Synthesis and properties of alkynethiolate gold(i) complexes

Article abstract of DOI:10.1039/b708966j

A series of alkynethiolate gold(i) derivatives have been synthesised by the cleavage of 4-monosubstituted 1,2,3-thiadiazoles in the presence of strong bases. The syntheses of the 1,2,3-thiadiazoles with p-cyanophenyl, p-tolyl, 2-thienyl, 3-thienyl and 9,9-dimethylfluoren-2-yl fragments are also described. All the complexes have been characterised by spectroscopic techniques and the complexes [Au(p-CH₃-C₆H₄-CC-S)PPh₃], [Au(3-C₄H₃S-CC-S)PPh₃] and PPN[Au(p-CH ₃-C₆H₄-CC-S)(C₆F₅)] by X-ray analysis. The electrochemically polymerizable mononuclear bis(alkynethiolate) gold(i) complex PPN[Au(3-C₄H₃S-CC-S) ₂] is also described, including its electropolymerization and electrochemical properties. This journal is The Royal Society of Chemistry.

Full text of DOI:10.1039/b708966j

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www.rsc.org/dalton | Dalton Transactions
Synthesis and properties of alkynethiolate gold(I) complexes†
Nora Lardie´s,a Inocencio Romeo,a Elena Cerrada,*a Mariano Laguna*a and Peter J. Skabarab
Received 14th June 2007, Accepted 21st September 2007
First published as an Advance Article on the web 12th October 2007
DOI: 10.1039/b708966j
A series of alkynethiolate gold(I) derivatives have been synthesised by the cleavage of
4-monosubstituted 1,2,3-thiadiazoles in the presence of strong bases. The syntheses of the
1,2,3-thiadiazoles with p-cyanophenyl, p-tolyl, 2-thienyl, 3-thienyl and 9,9-dimethylfluoren-2-yl
fragments are also described. All the complexes have been characterised by spectroscopic techniques
and the complexes [Au(p-CH3–C6H4–C≡C–S)PPh3], [Au(3-C4H3S–C≡C–S)PPh3] and
PPN[Au(p-CH3–C6H4–C≡C–S)(C6F5)] by X-ray analysis. The electrochemically polymerizable
mononuclear bis(alkynethiolate) gold(I) complex PPN[Au(3-C4H3S–C≡C–S)2] is also described,
including its electropolymerization and electrochemical properties.
An effective way of obtaining the alkynylthiolates is the
Introduction
ring cleavage of 4-monosubstituted 1,2,3-thiadiazoles with lib-
eration of nitrogen in the presence of strong bases such as
organolithium reagents, sodamide, sodium hydride and potassium
tert-butoxide.21,22 1,2,3-Thiadiazoles are an interesting class of
compounds not only as they are useful intermediates in or-
ganic synthesis but also for being important pharmacophores:
their cephalosporin derivatives exhibit antimicrobial activity,23
and compounds with a terminal 1,2,3-thiadiazole moiety are
antipsychotic agents,24 platelet-activating factors,25 angiotensin
II receptor antagonists26 and 4,5-disubstituted-1,2,3-thiadiazole
compounds have been tested as potent anticancer reagents.27
Many methods have been developed for the synthesis of 1,2,3-
thiadiazoles,28,29 of which we have chosen the Hurd–Mori
cyclization of a-methylene ketones as the most convenient
methodology.30,31 In this paper we describe the synthesis of 1,2,3-
thiadiazoles with the groups mentioned above.
We also report herein the synthesis of a metallopolymer
by electropolymerization using a 1,2,3-thiadiazole with a 3-
thienyl substituent as the starting material. Transition-metal–
polythiophene derivatives are an interesting group of materials
within the rapidly growing class that consists of conjugated
polymers with transition metals linked to or directly incorporated
into the p-conjugated polymer backbone. They are of particular
interest since they allow the electronic, optical and catalytic
properties of metal complexes to be incorporated within a
polymer film that can be deposited in precise locations. A few
metallopolymers with thiophene backbones have been described
to date, and these include structures based on dithiolenes,32–34
bithiophene-bithiazoles,35 azaferrocenes36 and terpyridines.37,38 To
the best of our knowledge the reported metallopolymer is the first
example with alkynethiolate units.
Transition metal chemistry with organosulfur ligands is an at-
tractive subject due to its relevance in biological, industrial and
environmental applications.1–4 The metal chemistry of alkynethi-
olate is almost unknown compared with the related aryl or
alkyl thiolates, although alkynethiolate compounds are known
as important intermediates in the synthesis of basic organic
compounds like dithiolenes5,6 and tetrathiafulvalenes,7,8 which are
excellent starting materials for the building of more complicated
coordination solids. This is probably because of the difficulty
in the synthesis of the ligands and the low yield and stability
of the synthesized complexes. Only a few complexes containing
alkynethiolate ligands are known.9–20 These ligands have the
special ability to be bound to a single or multi-metal centre
at both sulfur and alkyne portions, whilst the presence of a
reactive carbon–carbon triple bond adjacent to the chalcogen
atom coordinated at a transition metal affords the possibility
of chemical transformations at the ligands. Examples of such
transformations include trinuclear [Cp2Ti(l-SC≡CPh)2]2Ni with
a linear Ti2Ni spine,11 dinuclear derivatives [(C5H4SiMe3)2Ti(l-
SC≡CR)2MLn] (MLn = Mo(CO)4, Pd(C6F5)2, Pt(C6F5)2); [(C5H4-
5
SiMe3 )Ti( l - g :jP - C5H4PPh2 ) ( SC≡CtBu ) ( l - C≡CtBu )MLn ]
(MLn = Mo(CO)3, Pd(C6F5)2, Pt(C6F5)2)12 and [CpRu(PPh3)-
(C≡CPh)(l-E)ZrCp2] (E = S, Se)13 with a sulfur bridging the two
metallic centres.
In this paper we report on the preparation of some mononu-
clear alkynethiolate gold(I) complexes containing the fragments
p-cyanophenyl, p-tolyl, 2-thienyl, 3-thienyl and 9,9-dimethyl-
1
fluoren-2-yl, with the alkynethiolate acting as a g -(S) bonded
ligand. We also describe the preparation of some dinuclear struc-
tures where the two metal atoms are bridged by bis(phosphines)
such as bis(diphenylphosphine)methane, dppm or bis(diphenyl-
phosphine)ethane, dppe.
Results and discussion
aDepartamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales
de Arago´n, Universidad de Zaragoza-C.S.I.C., E-50009 Zaragoza, Spain
1,2,3-Thiadiazoles
bWestCHEM, Department of Pure and Applied Chemistry, University of
Strachclyde, Glasgow, UK G1 1XL
The method of Hurd and Mori30 gives access to 5-unsubstituted
1,2,3-thiadiazoles, and consists of reacting methyl ketones with
ethyl carbazate (or tosylhydrazide) to form acetylhydrazones (a
† CCDC reference numbers 650741–650743. For crystallographic data in
CIF or other electronic format see DOI: 10.1039/b708966j
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Scheme 1 General synthesis of 1,2,3-thiadiazoles and monoalkynethiolates.
stable intermediate which was not isolated) and successively with
thionyl chloride (Scheme 1). 4-(p-Cyanophenyl)-1,2,3-thiadiazole
(1) and 4-(p-tolyl)-1,2,3-thiadiazole (2) were previously synthe-
sized by us.39,40 Subsequently, we extended this work to new
thiadiazoles using 2-thiophene and 3-thiophene as ligands (3
and 4) considering the interesting properties that thiophene
ligands can contribute to alkynethiolate and dithiolene complexes.
