Gold(III) adducts of 2-vinyl- and 2-ethylpyridine and cyclometallated derivatives of 2-vinylpyridine: Crystal structure of the cyclometallated derivative [Au(k2-C,N-CH2CH(Cl)-C5H4N)(PPh3)Cl][PF6<

Article abstract of DOI:10.1016/j.jorganchem.2009.04.031

Reaction of Na[AuCl₄] with 2-vinylpyridine (vinpy) and 2-ethylpyridine (etpy) affords the N-bonded adducts Au(Rpy)Cl₃ (R = CH₂{double bond, long}CH, vinpy; CH₃CH₂, etpy). Cationic adducts, [Au(vinpy)<

Full text of DOI:10.1016/j.jorganchem.2009.04.031

Journal of Organometallic Chemistry 694 (2009) 2949–2955
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Gold(III) adducts of 2-vinyl- and 2-ethylpyridine and cyclometallated derivatives
of 2-vinylpyridine: Crystal structure of the cyclometallated derivative
[Au(k2-C,N–CH2CH(Cl)–C5H4N)(PPh3)Cl][PF6]
a
a
a
a
Maria Agostina Cinellu a, , Fabio Cocco , Giovanni Minghetti , Sergio Stoccoro , Antonio Zucca ,
*
Mario Manassero b
a Dipartimento di Chimica, Universita‘ degli Studi di Sassari, Via Vienna 2, I-07100 Sassari, Italy
b Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Universita‘ di Milano, Centro CNR, I-20133 Milano, Italy
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 1 April 2009
Received in revised form 21 April 2009
Accepted 22 April 2009
Available online 3 May 2009
Reaction of Na[AuCl4] with 2-vinylpyridine (vinpy) and 2-ethylpyridine (etpy) affords the N-bonded
adducts Au(Rpy)Cl3 (R = CH2@CH, vinpy; CH3CH2, etpy). Cationic adducts, [Au(vinpy)2Cl][X]2 (X = BF4,
PF6) and [Au(etpy)2Cl2][BF4], were also obtained by reaction of Au(Rpy)Cl3 with Rpy (1:1) and excess
NaBF4 or KPF6. Thermal activation of Au(vinpy)Cl3 in water gives the five-membered cycloaurated deriv-
ative [Au(k2-C,N–CH2CH(Cl)–C5H4N)Cl2] formally resulting through a trans nucleophilic addition of a
chloride onto the C@C bond. No cyclometallated derivatives are obtained by reactions of Au(etpy)Cl3.
An X-ray crystal structure determination on the PPh3 derivative [Au(k2-C,N–CH2CH(Cl)–C5H4N)(PPh3)Cl]
[PF6] was carried out.
Keywords:
Gold(III)
Nitrogen ligands
Cyclometallated derivatives
Alkene activation
Crystal structure
Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction
tives, have been reported previously with metal complexes of Pd
[9], Pt [9a,10], Co [11], Rh [12], Ir [13], Ru [14], Os [14d,e,15] and
The chemistry of cyclometallated gold(III) complexes contain-
ing C,N backbones [1] continues to attract great interest due to
the promising pharmacological activities manifested by a number
of derivatives, mainly as anti tumour agents [2], and the great po-
tential as homogeneous catalysts [3,4]. Actually, the enhanced sta-
bility of the gold(III) centre towards reduction granted by the
cyclometallated C,N ligand [5] is an important requirement for bio-
logical studies, and the less acidic character of these organo-
gold(III) compounds with respect to AuCl3, the most employed
gold(III) homogeneous catalyst, enables their use with acidic-sen-
sitive substrates.
Re [16]. In most cases C(sp2)–H activation of 2-vinylpyridine occurs
with formation of the cyclometallated derivatives [M(k2-C,N–
CH@CH–C5H4N)]. At variance, reaction with palladium(II) and plat-
inum(II) chlorides in alcoholic media resulted in the formation of
[M(k2-C,N–CH2CH(OR)–C5H4N)Cl]2 (M = Pd, Pt) [9a].
Surprisingly, the previously attempted auration of 2-vinylpyri-
dine with gold(III) bromide failed to give any cyclometallated spe-
cies [17].
2. Results and discussion
Following our interest in the synthesis and reactivity of cycloa-
urated derivatives of 2-substituted pyridines [6] and 6-substituted
2,2’-bipyridines [7], bearing a variety of alkyl, benzyl and aryl
groups, we report herein on the reaction of gold(III) chlorides with
2-vinylpyridine.
2-Vinylpyridines are versatile ligands, which have been widely
used to stabilize transition-metal–carbon bonds in a chelating
coordination mode, this being deemed to play a key role in cataly-
sis [8]. Cyclometallation reactions of 2-vinylpyridine, or its deriva-
2.1. Adducts
As previously observed with various 2-substituted-pyridines [6],
the reaction of Na[AuCl4] with 1 equiv. of 2-vinylpyridine (vinpy) in
MeCN–H2O affords the N-bonded adduct Au(vinpy)Cl3 (1). An ad-
duct was also previously described as the outcome of the reaction
of vinpy with Au2Br6 [17]. The 1H NMR spectrum in CD2Cl2 shows
the vinylic protons at lower field with respect to the free ligand,
thus ruling out coordination of the vinyl group to gold, as an upfield
shift is expected for a coordinated vinyl group. The large downfield
shift displayed by the Hc proton (cfr. Fig. 1 for numbering scheme)
* Corresponding author. Tel.: +39 079 229499; fax: +39 079 229559.
