Preparation, structure and reactivity of polynuclear gold(I) phosphanyl alkanethiolates

Article abstract of DOI:10.1002/ejic.200600939

The homoleptic gold(I) thiolates of formula [Au(SR)]_n, (R = CMe₃, CH₂CMe₃, CH₂CHMe₂, CPh₃) have been converted into their phosphane derivatives of general formula [Au(SR)-(L)] (L = PMe₃, PMe₂Ph, PMePh ₂, PPh₃) and [Au₂(SR)₂(dppe)] [dppe = 1,2-bis(diphenylphosphanyl)ethane], which have been characterized by elemental analysis, mass spectrometry, ¹H and ³¹P NMR spectroscopy and cyclic voltammetry. Complexes [Au(SCMe₃)(PMePh₂)] (1c), [Au₂(SCMe₃)₂(dppe)] (1e) and [Au(SCH ₂CMe₃)(PPh₃)] (3d) have been characterized in the solid state by X-ray diffraction: no aurophilic interactions have been found. The electrochemical behaviour of these phosphane thiolato derivatives shows two irreversible oxidation processes, the first of which involves 0.5 electrons per Au-SR. Chemical oxidation by [FeCp₂]BF₄ produces disulfide and cationic gold(I) complexes of formula [Au ₂(SR)(L)₂][BF₄] and [Au₂(SR)(dppe)] [BF₄], characterized by elemental analysis, mass spectrometry and ¹H and ³¹P NMR spectroscopy. All the complexes are presumably dimeric in the solid state as shown in the case of [Au ₄(SCMe₃)₂-(dppe)₂][BF ₄]₂ (5e) and [Au₄(SCH₂CMe ₃)₂(PMe₃)₄][BF₄] ₂ (7a), which have been fully characterized by X-ray diffraction. The aurophilic interactions form a structure of four gold atoms with pairs of atoms bonded by bridging thiolato ligands, which are arranged in an almost perfect square in the case of 7a and in an unprecedented zigzag sequence in the case of 5e. Complex 4a reacts with HSCMe₃ under basic conditions to give [Au(SCMe₃)(PMe₃)] and with LiX (X = Me, CH ₂CMe₃) to give a 1:1 mixture of [AuX(PMe₃)] and [Au(SCMe₃)(PMe₃)]. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.

Full text of DOI:10.1002/ejic.200600939

FULL PAPER
DOI: 10.1002/ejic.200600939
Preparation, Structure and Reactivity of Polynuclear Gold(I) Phosphanyl
Alkanethiolates
Antonella Battisti,[a] Oliver Bellina,[a] Pietro Diversi,*[a] Serena Losi,[b] Fabio Marchetti,[a]
and Piero Zanello[b]
Keywords: Gold(I) complexes / Tertiary phosphane complexes / Thiolates / Aurophilicity / Redox behaviour
The homoleptic gold(I) thiolates of formula [Au(SR)]n (R =
CMe3, CH2CMe3, CH2CHMe2, CPh3) have been converted
into their phosphane derivatives of general formula [Au(SR)-
(L)] (L = PMe3, PMe2Ph, PMePh2, PPh3) and [Au2(SR)2(dppe)]
[dppe = 1,2-bis(diphenylphosphanyl)ethane], which have
by elemental analysis, mass spectrometry and 1H and 31P
NMR spectroscopy. All the complexes are presumably di-
meric in the solid state as shown in the case of [Au4(SCMe3)2-
(dppe)2][BF4]2 (5e) and [Au4(SCH2CMe3)2(PMe3)4][BF4]2 (7a),
which have been fully characterized by X-ray diffraction.
been characterized by elemental analysis, mass spectrome- The aurophilic interactions form a structure of four gold
try, 1H and 31P NMR spectroscopy and cyclic voltammetry.
Complexes [Au(SCMe3)(PMePh2)] (1c), [Au2(SCMe3)2(dppe)]
atoms with pairs of atoms bonded by bridging thiolato li-
gands, which are arranged in an almost perfect square in the
(1e) and [Au(SCH2CMe3)(PPh3)] (3d) have been charac- case of 7a and in an unprecedented zigzag sequence in the
terized in the solid state by X-ray diffraction: no aurophilic
interactions have been found. The electrochemical behaviour
of these phosphane thiolato derivatives shows two irrevers-
case of 5e. Complex 4a reacts with HSCMe3 under basic con-
ditions to give [Au(SCMe3)(PMe3)] and with LiX (X = Me,
CH2CMe3) to give
a 1:1 mixture of [AuX(PMe3)] and
ible oxidation processes, the first of which involves 0.5 elec- [Au(SCMe3)(PMe3)].
trons per Au–SR. Chemical oxidation by [FeCp2]BF4 pro-
duces disulfide and cationic gold(I) complexes of formula
[Au2(SR)(L)2][BF4] and [Au2(SR)(dppe)][BF4], characterized
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2007)
patents.[5] So far attention has mostly been dedicated to the
few homoleptic thiolates, which are soluble in organic sol-
vents,[4k] and to the phosphane-thiolato derivatives carrying
biologically interesting substrates.[3d]
Introduction
Research on gold(I) thiolate complexes has produced nu-
merous reports over the past few decades, because of their
various practical applications such as, i.a., in gilding tech-
nology,[1] in the treatment of rheumatoid arthritis and in
cancer chemotherapy.[2] In fact some phosphane gold(I)
thiolates are the active principles of Auranofin and other
antiarthritic products,[3] whose therapeutic activity seems to
be correlated to their oxidation products in vivo. In particu-
lar Bruce et al., by thoroughly investigating the oxidation
of such thiolato-phosphane derivatives, have been able to
show that the final products are cationic gold clusters stabi-
lized in the solid state by aurophilic interactions.[3]
In this paper we describe the synthesis, the characteriza-
tion and the redox behaviour of a series of gold(I) thiolate
complexes derived from simple sterically demanding alka-
nethiols, where the alkyl group is the tert-butyl, sec-butyl
and neopentyl group. We have also studied triphenylmeth-
anethiol derivatives for comparison purposes. We have pre-
pared homoleptic, neutral derivatives with phosphanes, and
the corresponding cationic products prepared according to
the Bruce oxidative procedure[3] as a strategy for building
gold–gold interactions in the solid state. We report also the
structural characterization and a preliminary investigation
on the reactivity of these polynuclear cations.
In spite of many literature reports on the synthesis and
properties of gold thiolates,[4] complexes containing simple
aliphatic groups have been limited to some scattered scien-
tific reports[4a–4c,4g,4h] and some information deriving from
[a] Dipartimento di Chimica e Chimica Industriale dell’Università
di Pisa,
Results and Discussion
Via Risorgimento 35, 56126 Pisa, Italy
Fax: +39-50-2219410
Syntheses
E-mail: div@dcci.unipi.it
[b] Dipartimento di Chimica, Università di Siena,
Via Aldo Moro, 53100 Siena, Italy
The homoleptic thiolates [Au(SR)]n (R
CH2CHMe2, CH2CMe3, CPh3) have been prepared follow-
ing essentially two literature methods: addition of an excess
= CMe3,
Supporting information for this article is available on the
WWW under http://www.eurjic.org or from the author.
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(3:1) of the thiol to a solution of aqueous tetrachloroauric
acid, or alternatively the use of bis(2-hydroxyethyl) sulfide
as the auxiliary reducing agent before adding the thiol.[4c]
The two methods give similar yields (almost quantitative),
but the latter was preferred in the case of the neopen-
tanethiolate, owing to the necessity of saving the starting
thiol. In this case care must be used in controlling the tem-
perature to avoid the formation of metallic gold. The thiol-
ates have good stability either in the air or in the light and
are generally insoluble at room temperature in the most
common organic solvents, apart from the neopentanethiol-
ate that is slightly soluble in benzene and dichloromethane
after it has been kept for a while at 40–45 °C. Owing to
their insolubility the complexes were characterized only by
elemental analysis. They react easily with stoichiometric
amounts of the appropriate phosphane to yield the corre-
sponding gold(I) phosphane thiolates of formula
[Au(SR)(L)] (R = tert-butyl, L = PMe3 1a, PMe2Ph 1b,
PMePh2 1c, PPh3 1d; R = isobutyl, L = PMe3 2a, PMe2Ph
2b, PMePh2 2c, PPh3 2d; R = neopentyl, L = PMe3 3a,
PMe2Ph 3b, PMePh2 3c, PPh3 3d; R = trityl, L = PMe3 4a,
PMe2Ph 4b, PMePh2 4c, PPh3 4d).[4e,4h,4i] As far as we
know, only [Au(SCMe3)(PPh3)] (1d) and [Au(SCH2CH-
Me2)(PPh3)] (2d) have already been reported in the litera-
ture, 1d having been prepared by the reaction of
[AuCl(PPh3)] with [Pb(SCMe3)2][4c] and 2d by the reaction
of [AuCl(PPh3)] with the thiol in the presence of a
base.[4a]
Figure 1. View of the molecular structure of 1c. Ellipsoids are at
30% probability.
Table 1. Selected bond lenghts [Å] and angles [°] in 1c, 1e and 3d.
1c
Au–P
P–Au–S
C(6)–P–Au
C(1)–S–Au
2.261(2)
175.94(6)
115.6(2)
107.0(2)
Au–S
C(5)–P–Au
C(12)–P–Au
2.288(2)
113.9(3)
109.7(2)
1e
Au–P
P–Au–S
C(2)–P–Au
C(14)–S–Au
2.264(2)
176.9(1)
116.2(3)
107.3(4)
Au–S
C(1)–P–Au
C(8)–P–Au
2.290(3)
109.9(3)
115.6(3)
The reactions were carried out in benzene at room tem-
perature, the yields varying from 80 to 95%. The com-
pounds are crystalline colourless solids, stable in the air and
humidity, soluble in aromatic and chlorinated solvents and
insoluble in aliphatic hydrocarbons.