Thiadiazole 5 was chosen in order to improve the solubility of the
final alkynethiolate complexes that would then allow the growth
of suitable crystals for X-ray diffraction.
Clausen and Becher5 have already reported the synthesis
of thiadiazoles 1, 3 and 4 using a similar procedure as the
one we described here. All the methyl ketones used as start-
ing materials were commercially available apart from 2-acetyl-
9,9-dimethylfluorene (5-P2) which was obtained as shown in
Scheme 2.
The main feature in 1,2,3-thiadiazole compounds is the
deshielded, low field signal observed in their H NMR for the
aromatic proton (Hx) (Table 1).
1
Alkynethiolate gold(I) complexes
1,2,3-Thiadiazoles unsubstituted at the 5-position, described
above, were cleanly decomposed into alkynethiolates under the
t
influence of strong bases. The chosen conditions were BuOK
(0 ◦C in THF), n-BuLi (−65 ◦C in THF) or LiN(SiMe3)2 (0 ◦C in
THF) always under an argon atmosphere. Alkynethiolate ligands
act as nucleophiles (donor S) and gold(I) compounds are very
suitable for the formation of alkynethiolate complexes. Thus, we
have obtained mono and bis(alkynethiolate) gold(I) complexes by
addition of [AuClL], L = PPh3, PPh2Me, PPhMe2, PMe3, AsPh3
or PPN[AuCl(C6F5)] and the dinuclear derivatives [Au2Cl2(dppm)]
and [Au2Cl2(dppe)] (dppm = bis(diphenylphosphine)methane,
dppe = bis(dipehnylphosphine)ethane) (Scheme 1). In spite of
many attempts to react [Au2Cl2(dppm)] we were only able to obtain
the bis(alkynethiolate) gold(I) complex 12a (with the ligand p-
cyanophenyl) and we also found some difficulties with its analogue
[Au2Cl2(dppe)]. Therefore, we tried an alternative synthesis taking
advantage of the fact that the arsine is easily displaced by a
Scheme 2 (i) tBuOK/THF, (ii) CH3I, (iii) AlCl3/CH3COCl in CH2Cl2.
5330 | Dalton Trans., 2007, 5329–5338
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Table 1 Yields, mass spectra and 1H NMR (Hx) data of 1,2,3-thiadiazoles
R
Product Yields (%) m/z M+ (%)
1H NMR (Hx)
8.78 (s, 1H)
1
2
3
89
80
65
187 (38)
176 (42)
168 (22)
Fig. 1 Crystal structure of [Au(p-CH3–C6H4–C≡C–S)PPh3] (7a). Ther-
mal ellipsoids are drawn at the 50% probability level and H atoms have
been omitted for clarity.
8.59 (s, 1H)
8.50 (s, 1H)
4
5
50
83
168 (100)
279 (100)
8.51 (s, 1H)
8.65 (s, 1H)
phosphine. We succeeded in affording the two compounds shown
in Scheme 3. Unfortunately, all reactions carried out between every
alkynethiolate and dppm failed.
Fig. 2 Crystal packing of [Au(p-CH3–C6H4–C≡C–S)PPh3] (7a) perpen-
dicular to XY plane.
Scheme 3 Alternative synthesis to obtain bis(alkynethiolate) compounds.
The spectroscopic data (IR, 1H, 31P NMR) of all the mono and
dialkynethiolates are in agreement with their formulation. Thus,
their IR spectra show strong C≡C stretching bands between 2123
and 2152 cm−1. In the case of complex 11 the presence of the
C6F5 group is confirmed by the signals centered at −116.7 (d, Fo),
Fig. 3 Crystal structure of PPN[Au(p-CH3–C6H4–C≡C–S)(C6F5)] (11)
showing the anion. Thermal ellipsoids are drawn at the 50% probability
level and H atoms have been omitted for clarity.
1
−164.9 (t, Fp) and −166.1 (m, Fm) in the 19F NMR. Their 31P{ H}
NMR spectra show one signal indicating the presence of only one
compound apart from the dialkynethiolate 14b, which shows a
typical AB system. This can be due to some kind of impediment
in the phosphorus movement.
In general, all the alkynethiolate compounds presented here
are quite stable but they can decompose under humidity or
acid conditions to yield metallic gold and dithiafulvenes5,6 (by
dimerization between an alkynethiol and thioketene). When the
ligand L is triphenylarsine this decomposition process was faster
and metallic gold was shown even during the reaction, therefore
it was necessary to shorten the reaction times and to keep the
temperature to zero degrees.
The structure of [Au(p-CH3–C6H4–C≡C–S)PPh3] (7a),
PPN[Au(p-CH3–C6H4–C≡C–S)(C6F5)] (11) and [Au(3-C4H3S–
C≡C–S)PPh3] (9a) were confirmed by X-ray diffraction.
Perspective drawings of the structures are shown in Fig. 1–4
respectively. Bond distances and angles data are collected in
Tables 2–4.
Fig. 4 Crystal structure of complex [Au(3-C4H3S–C≡C–S)PPh3] (9a).
Thermal ellipsoids are drawn at the 50% probability level and H atoms
have been omitted for clarity.
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◦
˚
˚
Table 2 Bond lengths (A) and angles ( ) for [Au(p-CH3–C6H4–C≡C–S)-
PPh3] (7a)
(1.205(6) A) and the C–S–Au angle is smaller by more than five
degrees (106.72(13)◦ in 7a and 101.33(17)◦ in 11). This fact may be
attributed to the lower degree of steric hindrance arising from the
pentafluorophenyl group in the second structure, compared with
triphenyl phosphine.
Au(1)–P(1)
Au(1)–S(1)
S(1)–C(19)
2.2659(12)
2.3152(12)
1.686(4)
S(1)–C(19)
C(19)–C(20)
C(20)–C(21)
1.686(4)
1.205(6)
1.442(6)
˚
It is worth noting the presence of short interactions (3.229 A)
P(1)–Au(1)–S(1)
C(13)–P(1)–Au(1)
C(19)–S(1)–Au(1)
C(7)–P(1)–Au(1)
175.50(4)
111.50(12)
106.72(13)
113.54(12)
C(1)–P(1)–Au(1)
C(20)–C(19)–S(1)
C(19)–C(20)–C(21)
113.72(13)
173.9(4)
178.6(5)
between the metallic center and the H atoms of the phenyl ring
of the alkynethiolate in complex 7a. In the packing view the
molecules are stacked in such a way to allow enough space for
the bulky triphenylphosphine ligands (Fig. 2).
Complex 9a crystallizes in the triclinic space group P1 with two
independent molecules in the asymmetric unit joined through a
¯
◦
˚
Table 3 Bond lengths (A) and angles ( ) for PPN[Au(p-CH3–C6H4–
C≡C–S)(C6F5)] (11)
˚
˚
short Au · · · Au interaction of 3.0542(5) A which is shorter than
50–52
Au(1)–C(10)
Au(1)–S(1)
S(1)–C(1)
2.037(5)
2.3137(18)
1.686(6)
C(1)–C(2)
C(2)–C(3)
1.173(7)
1.464(7)
the sum of the van der Waals radii (3.60 A)
(Fig. 4).