E-mail address: cinellu@uniss.it (M.A. Cinellu).
0022-328X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2009.04.031

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M.A. Cinellu et al. / Journal of Organometallic Chemistry 694 (2009) 2949–2955
to CHN analyses is
a not ionic (KM in acetone solution
16
X
ꢁ1 cm2 molꢁ1) isomer of 1: no C–H activation occurred to give
a cyclometallated species, Au(vinpy-H)Cl2. At variance, under com-
parable conditions, N-coordinated 2-substituted pyridines, such as
2-benzyl- [6] and 2-aryl-pyridines [21] undergo C(sp2)–H bond
activation to give cycloaurated derivatives Au(C,N)Cl2.
The same product 5 was obtained by reaction of NaAuCl4 with
2 equiv. of vinpy in MeCN/H2O at reflux, but under these reaction
conditions also Au(vinpy)Cl3 as well as unidentified species are ob-
tained. Large decomposition with formation of metallic gold was
observed in both cases.
Fig. 1. Two possible conformations for vinpy.
on coordination,
Dd 0.71 ppm, with respect to the small shift of Ha,
D
d 0.02 ppm, suggests some kind of interaction of Hc with the
The 1H NMR spectrum of 5 shows the disappearance of the vinyl
protons and appearance of a new set of signals (in CD2Cl2) at d 3.22,
3.53 and 5.51 ppm with integral ratio 1:1:1; moreover a large
gold(III) centre, C–Hꢀ ꢀ ꢀAu, or with a chloride ligand, C–Hꢀ ꢀ ꢀCl. Both
C–Hꢀ ꢀ ꢀM (M = d8 metal) and C–Hꢀ ꢀ ꢀX (X = Cl, Br, I) interactions are
known to cause strong deshielding of the proton resonances [18]
and have often been observed in various gold(III) complexes [6,7].
In this case, such interactions are possible if the vinyl group is
oriented like in conformer B (Fig. 1). A 1H NOE difference spectrum
shows contacts between the methylenic Ha and the H-3 proton of
the pyridine (Fig. 2) thus supporting this structure.
As according to calculations [19] and NMR studies [20] the pre-
ferred conformation of free 2-vinylpiridine is A rather than B, steric
repulsion between the vinyl group and the AuCl3 moiety of the
complex is likely responsible of the change in the conformation
upon coordination.
Downfield shift of similarly positioned H in (L)AuCl3 adducts of
2-benzyl- and 2-methylbenzyl–pyridine have been previously ob-
served by us [6], and also found in the 2-ethylpyridine (etpy) ad-
duct, Au(etpy)Cl3 (2), synthesized for comparison. In this case the
methylenic protons shift downfield by 0.63 ppm, while the methyl
protons move downfield by only 0.22 ppm.
Two different kinds of cationic adducts have been obtained by
reaction in acetone of Au(Rpy)Cl3 (1 and 2) [R = CH@CH2, vinpy
(1); CH2CH3, etpy (2)] with an equimolar amount of the respec-
tive Rpy and excess NaBF4, or KPF6, namely [Au(vinpy)2Cl][X]2
(X = BF4, PF6), (3-BF4) and (3-PF6), and [Au(etpy)2Cl2][BF4] (4-
BF4). In the case of complex 2 the expected substitution of ethyl-
pyridine for one chloride ligand gave the monocationic complex 4
as a 1:4 mixture of the cis and trans isomers, as indicated by the
two sets of signals, partially overlapping, in the 1H NMR spectrum
(in CD3COCD3). In the case of complex 1, analytical data of 3-BF4
and 3-PF6 (C,H,N analyses and conductivity measurements) sug-
gested that replacement of two chloride ligands by one 2-vinyl-
pyridine had occurred to give a dicationic complex, where one
of the two vinylpyridines acts as a bidentate ligand through the
nitrogen atom and the C@C moiety of the vinyl group. In the 1H
NMR spectra of 3-BF4 and 3-PF6 in CD3COCD3 broad unresolved
clusters of signals indicate a very complex situation likely arising
from: (i) the presence of cis- and trans-N–Au–N isomers, (ii) rapid
chemical exchange between coordinated and non-coordinated vi-
nyl groups, and (iii) different conformations of the uncoordinated
vinyl group. Averaged signals are also observed even at low
temperature.
downfield shift (Dd = 1.04 ppm) of the pyridinic H-6 proton is ob-
served. NOE effects were observed between the proton at d 3.53
and those at d 5.51 and 3.22, when this signal was irradiated. In
the far-IR spectrum Au–Cl stretching vibrations are observed at
358 and 294 cmꢁ1, consistent, respectively, with Au–Cl trans to N
and trans to C [6].
On the whole, spectroscopic data suggest that 5 is the cycloau-
rated species [Au(k2-C,N–CH2CH(Cl)–C5H4N)Cl2] containing
a
C(sp3)–Au bond (Fig. 3). An analogous bromurated derivative was
suggested by Monaghan and Puddephatt as the probable interme-
diate in the formation of CH2@CH(Br)C5H4N by thermolysis of
Au(vinpy)Br3 at 200 °C [17]. Similar palladium(II) and platinum(II)
derivatives (cfr. Fig. 3) were isolated by reaction of 2-vinylpyridine
with [MCl4]2ꢁ (M = Pd, Pt) in ROH (R = Me, Et) [9a].
