A robust dimethylgold(III) complex stabilized by a 2-pyridyl-2-pyrrolide ligand

Article abstract of DOI:10.1016/j.jorganchem.2006.08.083

Reaction of isopropyl[(2-pyridyl)alkyl]amines such as N-isopropyl-N-2-methylpyridine or N-isopropyl-N-2-ethylpyridine with aqueous solutions of NaAuCl₄ led to the formation of [LAuCl₂][AuCl₄] in low yields, where L = pyridyl amine bound to gold in a bidentate fashion. Reaction of 2-(3,5-diphenyl-1H-pyrrol-2-yl)pyridine with aqueous NaAuCl₄, however, proceeded with formal loss of HCl and direct formation of the gold(III) amido complex L′AuCl₂, where L′ = deprotonated pyrrolyl ligand. Optimization of the reaction conditions to make the new amido complex identified MeCN:H₂O (1:2) as the best choice of solvent, affording product in 92% yield. This dichloro amido complex is a convenient precursor to L′AuMe₂, which was found to be air-stable and thermally robust.

Full text of DOI:10.1016/j.jorganchem.2006.08.083

Journal of Organometallic Chemistry 691 (2006) 4975–4981
www.elsevier.com/locate/jorganchem
A robust dimethylgold(III) complex stabilized
by a 2-pyridyl-2-pyrrolide ligand
´
Stephanie Schouteeten, Olivia R. Allen, Aireal D. Haley, Grace L. Ong,
*
Gavin D. Jones, David A. Vicic
Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, United States
Received 9 August 2006; received in revised form 19 August 2006; accepted 19 August 2006
Available online 5 September 2006
Abstract
Reaction of isopropyl[(2-pyridyl)alkyl]amines such as N-isopropyl-N-2-methylpyridine or N-isopropyl-N-2-ethylpyridine with aque-
ous solutions of NaAuCl4 led to the formation of [LAuCl2][AuCl4] in low yields, where L = pyridyl amine bound to gold in a bidentate
fashion. Reaction of 2-(3,5-diphenyl-1H-pyrrol-2-yl)pyridine with aqueous NaAuCl4, however, proceeded with formal loss of HCl and
direct formation of the gold(III) amido complex L0AuCl2, where L0 = deprotonated pyrrolyl ligand. Optimization of the reaction con-
ditions to make the new amido complex identified MeCN:H2O (1:2) as the best choice of solvent, affording product in 92% yield. This
dichloro amido complex is a convenient precursor to L0AuMe2, which was found to be air-stable and thermally robust.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Gold; Cross-coupling
1. Introduction
For instance, Me4Au2I2 (1) is known to detonate violently
upon melting at 78 ꢁC (Eq. (1)) [36]. (PR3)AuMe2X com-
plexes also thermally lose ethane (Eq. (2)) with rates that
are sensitive both to the nature of Xꢀ and the nature of
the phosphine ligand [37–44]. The mechanism of ethane
formation from 2 (Eq. (2)) is believed to first involve disso-
ciative loss of a phosphine, as the rates are severely
retarded in the presence of excess phosphine [41–43,45].
A similar dissociative mechanism is believed to take place
with gold acetylacetonate complexes 3 (Eq. (3)), where
one arm of the chelate dissociates to form a T-shaped inter-
mediate before loss of ethane occurs [46]
Although the chemistry of gold has recently undergone
a renaissance in synthetic organic chemistry [1–13], cataly-
sis involving two electron redox processes such as oxidative
additions and reductive eliminations has been slower to
develop [14–16]. This is perhaps surprising, as the reductive
elimination of organics like ethane from gold dimethyl
complexes has been known for some time. These reductive
elimination reactions have been exploited in materials and
heterogeneous chemistry, where the clean loss of gaseous
ethane has popularized the use of gold dimethyl complexes
in the syntheses of supported gold catalysts and as chemical
precursors to gold nanoparticles [17–35]. With such practi-
cal uses for gold(III) dialkyl complexes, fundamental stud-
ies on the synthesis of new derivatives, as well as on the
kinetics and mechanism of reductive elimination of cross-
coupled alkane are of significant importance.
CH3
H3C
H3C
I
Au
Au
ethane
ð1Þ
ð2Þ
I
CH3
1
R3P
X
CH3
CH3
Au
ethane
2
In general, the rate of alkane loss from gold dialkyls
greatly depends on the structure of the organometallics.
R
O
R
O
ethane
ð3Þ
Au
*
Corresponding author. Tel.: +1 479 575 5078.
H3C
CH3
E-mail address: dvicic@uark.edu (D.A. Vicic).
3
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.08.083