Coordination around the metallic center is nearly linear in
both molecules although one of the molecules shows a larger
deviation from linearity [P1–Au1–S1, 173.46(8)◦ and P2–Au2–S2,
175.38(8)◦]. Disorder was observed in both thiophene fragments,
in the form of two-fold rotation of the group about its longitudinal
axis. The principal effect of the disorder was to generate co-generic
S,C sites for both termini; but in one of the moieties an adjacent
carbon atom was also split into two partially occupied sites. The
C(10)–Au(1)–S(1)
C(1)–S(1)–Au(1)
C(2)–C(1)–S(1)
177.27(14)
101.33(17)
178.8(4)
C(1)–C(2)–C(3)
C(15)–C(10)–Au(1)
C(11)–C(10)–Au(1)
177.5(5)
123.9(4)
122.7(4)
◦
˚
Table 4 Bond lengths (A) and angles ( ) for [Au(3-C4H3S–C≡C–S)PPh3]2
(9a)
˚
bond lengths S–C [1.695(11), 1.659(10) A] and C≡C [1.174(13),
◦
Au(1)–P(1)
Au(1)–S(1)
Au(1)–Au(2)
Au(2)–P(2)
Au(2)–S(2)
2.268(2)
2.326(2)
3.0542(5)
2.2649(18)
2.3380(18)
C(1)–C(2)
C(7)–C(8)
S(1)–C(1)
S(2)–C(7)
1.174(13)
1.223(13)
1.695(11)
1.659(10)
˚
1.223(13) A] and angles S–C–C [175.1(9), 179.5(9) ] and C–C–C
[173.0(10), 174.0(9)◦] found within the alkynethiolate fragments
in both molecules show no unusual features, being quite similar to
those found in complexes 7a and 11. Despite the presence of short
gold–gold contacts, complex 9a does not show emissive properties.
In the case of the 4-(2-thienyl)-1,2,3-thiadiazol (3) we have
prepared a mononuclear bis(alkynethiolate) gold(I) derivative
(Scheme 4), which is susceptible to polymerization, giving a linear
metallopolymer through the thiophene units (Chart 1).
P(1)–Au(1)–S(1)
P(1)–Au(1)–Au(2)
S(1)–Au(1)–Au(2)
P(2)–Au(2)–S(2)
P(2)–Au(2)–Au(1)
S(2)–Au(2)–Au(1)
173.46(8)
107.85(6)
77.98(6)
175.38(8)
105.91(5)
78.57(5)
C(1)–S(1)–Au(1)
C(7)–S(2)–Au(2)
C(2)–C(1)–S(1)
C(1)–C(2)–C(3)
C(8)–C(7)–S(2)
C(7)–C(8)-C(9)
106.1(3)
100.8(3)
175.1(9)
173.0(10)
179.5(9)
174.0(9)
Complexes 7a and 11 show similar structures, namely, mononu-
clear derivatives with the gold(I) center coordinated to one p-
tolyl-alkynethiolate ligand in addition to a triphenylphosphine
in the case of 7a and a pentafluorophenyl group in 11. Both
molecules display the metallic center in a roughly linear co-
ordination (175.50(4)◦ and 177.27(14)◦ respectively) which is
characteristic in gold(I) derivatives. The Au–P and Au–S bond
Scheme 4 Synthesis of complex 17.
˚
lengths [2.2659(12) and 2.3152(12) A] in 7a are typical for gold(I)
complexes with thiolate and phosphine ligands.41–47 The Au–C and
˚
Au–S distances in 11 [2.037(5) and 2.3137(18) A] are in the same
range as those observed in pentafluorophenyl and thiolate gold(I)
complexes.48, 49 The geometric parameters of the SC≡CC6H4Me
˚
group are normal. Thus, the C≡C distance of 1.205(6) A in 7a
Chart 1 Proposed structure for the metallopolymer poly(17).
˚
and 1.173(7) A in 11 fall in the range of carbon–carbon triple
bonds and both S–C–C and C–C–C bonds are practically linear
[173.9(4)◦, 178.6(5)◦ in 7a and 178.8(4)◦, 177.5(5)◦ in 11]. These
distances are quite similar to those found in other alkynethio-
The redox properties of complex 17 have been studied by cyclic
voltammetry in dichloromethane (vs. Ag/AgCl) under argon,
using a glassy carbon disc working electrode and platinum wire
5
18
late derivatives: [(g -C5H5)Fe(CO)2(SC≡CSiMe3)] (1.205(4) A),
counter electrode, with a substrate concentration of 10−3
M
˚
t
14,15
˚
[Pt(PPh3)2(SC≡CR)2] (R = Me, Bu) (1.17 A in average),
and tetrabutylammonium hexafluorophosphate as the supporting
electrolyte. Only two irreversible electrochemical processes are
observed, one oxidation at +0.8 V, associated with the thiophene
ring and one reduction at −1.48 V (Fig. 5).
13
5
˚
[CpRu(PPh3)2(SC≡CR)] (1.209 A in average), [Ti(g -C5H4-
t
12
˚
SiMe3)2(SC≡C Bu)2] (1.144(14) A), [TiCp2(XC≡CPh)] (Cp =
11
˚
C5H5, MeC5H4; X = S, Se)(1.188(8) A). On comparison of both
structures, there are significant differences in the C–C triple bond
distances and the C–S–Au angles. Thus, the C–C bond length is
Electropolymerization was achieved by repetitive cycling over
the oxidation wave of the monomer (Fig. 6) over th◦e range 0.0 to
+1.1 V on ITO glass working electrodes and at 0 C to prevent
˚
considerably shorter in 11 (1.173(7) A) than that observed in 7a
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possible to calculate the optical band gap from the absorption
spectrum obtained from the deposited films on ITO glass (Fig. 7),
because of the long tail of the absorption peak, which extends
over the broad range of 400–950 nm. It is likely that the diffuse
absorption characteristics are a consequence of a range of different
conformers within the polymer chain. Polymer poly(17) does not
display luminescence properties.
Fig. 5 Cyclic voltammogram of 17 (solid line) and poly(17) (dashed line)
on glassy carbon working electrode respectively.
Fig. 7 Absorption spectra of 17 in CH2Cl2 (−) and poly(17) ( · · · )
deposited on ITO glass.
In summary, a family of alkynethiolate gold(I) derivatives
containing the fragments p-cyanophenyl, p-tolyl, 2-thienyl, 3-
thienyl and 9,9-dimethylfluoren-2-yl, have been synthesized by
preparing ‘in situ’ the alkynethiolate anions by ring cleavage of
the 1,2,3-thiadiazoles in the presence of strong bases. In all cases
1
the alkynethiolate is acting as a g -(S) bonded ligand and in the
particular case of [Au(p-CH3–C6H4–C≡C–S)PPh3], [Au(3-C4H3S–
C≡C–S)PPh3] and PPN[Au(p-CH3–C6H4–C≡C–S)(C6F5)] the
structure was confirmed by X-ray analysis. Higher nuclearities
have been obtained by using the bis(diphenylphosphine)s dppm
and dppe which permit the isolation of dinuclear derivatives.
Fig. 6 Polymerization of 17 on ITO glass working electrode at a scan
rate of 100 mV. Inset: plot of scan rate (origin of scan rate 25 mV s−1) vs.
maximum peak current of Eox.
decomposition of the polymer (poly(17)). The experiments were
run on a polymer coated electrode in monomer free solution.
The voltammogram displays the emergence of a new irreversible
redox wave indicative of the electrodeposition of the polymer
in dichloromethane on the working electrode. Deposition of a
thin dark brown, nearly black film on the working electrode
corresponding to the polymer is also observed. The relationship
between the maximum peak current and the scan rate (Fig. 6) is
linear (correlation coefficient r > 0.999) and is indicative of a redox
active polymer attached to an electrode surface.