Three plausible mechanisms can be proposed for the formation
of these cyclometallated derivatives, all implying the formation of
the M–N bond as the first step (in Scheme 1 the three mechanisms
are illustrated for the gold complexes). The first mechanism in-
volves the intramolecular insertion of the double bond into the
M–X bond (M = Au). In the second, it is assumed that the reaction
occurs via an external nucleophilic addition of X- (M = Au, X = Cl,
Br) or ROH (M = Pd, Pt) onto the metal-coordinated double bond.
In the third case, the electrophilic attack of the metal on the double
bond generates a secondary carbocation, unstable for the presence
of the electron-withdrawing pyridine, which undergoes nucleo-
philic attack by Xꢁ (M = Au) or ROH (M = Pd, Pt). In the latter case
deprotonation at the b-position of the carbocation to give the
cyclometallated derivatives [M](k2-C,N–CR0@CR00C5H4N) (R0,
R00 = H, alkyl) was observed for M = Pd [9b] and Rh [12b,22]. What-
ever the mechanism, the vinyl group in the adduct must be ori-
ented toward the metal centre in order to be prone to the
successive steps.
In our case, cyclometallation of the N-bonded 2-vinylpyridine
requires thermal activation. In order to get insight into the possible
mechanism, a CD3CN solution of Au(vinpy)Cl3 (1) in an NMR tube
was gradually heated and the reaction monitored by 1H NMR. Sig-
nals of 5 start to be recognizable after 30 min at 60 °C, together
with those of a new species 10; both species grow gradually and be-
come appreciable after 1 h at 78 °C. After this time the integral ra-
tio of the species is: 1:10:5 = 22.5:2.5:1. Species 10 features a
2.2. Cyclometallated derivatives
Heating of a suspension of Au(vinpy)Cl3 (1) in MeCN/H2O to 60–
80 °C resulted in the formation of a new species (5) that according
Fig. 2. NOE contacts in Au(vinpy)Cl3.
Fig. 3. Cyclometallated derivatives of 2-vinylpyridine.

M.A. Cinellu et al. / Journal of Organometallic Chemistry 694 (2009) 2949–2955
2951
Scheme 1. Plausible mechanisms for the cycloauration of 2-vinylpyridine (X = Cl, Br).
pattern of signals similar to that of 1, with resonances shifted with
respect to the corresponding in 1. Notably, the methynic proton,
Hc, is upfield shifted by 0.61 ppm with respect to that of 1, at var-
iance Ha is downfield shifted by 0.11 ppm, while Hb moves upfield
by only 0.07 ppm; the pyridine 6-H proton is also shifted upfield by
0.29 ppm. These data suggest that the new species 10 could be
either an adduct with the vinyl group oriented toward the gold
centre, i.e. in a more favourable position to undergo successive
reactions, or the cationic isomer [Au(vinpy)Cl2]Cl featuring a coor-
dinated vinyl group.
In the attempt to obtain the cyclometallated derivative
Au(CH@CHC5H4N)Cl2, thermal activation of 1 was carried out in
the presence of bases such as NEt3 and 2,6-lutidine, but complex
mixtures of unidentified products were obtained in both cases,
and, in the case of NEt3, large decomposition to metallic gold
was observed. Unreacted 1 was quantitatively recovered from a
dichloromethane solution when treated with K2CO3 at reflux.
As previously observed for platinum(II) [10], no metallacyclic
derivatives were obtained from the 2-ethylpyridine adduct 2.
Compound 5 is one of the few cycloaurated derivatives featur-
ing a N^C(sp3) auracycle [7a,23]: indeed reaction of gold(III) chlo-
rides with 2-vinyl substituted heterocycles could be a general
method to obtain this kind of compounds.
Reaction of 5 with an equimolar amount of PPh3 and excess
KPF6 in acetone solution caused replacement of a chloride ligand
to give [Au{k2-C,N–CH2CH(Cl)–C5H4N}(PPh3)Cl][PF6] (6). Crystals
of 6 were obtained by slow evaporation of an acetone solution.
Fig. 4. ORTEP view of the cation of 6. Ellipsoids are drawn at the 30% probability level.
Table 1
The structure consists of the packing of [Au{j
2-C,N–CH2CH(Cl)–
Selected bond distances (Å) and angles (°) for the cation of 6 with estimated standard
deviations (esd’s) on the last figure in parentheses.