The gold(I) dppe thiolates [Au2(SR)2(dppe)] (R = CMe3
1e; CH2CHMe2 2e; CH2CMe3 3e), have been prepared in
the same way by using a phosphane/Au = 1/2 molar ratio.
All the compounds have been characterized by elemental
analysis and NMR spectroscopy.
3d
Au–P
P–Au–S
C(7P)–P–Au
C(1)–S–Au
2.261(2)
177.2(1)
113.3(4)
107.0(4)
Au–S
C(1P)–P–Au
C(13P)–P–Au 114.7(3)
2.285(3)
112.1(4)
Well-formed crystals suitable for X-ray determination
have been obtained for [Au(SCMe3)(PMePh2)] (1c),
[Au2(SCMe3)2(dppe)] (1e) and [Au(SCH2CMe3)(PPh3)] (3d)
by crystallization from toluene at low temperature. None of
these complexes show the presence of aurophilic interac-
tions. The molecular structure of 1c is shown in Figure 1,
the most relevant distances and angles are also listed in
Table 1. The gold atom shows the expected linear coordina-
tion and Au–S and Au–P distances are very similar to those
observed in many other structurally characterized gold(I)
phosphanyl-thiolate complexes that are reported in the lit-
erature,[6] and closely correspond to those reported for
other gold(I) methyldiphenylphosphane derivatives.[6c]
Figure 2 shows the centrosymmetric structure of com-
pound 1e whose geometrical parameters around the gold
atom are listed in Table 1. The observed conformation of
the dppe ligand is a normal feature in almost all the gold(I)
diphosphanyl-thiolate complexes studied hitherto,[7] apart
from the cases with bidentate thiolate ligands, which result
in cyclic complexes.[8]
Figure 2. Projection of the molecular structure of 1e. Thermal ellip-
soids are at 30% probability. Ј = 1–x, 1–y, 1–z.
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Polynuclear AuI Phosphanyl Alkanethiolates
FULL PAPER
Finally, the most relevant distances and angles of 3d (the
molecular structure is shown in Figure S1 in the Supporting
Information) are listed in Table 1. The gold coordination is
very similar to that found in 1e and 3d and corresponds
very closely to that which has been found in the neutral
phosphanyl-thiolato complexes of gold(I) with tri-
phenylphosphane.[7f,9]
Oxidation of Gold Thiolates
In spite of the widespread use in several decomposition
techniques and some applications in galvanic processes, the
electrochemistry of gold complexes was until recently rather
poorly explored. A review summarizes the results of the re-
dox behaviour of gold and silver compounds.[11] In particu-
lar the Bruce group has found that gold phosphane thiol-
ates undergo two irreversible oxidation processes, that, in
agreement to theoretical studies, were assigned as sulfur-
and gold-centred, respectively.[3] Chemical complications
following oxidation have been elucidated by studying the
reaction with ferrocenium tetrafluoroborate.[3] The oxi-
dation process ultimately gives disulfide and a cationic clus-
ter that in the solid state appears to be constituted by a
dicationic tetragold system with gold–gold distances that
are in the range of typical distances for aurophilic interac-
tions.[3,10] Such reactivity has been observed in a variety of
phosphane and diphosphane gold thiolates, and in particu-
lar in the case of those derivatives that are the active prin-
ciples of Auranofin and of other antiarthritic drugs.[3]
The present study is aimed at elucidating the behaviour
of our systems towards both electrochemical and chemical
oxidation and exploiting the Bruce reaction in order to
build up polynuclear structures, and possibly to understand
how the structure and the geometry depend on the nature
of the ligands.
Figure 3. Cyclic voltammogram recorded at a platinum electrode
in CH2Cl2 solution containing [Au(SCH2CMe3)(PMe3)]
(1.8ϫ10–3 moldm–3) and [NBu4][PF6] (0.2 moldm–3). Scan rate:
0.2 Vs–1.
In agreement with the literature,[3] exhaustive oxidation
that corresponds to the first oxidation (Ew = +1.2 V) con-
sumes ca. half an electron per molecule, confirming that the
ligand centred[9] first process is coupled to fast chemical
reactions. Because of the partial overlapping of the solvent
discharge no attempts to identify the product arising from
the second gold-centred process have been carried out (the
standard reduction potential of the couple AuI/Au0 in water
is +1.69 V).
Table 2 consists of the electrode potentials from the first
oxidation of all the compounds studied: An attempt to ac-
count for the influence of the electronic effects from the
different substituents present in the phosphane or the thiol-
ate groups[12] on the location of the oxidation processes
(Table S1 in the Supporting Information) suggests that the
main contribution would arise from the inductive effects of
the substituents of the phosphane moieties. In fact, they
display the highest correlation coefficients, whereas the con-
tribution of the thiolate substituents greatly departs from
linearity. However, it has been considered that, given the
irreversibility of the electron removals, the potentials for the
first oxidation might have a thermodynamic meaning only
under the assumption that the kinetics of the coupled chem-
Electrochemical Studies
As representatively shown in Figure 3, which refers to ical complications proceed with similar rates.[13]
[Au(SCH2CMe3)(PMe3)], the gold thiolates with monopho- In fact, as in the case of the mononuclear complexes,
sphanes undergo two oxidation processes, both having fea- exhaustive oxidation at the first anodic process consumes
tures of chemical irreversibility.[12] Indeed, also limited to half an electron per gold atom, which means one electron
the first oxidation (peak A), it lacks the directly associated per molecule. The peak potentials for the first oxidation of
return peak even at high scan rates (2.0 Vs–1), thus indicat- the dinuclear derivatives are reported in Table 2.
ing that the oxidized product undergoes rapid chemical
complications.
Since in the mononuclear derivatives the SCMe3 group
seems to be a more efficient electron donor than the
Table 2. Peak potentials (V vs. SCE) for the first oxidation process exhibited by the present mono- and digold thiolates in CH2Cl2 solution.
[a]
[a]
[a]
Complex
Ep
Complex
Ep
Complex
Ep
[Au(SCMe3)(PMe3)] (1a)
[Au(SCMe3)( e2Ph)] (1b)
[Au(SCMe3)(PMePh2)] (1c)
[Au(SCMe3)(PPh3)] (1d)
[Au2(SCMe3)2(dppe)] (1e)
+0.97
+0.95
+1.03
+1.04
+0.90
[Au(SCH2CHMe2)(PMe3)] (2a) +0.97
[Au(SCH2CHMe2)(PPh3)] (2d) +1.09
[Au(SCPh3)(PMe3)] (4a)
+0.91
[Au(SCPh3)(PMe2Ph)] (4b) +0.96
[Au(SCPh3)(PMePh2)] (4c) +1.04
[Au(SCH2CMe3)(PMe3)] (3a)
[Au(SCH2CMe3)(PPh3)] (3d)
+1.00
+1.22
[Au(SCPh3)(PPh3)] (4d)
+1.07
[Au2(SCH2CHMe2)2(dppe)] (2e) +1.10
[Au2(SCH2CMe3)2(dppe)] (3e) +0.75
[a] Measured at 0.2 Vs–1. In turn the dinuclear derivatives exhibit a voltammetric profile qualitatively similar to those of the mononuclear
complexes {the cyclic voltammetric behaviour of [Au2(SCH2CMe3)2(dppe)] (3e) is illustrated in Figure S2 in the Supporting Information}.
Eur. J. Inorg. Chem. 2007, 865–875
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SCH2CMe3 ligand, it is puzzling that [Au2(SCMe3)2(dppe)] in the middle of the square of the four gold atoms, the two-
is oxidized less easily than [Au2(SCH2CMe3)2(dppe)], unless fold axis lying in the gold plane in the middle between the
a different relative arrangement of the thiolato groups in atoms Au and AuЈ and the mirror perpendicular to the axis
the complexes with dppe might be operative.
passing through the S and C(1) atoms. It is a common fea-
ture of the gold derivatives with this framework that the
PSP plane makes a dihedral angle with the Au4 plane acute
from the side of the sulfur atom. Our cation conforms to
this feature showing a torsion angle AuЈ–Au–AuЈЈ–S of
85.2º. The methyl groups of the phosphanes do not comply
with the high symmetry of the molecule, resulting in a sta-
tistical disorder between two limit conformations almost
equally populated and corresponding to different torsion
angles AuЈ–Au–P–C(5). For the sake of simplicity, only the
A conformation of the methyl groups, as marked by the
labels, has been drawn in the figure because of its slightly
higher frequency.
Chemical Oxidation
Following previous reaction conditions,[3] the phosphane
gold thiolates 1–3 have been reacted with [FeCp2][BF4]
(Scheme 1). In all cases (apart from the thiolates 4, which
react giving uncharacterized products) the reaction pro-
ceeds by consuming one mol of ferrocenium salt per two
mol of gold thiolate moiety, as shown by colour changes at
the equivalence point (the persistence of the green colour of
the ferrocenium ion indicates that the reaction is complete).
Scheme 1.
The solid residue, after evaporation of the solvent, is
washed with diethyl ether in order to extract ferrocene and
the disulfide (RSSR) (the oxidation product of the thiolato
ligand), which were identified by NMR spectroscopy. The
residue was crystallized from dichloromethane/hexane to
give grey to pale yellow crystals of 5–7, which are stable in
the air and insoluble in aliphatic and aromatic hydro-
carbons, and fairly soluble in acetone and dichloromethane.
All the products present satisfactory elemental analyses and
have been characterized by NMR spectroscopy and mass
Figure 4. View of the structure of the cationic part of 7a. Only the
most populated positions of the disordered phosphanes have been
represented. Thermal ellipsoids are at 30% probability. Ј = 1–x,
1–y, z; ЈЈ = x, y, –z.
