation. The carbon atoms C(1) and C(2) were refined
with some difficulty since the structure is close to that of a
C-centered lattice, suggesting that the symmetry of the mol-
ecule is higher than the symmetry of the generated lattice.
There also could be some ligand disorder, which would in-
fluence C(1) and C(2). The structure of 3a, for which data
was collected three times, is shown in Fig. 4.
Interestingly, the oxidative addition product of chlorine to
3a, namely 4, also crystallizes in a boat conformation. The
single bond formed between the two Au(II) centers in 4 is
clearly demonstrated by the crystallographic study. The
intramolecular Au—Au distance decreases from 3.0966(7) Å
(standard aurophilic bond) in 3a to 2.5611(5) Å (single
bond) in 4. The structure is shown in Fig. 5. There is a sig-
nificant twist of the two 5-membered rings in the molecule
about the very short Au(II)–Au(II) bond which presumably
arises from the constraints of the two different bridging lig-
ands.
interesting and somewhat unexpected NMR results were ob-
tained. Due to the symmetry of 1, the solution NMR spec-
trum is simple and consistent with the X-ray structure. Both
CH2 and CH3 protons couple to the 31P nuclei (I = 1/2) giv-
ing a doublet of quartets and a doublet of triplets, respec-
3
tively. The JP,H coupling constant (21.78 Hz) is larger than
2
the JP,H coupling constant (10.98 Hz). This phenomenon is
not uncommon in ethyl derivatives of four-coordinate P(V)
compounds, which often show a similar behavior (15) with
the extent of the three bond coupling depending primarily on
the P-C-C-H dihedral angle (16). The same observation was
made for the heterobridged complex 3b. The ethyl groups
3
2
show coupling constants of JP,H = 21.3 Hz and JP,H
=
7.8 Hz for the CH3 and CH2 groups, respectively.
The homoleptic complexes 1, 2a, and 2b each show only
a singlet in the 31P{1H} NMR resonating at δ 82.5, 67.4, and
66.6 ppm respectively. The heterobridged complexes 3a and
4
3b show a doublet, a JP,P coupling (8–11 Hz at 300 MHz)
Experimental
for each 31P nuclei. This coupling was not observed for the
oxidative addition product 4 wherein each 31P appears as a
single resonance. In complex 4 the chemical shift is down
field with respect to the unoxidized precursor complex 3a.
General
All reactions and manipulations were carried out under an
inert atmosphere with a positive nitrogen gas flow (pre-dried
by two columns of Drierite) using standard Schlenk tech-
niques. Solvents were distilled and kept under dinitrogen.
The following chemicals were purchased from Aldrich:
tetrahydrothiophene, aluminum trichloride, sodium sulfide
nonahydrate, thiophosphoryl chloride, bis(diphenylph-
osphino)methane, ethylbromide. Elemental sulfur was ob-
tained from J.T. Baker. The following compounds were
prepared using literature procedures: Et2P(S)P(S)Et2 (18),
Structural studies
The dinuclear gold(I) structures reported in the present
study are all neutral eight-membered ring metallocycles in
an elongated chair or boat conformation with short
transannular Au···Au interactions. Complex 1 does not con-
tain intermolecular Au···Au interactions, which is as ob-
served for the previously reported methyl derivative (10).