C5H4N}(PPh3)Cl]+ cations and [PF6]ꢁ anions in the molar ratio
1:1, with no unusual van der Waals contacts, in the non-centro-
symmetric space group Pna21 An ORTEP [24] view of the cation is
shown in Fig. 4 and selected bond parameters of the cation are
listed in Table 1. The gold atom displays a square-planar coordi-
nation with a slight square-pyramidal distortion, maximum dis-
placements from the best plane being +0.025(1) and
ꢁ0.013(5) Å for atoms Au and N, respectively. Bond parameters
Au–Cl(1)
Au–N
N–C(3)
2.370(1)
2.071(5)
1.364(8)
1.484(8)
Au–P(1)
Au–C(1)
C(1)–C(2)
C(2)–Cl(2)
2.279(1)
2.032(5)
1.513(8)
1.819(6)
C(2)–C(3)
Cl(1)–Au–P(1)
Cl(1)–Au–C(1)
P(1)–Au–C(1)
91.7(1)
173.6(2)
94.6(2)
Cl(1)–Au–N
P(1)–Au–N
N–Au–C(1)
93.3(1)
174.6(1)
80.3(2)

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M.A. Cinellu et al. / Journal of Organometallic Chemistry 694 (2009) 2949–2955
involving gold can be compared with those found in [AuCl(epi-
C1,N)(PPh3)][PF6] (7) (epi = 2-(1-ethyl-2-imidazolyl)phenyl) [25],
which shows the same atomic arrangement for the moiety involv-
ing Au, PPh3, Cl, the five-membered metallacycle and the hetero-
cyclic ring. In 7 there are two crystallographically independent
molecules, with very similar bond parameters, so we will refer
to the mean values. Thus, Au–Cl(1) 2.370(1) Å here and 2.365 Å
in 7. Similarly, Au–P(1) 2.279(1) and 2.303 Å, Au–N 2.071(5)
and 2.046 Å, Au–C(1) 2.032(5) and 2.052 Å, respectively. As can
be seen in Table 1, the C(1)–C(2) and C(2)–C(3) bond lengths
are typical of sp3–sp3 and sp2–sp3 single bonds. The C(2)–Cl(2)
bond length is normal. At difference with compound 7, the five-
membered metallacycle is definitely non-planar, with maximum
displacements from the best plane of +0.262(6) and ꢁ0.271(6) Å
for atoms C(1) and C(2), respectively. The distance of atom Cl(2)
from this plane is ꢁ2.084(2) Å. The dihedral angle between this
plane and the metal coordination plane is 13.4(3) Å. The pyridine
ring is strictly planar and forms a dihedral angle with the metal
coordination best plane of 17.2(3)°. C(2) is an asymmetric carbon
atom, but as the space group contains mirror planes both the
enantiomers are present in the crystals. Bond lengths and angles
in the anion are normal.
4. Experimental
2-Vinylpyridine and 2-ethylpyridine were purchased from com-
mercial sources (AlfaAesar) and were used as received.
H[AuCl4]ꢀ3H2O was obtained from Johnson Matthey; Na[AuCl4]
was prepared from HAuCl4 and NaHCO3 in a 1/1 molar ratio. All
the solvents were purified before use according to standard proce-
dures. All the reactions were performed in air. Elemental analyses
were performed with a Perkin–Elmer elemental analyzer 240B by
Mr. Antonello Canu (Dipartimento di Chimica, Università degli stu-
di di Sassari, Italy). Infrared spectra were recorded with a FT-IR Jas-
co 480P using nujol mulls. 1H, 13C{1H} and 31P{1H} NMR spectra
were recorded with a Varian VXR 300 spectrometer operating at
300.0, 75.4 and 121.4 MHz, respectively. Chemical shifts are given
in ppm relative to internal TMS for 1H, 13C{1H} and external H3PO4
(85%) for 31P{1H}. J values are given in Hz. NOE difference experi-
ments were performed by means of standard pulse sequences.
Conductivities were measured with a Philips PW 9505 conductim-
eter. Mass spectra were recorded on a VG 7070 instrument operat-
ing under FAB conditions, with 3-nitrobenzyl alcohol operating as
supporting matrix.
The spectroscopic data of 6 are consistent with the structure in
Fig. 4, showing that only this isomer, the thermodynamic product,
is formed as a result of the strong trans influence of the PPh3 ligand.
The far-IR spectrum shows the Au–Cl stretching vibration at
304 cmꢁ1, a value typical of a chlorine trans to a carbon atom [6].
In accordance with a trans-P–Au–N arrangement, the phosphorus
resonance is found at d 29.2 ppm. The downfield resonance of
the H-6 pyridine proton (d 9.46 ppm) indicates its proximity to
the chlorine atom. The –CH(Cl)CH2– fragment gives rise (in CD2Cl2)
to a well resolved ABCX (X = 31P) spin system, with dA 2.52, dB 3.17,
4.1. [Au(vinpy)Cl3] (1)
dC 5.51, JA–C = 5.1, JA–X = 4.0, JB–C = 4.8, JB–X = 1.8 Hz, and JA–B
10.5 Hz. The resonances of the methylenic protons are both shifted
upfield with respect to the starting compound ( dA 0.70 and dB
=
To a solution of 2-vinylpyridine (126.2 mg, 1.2 mmol) in acetoni-
trile (2 mL) and water (30 mL) was added an aqueous solution of
Na[AuCl4] (477.6 mg, 1.2 mmol). The resulting yellow suspension
was stirred for 2 days at room temperature, then filtered, washed
with water, ethanol and diethyl ether, and dried in vacuo. The
crude product was recrystallized from dichloromethane/diethyl
ether to give the analytical sample. Yield: 67%. M.p.: 126 °C. Anal.