Table 3. Selected bond lenghts [Å] and angles [°] in 7a. The apexes
in the atom labels have the same meaning as in Figure 4.
spectrometry. On the basis of the relative 2:1 ratio of the Au–AuЈ
3.112(1)
2.259(5)
90.0
47.72(9)
132.7(2)
104.3(5)
113(1)
Au–AuЈЈ
Au–S
S–Au–AuЈ
P–Au–AuЈ
Au–S–AuЈЈ
Au–P–C(5A)
Au–P–C(7A)
3.138(1)
2.332(4)
86.4(1)
96.1(1)
84.6(2)
117(1)
1H NMR signals from the phosphane and the thiolato
Au–P
AuЈ–Au–AuЈЈ
groups we have attributed a general formula [Au2(SR)(L)2]-
[BF4]. Actually, for similar compounds, the literature re-
ports[3] structures in the solid state that generally result
from the aggregation of the monocations in dimers of the
formula [Au4(SR)2(phosphane)4][BF4]2, where the tetranu-
clear arrangement of the gold atoms is due to aurophilic
interactions.
S–Au–AuЈЈ
P–Au–AuЈЈ
Au–S–C(1)
Au–P–C(6A)
115(1)
This structure is similar to those reported for [Au4(SMe)2-
(PMe3)4]2+[6d] and [Au4(SCMe3)2(PPh3)4]2+ [15]
prepared by
,
Well-formed crystals suitable for structural determi- different routes.
nation have been obtained in the case of 5e and 7a by The structure of the tetranuclear cation present in the
crystallization from dichloromethane/hexane or dichloro- crystal of 5e·CH2Cl2 is shown in Figure 5 and the bond
methane/diethyl ether solutions.
lengths and angles around the metal are listed in Table 4.
The structure of the
tetranuclear
cation The projection has been done down the twofold axis, which
[Au4(SCH2CMe3)2(PMe3)4]2+ is sketched in Figure 4 and relates the two moieties of the cation, point group 2 (C2 in
the most significant bond lengths and angles are listed in the Schoenflies notation). The gold atoms are arranged in
Table 3. The four gold atoms make a square ring by means a sort of zigzag chain. A similar metal arrangement has
of four aurophilic interactions. Such an arrangement is very been found in Ag,[16a,16b] Ag–Pd[16c] Ni,[16d] Mo[16e] and
frequent in phosphanyl-thiolato complexes of gold(I), no- Ta[16f] derivatives, but it has never been reported for gold.
tably with the trimethylphosphane.[6e,14] The cation belongs Different from almost all these examples, where the metal
to the point group 2/m (C2h), possessing the inversion centre chain is lying on a plane, the chain of gold atoms is mark-
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Eur. J. Inorg. Chem. 2007, 865–875

Polynuclear AuI Phosphanyl Alkanethiolates
FULL PAPER
edly puckered so that it may be described as a tetrahedron
It is not clear if such structures will survive in solution
heavily distorted by the stretching of some edges. The three (the literature is not conclusive in this regard). ESI-MS
shortest edges correspond to the drawn bonds Au(1)–Au(2), spectra of these complexes in methanol show peaks that can
Au(2)–Au(2Ј) and Au(2Ј)–Au(1Ј), while the other three, be attributed both to the corresponding dinuclear mono-
Au(1)···Au(2Ј) and Au(2)···Au(1Ј), 3.717 Å, and Au(1)··· cation and to the tetranuclear dication. However, in the
Au(1Ј), 4.903 Å, correspond to non-bonding distances. The case of [Au4(SCH2CHMe2)2(PMe3)4][BF4]2 (6a) and
torsion angle Au(1)–Au(2)–Au(2Ј)–Au(1Ј), which in an un- [Au4(SCH2CHMe2)2(PPh3)4][BF4]2 (6d), the spectra show,
distorted tetrahedron is 70.5º, in our chain rises to 107.8º in addition to the peaks at m/z = 635 and 1007 for
and only one of the twofold axes of the ideal tetrahedron is [Au2(SR)(PMe3)2]+ and [Au4(SR)2(PMe3)4]2+, respectively,
preserved.
species at high molecular weights, e.g. [Au3(SR)3(PMe3)2]+,
[Au3(SR)2(PMe3)2]+ and [Au3(SR)(PMe3)3]+, but it is not
certain if those species derive from fragmentation of the
tetranuclear species or from the aggregation of small frag-
ments. Moreover, close inspection of the peak correspond-
ing to [Au2(SR)(PMe3)2]+ shows that, in addition to the ex-
pected M, M + 1, M + 2 peaks, signals at M + 1/2 are
present, which are assigned to the dicationic species
[Au4(SR)2(PMe3)4]2+. These observations suggest that tetra-
nuclear species are present in solution (perhaps together
with the dinuclear ones) although further experimental evi-
dences are necessary in order to draw clear-cut conclusions.
Reactions with Nucleophiles
Thiolate Anions
The cationic gold clusters can be converted back to the
neutral thiolates by reaction with the thiolato anion gener-
ated in situ: in fact reacting [Au4(SCMe3)2(PMe3)4][BF4]2
(4a) with 2 equiv. of 2-methyl-2-propanethiol in the pres-
ence of a base (ethanolamine) produces almost quantita-
tively [Au(SCMe3)(PMe3)] (2a). The reaction can easily be
Figure 5. View of the structure of the cationic part of 5e projected
down the twofold axis. The phenyl groups of dppe have been omit-
ted apart from the carbon atoms connected to the phosphorus
atoms. Thermal ellipsoids are at 30% probability. Ј = –x, y,
1/2 – z.
1
followed by H NMR spectroscopy. By adding a stoichio-
Table 4. Selected bond lenghts [Å] and angles [°] in 3d. The apexes
in the atom labels have the same meaning as in Figure 4.
metric amount of 2-methyl-2-propanethiol and ethanol-
amine in a 1:1 molar ratio to a CD2Cl2 solution of the di-
cation the signals from the initial cationic complex 4a disap-
pear immediately and the resonances from the protons of
the neutral thiolate 2a arise.
Au(1)–Au(2)
Au(1)–P(1)
Au(1)–SЈ
2.986(1)
2.281(4)
2.320(4)
92.3(1)
172.8(2)
168.4(2)
85.4(1)
107.8(1)
111.3(6)
111.2(7)
112.5(6)
112.2(7)
Au(2)–Au(2Ј)
Au(2)–P(2)
Au(2)–S
Au(2)–Au(1)–SЈ
Au(1)–Au(2)–Au(2Ј) 74.49(3)
P(2)–Au(2)–Au(1)
S–Au(2)–Au(2Ј)
Au(1)–SЈ–Au(2Ј)
Au(2)–S–C(27)
Au(1)–P(1)–C(7)
Au(2)–P(2)–C(14)
Au(2)–P(2)–C(21)
3.152(1)
2.285(5)
2.346(5)
87.0(1)
Au(2)–Au(1)–P(1)
P(1)–Au(1)–SЈ
P(2)–Au(2)–S
S–Au(2)–Au(1)
P(2)–Au(2)–Au(2Ј)
Au(1)–SЈ–C(27Ј)
Au(1)–P(1)–C(1)
Au(1)–P(1)–C(13)
Au(2)–P(2)–C(15)
92.6(1)
82.7(1)
105.6(2)
107.3(7)
113.8(6)
110.3(6)
118.0(6)
Lithium Alkyls
Wedecidedtostudythereactionof[Au4(SCMe3)2(PMe3)4]-
[BF4]2 with LiMe and LiCH2CMe3 because of the spectral
Although both Au(1)–Au(2) and Au(2)–Au(2Ј) distances simplicity of the expected alkyl derivatives.
fall within the aurophilic bond range, the second one,
The reactions have been carried out with an excess
3.152 Å, suggests a rather weak interaction and being asso- of the alkylating agent in dichloromethane. When
ciated with a wide Au–S–Au angle, 105.6º, is in keeping [Au4(SCMe3)(PMe3)4][BF4]2 was reacted with LiMe, after
with the suggested relationship between this angle and the hydrolysis and extraction with benzene, a solid was ob-
1
strength of the gold–gold interaction.[15]
tained whose H NMR spectrum shows, in addition to the
Hence, the corrected formulations for the complexes in signals of [Au(SCMe3)(PMe3)], two doublets at δ =
the solid state are [Au4(SR)2(L)4][BF4]2. On the basis of 0.59 ppm (J = 8.8 Hz) and 1.23 ppm (J = 8.4 Hz). These
these results and on the literature reports we think that the signals, having a relative intensity of 3:1, could be attributed
other cationic compounds prepared have a similar struc- quite naturally to the PMe3 and AuMe protons in
ture, based on a core of four gold atoms associated by auro- [Au(Me)(PMe3)]. Accordingly the 31P NMR spectrum of
philic interactions.
the reaction mixture shows the presence of signals at δ =
Eur. J. Inorg. Chem. 2007, 865–875
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869

A. Battisti, O. Bellina, P. Diversi, S. Losi, F. Marchetti, P. Zanello
FULL PAPER
–3.51 ppm, corresponding to the gold phosphanyl thiolate
[Au(SCMe3)(PMe3)], and δ = 10.74 ppm, which seems logi-
cal to attribute to [Au(Me)(PMe3)].
Surprisingly our NMR spectroscopic data are not in
agreement with those reported in the literature for
[Au(Me)(PMe3)], prepared from [Au(Cl)(PMe3)] by alky-
Conclusions
We report here the synthesis and characterization of a
series of gold(I) thiolates, in which the thiolato ligands con-
tain aliphatic C4 and C5 alkyls with different steric hin-
drance, or a trityl group. The aliphatic thiols give neutral
gold thiolates that do not exhibit any Au–Au bonding inter-
actions in the solid state, but upon oxidation afford cationic
derivatives that at least in the solid state dimerize to dicat-
ionic tetranuclear species with pairs of gold atoms bonded
by aurophilic interactions. As in the majority of the litera-
ture reports, the arrangement was found to be almost
square in the case of 7a but in the case of 5e, where dppe
is the phosphane supporting ligand, an unusual zigzag or-
ganization has been found. It is obviously premature to
make a pertinent theory but we are attempting to attribute
this peculiar structure to the presence of a chelating phos-
phane.