The molecule crystallizes in the monoclinic space group
Na[S2PEt2]·2H2O
(19),
[NH4][S2PPh2]
(20),
© 2001 NRC Canada

900
Can. J. Chem. Vol. 79, 2001
Fig. 4. Thermal ellipsoid view (50%) of the boat form for the
molecular structure of complex 3a showing the atom labeling
scheme. Atoms are represented by thermal ellipsoids at the 50%
probability level. Selected bond lengths (Å) and angles (°):
Au(1)—Au(2) 3.0966(7), Au(1)—S(1) 2.339(3),
Au(2)—S(2) 2.317(3), Au(1)—C(1) 2.052(12),
Au(2)—C(2) 2.080(12), C(1)—P(2) 1.756(14),
P(1)—S(1) 2.031(4) Å; C(1)-Au(1)-S(1) 178.4(4),
C(2)-Au(2)-Au(1) 87.9(4), C(5)-P(1)-S(2) 110.2(4),
Fig. 5. Molecular structure of the Au(II)–Au(II) complex 4
showing the atom labeling scheme. Atoms are represented as
thermal ellipsoids at the 50% probability level. There is a signifi-
cant twist to the two chelate rings about the nearly linear
Cl-Au-Au-Cl axis with the C(2)-Au(2)-S(2) axis offset by about
20o from the C(1)-Au(1)-S(1) axis. Selected bond lengths (Å)
and angles (°): Au(1)—Au(2) 2.5611(5), Au(1)—C(1) 2.075(8),
Au(2)—C(2) 2.063(8), Au(1)—Cl(1) 2.392(2),
Au(1)—S(1) 2.401(2), Au(2)—S(2) 2.376(2) Å;
C(1)-Au(1)-S(1) 177.8(3), Cl(1)-Au(1)-S(1) 91.05(7),
S(1)-P(1)-S(2) 113.00(13)°.
X-ray crystallography
Crystals that were used in diffraction intensity measure-
ments at room temperature were mounted on the tip of a
quartz fiber with fast-adhesive glue. Single crystal diffrac-
tion analysis was carried out on complex 1 at Texas A&M
using an automated Nicolet R3 four-circle diffractometer uti-
lizing the Wyckoff scanning technique with graphite
monochromated Mo Kα (λ = 0.71073 Å) radiation. Refined
cell parameters were determined from setting angles of 25
reflections with 20° < 2θ < 30°. The unit cell was deter-
mined using search, center, index, and least-squares refine-
ment routine. The Laue class and lattice dimensions were
verified by axial oscillation photography. The intensity data
were corrected for absorption, Lorentz, and polarization ef-
fects. An empirical absorption correction was performed
based on ψ scans of five strong reflections spanning a range
of 2θ values. All data processing were performed on a Data
General Eclipse S140 minicomputer using the SHELXTL
crystallographic package (version 5.1) and Siemens
SHELXTL PLUS (Micro Vax II) (28). The systematic ab-
sences were consistent with the space group assigned. The
structure was solved using direct-methods to determine the
gold atom positions, while all other atoms were located with
difference Fourier maps. Structure refinement was carried
out using SHELX 93. The position of the hydrogen atoms
were calculated by assuming idealized geometries, C—H =
0.93 Å.
Ph2P(S)-S-S-P(S)Ph2 (21), H[AuCl4]·3H2O (22), [Au(tht)Cl]
(23), [Au2{dppm}2]Cl2 (24), [Au2{dppm}Cl2] (25),
[Au{(CH2)2PMe2}]2 (26), and PhI·Cl2 (27). All chemicals
were used as received.
Instrumentation
Melting points were measured on a Unimelt (A.H. Thomas
Co, Philadelphia, PA) capillary melting point apparatus and
are uncorrected. Elemental analyses were performed at
Desert Analytics Inc., Tucson AZ. 1H NMR spectra were ob-
tained on a Varian XL-200 spectrometer operating at
200 MHz, or a Varian UnityPlus-300 spectrometer operating
1
at 299.9 MHz. H NMR data are expressed in parts per mil-
lion (ppm) downfield referenced internally to the residual
proton impurity in the deuterated solvent, and are reported
as: chemical shift position (1H NMR (δ)), multiplicity (s =
singlet, d = doublet, t = triplet, q = quartet, m = multiplet,
br = broad), coupling constant (J (Hz)), relative integral, and
assignment. All 31P{1H} NMR spectra were obtained on ei-
ther a Varian XL 200 MHz broadband spectrometer operat-
ing at 81 MHz, or a Varian UnityPlus-300 spectrometer
operating at 121.4 MHz with chemical shifts reported rela-
tive to a 85% H3PO4 in D2O external standard solution. Pos-
itive fast atom bombardment (+FAB–DIP) (DIP = direct
insertion probe) mass spectra were acquired on a VG Ana-
lytical (Manchester, U.K.) 70S high resolution, double fo-
cusing mass spectrometer. Samples for analyses were
prepared by dissolving the solid compound in appropriate
solvent with a nitrobenzylalcohol (NBA) matrix added.