Calc. for C7H7AuCl3N: C, 20.58; H, 1.73; N, 3.43. Found: C, 20.72; H,
D
D
0.36 ppm) likely due to the anisotropic shielding of one phenyl ring
of the cis PPh3 ligand. Comparable NOE effects were observed be-
tween these protons and the phenyl protons of PPh3 centered at
d 7.80. NOE effects were also observed between the HC proton
and the H-3 of the pyridine when this signal was irradiated, and
between HC and both HA and HB, when the HC signal was irradi-
ated; the larger effect observed with HA indicates that these pro-
tons are on the same side of the metallacycle plane.
1.96; N, 3.43%. IR (m
/cmꢁ1, nujol): 1602 m, 1560 m, 1165 m, 963
w, 939 s, 780 vs, 759 s, 722 m, 365 vs (Au–Cl). 1H NMR (CD2Cl2,
At variance, reaction of 5 with 1 equiv. of vinpy and excess KPF6
failed to give the cationic derivative [Au{k2-C,N–CH2CH(Cl)–
C5H4N}(CH2@CH–C5H4N)Cl][PF6] (8-PF6), analogous to 6-PF6. Nev-
ertheless, 8-PF6 could be obtained by using an equivalent of AgPF6
to abstract a chloride ligand. According to its 1H NMR spectrum,
complex 8-PF6 is a mixture of the two possible isomers: that with
the N-bonded vinpy ligand trans to the pyridine nitrogen or to the
CH2 group in a 1:2 molar ratio. This is in accordance with the com-
parable trans influences of the pyridine and the chloride ligands.
293 K): d 6.08 (d, Jbc = 11.1 Hz, 1H, Hb), 6.27 (d, Jac = 17.5 Hz, 1H,
Ha), 7.55 (dd, Jcb = 11.1, Jca = 17.5 Hz, 1H, Hc), 7.65 (td, JHH = 6.5,
3
3
4
4JHH = 1.5 Hz, 1H, H-5), 7.97 (dd, JHH = 8.1, JHH = 1.3 Hz, 1H, H-
3
4
3), 8.14 (td, JHH = 7.5, JHH = 1.4 Hz; 1H, H-4), 8.69 (d;
3JHH = 6.0 Hz; 1H, H-6); (CD3COCD3, 293 K): d 6.15 (d, Jbc = 11.3 Hz,
1H, Hb), 6.47 (d, Jac = 17.1 Hz, 1H, Ha), 7.58 (dd, Jcb = 11.3,
2
Jca = 17.1 Hz, 1H, Hc), 7.91 (t, JHH = 6.7 Hz, 1H, H-5), 8.31 (d,
3JHH = 8.1 Hz, 1H, H-3), 8.39 (t, JHH = 7.7 Hz, 1H, H-4), 9.23 (d,
3
3JHH = 6.1 Hz, 1H, H-6). 13C NMR (CD3COCD3, 293 K): d 127.0
(@CH2), 127.2 (C-5), 128.0 (C-3), 133.9 (@CH), 143.6 (C-4), 150.7
(C-6), 156.1 (C-2).
3. Conclusions
4.2. [Au(etpy)Cl3] (2)
Neutral and cationic gold(III) adducts of 2-ethyl- and 2-vinyl-
pyridine have been synthesized and characterized by IR and
NMR spectroscopies. A new cycloaurated derivative featuring a
Au–C(sp3) bond, [Au{k2-C,N–CH2CH(Cl)C5H4N}Cl2], was also ob-
tained from the neutral adduct Au(vinpy)Cl3 by thermal activa-
tion. Plausible mechanisms are proposed for its formation.
Reaction of the cyclometallated derivative with PPh3 resulted in
the displacement of one chloride ligand with formation of the
To a solution of 2-ethylpyridine (107.2 mg, 1.0 mmol) in aceto-
nitrile (2 mL) and water (30 mL) was added an aqueous solution
of Na[AuCl4] (397.9 mg, 1.0 mmol). The resulting yellow suspen-
sion was stirred for 2 days at room temperature, then filtered,
washed with water, ethanol and diethyl ether, and dried in vacuo.
The crude product was recrystallized from dichloromethane/
diethyl ether to give the analytical sample. Yield: 78%. M.p.:
195 °C. Anal. Calc. for C7H9AuCl3N: C, 20.48; H, 2.21; N, 3.41.
thermodinamic product only, i.e. that with
a trans-P–Au–N
arrangement.

M.A. Cinellu et al. / Journal of Organometallic Chemistry 694 (2009) 2949–2955
2953
Found: C, 20.23; H, 2.05; N, 3.38%. IR (
m
/cmꢁ1, nujol): 1604 s,
4.6. [Au{CH2CH(Cl)C5H4N}Cl2] (5)
1565 m, 1455 vs, 1167 m, 1060 m, 893 m, 807 vs, 768 vs, 365
vs and 341 sh (Au–Cl). 1H NMR (CDCl3, 293 K): d 1.53 (t,
3
3JHH = 7.5 Hz, 3H, CH3), 3.46 (q, JHH = 7.5 Hz, 2H, CH2), 7.57 (t,
3
3JHH = 7.5 Hz, 1H, H-5), 7.66 (d, JHH = 8.1 Hz, 1H, H-3), 8.08 (td,
3JHH = 7.9, 4JHH = 1.4 Hz; 1H, H-4), 8.63 (dd; 3JHH = 5.7,
3
4JHH = 1.2 Hz; 1H, H-6); (CD3COCD3, 293 K): 1.53 (t, JHH = 7.6 Hz,
3
3
1H, CH3), 3.44 (q, JHH = 7.6 Hz, 1H, CH2), 7.85 (td, JHH = 6.8,
4JHH = 1.6 Hz, 1H, H-5), 7.98 (dd, JHH = 7.8, JHH = 1.3 Hz, 1H, H-
3
4
3
4
3), 8.36 (td, JHH = 7.7, JHH = 1.5 Hz; 1H, H-4), 9.19 (dd;
3JHH = 5.8, JHH = 1.0 Hz; 1H, H-6). FAB mass spectrum m/z: 410
4
[M+H]+. 13C NMR (CDCl3, 293 K): 12.3 (CH3), 32.4 (CH2), 125.4
(C-5), 127.6 (C-3), 141.9 (C-4), 149.2 (C-6), d 163.4 C-2).