Apart from this dinuclear–tetranuclear issue, these
cationic thiolates behave towards nucleophiles as
[Au(SR)(PMe3)]-stabilized [Au(PMe3)]+ cations losing the
neutral complex and adding the nucleophile. This reactivity
confirms that the aurophilic interactions and also the bridg-
ing thiolato ligands, which are responsible for the variety of
structures in the solid state for gold(I), are easily disrupted
in solution.
lation with LiMe in diethyl ether (δ = 0.21 ppm, JP,H
=
8.9 Hz and δ = 0.57 ppm, JH,H = 8.7 Hz).[17] We have pre-
pared [Au(Me)(PMe3)] following the reported procedure,[18]
1
and we found the same H NMR signals as the methyl de-
rivative formed by reacting [Au4(SCH2CHMe2)2(PMe3)4]-
[BF4]2 with LiMe. The 31P NMR spectrum showing a signal
at δ = 12.35 ppm is rather consistent with the above value
of δ = 10.74 ppm. The product reacts rapidly and quantita-
tively in deuterated benzene with an excess of trifluoroacetic
acid, forming methane and [Au(OOCF3)(PMe3)] as shown
1
by the immediate appearance in the H NMR spectrum of
a singlet at δ = 0.14 ppm (methane) and in the 31P NMR
spectrum of a signal at δ = –16.14 ppm, to be attributed to
[Au(OOCF3)(PMe3)]. This was unequivocally identified by
1
purification and comparison of the H NMR spectrum in
CDCl3 with that reported in the same solvent (δ =
1.68 ppm, d, JP,H = 11.36 Hz).[19]
Only an X-ray single-crystal determination could posi-
tively clarify this point but so far we have not been able to
prepare suitable crystals.
[Au4(SCMe3)2(PMe3)4][BF4]2 was similarly reacted with
LiCH2CMe3 yielding an equimolar mixture of
[Au(SCMe3)(PMe3)] and [Au(CH2CMe3)(PMe3)]. The neo-
Experimental Section
pentylgold derivative, which has not been reported in the All manipulations and reactions were carried out under dinitrogen
or argon using standard techniques. Diethyl ether and benzene
were distilled prior to use, first over K/benzophenone and later over
LiAlH4. n-Pentane, CH2Cl2 and ethanol were dried under vacuum
over molecular sieves. 1H and 31P NMR spectra were recorded with
a Varian Gemini 200 instrument, working at 200 MHz. Centesimal
analysis have been executed in the microanalysis laboratory of Di-
partimento di Scienze Farmaceutiche dell’Università di Pisa. The
mass spectra were obtained by an Ion Spray technique with the
Perkin–Elmer instrument SCIEX API III, in methanol solution.
Material and apparatus for electrochemistry have been described
literature thus far, was prepared by alkylation of the corre-
sponding chloro derivative with LiCH2CMe3 in diethyl
ether. The product was isolated as a white crystalline solid,
which, even when stored under nitrogen at room tempera-
ture and out of light, becomes gradually grey after a few
weeks. However, the complex shows well resolved NMR
1
spectra in CD2Cl2. The H NMR spectrum shows a singlet
at δ = 1.01 ppm and a doublet at δ = 1.22 ppm (JH,H
=
8.4 Hz) corresponding to the methyl and methylene pro-
tons, respectively, of the neopentyl group and a doublet at elsewhere.[20] All of the potential values refer to the Saturated Calo-
mel Electrode (SCE). Under the present experimental conditions
the one-electron oxidation of ferrocene occurs at +0.39 V.
[Au(SCMe3)]n was prepared according to the literature.[3a]
[Au(SCH2CHMe2)]n was prepared in the same way (yield 93%).
C4H9AuS (286.15): calcd. C 16.79, H 3.17; found C 16.64, H 3.20.
Neopentanethiol was prepared by a literature procedure[21] from
the corresponding neopentyl tosylate, obtained from neopentyl
alcohol and tosyl chloride in pyridine [yield 95%. 1H NMR
(CDCl3): δ = 0.91 (s, 9 H, CMe3), 2.46 (s, 3 H, MePh), 3.67 (s, 2
H, CH2S) ppm] by treatment with NaSH in methoxyethanol [yield
δ = 1.41 ppm (JP,H = 8.4 Hz) corresponding to the trimeth-
ylphosphane; accordingly the 31P NMR spectrum shows a
singlet at δ = 16.60 ppm. The reaction with trifluoroacetic
acid in deuteriobenzene gave neopentane (singlet at δ =
0.89 ppm) and [Au(OOCF3)(PMe3)], as expected.
These results show that, from the reaction of the above
cationic gold thiolates with alkyllithium reagents, half of
the metal centres undergo alkylation and the other half are
released as a neutral phosphane thiolate:
1
21%. H NMR (CDCl3): δ = 0.96 (s, 9 H, Me), 1.20 (t, 1 H, JH,H
= 8.8 Hz, SH), 2.41 (d, 2 H, JH,H = 8.8 Hz, CH2S) ppm].
Preparation of [Au(SCH2CMe3)]n
Method A: Neopentanethiol (0.327 g, 3.14 mmol) was added drop-
wise to an aqueous solution of H[AuCl4] (29.34 wt.-% Au) (0.676 g,
1 mmol Au) in EtOH (2.6 mL). An exothermic reaction occurred
with the formation of a brown solid that turned white in 30 min.
The mixture was heated at 50 °C for 10 min, and the white solid
was then separated from the solvent by settling, washed first with
870
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Eur. J. Inorg. Chem. 2007, 865–875

Polynuclear AuI Phosphanyl Alkanethiolates
FULL PAPER
EtOH (2ϫ10 mL) and then with Et2O (2ϫ10 mL). The residual
solvent was removed under vacuum to give a solid product (0.294 g,
98%), which is insoluble in the most common organic solvent.
C5H11AuS (300.17): calcd. C 20.01, H 3.69; found C 20.0, H 4.0.
Complex 2c: Grey oil. Yield 81%. C17H22AuPS (486.37): calcd. C
41.98, H 4.56; found C 41.78, H 4.25. H NMR (C6D6): δ = 1.26
(d, 6 H, JH,H = 6.2 Hz, Me2), 1.34 (d, 3 H, JH,P = 9.5 Hz, PMe),
2.11 (m, 1 H, JH,H = 6.4 Hz, CH), 3.38 (d, 2 H, JH,H = 6.2 Hz,
CH2), 6.8–7.4 (10 H, br. m, PPh2) ppm. 31P NMR (C6D6): δ =
23.53 ppm.
1
Method B: An aqueous solution of bis(2-hydroxyethyl) sulfide
(2 mL, 2.0 mmol) was added dropwise at 0 °C to a solution of
H[AuCl4]·xH2O (1.05 mmol) in water (1 mL) and EtOH (2.6 mL).
The stirring was maintained until the solution turned colourless.
Neopentanethiol (0.109 g, 1.05 mmol) was added and a white solid
began to precipitate immediately from the solution. After stirring
for 30 min, the solid product was separated, washed as described
above and dried under vacuum (0.234 g, 78%).
Complex 2d: White crystals. Yield 75%. C22H24AuPS (548.44):
1
calcd. C 48.18, H 4.41; found C 48.0, H 4.3. H NMR (C6D6): δ =
1.27 (d, 6 H, JH,H = 6.6 Hz, Me2), 2.10 (m, 1 H, JH,H = 6.6 Hz,
CH), 3.37 (d, 2 H, JH,H = 6.6 Hz, SCH2), 6.7–7.4 (15 H, br. m,
PPh3) ppm. 31P NMR (C6D6): δ = 38.64 ppm.
Complex 2e: White solid. Yield 65%. C34H42Au2P2S2 (970.72):
1
calcd. C 42.07, H 4.36; found C 41.8, H 4.2. H NMR (C6D6): δ =
Reaction of [Au(SCMe3)]n with L (L = PMe3, PMe2Ph, PMePh2,
PPh3, dppe). Formation of [Au(SCMe3)(L)] (1a, 1b, 1c, 1d, 1e): The
reaction of [Au(SCMe3)]n with PMe3 is reported as an example.
1.25 (d, 12 H, JH,H = 6.6 Hz, Me2), 2.09 (m, 2 H, JH,H = 6,6 Hz,
CH), 2.57 (br. s, 4 H, PCH2), 3.37 (d, 4 H, JH,H = 6.6 Hz, CH2),
6.7–7.5 (20 H, br. m, PPh2) ppm. 31P NMR (C6D6): δ = 37.60 ppm.
Trimethylphosphane (0.6 mL of
a 1  solution in toluene,
0.6 mmol) was added to a suspension of [Au(SCMe3)]n (0.152 g,
0.53 mmol) in toluene (10 mL) while stirring. The solid immedi-
ately dissolved to give a clear colourless solution, which was kept
stirring for a further 30 min. The solution was concentrated under
vacuum to ca 3 mL and pentane (15 mL) was added causing a
white solid to precipitate. The solid was washed twice with pentane
(15 mL) and recrystallized from toluene to give 0.187 g (98%) of
1a. C7H18AuPS (362.23): calcd. C 23.21, H 5.01; found C 23.3, H
Reaction of [Au(SCH2CMe3)]n with L (L = PMe3, PMe2Ph,
PMePh2, PPh3, dppe). Formation of [Au(SCH2CMe3)(L)] (3a, 3b,
3c, 3d, 3e): The following complexes were prepared as described
above.