X-ray data for complexes 2a, 3a, and 4 were collected at
Harvard University on a Siemens (Bruker) SMART CCD
(charge coupled device) based diffractometer equipped with
a LT-2 low temperature apparatus operating at 213 K. Data
for 2a was collected three times including once at room tem-
perature. A suitable crystal was chosen in each case and
mounted on a glass fiber using grease. Data were measured
© 2001 NRC Canada

van Zyl et al.
Table 1. Crystal data and structure refinement for compounds 1, 2a, 3a, and 4.
901
1
2a
3a
4
Empirical formula
FW
C8H20Au2P2S4
700.35
C24H20Au2P2S4
892.51
C16H20Au2P2S4
732.31
C16H20Au2Cl2P2S4
803.21
Crystal system
Space group
a (Å)
b (Å)
c (Å)
Monoclinic
P21/n
6.5660(10)
15.606(3)
8.338(2)
90
94.69(3)
90
851.5(3)
2.731
Tetragonal
I4/m
15.8963(4)
15.8963(4)
12.0938(4)
90
90
90
3056.0(2)
1.940
4
Monoclinic
P21/c
7.5146(6)
9.0287(7)
28.734(2)
90
97.346(2)
90
1933.5(3)
2.516
Triclinic
P1
9.1519(9)
9.669(1)
18.419(1)
106.193(2)
95.353(2)
102.084(2)
1100(2)
2.424
α (°)
β (°)
γ (°)
U (Å3)
Dc (g cm–1)
Z
2
4
2
F(000)
µ(Mo Kα) (mm–1)
T (K)
640
17.863
293(2)
1664
9.979
213(2)
1344
15.532
213(2)
740
13.893
213(2)
Theta range (°)
Reflections collected
Unique reflections
GoF on F2
2.61–22.48
1201
1093
1.81–27.62
7028
1709
2.37–22.50
5844
2508
2.26–23.27
5638
3145
1.073
1.076
1.013
1.098
Final R[I > 2σ(I)]/R1, wR2
R (all data)/R1, wR2
ρ(max. min.) (e Å–3)
0.0389, 0.0973
0.0475, 0.1006
1.651 and –1.267
0.0243, 0.0633
0.0305, 0.0683
0.761 and –0.696
0.0421, 0.0967
0.0527, 0.1006
1.999 and –2.194 1.932 and –2.409
0.0384, 0.1086
0.0411, 0.1130
using omega scans of 0.3° per frame for 30 s, such that a
hemisphere was collected. A total of 1271 frames were col-
lected. The first 50 frames were collected again at the end of
the data collection to monitor for decay. Cell parameters
were retrieved using SMART software (29) and refined us-
ing SAINT on all observed reflections. Data reduction were
performed using SAINT software (30) which corrects for Lp
and decay. Absorption corrections were applied
(semi-empirical from psi-scans) using SADABS (31) sup-
plied by G. Sheldrick. The structures were solved by direct
methods using the SHELXS 97 (32) program and refined by
least-squares method on F2, SHELXL 97 (33). The struc-
tures were solved in space groups consistent with analysis of
systematic absences. All non-hydrogen atoms were refined
anisotropically. The crystals used for diffraction showed no
decomposition during data collection. Crystallographic data
and structure refinement results are listed in Table 1. Bond
lengths and angles are reported in the appropriate figure cap-
tions.
days in the closed system the CH2Cl2 solvent diffused into
the hexane yielding crystals and trace amounts of dark
brown decomposition product (Au2S?). Crystals of 1 suit-
able for X-ray crystallographic studies were obtained as col-
orless plates, yield 0.36 g (73%), mp 153°C. +FAB-MS
1
(NBA/CH2Cl2) m/z: 701 ([M + 1]+). H NMR (200 MHz,
CDCl3, 19°C) δ: 1.36 (dt, JP,H = 21.78 Hz, 12H, 4CH3), 2.33
(dq, JP,H = 10.98 Hz, 8H, 4CH2). 31P NMR (CH2Cl2 with
85% H3PO4 insert in 85% D2O, 200 MHz, 20°C) δ: 82.59
(s). Anal. calcd. for C8H20P2S4Au2: C 13.72, H 2.88; found:
C 13.62, H 2.81.