4976
S. Schouteeten et al. / Journal of Organometallic Chemistry 691 (2006) 4975–4981
We are interested in the reductive elimination chemistry of
gold because of its relevance to the emerging field of alkyl–
alkyl cross-coupling chemistry [47–54]. Eqs. (1)–(3) suggest
that if a AuIIIðRalkylÞðR0alkylÞ species can be formed under
conditions typically employed for cross-coupling reactions,
then depending on the ligand, reductive elimination of
cross-coupled alkane could indeed occur. Catalysis would
additionally require that the resulting Au(I) fragment be
capable of oxidatively adding an alkyl electrophile, and
there are in fact reports of facile gold-mediated oxidative
additions of alkyl halides with (PR3)AuX [55–58]. We won-
dered if new amido complexes could be developed that
might be able to mimic the reductive elimination and oxi-
dative addition chemistry of the well-known gold phos-
phine complexes (Fig. 1). Amido-based ligands were
chosen as targets because their amine precursors are air-
stabile and relatively easy to prepare, and because they
could potentially support the Au(I)–Au(III) redox cycle
shown in Scheme 1. This cycle involves d8 and d10 gold
intermediates that are also isoelectronic with the Pd(II)
and Pd(0) intermediates that are well-known to catalyze
aryl-aryl cross-coupling reactions.
With the new amido ligands, it will be especially impor-
tant to study the relationship between ligand dissociation
from 4 to 5 with catalytic cross-coupling activities, as
reductive eliminations of alkane from amido dialkyl com-
plexes of gold may also require the initial formation of a
three-coordinate species. We anticipated that ligands 6–8
(Chart 1), once deprotonated and bound to gold, will have
varying degrees of flexibility and will allow us to probe sys-
tematically the effect of coordination environment on the
reductive elimination step described in Scheme 1. Our lab
is working to prepare well-defined gold dimethyl complexes
based on 6–8, and here we report progress towards that
goal.
2. Results and discussion
Addition of 1 equiv. of the aminopyridine ligand 6 to an
aqueous solution of NaAuCl4 led to an instant precipita-
tion of the new gold complex 9 (Eq. (4)) in moderate yields.
The precipitate was immediately filtered, as it was found
that continued stirring of the resulting suspension led to
eventual redissolution of 9 to afford a complex mixture
which we were unable to characterize. Once complex 9
has been isolated, however, it is quite stable in organic sol-
vents. X-ray quality crystals were grown by vapor diffusion
of diethyl ether into an acetonitrile solution of 9 to give
bright yellow crystals
X
Au PR3
RN
L
neutral donor
ligand
monoanionic
ligand
Fig. 1. Replacing the halide in XAuMe2PR3 with an amido moiety is part
of our strategy for developing new ligands for gold catalysts. The known
reactivities of XAuPR3 complexes towards oxidative additions and of
XAuMe2PR3 complexes towards reductive eliminations inspire this
approach.
AuCl4
N
NaAuCl4
N
N
H
ð4Þ
Au
H2O
49 %
HN
Cl
Cl
9
6
L
The ORTEP diagram of 9 is shown in Fig. 2, and the X-ray
structure confirms a cationic gold complex containing a
AuCl4 counter-ion. The N2AuCl2 (where N2 = N-isopro-
pyl-N-2-methylpyridine) cationic core of 9 adopts a
square-planar arrangement typically seen for d8-metal
complexes. The nitrogen atom of the amino ligand retains
its tetrahedral geometry, which places the i-propyl ligand
above the plane of the pyridine ring. Additionally, the ste-
ric bulk of the organic ligand was found to be relatively
shielding, as no intermolecular Auꢁ ꢁ ꢁAu or Auꢁ ꢁ ꢁCl con-
tacts closer than the sum of the van der Waals interactions
were observed in the solid-state packing diagram.
L
NR
NR
Au
Au
Me
Me
Me
Me
4
5
- ethane
[(L-NR)Au]
R'
R
R
X
Similar coordination chemistry to gold was observed
with the ligand 7, which contains an extra methylene group
in the amino linker. Upon addition of 7 to an aqueous
X
R'
R
(L-NR)Au
(L-NR)Au
R
Ph
N
N
N
N
HN
H
HN
Nu-X
R' Nu
Ph
8
6
7
Scheme 1. Possible catalytic cycle involving gold-amido complexes in
cross-coupling catalysis.
Chart 1. Precursors to the amido ligands targeted for this study.