The cyclic voltammogram of poly(17) is depicted in Fig. 5
(dashed line). There are two irreversible reductions at −0.92 and
−1.21 V and one irreversible oxidation at +0.34 V, shifted to a
lower potential by 0.46 V compared to the monomer. This fact
reveals a stronger electron donor character of the polymer in
accordance with a higher conjugation. The organic segment of
the polymer is restricted to a repeat unit consisting of acetylene–
bithiophene–acetylene fragments. A short conjugated chain of
this length would not be expected to give such a low oxidation
potential,53 indicating that there is indeed a significant degree of
conjugation throughout the entire chain involving the Au centers.
The electrochemical band gap of the polymer estimated from
the difference between the onset potentials for the reduction and
the oxidation process is ca. 0.9 eV.
Experimental
General procedures and materials
All reactions and product manipulations were performed under an
atmosphere of argon using standard Schlenk techniques. THF was
dried over and distilled from Na. NMR spectra were recorded on a
Varian Gemini 300 MHz or a Bruker ARX 400 MHz spectrometer,
IR spectra measured with Perkin-Elmer 883 or Perkin-Elmer FT-
IR Espectrum One, KBr pellets and mass spectra were obtained
with a VG Autospec mass spectrometer operating in Electron
Impact (EI) mode and Liquid Secondary Ion Mass Spectrometry
(LSIMS) mode. Elemental compositions were analysed with a
Perkin Elmer 240B or Perkin Elmer 2400B. Cyclic voltammetry
was performed on CH instruments 660A and EG&G PAR
273A electrochemical workstations with iR compensation using
Ag/AgCl as the reference electrode. Absorption spectroscopy
was carried out on a Unicam UV 300 spectrophotometer.
[AuCl(PPh3)], [AuCl(PPh2Me)], [AuCl(PPhMe2)], [AuCl(PMe3)],
[AuCl(AsPh3)], [Au2Cl2(l-dppe)], [Au2Cl2(l-dppm)], PPN[AuCl2]
and PPN[AuCl(C6F5)] were synthesized by replacement of tht
from [AuCl(tht)]54 or [Au(C6F5)(tht)]55 with the appropriate phos-
phine or PPNCl.
The electronic absorption spectrum of the monomer displays
two bands with maxima at 274 and 301 nm, whilst that of the
polymer has a peak at ca. 390 nm. For the polymer it was not
Synthesis of 4-(p-cyanophenyl)-1,2,3-thiadiazole (1). p-Cyano-
acetophenone (12.34 g, 85 mmol) and ethylcarbazate (8.85 g,
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85 mmol) were dissolved in toluene (75 ml), with a catalytic
amount of p-toluenesulfonic acid, in a Dean–Stark apparatus.
The solution was refluxed until no more water condensed (ca. 3 h).
The solvent was evaporated under vacuum and after cooling on a
water-ice bath, SOCl2 (80 ml) was added dropwise. The water-ice
bath was removed, with caution because of the HCl gas evolved,
allowing the solution to warm to room temperature and stand
overnight. Residual SOCl2 was evaporated in vacuo. The residue
was dissolved in dichloromethane, washed with water twice and
filtered through silica. Evaporation gave 4-(p-cyanophenyl)-1,2,3-
thiadiazole as a white compound (89%). Found: C, 57.31; H, 2.62;
N, 22.48; S, 16.96. C9H5N3S requires C, 57.70; H, 2.70; N, 22.44;
S, 17.13; m/cm−1: 2231 (C≡N) (KBr); dH (CDCl3): 8.78 (1H, s),
8.17 (2H, d, J = 8.0 Hz), 7.79 (2H, d, J = 8.0 Hz); m/z 187 ([M]+,
38%), 159 ([M − 2N]+, 100%) (LSIMS+).
(2.06 ml, 29 mmol) in dry dichloromethane (20 ml) (Friedel–Crafts
conditions). The reaction mixture was stirred overnight at room
temperature and then washed with water and dried with MgSO4.
The solvent was removed in vacuo and the residue was purified by
column chromatography (silica, dichloromethane–hexane 60 : 40)
to yield an orange oil (78%). Found: C, 86.22; H, 6.70. C17H16O
requires C, 86.33; H, 6.77. dH (CDCl3): 8.11 (1H, s), 8.03–8.00
(1H, dd, J = 7.9; 1.8 Hz), 7.84–7.81 (2H, m), 7.53–7.51(1H, m),
7.45–7.40 (2H, m), 2.71 (3H, s), 1.57 (6H, s); m/z 237 ([M]+, 100%)
(LSIMS+).
Synthesis of 4-(9,9-dimethylfluoren-2-yl)-1,2,3-thiadiazole (5).
Compound 5 was prepared by a procedure similar to 1 using
2-acetyl-9,9-dimethylfluorene 5-P2 (5.91 g, 25 mmol). Pale brown
solid (83%). Found: C, 72.99; H, 4.74; N, 9.82; S, 11.06. C17H14N2S
requires C, 73.38; H, 5.04; N, 10.07; S, 11.51; dH (CDCl3): 8.65 (1H,
s), 8.17 (1H, s), 7.97–7.93 (1H, dd, J = 8.1; 1.8 Hz), 7.82–7.73 (2H,
m), 7.46–7.43 (1H, m), 7.36–7.31 (2H, m), 1.53 (6H, s); m/z 279
([M]+, 100%) (LSIMS+).
Synthesis of 4-(p-tolyl)-1,2,3-thiadiazole (2). Compound 2 was
prepared by a procedure similar to 1 using p-methylacetophenone
(11.42 g, 85 mmol). Once the SOCl2 was evaporated the residue was
crystallized in a mixture hexane–diethyl ether (1 : 1). The solid was
dissolved in diethyl ether and filtered through silica and activated
carbon. Evaporation gave the product as white solid (80%). Found:
C, 61.18; H, 4.42; N, 15.89; S, 17.76. C9H8N2S requires C, 61.35;
H, 4.65; N, 15.92; S, 18.20; dH (CDCl3): 8.59 (1H, s), 7.94 (2H, d,
J = 7.9 Hz), 7.32 (2H, d, J = 7.8 Hz), 2.42 (3H, s); m/z 176 ([M]+,
42%), 148 ([M − 2N]+, 100%) (LSIMS+).
Synthesis of [Au(p-CN–C6H4–C≡C–S)L], L = PPh3 (6a), AsPh3
(6b), PPh2Me (6c). To an ice-cooled solution of 4-(p-
cyanophenyl)-1,2,3-thiadiazole 1 (37 mg, 0.2 mmol) in dry THF
(25 ml) was added tBuOK (25 mg, 0.22 mmol). The mixture was
stirred, under an argon atmosphere, for 1 h and then [AuCl(PPh3)]
(79 mg, 0.16 mmol), [AuCl(AsPh3)] (86 mg, 0.16 mmol) or
[AuCl(PPh2Me)] (69 mg, 0.16 mmol) was added. The mixture was
stirred for a further 6 h. The resulting solution was then filtered
through Celite to eliminate KCl. The solvent was evaporated under
vacuum to 5 ml and hexane (20 ml) was added to precipitate the
corresponding product, which was filtered off. L = PPh3 (6a),
orange solid (88%). Found: C, 52.80; H, 2.78; N, 2.65; S, 5.55.