A suspension of 1 (408.5 mg, 1.0 mmol) in acetonitrile (1.5 mL) and
water (60 mL) was heated under reflux for 2 h, then filtered off,
washed with water, ethanol and diethyl ether, and dried in vacuum
to yield a yellow solid. Recrystallization from acetone/diethyl ether
gave the analytical sample. Yield: 20%. M.p.: 173 °C. Anal. Calc. for
C7H7AuCl3N: C, 20.58; H, 1.73; N, 3.43. Found: C, 20.68; H, 1.63;
4.3. [Au(vinpy)2Cl][PF6]2 (3-PF6)
To
a solution of 1 (150.0 mg, 0.37 mmol) in acetonitrile
(50.0 mL) were added KPF6 (204.3 mg, 1.11 mmol) and vinpy
(38.9 mg, 0.37 mmol). The resulting mixture was stirred for 1 day
at room temperature and then evaporated to dryness. The residue
was extracted with chloroform to remove unreacted 1, washed
with water and recrystallized from acetone/diethyl ether to give
the analytical sample as a whitish powder. Yield 55%. Anal. Calc.
for C14H14AuClF12N2P2: C, 22.95; H, 1.93; N, 3.82. Found: C,
22.97; H, 2.03; N, 3.71%. KM (5 ꢂ 10ꢁ4 M, acetone)
N, 3.38%. IR (m
/cmꢁ1, nujol): 1602 m, 1288 m, 1164 m, 939 m, 782
s, 719 m, 553 s, 365 s and 355 m-sh (Au–Cl), 281 m. 1H NMR
(CD2Cl2, 293 K): d 3.22 (t, Jab = Jac = 9.3 Hz, 1H, Ha), 3.53 (dd,
Jba = 9.3, Jbc = 6.4 Hz, 1H, Hb), 5.51 (dd, Jca = 9.3, Jcb = 6.4 Hz, 1H,
3
3
Hc), 7.74 (t, JHH = 6.7 Hz, 1H, H-5), 7.94 (d, JHH = 7.9 Hz, 1H, H-3),
3
3
8.28 (t, JHH = 7.1 Hz, 1H, H-4), 9.61 (d, JHH = 5.8 Hz, 1H, H-6);
(CD3COCD3, 293 K): d 3.23 (dd, Jab = 9.1, Jac = 7.8 Hz, 1H, Ha), 3.50
(dd, Jba = 9.1, Jbc = 5.8 Hz, 1H, Hb), 5.87 (dd, Jca = 7.8, Jcb = 5.8 Hz,
210
X m
ꢁ1 cm2 molꢁ1. IR ( /cmꢁ1, nujol): 1623 s, 1574 w, 1509 m,
3
3
1H, Hc), 7.97 (t, JHH = 6.1 Hz, 1H, H-5), 8.12 (d, JHH = 8.2 Hz, 1H,
1173 w, 844 vs (PF6), 779 s, 558 s, 357 w (Au–Cl).
3
4
H-3), 8.53 (td, JHH = 7.8, JHH = 1.3 Hz, 1H, H-4), 9.53 (d,
3JHH = 5.2 Hz, 1H, H-6); (CD3CN, 293 K):
d
3.20 (dd, Jab = 9.1,
4.4. [Au(vinpy)2Cl][BF4]2 (3-BF4)
Jac = 8.0 Hz, 1H, Ha), 3.47 (dd, Jba = 9.1, Jbc = 6.0 Hz, 1H, Hb), 5.57
3
(dd, Jca = 8.0, Jcb = 6.0 Hz, 1H, Hc), 7.76 (t, JHH = 6.8 Hz, 1H, H-5),
To
a solution of 1 (150.0 mg, 0.37 mmol) in acetonitrile
3
3
4
7.94 (d, JHH = 8.2 Hz, 1H, H-3), 8.32 (td, JHH = 7.8, JHH = 1.5 Hz,
(50.0 mL) were added NaBF4 (162.5 mg, 1.48 mmol) and vinpy
(38.9 mg, 0.37 mmol). The resulting mixture was stirred for 1 day
at room temperature and then evaporated to dryness. The residue
was extracted with chloroform to remove unreacted 1, washed
with water and recrystallized from acetone/diethyl ether to give
the analytical sample as a whitish powder. Yield 50%. Anal. Calc.
for C14H14AuB2ClF8N2: C, 27.28; H, 2.29; N, 4.55. Found: C, 27.68;
1H, H-4), 9.47 (d, JHH = 6.0 Hz, 1H, H-6). 13C NMR (CD3COCD3,
3
293 K): d 52.1 (CH2–Au), 62.9 (CH–Cl), 126.3 (C-5), 127.7 (C-3),
144.6 (C-4), 149.3 (C-6).