Complex 3a: White crystals. Yield 99%. C8H20AuPS (376.25):
1
calcd. C 25.5, H 5.4; found C 25.54, H 5.36. H NMR (CD2Cl2):
δ = 1.02 (s, 9 H, CMe3), 1.56 (d, 9 H, JH,P = 10.3 Hz, PMe3), 2.80
(s, 2 H, SCH2) ppm. 1H NMR (C6D6): δ = 0.62 (d, 9 H, JH,P
=
1
5.3. H NMR (C6D6): δ = 1.90 (s, 9 H, CMe3), 0.55 (d, 9 H, JH,P
10.3 Hz, PMe3), 1.33 (s, 9 H, CMe3), 3.37 (s, 2 H, SCH2) ppm. 31P
= 9.5 Hz, PMe3) ppm. 31P NMR (C6D6): δ = 0.61 ppm.
NMR (CDCl3): δ = 0.10 ppm. 31P NMR (C6D6): δ = –1.03 ppm.
The complexes 1b–1e were prepared in a similar manner to that of
[Au(SCMe3)]n by reaction with the appropriate phosphane.
Complex 3b: Crystallized from Et2O. Yield 85%. C13H22AuPS
(438.32): calcd. C 35.62, H 5.06; found C 35.52, H 5.4. H NMR
1
(C6D6): δ = 0.98 (d, 6 H, JH,P = 7.3 Hz 1.34, PMe2), (s, 9 H, CMe3);
3.42 (s, 2 H, CH2S), 7.00 (3 H, br. m, PPh), 7.27 (2 H, br. m,
PPh) ppm. 31P NMR (C6D6): δ = 3.53 ppm.
Complex 1b: Yield 90%. C12H20AuPS (424.30): calcd. C 33.97, H
4.75; found C 33.52, H 4.95. 1H NMR (C6D6): δ = 1.95 (s, 9 H,
CMe3), 0.81 (d, 6 H, JH,P = 9.5 Hz PMe2), 7.02 (5 H, br. m,
PPh) ppm. 31P NMR (C6D6): δ = 13.01 ppm.
Complex 3c: Crystallized from Et2O. Yield 90%. C18H24AuPS
1
(500.39): calcd. C 43.21, H 4.83; found C 43.10; H 5.01. H NMR
Complex 1c: Yield 97%. C17H22AuPS (486.37): calcd. C 41.98, H
4.56; found C 41.79, H 4.45. 1H NMR (C6D6): δ = 1.94 (s, 9 H,
CMe3), 1.21 (d, 3 H, JH,P = 8.8 Hz, PMe), 7.10 (10 H, br. m,
PPh2) ppm. 31P NMR (C6D6): δ = 25.00 ppm.
(C6D6): δ = 1.29 (d, 3 H, PMe), 1.32 (s, 9 H, CMe3); 3.41 (s, 2 H,
CH2S); 6.92 (6 H, br. m, PPh); 7.28 (m, 4 H, PPh2) ppm. 31P NMR
(C6D6): δ = 16.64 ppm.
Complex 3d: White crystals from toluene at –5 °C. Yield 97%.
C23H26AuPS (562.47): calcd. C 49.11, H 4.66; found C 48.93, H
4.8. 1H NMR (CD2Cl2): δ = 1.05 (s, 9 H, CMe3), 2.92 (s, 2 H,
Complex 1d: Yield 95%. C22H24AuPS (548.44): calcd. C 48.18, H
4.41; found C 47.96, H 4.27. 1H NMR (C6D6): δ = 1.92 (s, 9 H,
CMe3), 6.80–6.92 (9 H, br. m, PPh3), 7.25–7.40 (6 H, br. m,
PPh3) ppm. 31P NMR (C6D6): δ = 38.77 ppm.
1
SCH2), 7.53–7.54 (15 H, br. m, PPh3) ppm. H NMR (C6D6): δ =
1.31 (s, 9 H, CMe3), 3,40 (s, 2 H, SCH2), 6.88 (m, 9 H, PPh3), 7.29
(6 H, br. m, PPh3) ppm. 31P NMR (CDCl3): δ = 39.26 ppm. 31P
NMR (C6D6): δ = 36.21 ppm.
Complex 1e: Yield 89%. C34H42Au2P2S2 (970.72): calcd. C 42.07,
H 4.36; found C 41.95, H 4.28. H NMR (C6D6): δ = 1.90 (s, 9 H,
1
CMe3), 2.68 (s, 4 H, PCH2), 6.8–7.0, 7.4–7.6 (20 H, br. m,
Complex 3e: Crystallized from toluene at –5 °C. Yield 90%.
C36H46P2S2Au2 (998.77): calcd. C 43.29, H 4.64; found C 43.09, H
4.47. 1H NMR (CDCl3): δ = 1.07 (s, 18 H, CMe3), 2.71 (s, 4 H,
CH2S), 3.02 (s, 4 H, PCH2), 7.29–7.67 (20 H, br. m, PPh2) ppm.
1H NMR (C6D6): δ = 1.29 (s, 18 H, CMe3), 2.68 (s, 4 H, PCH2),
3.41(s, 4 H, CH2S), 6.91 (12 H, br. m, PPh2), 7.51 (8 H, br. m,
PPh2) ppm. 31P NMR (C6D6): δ = 37.38 ppm.
PPh2) ppm. 31P NMR (C6D6): δ = 37.64 ppm.
Reaction of [Au(SCH2CHMe2)]n with L (L = PMe3, PMe2Ph,
PMePh2, PPh3, dppe). Formation of [Au(SCH2CHMe2)(L)] (2a, 2b,
2c, 2d, 2e): The following complexes were prepared as described
before.
Complex 2a: White solid. Yield 79%. C7H18AuPS (362.23): calcd.
C 23.21, H 5.01; found C 22.97, H 4.88. 1H NMR (C6D6): δ = 0.45
(d, 9 H, JH,P = 9.9 Hz, PMe3), 1.23 (d, 6 H, JH,H = 6.6 Hz, Me2),
2.10 (m, 1 H, JH,H = 6.6 Hz, CH), 3.32 (d, 2 H, JH,H = 6.6 Hz,
SCH2) ppm. 31P NMR (C6D6): δ = –0.40 ppm.
Preparation of [Au(SCPh3)]n. Method A: Triphenylmethanethiol
(1.076 g, 3.9 mmol) suspended in EtOH (10 mL) was added slowly
to a solution of H[AuCl4]·xH2O (1.3 mmol) in water (1 mL) and
EtOH (5 mL): the mixture was stirred for 3 h and a beige solid was
formed. The solid was separated and washed with water
(2ϫ30 mL), EtOH (20 mL) and Et2O (20 mL). A beige solid was
obtained (0.565 g, 92%). C19H15AuS (472.36): calcd. C 48.31, H
3.20; found C 46.7, H 2.9. Mp: 128° (dec).
Complex 2b: Grey oil. Yield 77%. C12H20AuPS (424.30): calcd. C
1
33.97, H 4.75; found C 33.77, H 4.53. H NMR (C6D6): δ = 0.86
(d, 6 H, JH,P = 9.9 Hz, PMe2), 1.30 (d, 6 H, JH,H = 6.6 Hz, Me2),
2.14 (m, 1 H, JH,H = 6.6 Hz, CH), 3.37 (d, 2 H, JH,H = 6.6 Hz,
SCH2), 6.8–7.3 (5 H, br. m, PPh) ppm. 31P NMR (C6D6): δ =
11.31 ppm.
Method B: Bis(2-hydroxyethyl) sulfide (0.3 mL, 3 mmol) was added
dropwise whilst stirring to 0.671 g of a solution of H[AuCl4]·xH2O
Eur. J. Inorg. Chem. 2007, 865–875
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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871

A. Battisti, O. Bellina, P. Diversi, S. Losi, F. Marchetti, P. Zanello
FULL PAPER
(1.0 mmol) in water (10 mL) at 0 °C, causing a precipitate to form.
Triphenylmethanethiol (0.276 g, 1 mmol) in CHCl3 (20 mL) was
added slowly in ca. 20 min and the reaction mixture stirred for
1 hour giving a grey precipitate. After addition of MeOH (40 mL),
the solid was separated, washed with MeOH (2ϫ40 mL) and dried
(0.40 g, 85%).
Complex 5c: Colourless crystals. Yield 95%. C60H70Au4B2F8P4S2
(1940.72): calcd. C 37.1, H 3.6; found C 37.4, H 3.7. 1H NMR
(CD3COCD3): δ = 1.68 (s, 18 H, CMe3), 2.42 (d, 12 H, JH,P
10,3 Hz, PMe), 7.58 (m, 24 H, PPh), 7.84 (m, 16 H, PPh) ppm. H
=
1
NMR (CD2Cl2): δ = 1.67 (s, 18 H, CMe2Ph3), 2.20 (d, 12 H, JH,P
=
10.3 Hz, PMe), 7.52 (40 H, br. m, PPh) ppm. 31P NMR (CD2Cl2): δ
= 27.51 ppm. ESI-MS (methanol): m/z = 883 [Au2(SCMe3)-
(PMePh2)2]+, 817 {[Au2(SCMe3)(PMePh2)2]+ – C4H8}.
Reaction of [Au(SCPh3)]n with L (L = PMe3, PMe2Ph, PMePh2,
PPh3, dppe): Formation of [Au(SCPh3)(L)] (4a, 4b, 4c, 4d, 4e)
Complex 5d: Colourless crystals. Yield 96%. C80H78Au4B2F8P4S2
(2189.00): calcd. C 43.9, H 3.6; found C 43.6, H 3.4. 1H NMR
(CD3COCD3): δ = 1.70 (s, 9 H, CMe3), 7.62 (15 H, br. m,
PPh3) ppm. 1H NMR (200 MHz, CD2Cl2): δ = 1.75 (s, 9 H, CMe3),
Complex 4a: pale yellow crystals. Yield 61%. C21H24AuPS (536.43):
calcd. C 46.0, H 4.4; found C 45.7, H 4.2. Mp = 118 °C (dec). H
NMR (C6D6): δ = 0.37 (d, 9 H, JPH = 10.2 Hz, PMe3), 6.8–7.4 (9
H, br. m, CPh3), 8.06 (d, 6 H, JH,H = 7.3 Hz, CPh3) ppm.31P NMR
(C6D6): δ = 6.41 ppm.