C27H19AuNPS requires C, 52.53; H, 3.10; N, 2.27; S, 5.19; m/cm−1:
2224 (C≡N), 2150 and 2102 (C≡C) (KBr); dH (CDCl3): 7.60–7.40
(17H, m), 7.35 (2H, d, J = 9.6 Hz); dP (CDCl3): 37.7 (s); m/z 1409
(85%), 618 ([M]+, 8%), 459 ([AuPPh3]+, 100%) (LSIMS+). L =
AsPh3 (6b), brown solid (59%). Found: C, 48.89; H, 2.75; N, 2.38;
S, 5.07. C27H19AsAuNS requires C, 49.03; H, 2.90; N, 2.11; S, 4.80;
dH (CDCl3): 7.48–7.45 (17H, m), 7.37 (2H, d, J = 7.8 Hz); m/z
662 ([M]+, 5%), 503 ([AuAsPh3]+, 35%) (LSIMS+). L = PPh2Me
(6c), orange solid (61%). Found: C, 47.42; H, 2.80; N, 2.88; S, 6.14.
C22H17AuNPS requires C, 47.59; H, 3.08; N, 2.52; S, 5.77; m/cm−1:
2222 (C≡N), 2141 and 2101 (C≡C) (KBr); dH (CDCl3): 7.70–7.20
(12H, m), 7.35 (2H, d, J = 9.6 Hz), 2.13 (3H, d, J = 9.9 Hz); dP
(CDCl3): 22.3 (s); m/z 556 ([M]+, 8%), 397 ([AuPPh2Me]+, 100%)
(LSIMS+).
Synthesis of 4-(2-thienyl)-1,2,3-thiadiazole (3). Compound 3
was prepared by a procedure similar to 1 using 2-acetylthiophene
(10.74 g, 85 mmol). Recrystallisation from cyclohexane gave pale
yellow needles (65%). Found: C, 42.66; H, 2.29; N, 16.68; S,
38.29. C6H4N2S2 requires C, 42.83; H, 2.40; N, 16.65; S, 38.12;
dH (CDCl3): 8.50 (1H, s), 7.63 (1H, dd, J = 3.6; 1.2 Hz), 7.41 (1H,
dd, J = 5.1; 1.2 Hz), 7.14 (1H, dd, J = 5.1; 3.6 Hz); m/z 168 ([M]+,
22%), 140 ([M − 2N]+, 100%), 96 ([M − S − C]+, 82%) (LSIMS+).
Synthesis of 4-(3-thienyl)-1,2,3-thiadiazole (4). Compound 4
was prepared by a procedure similar to 1 using 3-acetylthiophene
(10.74 g, 85 mmol). Recrystallisation from cyclohexane gave pale
orange needles (50%). Found: C, 42.75; H, 2.06; N, 16.37; S,
37.80. C6H4N2S2 requires C, 42.83; H, 2.40; N, 16.65; S, 38.12;
dH (CDCl3): 8.51 (1H, s), 8.00–7.97 (1H, m), 7.62–7.60 (1H, m),
7.46–7.44 (1H, m); m/z 168 ([M]+, 100%), 140 ([M − 2N]+, 13%)
(LSIMS+).
Synthesis of 9,9-dimethylfluorene (5-P1). To an iced-cooled
solution of fluorene (5.0 g, 30 mmol) in dry THF (30 ml), under
t
argon atmosphere, was added BuOK (7.43 g, 66 mmol) and the
Synthesis of [Au(p-CH3–C6H4–C≡C–S)L], L = PPh3 (7a), AsPh3
(7b), PPh2Me (7c). Compounds 7 were prepared by a procedure
similar to 6 but using 4-(p-tolyl)-1,2,3-thiadiazole 2 (35 mg,
0.2 mmol) as a starting material. Recrystallisation was achieved
from a mixture of dichloromethane–ethanol. L = PPh3 (7a), yellow
solid (69%). Found: C, 53.06; H, 3.31; S, 5.37. C27H22AuPS requires
C, 53.44; H, 3.63; S, 5.23; m/cm−1: 2152 (C≡C) (KBr); dH (CDCl3):
7.56–7.44 (15H, m), 7.25 (2H, d, J = 6.9 Hz), 7.01 (2H, d, J =
7.8 Hz). 2.28 (3H, s); dP (CDCl3): 38.0 (s); m/z 1409 (27%), 721
([AuS(alquino)2PPh3]+, 18%), 606 ([M]+, 11%) (LSIMS+). L =
AsPh3 (7b), green solid (62%). Found: C, 49.80; H, 3.67; S, 5.12.
C27H22AsAuS requires C, 49.95; H, 3.42; S, 4.94; m/cm−1: 2147
(C≡C) (KBr); dH (CDCl3): 7.60–7.40 (15H, m), 7.25 (2H, d,
solution was stirred at room temperature for 1.5 h. CH3I (3.74 ml,
60 mmol) was added and a white precipitate of KI was formed.
The reaction mixture was stirred for a further 2 h. The KI was
then eliminated through filtration and the evaporation of THF
afforded the product as a yellow solid (96%). Found: C, 92.42; H,
6.80. C15H14 requires C, 92.78, H, 6.70; dH (CDCl3): 7.73–7.70 (2H,
m), 7.40–7.41 (2H, m), 7.36–7.30 (4H, m), 1.48 (6H, s); m/z 194
([M]+, 100%), 179 ([M − CH3]+, 98%) (LSIMS+).
Synthesis of 2-acetyl-9,9-dimethylfluorene (5-P2). To an iced-
cooled solution of compound 5-P1 (5.62 g, 29 mmol) in dry
dichloromethane (30 ml), under argon atmosphere, was added
dropwise a solution of AlCl3 (3.87 g, 29 mmol) and acetyl chloride
5334 | Dalton Trans., 2007, 5329–5338
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J = 7.2 Hz), 7.00 (2H, d, J = 7.8 Hz), 2.28 (3H, s); m/z 1540
(53%), 650 ([M]+, 8%), 503 ([AuAsPh3]+, 100%) (LSIMS+). L =
PPh2Me (7c), yellow solid (85%). Found: C, 48.16; H, 3.87; S,
6.12. C22H20AuPS requires C, 48.53; H, 3.68; S, 5.88; m/cm−1:
2145 (C≡C) (KBr); dH (CDCl3): 7.60–7.40 (10H, m), 7.26 (2H,
d, J = 8.1 Hz), 7.00 (2H, d, J = 8.1 Hz), 2.30 (3H, s), 2.13 (3H,
d, J = 9.9 Hz); dP (CDCl3): 22.6 (s); m/z 544 ([M]+, 8%), 397
([AuPPh2Me]+, 100%) (LSIMS+).
H, 2.71; S, 10.25. C24H18AuPS2 requires C, 48.16; H, 3.03; S, 10.72;
m/cm−1: 2138 (C≡C) (KBr); dH (CDCl3): 7.61–7.48 (15H, m), 7.21–
7.08 (3H, m); dP (CDCl3): 37.7 (s); m/z 1409 (70%), 721 (21%), 598
([M]+, 13%) (LSIMS+). L = AsPh3 (9b), brown solid (96%). Found:
C, 44.66; H, 2.55; S, 9.64. C24H18AsAuS2 requires C, 44.88; H, 2.81;
S, 9.99; m/cm−1: 2139 (C≡C) (KBr); dH (CDCl3): 7.60–7.40 (m);
m/z 1541 (81%), 809 (75%), 642 ([M]+, 37%), 503 ([AuAsPh3]+,
100%) (LSIMS+). L = PPh2Me (9c), white solid (92%). Found: C,
42.17; H, 2.65; S, 11.72. C19H16AuPS2 requires C, 42.54; H, 3.00;
S, 11.96; m/cm−1: 2139 (C≡C) (KBr); dH (CDCl3): 7.68–7.50 (10H,
m), 7.20–7.08 (3H, m), 2.17 (3H, d, J = 10.5 Hz); dP (CDCl3): 22.0
(s); m/z 1223 (74%), 536 ([M]+, 14%), 397 ([AuPPh2Me]+, 100%)
(LSIMS+). L = PPhMe2 (9d), brown solid (47%). Found: C, 35.10;
H, 2.56; S, 14.00. C14H14AuPS2 requires C, 35.44; H, 2.95; S, 13.50;
m/cm−1: 2140 (C≡C) (KBr); dH (CDCl3): 7.73–7.50 (5H, m), 7.17–
7.06 (3H, m), 1.83 (6H, d, J = 10.5 Hz); dP (CDCl3): 8.9 (s); m/z
474 ([M]+, 35%), 335 ([AuPPhMe2]+, 100%) (LSIMS+). L = PMe3
(9e), pale brown solid (77%). Found: C, 25.79; H, 2.45; S, 15.09.