4.7. [Au{CH2CH(Cl)C5H4N}(PPh3)Cl][PF6] (6-PF6)
H, 2.25; N, 4.63%. KM (5 ꢂ 10ꢁ4 M, acetone) 200
X .
ꢁ1 cm2 molꢁ1
IR (m
/cmꢁ1, nujol): 1625 s, 1511 m, 1061 vs-broad (BF4), 781 s,
552 w, 522 w, 358 m (Au-Cl).
4.5. [Au(etpy)2Cl2][BF4] (4-BF4)
To a solution of 2 (410.5 mg, 1.0 mmol) in acetonitrile (100 mL)
were added NaBF4 (548.9 mg, 5.0 mmol) and etpy (107.2 mg,
1.0 mmol). The resulting mixture was stirred for 2 days at room
temperature and, then evaporated to dryness. The residue was ex-
tracted with chloroform to remove unreacted 2, washed with
water and recrystallized from acetone/diethyl ether to give the
analytical sample as a whitish powder. Yield: 38%. M.p.: 157 °C.
Anal. Calc. for C14H18AuBCl2F4N2: C, 29.55; H, 3.19; N, 4.92. Found:
C, 29.33; H, 3.07; N, 4.85%. KM (5 ꢂ 10ꢁ4 M, acetone)
To a stirred solution of 5 (0.075 mmol) in acetone (25 mL) were
added PPh3 (0.075 mmol) and KPF6 (0.225 mmol). The solution
was stirred for 3 h, then concentrated to small volume and diethyl
ether added to give a yellow precipitate which was filtered, washed
with diethyl ether, and dried in vacuo. Recrystallization from
dichloromethane/diethyl ether gave the analytical sample. Yield:
69%. Mp: 191 °C. Anal. Calc. for C25H22AuCl2F6NP2: C, 38.58; H,
160
X m
ꢁ1 cm2 molꢁ1. IR ( /cmꢁ1, nujol): 1608 vs, 1568 m, 1217 m,
2.85; N, 1.80. Found: C, 38.62; H, 2.24; N, 1.85%. IR (m
/cmꢁ1, nujol):
1167 m, 1096 vs(sh), 1056 vs(broad) (BF4), 805 s, 762 vs, 520 s,
477 w, 446 m, 376 vs (Au–Cl), 284 w, 255 w. 1H NMR (CD3COCD3,
293 K): d 1.61 (t, 3JHH = 7.8 Hz, 3H, CH3 B), 1.63 (t, 3JHH = 7.8 Hz, 3H,
CH3 A), 3.63 (q, 3JHH = 7.8 Hz, 2H, CH2 A), 3.69 (q, 3JHH = 7.8 Hz, 2H,
1611 m, 1281 s, 1216 m, 1102 s (PPh3), 840 vs (PF6), 776 m, 748 s,
717 m, 691 s, 558 s, 537 s, 503 m, 304 m (Au–Cl). 1H NMR (CD2Cl2,
293 K): d 2.52 (ddd, Jab = 10.5, Jac = 5.1, JH-P = 4.0 Hz, 1H, Ha), 3.17
(ddd, Jba = 10.5, Jbc = 4.8, JH–P = 1.8 Hz, 1H, Hb), 5.51 (broad t, 1H,
3
CH2 B), 7.96 (t + t, overlapping, JHH = 7.6 Hz, 1H A + 1H B, H-5),
3
3
4
Hc), 7.65–7.85 (m, 16 H, CH PPh3 + H-5), 7.96 (d, JHH = 8.1 Hz, 1H,
8.09 (d + d, overlapping, JHH = 8.0, JHH = 1.4 Hz, 1H A + 1H B, H-
3
4
3
4
H-3), 8.30 (td, JHH = 7.8, JHH = 1.5 Hz, 1H, H-4), 9.46 (pseudo-t,
3JHH = 5.0 Hz, 1H, H-6); (CD3COCD3, 293 K): d 3.01–3.06 (m, 2H,
Ha + Hb), 6.03 (pseudo-t, Jca = Jcb = 6.4 Hz, 1H, Hc); 7.71–8.03 (m,
3), 8.47 (td, JHH = 7.7, JHH = 1.5 Hz, 1H, H-4 A), 8.49 (td,
3JHH = 7.8, JHH = 1.5 Hz, 1H, H-4 B), 9.26 (dd, JHH = 6.2,
4
3
4JHH = 1.1 Hz, 1H, H-6 B), 9.28 (dd, JHH = 6.2, JHH = 1.1 Hz, 1H, H-
6 A), A:B = 4:1. FAB mass spectrum m/z: 480 [MꢁH]+, 444 [M–
2H–Cl], 410 [M–H–2Cl].
3
4
3
15 H, CH PPh3), 8.06 (td, JHH = 6.8 Hz, 1H, H-5), 8.15 (d,
3
4
3JHH = 8.0 Hz, 1H, H-3), 8.54 (td, JHH = 7.8, JHH = 1.6 Hz, 1H, H-4),

2954
M.A. Cinellu et al. / Journal of Organometallic Chemistry 694 (2009) 2949–2955
9.47 (pseudo-t, 3JHH = 5.1, 1H, H-6). 31P NMR (CD2Cl2, 293 K): d 29.2
(s, PPh3), -144.2 (sept, PF6). Crystals of X-ray quality were obtained
by slow evaporation of an acetone solution.
fractometer at 150 K, using Mo K
a radiation (k = 0.71073) with a
graphite crystal monochromator in the incident beam. No crystal
decay was observed, so that no time-decay correction was needed.