1
1
7.48 (15 H, br. m, PPh3) ppm. H NMR (CD3OD): δ = 1.64 (s, 9
H, CMe3), 7.49 (15 H, br. m, PPh3) ppm. 31P NMR (CD2Cl2): δ =
43.02 ppm. ESI-MS (methanol): m/z = 1007.3 [Au2(SCMe3)-
(PPh3)2]+, 87 [BF4]–.
Complex 4b: Pale yellow crystals. Yield 46%. C26H26AuPS (598.50):
1
calcd. C 51.1, H 4.3; found C 50.7, H 4.1. H NMR (C6D6): δ =
0.69 (d, 6 H, JH,P = 9.9 Hz, PMe2), 6.8–8.2 (m, 14 H, CPh3 + PPh),
8.08 (d, 6 H, JH,H = 7.3 Hz, CPh3) ppm. 31P NMR (C6D6): δ =
40.18 ppm.
Reaction of [Au(SCH2CHMe2)(L)] (L = PMe3, PMe2Ph, PMePh2,
PPh3) with [FeCp2][BF4]. Formation of [Au4(SCH2CHMe2)2(L)4]-
[BF4]2 (6a, 6b, 6c, 6d): Following the above procedure
[Au(SCH2CHMe2)(PMe3)] (0.130 g, 0.36 mmol) in CH2Cl2 (10 mL)
was treated with [FeCp2][BF4] (0.050 g, 0.18 mmol). The solvent
was evaporated under vacuum and the residue was washed with
pentane (2ϫ30 mL) and benzene (2ϫ30 mL). Crystallization from
Complex 4c: Pale yellow microcrystals. Yield 52%. C31H28AuPS
(660.57): calcd. C 55.4, H 4.2; found C 55.2, H 4.1. 1H NMR
(C6D6): δ = 1.07 (d, 3 H, JH,P = 9.2 Hz, PMe), 6.8–8.2 (m, 19 H,
CPh3 + PPh2), 8.09 (d, 6 H, JH,H = 7.7 Hz, CPh3) ppm.31P NMR
(C6D6): δ = 42.07 ppm.
CH2Cl2/Et2O afforded
a
white solid (0.111 g, 86%).
Complex 4d: White solid. Yield 71%. C36H30AuPS (722.64): calcd.
C 59.0, H 4.1; found C 58.7, H 3.9. Mp = 140 °C (dec). H NMR
C20H54Au4B2F8P4S2 (1444.15): calcd. C 16.6, H 3.7; found C 16.5,
H 3.7. H NMR (CD3COCD3): δ = 1.22 (d, 12 H, JH,H = 6.6 Hz,
1
1
(C6D6): δ = 6.8–7.3 (m, 24 H, PPh3 + CPh3), 8.08 (d, 6 H, JH,H
=
Me2), 1.81 (d, 36 H, JPH = 11.7 Hz, PMe3), 3.17 (d, 4 H, JH,H
6,6 Hz, CH2) ppm. 31P NMR (CD3COCD3): δ = 2.80 ppm. ESI
(MeOH): m/z
635 [Au2(SCH2CHMe2)(PMe3)2]+, 349 [Au-
=
7.3 Hz, CPh3) ppm. 31P NMR (C6D6): δ = 48.22 ppm.
=
Complex 4e: Pale yellow microcrystals. Yield 87%. C64H54Au2P2S2
(1343.14): calcd. C 57.2, H 4.0; found C 56.8, H 4.2. 1H NMR
(C6D6): δ = 2.0–2.5 (4 H, br. m, PCH2), 6.8–7.4 (m, 50 H, PPh2 +
CPh3), 8.05 (d, 12 H, JH,H = 7.7 Hz, CPh3) ppm. 31P NMR (C6D6):
δ = 42.88 ppm.
(PMe3)2]+, 273 [Au(PMe3)]+. From the hydrocarbon extracts the
solvent was evaporated leaving a solid residue, from which ferro-
cene [1H NMR (CD2Cl2): δ = 4.12 ppm] was obtained by sublima-
tion under vacuum at 40 °C leaving a residue identified as
(SCH2CHMe2)2 [1H NMR (200 MHz, CD2Cl2): δ = 0.99 (d, 12 H,
JH,H = 6.6 Hz, Me2), 1.83 (m, 2 H, JH,H = 6.6 Hz, CH), 2.59 (d, 4
H, JH,H = 6.6 Hz, CH2) ppm].
Reaction of [Au(SCMe3)(L)] (L = PMe3, PMe2Ph, PMePh2, PPh3)
with [FeCp2][BF4]. Formation of [Au4(SCMe3)2(L)4][BF4]2 (L = 5a,
5b, 5c, 5d): The reaction of [Au(SCMe3)(PMe3)] with [FeCp2][BF4]
is reported as an example. [FeCp2][BF4] (0.037 g, 0.136 mmol) was
added to a solution of [Au(SCMe3)(PMe3)] (0.100 g, 0.276 mmol)
in dichloromethane (10 mL) and the mixture was stirred for 30 min
giving a deep yellow solution. The solvent was evaporated and the
solid residue was washed with Et2O (2ϫ10 mL), followed by ben-
zene (10 mL), dried under vacuum and crystallized from dichloro-
methane at –5 °C as colourless crystals (0.094 g, 94%).
C20H54Au4B2F8P4S2 (1444.15): calcd. C 16.6, H 3.8; found C 16.9,
Complex 6b: Off-white crystals. Yield 55%. C40H62Au4B2F8P4S2
(1692.43): calcd. C 28.4, H 3.7; found C 28.2, H 3.5. 1H NMR
(CD3COCD3): δ = 1.12 (d, 12 H, JH,H = 6.6 Hz, Me2), 2.06 (d, 24
H, JPH = 11.0 Hz, PMe2), 3.21 (d, 4 H, JH,H = 6.2 Hz, CH2), 7.6–
8.0 (20 H, br. m, PPh) ppm. 31P NMR (CD3COCD3): δ =
14.83 ppm.
Complex 6c: Pale yellow solid. Yield 57%. C60H70Au4B2F8P4S2
(1940.72): calcd. C 37.1, H 3.6; found C 36.8, H 3.4. 1H NMR
(CD3COCD3): δ = 1.16 (d, 12 H, JH,H = 6.6 Hz, Me2); 3.26 (d, 4
H, JH,H = 6.2 Hz, CH2), 2.39 (d, 12 H, JPH = 10.3 Hz, PMe), 7.2–
8.0 (40 H, br. m, PPh2) ppm. 31P NMR (CD3COCD3): δ =
27.86 ppm.
1
H 3.4. H NMR (CD3COCD3): δ = 1.60 (s, 18 H, CMe3), 1.83 (d,
36 H, JH,P = 11.7 Hz, PMe3) ppm. 1H NMR (CD2Cl2): δ = 1.60 (s,
18 H, CMe3), 1.71 (d, 36 H, JH,P = 11.0 Hz, PMe3) ppm. 31P NMR
(CD2Cl2):
δ = 4.58 ppm. ESI-MS (methanol): m/z = 635
[Au2(SCMe3)(PMe3)2]+, 579 {[Au2(SCMe3)(PMe3)2]+ – C4H8}, 273
[Au(PMe3)]+, 87 [BF4]–. The organic phase was evaporated to dry-
ness giving a solid from which ferrocene sublimates as yellow-
Complex 6d: Grey solid. Yield 79%. C80H78Au4B2F8P4S2 (2189.00):
calcd. C 43.9, H 3.6; found C 43.8, H 3.3. 1H NMR (CD3COCD3):
δ = 1.06 (d, 12 H, JH,H = 6.2 Hz, Me2), 1.86 (m, 2 H, JH,H = 6.4 Hz,
CH), 3.13 (d, 4 H, JH,H = 6.2 Hz, CH2), 7.3–7.8 (60 H, br. m,
PPh3) ppm. 31P NMR (CD3COCD3): δ = 35.00 ppm. ESI-MS
(MeOH): m/z = 1007 [Au2(SCH2CHMe2)(PPh3)2]+, 721 [Au-
(PPh3)2]+, 459 [Au(PPh3)]+.
1
orange crystals at 40 °C under high vacuum. H NMR (CD2Cl2):
δ = 4.18 ppm. The white residue was identified as (SCMe3)2. 1H
NMR(CD2Cl2): δ = 1.31 ppm.
Complex 5b: Colourless crystals. Yield 92%. C40H62Au4B2F8P4S2
(1692.43): calcd. C 28.4, H 3.7; found C 28.1, H 3.5. 1H NMR
(CD3COCD3): δ = 1.65 (s, 18 H, CMe3); 7.60 (m, 12 H, PPh); 7.95
Reaction of [Au(SCH2CMe3)(L)] (L = PMe3, PMe2Ph, PMePh2,
PPh3) with [FeCp2][BF4]. Formation of [Au4(SCH2CMe3)2(L)4]-
[BF4]2 (7a, 7b, 7c, 7d)
1
(m, 8 H, PPh) ppm. H NMR (CD2Cl2): δ = 1.67 (s, 18 H, CMe3),
1.93 (d, 24 H, JH,P = 11.0 Hz, PMe2), 7.62 (m, 20 H, PPh) ppm.
31P NMR (CD2Cl2): δ = 15.92 ppm. ESI-MS (methanol): m/z =
Complex 7a: crystallized from dichloromethane/n-hexane to give a
759 [Au2(SCMe3)(PMe2Ph)2]+, 703 {[Au2(SCMe3)(PMe2Ph)2]+
C4H8}.