C9H12AuPS2 requires C, 26.19; H, 2.93; S, 15.56; m/cm−1: 2141
(C≡C) (KBr); dH (CDCl3): 7.23–7.04 (3H, m), 1.58 (9H, d, J =
0.8 Hz); dP (CDCl3): −3.5 (s); m/z 851 ([S(AuPMe3)2]+, 100%), 685
([M + AuPMe3]+, 5%), 412 ([M]+, 7%), 349 (45%) (LSIMS+).
Synthesis of [Au(2-C4H3S–C≡C–S)L], L = PPh3 (8a), AsPh3
(8b), PPh2Me (8c), PPhMe2 (8d), PMe3 (8e). To an ice-cooled
solution of 4-(2-thienyl)-1,2,3-thiadiazole 3 (84 mg, 0.5 mmol) in
dry THF (25 ml) was added tBuOK (62 mg, 0.55 mmol), for R =
PPh2Me was added LiN(SiMe3)2 1 M in hexane (0.5 ml, 0.5 mmol).
The mixture was stirred, under an argon atmosphere, for 1 h and
then [AuCl(PPh3)] (198 mg, 0.4 mmol), [AuCl(AsPh3)] (215 mg,
0.4 mmol), [AuCl(PPh2Me)] (216 mg, 0.5 mmol), [AuCl(PPhMe2)]
(148 mg, 0.4 mmol) or [AuCl(PMe3)] (123 mg, 0.4 mmol) were
added. The mixture was stirred for a further 6 h. The resulting
solution was then filtered through Celite to eliminate KCl. The
solvent was evaporated under vacuum to 5 ml and diethyl ether
(20 ml) was added to precipitate the corresponding product, which
was filtered off. L = PPh3 (8a), pale brown solid (71%). Found: C,
47.84; H, 2.68; S, 10.88. C24H18AuPS2 requires C, 48.16; H, 3.03;
S, 10.72; m/cm−1: 2125 (C≡C) (KBr); dH (CDCl3): 7.55–7.44 (15H,
m), 7.03–7.00 (2H, m), 6.86 (1H, dd, J = 5.1, 3.6 Hz); dP (CDCl3):
37.7 (s); m/z 721 (34%), 598 ([M]+, 21%), 459 ([AuPPh3]+, 100%)
(LSIMS+). L = AsPh3 (8b), yellow solid (72%). Found: C, 44.68;
H, 2.42; S, 10.46. C24H18AsAuS2 requires C, 44.88; H, 2.81; S,
9.99; m/cm−1: 2124 (C≡C) (KBr); dH (CDCl3): 7.52–7.44 (15H, m),
7.04–6.85 (3H, m); m/z 642 ([M]+, 18%), 503 ([AuAsPh3]+, 57%),
154 (100%) (LSIMS+). L = PPh2Me (8c), pale brown solid (55%).
Found: C, 42.32; H, 2.99; S, 11.63. C19H16AuPS2 requires C, 42.54;
H, 3.00; S, 11.96; m/cm−1: 2126 (C≡C) (KBr); dH (CDCl3): 7.64–
7.43 (10H, m), 7.02–6.83 (3H, m), 2.11 (3H, m); dP (CDCl3): 21.6
(s); m/z 597 (40%), 536 ([M]+, 12%), 397 ([AuPPh2Me]+, 100%)
(LSIMS+). L = PPhMe2 (8d), orange solid (20%). Found: C, 35.10;
H, 2.58; S, 14.00. C14H14AuPS2 requires C, 35.44; H, 2.95; S, 13.50;
m/cm−1: 2124 (C≡C) (KBr); dH (CDCl3): 7.74–7.48 (5H, m), 7.22–
6.87 (3H, m), 1.81 (6H, d, J = 10.2 Hz); dP (CDCl3): 9.6 (s);
m/z 425 (75%), 475 ([M + H]+, 5%), 643 (57%) (LSIMS+). L =
PMe3 (8e), yellow solid (25%). Found: C, 26.59; H, 2.76; S, 15.31.
C9H12AuPS2 requires C, 26.19; H, 2.93; S, 15.56; m/cm−1: 2123
(C≡C) (KBr); dH (CDCl3): 7.03–6.84 (3H, m), 1.58 (9H, d, J =
12.0 Hz); dP CDCl3): −3.4 (s); m/z 461 (42%), 412 ([M]+, 42%),
401 ([M − C]+, 69%), 349 ([Au(PMe3)2]+, 100%) (LSIMS+).
Synthesis of [Au(2-C15H13C≡C–S)L], L = PPh3 (10a), AsPh3
(10b), PPh2Me (10c), PMe3 (10e),. To an ice-cooled solution of 4-
(9,9-dimethylfluoren-2-yl)-1,2,3-thiadiazole 5 (133 mg, 0.5 mmol)
t
in dry THF (25 ml) was added BuOK (62 mg, 0.55 mmol). The
mixture was stirred, under an argon atmosphere, for 1 h and
then [AuCl(PPh3)] (198 mg, 0.4 mmol), [AuCl(AsPh3)] (215 mg,
0.4 mmol), [AuCl(PPh2Me)] (173 mg, 0.4 mmol) or [AuCl(PMe3)]
(123 mg, 0.4 mmol) were added. The mixture was stirred for
a further 6 h. The resulting solution was then filtered through
Celite to eliminate KCl. The solvent was evaporated under
vacuum to 5 ml and hexane (20 ml) was added to precipitate
the corresponding product, which was filtered off. L = PPh3 (10a),
yellow solid (80%). Found: C, 58.96; H, 3.82; S, 4.08. C35H28AuPS
requires C, 59.32; H, 3.95; S, 4.52; m/cm−1: 2132 (C≡C) (KBr); dH
(CDCl3): 7.68–7.30 (22H, m), 1.45 (6H, s); dP (CDCl3): 37.5 (s);
m/z 721 ([Au(PPh3)2]+, 100%), 708 ([M]+, 19%) (LSIMS+). L =
AsPh3 (10b), pale brown solid (74%). Found: C, 55.46; H, 3.44; S,
3.90. C35H28AsAuS requires C, 55.85; H, 3.72; S, 4.26; m/cm−1: 2132
(C≡C) (KBr); dH (CDCl3): 7.62–7.45 (22H, m), 1.41 (6H, s); m/z
1541 (12%), 809 (30%), 752 ([M]+, 18%), 503 ([AuAsPh3]+, 100%)
(LSIMS+). L = PPh2Me (10c), yellow solid (98%). Found: C, 55.35;
H, 3.82; S, 4.58. C30H26AuPS requires C, 55.73; H, 4.02; S, 4.95;
m/cm−1: 2132 (C≡C) (KBr); dH (CDCl3): 7.68–7.30 (17H, m), 2.17
(3H, d, J = 9.3 Hz), 1.46 (6H, s); dP (CDCl3): 21.9 (s); m/z 1223
(25%), 646 ([M]+, 6%), 397 ([AuPPh2Me]+, 100%) (LSIMS+). L =
PMe3 (10e), pale brown solid (87%). Found: C, 45.63; H, 3.85;
S, 5.79. C20H22AuPS requires C, 45.98; H, 4.25; S, 6.14; m/cm−1:
2131 (C≡C) (KBr); dH (CDCl3): 7.67–7.28 (7H, m), 1.60 (9H,
d, J = 12.6 Hz), 1.44 (6H, m); dP (CDCl3): −3.5 (s); m/z 851
([S(AuPMe3)2]+, 50%), 522 ([M]+, 10%), 349 ([Au(PMe3)2]+, 100%)
(LSIMS+).