[AuS2PPh2]2 (2a) (9)
Method A: A 50-mL Schlenk tube was charged with a solu-
tion of [NH4][S2PPh2] (0.11 g, 0.415 mmol) in THF (40 mL)
at room temperature. Upon dissolution, [Au(tht)Cl] (0.131 g,
0.408 mmol) was added in one portion. The solution imme-
diately afforded a white precipitate (NH4Cl). The mixture
was stirred for 1 hour at room temperature. The solvent was
removed in vacuo, and CH2Cl2 (40 mL) was added to extract
the product. The mixture was filtered through anhydrous
MgSO4 (3 mm). The solvent was evaporated under reduced
pressure, washed with dry ether, and vacuum dried for 1
hour.
Preparation of compounds
[AuS2PEt2]2 (1) (9)
A 50-mL Schlenk tube was charged with a solution of
Na[S2PEt2]·2H2O (0.16 g, 0.72 mmol) and [Au(tht)Cl]
(0.22 g, 0.70 mmol) in THF (35 mL) and stirred for 1 h at
room temperature. The solvent was subsequently evaporated
under reduced pressure, the crude mixture was extracted
with CH2Cl2 (30 mL), active charcoal was added, and the
mixture filtered through anhydrous MgSO4 to remove water
and NaCl. The volume of the filtrate was reduced in vacuo
to 5 mL, and the clear solution transferred to a 10 mL
test-tube, which was transferred to a larger vial that con-
tained hexane. The larger vial was corked and after three
Method B: Similar to Method A, but after THF was re-
moved in vacuo, water (40 mL) was added to dissolve the
NH4Cl. The product (a wet yellow paste, stable in water)
was filtered and washed consecutively with methanol and
ether. The yellow product was dried in the air.
Method C: To a 100-mL beaker was added a solution of
Ph2P(S)S-SP(S)Ph2 (0.2 g, 0.40 mmol) and [Au(tht)Cl]
(0.26 g, 0.80 mmol) in benzene (40 mL) at room tempera-
© 2001 NRC Canada

902
Can. J. Chem. Vol. 79, 2001
ture. The mixture was heated to boiling for 20 min, which
diately turned deep orange. The reaction mixture was stirred
for 30 min with a gradual increase of temperature until room
temperature was reached. The solvent was partially removed
under reduced pressure, and subsequently ether was added
when the solution became sufficiently concentrated to in-
duce precipitation of the product. The product was filtered,
dried under vacuum for 2 h, and stored in a refrigerator,
yield 78%, mp at ~ 205°C. +FAB-MS (NBA/CHCl3) m/z: is
yielded
a
clear solution. Upon cooling,
a
yellow
microcrystalline powder was obtained, which was filtered on
a frit and washed with ether. Yields: Method A: 55% (some
loss occurs due to the limited solubility of the product in
CH2Cl2.); Method B: 78% (this was our best method);
Method C: 28% (as crystallized product), mp 295°C (dec.).
+FAB-MS (insolubility of product prevented satisfactory
spectrum to be obtained). The complex is partially soluble in
chlorinated solvents and THF, and insoluble in ether and
1
similar to 3a, ([M – Cl2]+). H NMR (CDCl3, 300 MHz,
20°C) δ: 8.05–7.90 (m, 4H, Ph), 7.60–7.40 (m, 6H, Ph), 2.05
(d, JP,H = 7.79 Hz, 4H, 2CH2), 1.81 (d, JP,H = 8.19 Hz, 6H,
2CH3). 31P NMR (300 MHz, CDCl3, 20°C) δ: 70.06 (s, no
4JP,P coupling detected, PPh2), 42.02 (s, no 4JP,P coupling de-
tected, PMe2). Anal. calcd. for C16H20Cl2P2S2Au2: C 23.92,
H 2.51; found: C 22.84, H 2.49 (some loss of Cl2 is ex-
pected). Orange needles suitable for X-ray crystallographic
studies were obtained from a concentrated CH2Cl2 solution
layered with hexane.