–
beige product. Yield 90%. C22H58Au4B2F8P4S2 (1472.20): calcd. C
1
17.9, H 4.0; found C 17.7, H 3.8. H NMR (CD2Cl2): δ = 1.11 (s,
872
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© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2007, 865–875

Polynuclear AuI Phosphanyl Alkanethiolates
18 H, CMe3), 1.69 (d, 36 H, JH,P = 10,8 Hz, PMe3), 3.10 (s, 4 H, a few minutes the resulting spectra showed the disappearance of
FULL PAPER
CH2S) ppm. 1H NMR (CD3COCD3): δ = 1.12 (s, 18 H, CMe3),
1.82 (d, 36 H, JH,P = 11.3 Hz, PMe3), 3.19 (s, 4 H, CH2S) ppm.
31P NMR (CD2Cl2): δ = 2.96 ppm. ESI-MS (methanol): m/z 649
[Au2(SCH2CMe3)(PMe3)2]+, 349.1 [Au(PMe3)2]+, 87 [BF4]– ppm.
From the ethereal phase ferrocene and (SCH2CMe3)2 were isolated.
the starting products and the presence of the signals of pure
[Au(SC4H9)(PMe3)].
[Au(Me)(PMe3)]: LiMe (0.3 mL of a 1.6  solution in Et2O,
0.5 mmol) was added to a suspension of [Au(Cl)(PMe3)] (0.150 g,
0.5 mmol) in Et2O (10 mL) and kept at –10 °C. The solution be-
came yellow, then returned slowly to colourless. The reaction mix-
ture was kept for 30 min at –10 °C and then for 2 h at room tem-
perature. The mixture was cooled to 0 °C and was hydrolyzed with
H2O (10 mL). The ethereal phase was separated, desiccated over
anhydrous sodium sulfate and the solvents evaporated to dryness
under vacuum. A light grey solid was recovered (0.094 g, 65%),
which was stored away from the light. C4H12AuP (288.08): calcd.
C 16.68, H 4.20; found C 16.49, H 4.05. 1H NMR (C6D6): δ = 0.55
(9 H, d, JH,P = 8.4 Hz, PMe3), 1.26 (3 H, d, JH,H = 8.4 Hz,
CH3) ppm. 31P NMR (C6D6): δ = 12.35 ppm.
Complex 7b: Crystallized as off-white crystals from CH2Cl2. Yield
86%. C42H66Au4B2F8P4S2 (1720.49): calcd. C 29.3, H 3.9; found C
29.5, H 4.2. 1H NMR (CD2Cl2): δ = 1.15 (s, 18 H, CMe3), 1.93 (d,
6 H, JH,P = 12.8 Hz, PMe2), 3.20 (s, 4 H, CH2S), 7.67 (5 H, br. m,
PPh) ppm. 1H NMR (CD3COCD3): δ = 1.12 (s, 18 H, CMe3), 3.22
(s, 4 H, CH2S), 7.63 (3 H, br. m, PPh), 7.94 (2 H, br. m, PPh) ppm.
31P NMR (CD2Cl2): δ = 15.23 ppm.
Complex 7c: Crystallized from CH2Cl2. Yield 82%.
C62H74Au4B2F8P4S2 (1968.77): calcd. C 37.8, H 3.8; found C 37.7,
1
H 3.6. H NMR (CD2Cl2): δ = 1.17 (s, 18 H, CMe3), 2.19 (d, 3 H,
[Au(CH2CMe3)(PMe3)]: Li(CH2CMe3) (0.038 g, 0.49 mmol) was
added to a suspension of [Au(Cl)(PMe3)] (0.150 g, 0.49 mmol) in
diethyl ether (15 mL) and the reaction was carried out as above.
The mixture was then hydrolyzed with water (10 mL), the organic
phase was dried with Na2SO4, concentrated and kept overnight at
–20 °C. A white solid was obtained (0.149 g, 89%). C8H20AuP
JH,P = 9.2 Hz, PMe), 3.26 (s, 4 H, CH2S); 7.60 (10 H, br. m,
PPh2) ppm. 1H NMR (CD3COCD3): δ = 1.14 (s, 18 H, CMe3); 2.41
(s, 3 H, PMe), 3.37 (s, 4 H, CH2S), 7.58 (6 H, br. m, PPh2), 7.84
(4 H, br. m, PPh2) ppm. 31P NMR (CD2Cl2): δ = 28.32 ppm.
Complex 7d: Yellow crystals from dichloromethane/hexane. Yield
90%. C82H82Au4B2F8P4S2 (2217.05): calcd. C 44.4, H 3.7; found C
1
(344.19): calcd. C 27.92, H 5.86; found C 27.65, H 5.90. H NMR
1
44.5, H 3.9. H NMR (CD2Cl2): δ = 1.19 (s, 18 H, CMe3), 3.32 (s,
(C6D6): δ = 0.53 (d, 9 H, JH,P = 8.8 Hz, PMe3), 1.55 (s, 9 H, CH3),
4 H, CH2S), 7.44 (m, 15 H, PPh3) ppm.1H NMR (CD3COCD3): δ
= 1.16 (s, 18 H, CMe3), 3.46 (s, 4 H, CH2S), 7.51 (m, 15 H,
PPh3) ppm. 31P NMR (CD2Cl2): δ = 42.90 ppm.
1
2.10 (d, 2 H, JH,H = 8.8 Hz, CH2) ppm. H NMR (CD2Cl2): δ =
1.01 (s, 9 H, CH3), 1.23 (d, 2 H, JH,H = 8.4 Hz, CH2), 1.41 (d, 9
H, JH,P = 8.4 Hz, PMe3) ppm. 31P NMR (C6D6): δ = 13.16 ppm.
Reaction of [Au2(SR)2(dppe)] (R = CMe3, CH2CHMe2, CH2CMe3)
with [FeCp2][BF4]. Formation of [Au4(SR)2(dppe)2][BF4]2 (5e, 6e, 7e)
Reaction of [Au4(SCMe3)2(PMe3)4][BF4]2 with Methyllithium. For-
mation of [Au(SCMe3)(PMe3)] and [Au(Me)(PMe3)]: A large excess
of LiMe (0.5 mL of a 1.6  solution in Et2O, 0.8 mmol), was added
Complex 5e: pale yellow crystals. Yield 93%. C60H66Au4B2F8P4S2
to
a solution of [Au4(SCH2CHMe2)2(PMe3)4][BF4]2 (0.052 g,
(1936.69): calcd. C 37.2, H 3.4; found C 36.7, H 3.0. 1H NMR
0.04 mmol) in CH2Cl2 (15 mL). A white precipitate formed imme-
diately. The mixture was stirred for 2 h, and then water (10 mL) was
added. The organic layer was separated, desiccated over anhydrous
sodium sulfate, and was then evaporated to dryness to leave a light
yellow solid showing NMR spectra that are the sum of of both
(CD3COCD3): δ = 1.65 (s, 18 H, CMe3), 3.28 (d, 8 H, JH,P
=
13.2 Hz, PCH2), 7.72 (20 H, br. m, PPh2) ppm. 1H NMR
(200 MHz, CD2Cl2): δ = 1.58 (s, 18 H, CMe3), 2.97 (d, 8 H, JH,P
= 12.8 Hz, PCH2), 7.60 (20 H, br. m, PPh2) ppm. 1H NMR
(CD3OD): δ = 1.57 (s, 18 H, CMe3), 3.04 (d, 8 H, JH,P = 13.2 Hz,
PCH2), 7.62 (15 H, br. m, PPh2) ppm. 31P NMR (CD2Cl2): δ =
1
the signals of [Au(SCMe3)(PMe3)] and [Au(Me)(PMe3)]. H NMR
(C6D6): δ = 0.62 (d, 9 H, JP,H = 8.8 Hz, [Au(Me)PMe3], 1.20 (d, 3
H, JH,H = 8.4 Hz, CH3) [Au(Me)(PMe3)], 1.48 (s, 9 H, SCMe3),
1.57 (d, 9 H, JH,P = 10.3 Hz, SAuPMe3) ppm. 31P NMR (C6D6): δ
= 10.74 ([Au(Me)(PMe3)]), 2.95 ([Au(SCMe3)(PMe3)]) ppm.
37.87 ppm. ESI-MS (methanol): m/z
= 880.9 ([Au2(SCMe3)-
(dppe)]+), 1167 [Au3(SCMe3)2(dppe)]+, 87 [BF4]–.
Complex 6e: Pale grey solid. Yield 82%. C60H66Au4B2F8P4S2
(1936.69): calcd. C 37.2, H 3.4; found C 36.8, H 3.3. 1H NMR
(CD3COCD3): δ = 1.00 (d, 12 H, JH,H = 6.6 Hz, Me2), 1.84 (m, 2
H, JH,H = 6.6 Hz, CH), 2.84 (d, 4 H, JH,H = 5.9 Hz, CH2), 3.17
(m, 8 H, PCH2), 7.2–8.0 (40 H, br. m, PPh2) ppm. 31P NMR
(CD3COCD3): δ = 37.91 ppm.
Reaction of [Au4(SCMe3)2(PMe3)4][BF4]2 with Neopentyllithium.
Formation of [Au(SCMe3)(PMe3)] and [Au(CH2CMe3)(PMe3)]: So-
lid LiCH2CMe3 (0.004 g, 0.05 mmol) was added to a solution of
[Au4(SCMe3)2(PMe3)4][BF4]2 (0.034 g, 0.025 mmol) in CH2Cl2
(15 mL) kept at –20 °C. The mixture was warmed to room tempera-
ture. After stirring for 2 h water (10 mL) was added dropwise, the
organic phase was separated, dried with anhydrous sodium sulfate
and the solvents evaporated to dryness to give a light yellow solid
whose NMR spectra show both the signals of [Au(SCMe3)(PMe3)]
Complex 7e: Clear beige crystals. Yield 89%. C62H70Au4B2F8P4S2
(1964.74): calcd. C 37.9, H 3.6; found C 38.0, H 4.0. 1H NMR
(CD2Cl2): δ = 1.13 (s, 18 H, CMe3), 2.94 (d, 8 H, JH,P = 12.5 Hz
CH2P), 3.36 (s, 4 H, CH2S), 7.50 (20 H, br. m, PPh2) ppm. 1H
NMR (CD3COCD3): δ = 1.10 (s, 18 H, CMe3), 3.15 (d, 8 H, JH,P
= 13.2 Hz CH2P), 3.60 (s, 4 H, CH2S), 7.48 (m, 20 H, PPh2) ppm.