Synthesis of [Au(3-C4H3S–C≡C–S)L], L = PPh3 (9a), AsPh3
(9b), PPh2Me (9c), PPhMe2 (9d), PMe3 (9e),. To an ice-cooled
solution of 4-(3-thienyl)-1,2,3-thiadiazole 4 (84 mg, 0.50 mmol)
t
in dry THF (25 ml) was added BuOK (62 mg, 0.55 mmol).
The mixture was stirred, under argon atmosphere, for 1 h and
then [AuCl(PPh3)] (198 mg, 0.4 mmol), [AuCl(AsPh3)] (215 mg,
0.4 mmol), [AuCl(PPh2Me)] (173 mg, 0.5 mmol), [AuCl(PPhMe2)]
(148 mg, 0.4 mmol) or [AuCl(PMe3)] (123 mg, 0.4 mmol) were
added. The mixture was stirred for a further 6 h. The resulting
solution was then filtered through Celite to eliminate KCl. The
solvent was evaporated under vacuum to 5 ml and hexane (20 ml)
was added to precipitate the corresponding product, which was
filtered off. L = PPh3 (9a), orange solid (97%). Found: C, 47.88;
Synthesis of PPN[Au(p-CH3–C6H4–C≡C–S)(C6F5)] (11).
Compound 11 was prepared by a procedure similar to 7 using
PPN[AuCl(C6F5)] (375 mg, 0.4 mmol). White solid (66%). Found:
C, 57.99; H, 3.19; N, 1.20; S, 2.59. C51H37AuF5NP2S requires C,
58.31; H, 3.52; N, 1.33; S, 3.05; m/cm−1: 2143 (C≡C) (KBr); dH
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(CDCl3): 7.66–7.44 (30H, m), 7.15 (2H, d, J = 8.4 Hz), 6.91 (2H,
d, J = 7.8 Hz), 2.17 (3H, s); dF (CDCl3): −116,7 (d, Fo), −164,9
(t, Fp), −166,1 (m, Fm).
was added dppe (93 mg, 0.23 mmol). The reaction mixture was
stirred for 14 h. The solvent was removed in vacuo and hexane was
added to precipitate the product as an orange solid (98%). Found:
C, 42.61; H, 2.65; S, 11.59. C38H30Au2P2S4 requires C, 42.62; H,
2.80; S, 11.96; m/cm−1: 2126 (C≡C) (KBr); dH (CDCl3): 7.58–7.24
(20H, m), 7.17–6.83 (6H, m), 2.72 (4H, s); dP (CDCl3): dA 41.1,
dB 34.5, JAB = 470.6 Hz; m/z 1071 ([M]+, 7%), 931 ([Au2(C4H3S–
C≡C–S)dppe]+, 12%), 899 ([Au2(C4H3S–C≡C–S)dppe–S]+, 6%),
307 (100%) (LSIMS+).
Synthesis of [Au2(p-CN–C6H4–C≡C–S)2L], L = dppm (12a),
dppe (12b). 4-(p-Cyanophenyl)-1,2,3-thiadiazole
1 (37 mg,
0.2 mmol) was reacted as described above but adding [Au2(l-
dppm)Cl2] (68 mg 0.08 mmol) or [Au2(l-dppe)Cl2] (69 mg
0.08 mmol). L = dppm (12a), orange solid (80%). Found: C, 46.81;
H, 2.89; N, 2.62; S, 5.53. C43H30Au2N2P2S2 requires C, 47.18; H,
2.76; N, 2.55; S, 5.86; m/cm−1: 2221 (C≡N) (KBr); dH (CDCl3):
8.00–6.50 (28H, m), 3.02 (2H, s); dP (CDCl3): 36.4 (s); m/z 1093
([M]+, 12%), 899 (57%), 579 ([Au(dppm)]+, 100%) (LSIMS+). L =
dppe (12b), yellow solid (95%). Found: C, 47.94; H, 2.55; N, 2.90; S,
6.23. C44H32Au2N2P2S2 requires C, 47.66; H, 2.91; N, 2.53; S, 5.78;
m/cm−1: 2223 (C≡N), 2143 and 2103 (C≡C) (KBr); dH (CDCl3):
7.61–7.36 (24H, m), 7.30 (2H, d, J = 7.9 Hz), 6.78–6.54 (2H, m),
2.71 (4H, s); dP (CDCl3): 34.7 (s); m/z 950 (48%), 825 (10%), 579
(19%) (LSIMS+).
Synthesis of [Au2(3-C4H3S–C≡C–S)2(dppe)] (15b). Com-
pound 15b was prepare by a procedure similar to 9 using
[Au2Cl2(dppe)] (173 mg, 0.2 mmol). Yellow solid (79%). Found: C,
42.57; H, 2.60; S, 11.76. C38H30Au2P2S4 requires C, 42.62; H, 2.80;
S, 11.96; m/cm−1: 2140 (C≡C) (KBr); dH (CDCl3): 7.65–7.41 (20H,
m), 7.27–7.00 (6H, m), 2.72 (4H, s); dP (CDCl3): 35.7 (s); m/z 1071
([M]+, 17%), 931 ([Au2(C4H3S–C≡C–S)dppe]+, 100%), 825 (50%),
579 (78%) (LSIMS+).
Synthesis of [Au2(2-C15H13C≡C–S)2(dppe)] (16b). Compound
16b was prepare by a procedure similar to 15 using [Au2Cl2(dppe)]
(173 mg, 0.2 mmol). Yellow solid (74%). Found: C, 55.43; H,
3.49; S, 4.54. C60H50Au2P2S2 requires C, 55.81; H, 3.88; S, 4.96;
m/cm−1: 2132 (C≡C) (KBr); dH (CDCl3): 7.65–7.26 (34H, m), 2.70
(4H, s), 1.37 (12H, s); dP (CDCl3): 35.8 (s); m/z 1845 (52%), 1041
[Au2(C15H13C≡C–S)dppe]+, 85%), 825 (85%), 579 ([Au(dppm)]+,
100%) (LSIMS+).
Synthesis of [Au2(p-CH3–C6H4–C≡C–S)2(dppe)] (13b). To a
solution of compound 7b (61 mg, 0.94 mmol) in dry THF (50 ml)
was added dppe (18.67 mg, 0.047 mmol). The reaction mixture
was stirred for 7 h. The solvent was removed in vacuo and hexane
was added to precipitate the product as a pale grey solid (53%).
Found: C, 49.00; H, 3.61; S, 5.55. C44H38Au2P2S2 requires C, 48.58;
H, 3.50; S, 5.89; m/cm−1: 2146 (C≡C) (KBr); dH (CDCl3): 7.70–
7.25 (20H, m), 7.21 (4H, d, J = 7.8 Hz), 6.98 (4H, d, J = 7.8 Hz),
2.71 (4H, s), 2.29 (6H, s); dP (CDCl3): 36.2 (s); m/z 1845 (34%),
939 ([Au2(CH3–Ph–C≡C–S)dppe]+, 100%), 825 (12%), 579 (18%)
(LSIMS+).