The collected frames were processed with the software SAINT [26]
and an empirical absorption correction was applied (SADABS) [27]
to the collected reflections. The calculations were performed using
the Personal Structure Determination Package [28] and the physi-
cal constants tabulated therein [29]. The structure was solved by
direct methods (SHELXS) [30] and refined by full-matrix least-
4.8. [Au{CH2CH(Cl)C5H4N}(CH2@CHC5H4N)Cl][PF6] (8-PF6)
To an acetone solution of 5 (83.0 mg, 0.2 mmol) were added 2-
vinylpyridine (21.3 mg, 0.2 mmol) and AgPF6 (51.3 mg, 0.2 mmol),
with stirring. The resulting mixture was stirred for 6 h at room
temperature, then silver chloride was filtered off and the solution
evaporated to dryness. The residue was extracted with dichloro-
methane, filtered and concentrated to small volume; addition of
diethyl ether gave a grey solid that was filtered off and dried in va-
cuo. Yield 77%. Mp: 99 °C. Anal. Calc. for C14H14AuCl2F6N2P
(623.11): C, 26.99; H, 2.26; N, 4.50. Found: C, 27.15; H, 2.36; N,
squares using all reflections and minimising the function
P
2
2
wðF2o ꢁ kFc Þ (refinement on F2). All the non-hydrogen atoms
were refined with anisotropic thermal factors. The hydrogen atoms
were placed in their ideal positions (C–H = 0.97 Å), with the ther-
mal parameter U 1.10 times that of the carbon atom to which they
are attached, and not refined. As the space group is non centrosym-
metric, full refinement of the correct structure model led to
R2 = 0.046 and R2w = 0.083, full refinement of the inverted structure
led to R2 = 0.101 and R2w = 0.169. In the final Fourier map the max-
imum residual was 2.34(31) e Åꢁ3 at 1.98 Å from P1.
4.42%. IR (m
/cmꢁ1, nujol): 1609 m, 1168 w, 970 w, 840 vs (PF6),
780 w, 721 m, 557 m, 375 m (Au–Cl), 305 w (Au–Cl). 1H NMR
(CD3COCD3, 293 K): d 3.61 (dd, Jab = 8.7, Jac = 5.2 Hz, 1H, Au–CHaHb
A), 3.63 (dd, Jab = 8.8, Jac = 4.2 Hz, 1H, Au–CHaHb B), 3.75 (dd,
Jba = 8.8, Jbc = 6.3 Hz, 1H, Au–CHaHb B), 3.76 (dd, Jba = 8.7 Hz,
Jbc = 5.9 Hz, 1H, Au–CHaHb A), 5.94–6.12 (m + d + d, 4H, CHCl
A + CHCl B + =CHaHb A + =CHaHb B), 6.44 (d, Jac = 17.3 Hz, 1H,
=CHaHb A), 6.52 (dd, Jac = 17.0, Jab = 1.5 Hz, 1H, =CHaHb B), 7.63–
7.81 (ms, 2H, =CHc A + B), 7.9–9.5 (ms, 16H, pyH A + B); A:B = 1:2.
Acknowledgement
F.C. gratefully acknowledges the Fondazione Banco di Sardegna
for a two-year fellowship. We are grateful to the University of Sas-
sari for financial support (FAR 2007) and Johnson Matthey for a
generous loan of HAuCl4.
5. X-ray data collection and structure determination
Crystal data are summarised in Table 2. The diffraction experi-
ment was carried out on a Bruker APEX II CCD area-detector dif-
Appendix A. Supplementary data
CCDC 725517 contains the supplementary crystallographic 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. Supplementary data associated with this article
can be found, in the online version, at doi:10.1016/j.jorganchem.
2009.04.031.
Table 2
Crystallographic data and structure refinement details for 6.
Compound formula
M
Colour
Crystal system
Space group
a (Å)
C25H22AuCl2F6NP2
780.27
Colourless
Orthorhombic
Pna21
20.8361(12)
15.6902(9)
8.3264(5)
90
90
90
2722.1(3)
4
1504
b (Å)
c (Å)
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0.15 ꢂ 0.22 ꢂ 0.31
l
(Mo K
a
) (cmꢁ1
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57.65
Minimum and maximum transmission
Factors
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h-Range
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0.0381
a
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P
P
P
P
2
2
2
2
1=2
R2 ¼ ½ ðjF2o ꢁ kFc j= Fo2ꢃ; R2w ¼ ½ wðFo2 ꢁ kFc Þ = wðFo2Þ ꢃ
.
a
P
2
2
1=2
2
b
½
wðF2o ꢁ kFc Þ =ðNo ꢁ NvÞꢃ
,
where
w ¼ 4F2o=
r
ðF2oÞ ;
r
ðF2oÞ ¼ ½r2ðF2oÞþ
ð0:05F2oÞ ꢃ1=2, No is the number of observations and Nv the number of variables.
2

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