31P NMR (CD2Cl2): δ = 39.11 ppm. ESI-MS (methanol): m/z =
895 [Au2(SCMe3)(dppe)]+, 87 [BF4]–.
1
and [Au(CH2CMe3)(PMe3)]. H NMR (CD2Cl2): δ = 1.01 (s, 9 H,
CCMe3), 1.23 (d, 2 H, JH,H = 8.8 Hz, CH2), 1.41 (d, 9 H, JH,P
8.4 Hz, CAuPMe3), 1.48 (s, 9 H, SCMe3), 1.57 (d, 9 H, JH,P
=
=
10.3 Hz, SAuPMe3) ppm. 31P NMR (CD2Cl2):
δ = 2.95
([Au(SCMe3)(PMe3)]); 16.58 ([Au(CH2CMe3)(PMe3)]) ppm.
Reaction of [Au4(SC4H9)2(PMe3)4][BF4]2 with 2-Methyl-2-pro-
panethiol in the Presence of Ethanolamine: The reaction was moni-
tored by H NMR spectroscopy. Two NMR tubes were prepared
containing a solution of [Au4(SC4H9)2(PMe3)4][BF4]2 (0.010 g,
X-ray Diffraction: Crystals of 1c, 1e and 3d were obtained by cool-
ing toluene solutions, and 5e and 7a were obtained from dichloro-
methane/pentane solutions. The X-ray diffraction experiments were
1
0.0069 mmol) in CD2Cl2 (0.5 mL) and a solution of 2-methyl-2- carried out at room temperature (T = 293 K) by means of a Bruker
propanethiol (0.0138 mmol) and ethanolamine (0.0138 mmol) in P4 diffractometer by operating with a graphite-monochromated
CD2Cl2 (0.5 mL). After recording the NMR spectra of the two Mo-Kα radiation. The samples were sealed in glass capillaries under
samples as a blank the two solutions were added together and after an atmosphere of dinitrogen. The intensity data collection was car-
Eur. J. Inorg. Chem. 2007, 865–875
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
873

A. Battisti, O. Bellina, P. Diversi, S. Losi, F. Marchetti, P. Zanello
FULL PAPER
Table 5. Crystal data and structure refinements.
1c
1e·diethyl ether
3d
5e·CH2Cl2
7a
Empirical formula
C17H22AuPS
486.34
C38H52Au2OP2S2
1044.79
C23H26AuPS
562.43
C61H68Au4B2Cl2F8P4S2 C22H58Au4B2F8P4S2
Formula mass [gmol–1]
2021.54
monoclinic
C2/c (No. 15)
23.652(4)
17.030(2)
19.806(3)
–
1472.17
orthorhombic
Pnnm (No. 58)
10.320(1)
10.511(1)
20.637(2)
–
Crystal system
Space group
a [Å]
b [Å]
c [Å]
α [°]
β [°]
triclinic
triclinic
monoclinic
P21/n (No. 14)
12.896(2)
14.001(3)
12.958(2)
–
109.43(1)
–
2206.4(7)
4
¯
¯
P1 (No. 2)
P1 (No. 2)
7.881(1)
11.149(1)
12.122(1)
106.701(7)
105.168(9)
106.092(9)
910.3(2)
2
8.986(2)
10.837(1)
11.449(2)
94.423(9)
90.51(1)
109.33(1)
1048.2(3)
1
121.96(1)
–
–
–
γ [°]
V [Å3]
6768.4(17)
4
1.984
2238.6(4)
2
2.184
Z
Dcalc [Mgm–3]
µ [mm–1]
No. measured
1.774
8.272
4082
1.655
7.192
4700
1.693
6.839
4834
8.937
7672
13.349
3107
No. unique [Rint
]
3306 [0.0431]
185
0.0305, 0.0696
0.0386, 0.0729
1.042
3897 [0.0313]
195
0.0436, 0.1042
0.0687, 0.1147
1.071
3982 [0.0496]
236
0.0510, 0.1077
0.0976, 0.1268
1.012
6654 [0.0694]
343
0.0662, 0.1199
0.1619, 0.1533
0.979
2382 [0.0570]
73
0.0565, 0.1196
0.1194, 0.1454
1.003
No. parameters
R1, wR2 [IϾ2σ(I)][a]
R1, wR2 [all data][a]
Goodness of fit[a] on F2
[a] R(Fo) = Σ||Fo| – |Fc||/Σ|Fo|; Rw(Fo2) = {Σ[w(Fo – Fc ) ]/Σ[w(Fo2)2]}1/2; w = 1/[σ2(Fo2) + (AQ)2 + BQ] where Q = [MAX(Fo2,0) + 2Fc ]/
2
2 2
2
2
2 2
3; GOF = {Σ[w(Fo – Fc ) ]/(N – P)}1/2, where N, P are the numbers of observations and parameters, respectively.
ried out with the ω/2θ scan mode, collecting a redundant set of
data. Three standard reflections were measured every 97 measure-
ments to for check sample decay. The intensities were corrected for
Lorentz and polarization effects and for absorption. In the case of
1e and 7a the absorption correction was made by means of an
integration method based on the crystal habit.[22] For 1e, 3d and
5e, the crystal fragments used in the data collection were rather
irregular, therefore a precise numerical correction was impossible
and a semi-empirical method was used.[22] The structure solutions
were obtained by means of the automatic direct methods contained
in the SHELXS97 program.[23] The refinement, based on full-ma-
trix least-squares on F2, were done by means of the SHELXL97
program.[22] Some other utilities contained in the WINGX suite
were also used.[24] The more relevant crystal parameters are listed
in Table 1.
The asymmetric unit of compound 5e is made up of one half of
the cation [Au4(StBu)2(dppe)2]2+ located on the twofold axis, one
half of a dichloromethane molecule similarly located on the twofold
–
–
axis and one BF4 anion. The BF4 anion presents a remarkable
disorder and was refined as a rigid group distributed on two limit
positions with variable occupancy, fixing the total occupancy to
1.0. The hydrogen atoms were placed in calculated positions and
were allowed to “ride” on the connected carbon atoms. Anisotropic
thermal parameters were used for all the heavy atoms, excluding
those of the disordered anion. The reliability factors obtained in
the last refinement cycle are listed in Table 5.
The asymmetric unit of compound 7a is made up of one fourth of
the cation [Au4(SCH2tBu)2(PMe3)4]2+, with 2/m symmetry and one
BF4– anion located on the twofold axis. Both the –PMe3 group and
the anion present a remarkable disorder. The –PMe3 group was
refined as a rigid group distributed, with different occupancy, on
two positions related by rotation around the Au–P bond; the occu-
pancies were refined fixing the total occupancy to 1.0. The disorder
of the tetrahedral anion was instead due to a misalignment between
the twofold axis of the crystal and the corresponding operator of
The asymmetric unit of compound 1c consists of one molecule
[Au(StBu)(PMePh2)]. The hydrogen atoms were placed in calcu-
lated positions and during the refinement were allowed to “ride”
on the connected carbon atoms. In the last of the refinement cycles
all the heavy atoms were refined with anisotropic thermal param-
eters obtaining the reliability factors listed in Table 5.
–
the group. The BF4 unit was therefore simply introduced in the
model with occupancy 1/2. The hydrogen atoms were placed in
calculated positions and were allowed to “ride” on the connected
carbon atoms. Anisotropic thermal parameters were used for all
the heavy atoms, excluding those of the disordered groups. The
reliability factors obtained in the last refinement cycle are listed in
Table 5.
The asymmetric unit of compound 1e consists of one half of the
molecule [Au2(StBu)2(dppe)] riding the inversion centre. A series
of maxima around another inversion centre was interpreted as a
disordered ethyl ether molecule. The maxima were fitted with the
positional parameters of a well-refined ethyl ether molecule from
the literature and were refined as a rigid group with isotropic ther-
mal parameters. The hydrogen atoms were placed in calculated po- CCDC-603883 (for 1c), -603884 (for 1e), -603885 (for 3d), -603886
sitions and anisotropic thermal parameters were used for the heavy
atoms of the main molecule. The reliability factors obtained in the
last refinement cycle are listed in Table 5.
(for 5e) and -603887 (for 7a) contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
The asymmetric unit of compound 3d consists of one molecule
[Au(SCH2tBu)(PPh3)]. The hydrogen atoms were placed in calcu-
lated positions and during the refinement were allowed to “ride”
on the connected carbon atoms. In the last of the refinement cycles
all the heavy atoms were refined with anisotropic thermal param-
eters thus obtaining the reliability factors listed in Table 5.
Supporting Information (see also the footnote on the first page of
this article): Additional figures for compounds 1c, 1e, 3d, 5e and
7a (crystal structure, cyclic voltammogram) and a table relating
electrochemical behaviour and the inductive electronic effects of the
ligands are available.
874
www.eurjic.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2007, 865–875

Polynuclear AuI Phosphanyl Alkanethiolates
FULL PAPER
Chem. 1998, 561, 1; c) B.-C. Tzeng, A. Schier, H. Schmidbaur,
Inorg. Chem. 1999, 38, 3978; d) D. R. Smyth, B. R. Vincent,
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Acknowledgments
We thank Ceramvetro (Florence) for the generous gift of gold.
P. Zanello gratefully acknowledges the financial support of the
Università di Siena (PAR 2005).
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Received: October 4, 2006
Published Online: January 12, 2007
Eur. J. Inorg. Chem. 2007, 865–875
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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