Synthesis of PPN[Au(2-C4H3C≡C–S)2] (17). To an ice-cooled
solution of 4-(2-thienyl)-1,2,3-thiadiazole 3 (34 mg, 0.2 mmol) in
dry THF (15 ml) was added LiN(SiMe3)2 1 M in hexane (0.2 ml,
0.2 mmol). The mixture was stirred, under an argon atmosphere,
for 1 h and then PPN[AuCl2] (81 mg, 0.1 mmol) was added. The
mixture was stirred for a further 5 h. The resulting solution was
Synthesis of [Au2(2-C4H3S–C≡C–S)2(dppe)] (14b). To a solu-
tion of compound 8b (302 mg, 0.47 mmol) in dry THF (15 ml)
Table 5 Crystal data and data collection and refinement for complexes [Au(p-CH3–C6H4–C≡C–S)PPh3] (7a), [Au(3-C4H3S–C≡C–S)PPh3] (9a) and
PPN[Au(p-CH3–C6H4–C≡C–S)(C6F5)] (11)
7a
9a
11
Empirical formula
Mol wt
Color, habit
C54H88Au2P2S2
1257.24
C24H18AuPS2
598.44
C51H37AuF5NP2S
1049.78
Colorless, needle
Monoclinic, P2(1)/n
9.759(4)
23.066(12)
19.794(14)
90
100.25(5)
90
Yellow, prism
Yellow, block
¯
¯
Space group
Triclinic, P1
Triclinic, P1
˚
a/A
9.382(5)
10.0385(9)
12.8538(12)
18.5414(17)
72.878(2)
79.661(2)
68.013(2)
2116.63
˚
b/A
11.292(5)
12.643(5)
81.910(5)
68.730(5)
66.010(5)
1140.3(9)
1
˚
c/A
a/◦
b/◦
c /◦
V/A
Z
3
˚
4385(4)
4
1.590
4
D(calc)/g cm−3
Crystal size/mm3
l/mm−1
1.831
1.881
0.24 × 0.27 × 0.29
0.065 × 0.18 × 0.11
0.13 × 0.62 × 0.06
6.626
7.241
3.534
Temp/K
173(2)
100(2)
100(2)
h Range/◦
1.73 ≤ h ≤ 25.01
1.76 ≤ h ≤ 28.30
1.37 ≤ h ≤ 27.03
No. of data collected
No. of unique data
R1a(F2 > 2r(F2))
wR2b(all data)
Sc (all data)
4828
16 867
26 877
4019 [R(int) = 0.0153]
0.0197
0.0472
7228 [R(int) = 0.0571]
0.0445
0.0961
9519 [R(int) = 0.0468]
0.0349
0.1017
1.034
0.704
1.087
ꢀ
ꢀ
ꢀ
ꢀ
2
a R1(F) = ꢀFo| − |Fcꢀ/ |Fo|. b wR2(F2) = [ [w(Fo − Fc2)2]/ [w(Fo2)2]1/2 w−1 = [r2(Fo2) + (aP)2 + bP], where P = [max(Fo2, 0) + 2Fc2)]/3. c S =
ꢀ
2
[
[w(Fo − Fc2)2]/(n − p)]1/2, where n is the number of reflections and p the number of refined parameters.
5336 | Dalton Trans., 2007, 5329–5338
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then filtered through Celite to eliminate KCl. The solvent was
evaporated under vacuum to 5 ml and diethyl ether (20 ml) was
added to precipitate an orange solid, which was filtered off (77%).
Found: C, 56.57; H, 3.75; S, 11.88. C48H36AuP2NS4 requires C,
56.85; H, 3.58; S, 12.64; m/cm−1: 2125 (C≡C) (KBr); dH (CDCl3):
7.63–7.61 (15H, m), 7.47–7.44 (50H, m), 6.88–6.74 (6H, m); m/z
475 ([M]−, 68%) (EM). UV-Vis (CH2Cl2): 267, 301 nm
10 A. Cabrera, E. Delgado, C. Pastor, M. A. Maestro and F. Zamora,
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Crystals suitable for X-ray diffraction were obtained by slow dif-
fusion of diethyl ether or hexane into dichloromethane solutions.
A summary of the fundamental crystal and refinement data of
compounds 7a, 11 and 9a is given in Table 5. The crystals were
mounted on glass fibre with inert oil and centered on a Siemens
P4 diffractometer in the case of 7a, and on a Bruker-Siemens
Smart CCD diffractometer for 11 and 9a using in both cases
18 E. Delgado, B. Donnadieu, S. Garcia and F. Zamora, J. Organomet.
Chem., 2002, 649, 21.
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˚
monochromated Mo-Karadiation (k = 0.7107 A), scan type h–2h.
Cell constants were refined from setting angles of 36 reflections in
the range 2h 25–40 for 1. Absorption corrections were applied on
the basis of w scans in the case of 7a with transmission factors
0.219–0.304. The diffraction frames were integrated using the
SAINT56 package and corrected for absorption with SADABS57
in the case of 11 and 9a.
The structures were solved by direct methods using SHELXS.58
Full-matrix least squares refinement was carried out using
SHELXTL59 minimizing w(Fo2* − Fc )2. Hydrogen atoms were
2
included using a riding model. Weighted R factors (Rw) and all
goodness of fit S values are based on F2; conventional R factors
(R) are based on F.
29 M. Fujita, T. Kobari, T. Hiyama and K. Konda, Heterocycles, 1993,
In the case of complex 9a disorder was observed in both
thiophene fragments. Similarity restraints were applied to both
components of both groups, in an attempt to model the resulting
average electron density without losing chemically reasonable geo-
metrical parameters. Although the final refinement was successful,
we do not recommend the use of the resulting geometry as a model
for this type of group. Loose similarity restraints were also applied
to the displacement parameters of sites from different disorder
components that approached each other too closely.
36, 33.
30 C. D. Hurd and R. I. Mori, J. Am. Chem. Soc., 1955, 77, 5359.
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33 C. L. Kean and P. G. Pickup, Chem. Commun., 2001, 815.
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35 B. J. MacLean and P. G. Pickup, J. Mater. Chem., 2001, 11, 1357.
36 P. D. Byrne, P. Muller and T. M. Swager, Langmuir, 2006, 22, 10596.
37 J. Hjelm, R. W. Handel, A. Hagfeldt, E. C. Constable, C. E. Housecroft
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38 J. Hjelm, R. W. Handel, A. Hagfeldt, E. C. Constable, C. E. Housecroft
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39 E. Cerrada, C. Diaz, M. Laguna, I. Romeo, H. Teruel and N. Urzay,
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40 E. Cerrada, J. Garrido, M. Laguna, N. Lardies and I. Romeo, Synth.
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Acknowledgements
We thank the Ministerio de Ciencia y Tecnolog´ıa Spain for
financial support (CTQ2005–08099-C03–01). We also thank Prof.
Dr L. R. Falvello for his help in X-ray discussions.
41 K. Nomiya, S. Yamamoto, R. Noguchi, N. Yokoyama, C. Kasuga, K.
Ohyama and C. Kato, J. Inorg. Biochem., 2003, 95, 208.
42 S. Watase, T. Kitamura, N. Kanehisa, M. Shizuma, M. Nakamoto, Y.
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43 M. Preisenberger, A. Schier and H. Schmidbaur, J. Chem. Soc., Dalton
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