1
hexane. H NMR (300 MHz, CDCl3, 20°C) δ: 8.06–7.92 (m,
8H, Ph), 7.58–7.38 (m, 12H, Ph). 31P NMR (200 MHz,
CDCl3, 19°C) δ: 67.43 (s). Anal. calcd. for C24H20P2S4Au2:
C 32.32, H 2.24, S 14.33; found: C 32.92, H 2.13, S 13.86.
[AuS2P(C6H4-p-Me)2]2 (2b)
Starting from [NH4][S2P(C6H4-p-Me)2] the toluene deriva-
tive was obtained in the same manner as described in
Method A for 2a, yield 77%, mp 275°C. 1H NMR
(200 MHz, CDCl3, 20°C) δ: 7.90–7.78 (m, 8H, Ph),
7.22–7.12 (m, 8H, Ph), 2.37 (br s, 12H, 4Me). 31P NMR
(200 MHz, CDCl3, 20°C) δ: 66.62 (s). Anal. calcd. for
C28H28P2S4Au2: C 35.45, H 2.97; found: C 35.62, H 3.08.
[Au2{dppm}{S2PPh2}2]n (5)
A 50-mL Schlenk tube was charged with a solution of 2a
(0.1 g, 0.11 mmol) in CH2Cl2 (10 mL) at room temperature.
To the yellow suspension was added dppm (0.043 g, 0.11
mmol) in one portion. The initial suspension became a clear
solution after a few minutes, followed by formation of a
white precipitate that emerged after 30–40 min. The solvent
was subsequently removed under reduced pressure until a
concentrated solution was obtained. Ether was added in ex-
cess to precipitate and consolidate the solid. The product
was filtered on a frit and washed with ether. The product is a
white solid and is sparingly soluble in polar and non-polar
solvents, yield 72%, mp 227°C. 1H NMR (300 MHz, CDCl3,
20°C) δ: 8.28–8.12 (m, 8H, Ph), 7.80–7.62 (m, 12H, Ph),
7.50–7.35 (m, 8H, Ph), 7.26–7.10 (m, 12H, Ph), 4.26 (br s,
2H, PCH2P). Anal. calcd. for C49H42P4S4Au2: C 46.09,
H 3.32, S 10.04; found: C 45.07, H 3.42, S 8.83.
Au2[(CH2)2PMe2](S2PPh2) (3a)
A 50-mL Schlenk tube was charged with a solution of 2a
(75.8 mg, 0.085 mmol) and [Au(CH2)2PMe2]2 (48 mg,
0.085 mmol) in CH2Cl2 (10 mL) at room temperature. An
orange–yellow colored suspension was initially obtained
since both starting materials are sparingly soluble in CH2Cl2.
After the reaction mixture had been stirred for 10 min, a
clear orange solution was obtained, and stirring was contin-
ued for an additional 20 min, followed by filtration through
anhydrous MgSO4. The filtrate solution was concentrated by
evaporation of the solvent under reduced pressure, and ether
was added to precipitate the product, which was filtered on a
frit and air dried. Colorless blocky crystals suitable for
X-ray studies were obtained from a concentrated CH2Cl2 so-
lution layered with either ether or hexane, yield 52.3 mg
(84%), mp 208°C (dec.). +FAB-MS (NBA/CHCl3) m/z: 733
Acknowledgments
The authors acknowledge the support of the Robert A.
Welch Foundation for this work. J.M.L-de-L. also thanks the
University of La Rioja for financial support and the opportu-
nity to pursue these studies in 1998 at Texas A&M.
1
([M + 1]+). H NMR (300 MHz, CDCl3, 20°C) δ: 8.22–8.08
(m, 4H, Ph), 7.48–7.35 (m, 6H, Ph), 1.24 (d, JP,H = 13.2 Hz,
4H, 2CH2), 1.10 (d, JP,H = 12.6 Hz, 6H, 2CH3). 31P NMR
(300 MHz, CDCl3, 20°C) δ: 68.52 (d, JP,P = 11.9 Hz, PPh2),
34.78 (d, JP,P = 11.9 Hz, PMe2). Anal. calcd. for
C16H20P2S2Au2: C 26.24, H 2.75; found: C 26.32, H 2.81.
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