S. Schouteeten et al. / Journal of Organometallic Chemistry 691 (2006) 4975–4981
4977
plexes 9 and 10 without the AuCl4 counter-ion are much
more desirable. Not only would such methods provide
cheaper amino complexes by using half the amount of gold,
but they would also afford intermediates that could poten-
tially be converted to the desired amido complexes without
the inherent purification problems involved when using 9
and 10. Therefore, the search for alternative methods to
prepare [LAuCl2]Cl, where L = 6 or 7, or their amido
derivatives, is ongoing in our labs.
Ph
Ph
NaAuCl4
N
N
ð6Þ
Ph
MeCN/H2O
92 %
N
N
H
Au
Cl
11
Ph
Cl
Fig. 2. ORTEP diagram of 9. Ellipsoids shown at the 50% level. Selected
bond lengths (A): Au(1)–N(1) 2.024(7), Au(1)–N(2) 2.046(7), Au(1)–Cl(2)
8
˚
The coordination chemistry of the 2-(3,5-diphenyl-1H-pyr-
rol-2-yl)pyridine ligand (8) with gold was substantially dif-
ferent than the amino-pyridine ligands 6 and 7. When
mixed with aqueous NaAuCl4, ligand 8 led directly to the
desired amido complex 11 without proceeding through
intermediate AuCl4 salts of the amine (Eq. (6)). The reac-
tion proceeds through the formal loss of HCl and the pre-
cipitation of the red-brown amido complex 11 in high
isolated yields (Eq. (6)). Optimization of this reaction iden-
tified MeCN:H2O (1:2) as the best choice of solvent, afford-
ing 11 in 92% yield. Interestingly, addition of extraneous
bases like NEt3 did not promote the reaction, but in fact
led to lower yields of 11.
2.264(4), Au(1)–Cl(1) 2.266(4), Au(2)–Cl(3) 2.278(4). Selected bond angles
(ꢁ): N(1)–Au(1)–N(2) 82.7(3), N(1)–Au(1)–Cl(2) 175.19(19), N(2)–Au(1)–
Cl(2) 92.8(2), N(1)–Au(1)–Cl(1) 94.8(2), N(2)–Au(1)–Cl(1) 176.12(19),
C(6)–N(2)–C(7) 113.8(6), C(5)–C(6)–N(2) 110.5(6).
solution of NaAuCl4, complex 10 was found to immedi-
ately precipitate from solution (Eq. (5))
AuCl4
NaAuCl4
N
H2O
N
NH
ð5Þ
24 %
Cl Au
Cl
N
H
7
10
The ORTEP diagram of 10 is shown in Fig. 3, and the X-
ray structure confirms the bidentate coordination of 7 lead-
ing to a six-membered ring. A substantial pucker in the
metallacycle is required to achieve a planar N2AuCl2 core
in 10 (N2 = N-isopropyl-N-2-ethylpyridine), and the plane
of the pyridine ring is now substantially twisted out of
the Cl(1)–Au(1)–Cl(2) plane. Again, pairing of the ami-
no-gold cation with a AuCl4 counter-ion was observed.
Synthetically, methods to prepare the cationic amino com-
The X-ray structure of 11 is shown in Fig. 4. The Au–Cl
˚
bond trans to the anionic ligand measures 2.280(8) A and is
slightly longer than the Au–Cl bond trans to the pyridyl
˚
nitrogen (2.261(8) A). Also of note is that because of the
Fig. 3. ORTEP diagram of 10. Ellipsoids shown at the 50% level. Selected
˚
bond lengths (A): Au(1)–N(1) 2.027(6), Au(1)–N(2) 2.071(8), Au(1)–Cl(2)
Fig. 4. ORTEP diagram of 11. Ellipsoids shown at the 50% level. Selected
bond lengths (A): Au(1)–N(1) 1.965(17), Au(1)–N(2) 2.080(14), Au(1)–
Cl(2) 2.261(8), Au(1)–Cl(1) 2.280(8). Selected bond angles (ꢁ): N(1)–
Au(1)–N(2) 83.0(6), N(1)–Au(1)–Cl(2) 171.2(5), N(2)–Au(1)–Cl(2) 94.1(5),
N(1)–Au(1)–Cl(1) 95.1(5), N(2)–Au(1)–Cl(1) 176.9(5), Cl(2)–Au(1)–Cl(1)
87.5(4), N(2)–C(6)–C(5) 113(2), N(1)–C(5)–C(6) 115.2(18).
˚
2.268(4), Au(1)–Cl(1) 2.276(6), Au(2)–Cl(4) 2.275(3), Au(2)–Cl(6)
2.278(3), Au(2)–Cl(5) 2.279(6), Au(2)–Cl(3) 2.280(6). Selected bond angles
(ꢁ): N(1)–Au(1)–N(2) 91.3(3), N(1)–Au(1)–Cl(2) 177.77(15), N(2)–Au(1)–
Cl(2) 86.5(2), N(1)–Au(1)–Cl(1) 91.6(2), N(2)–Au(1)–Cl(1) 176.32(15),
C(1)–C(6)–C(7) 111.7(6), N(2)–C(7)–C(6) 112.9(6).

4978
S. Schouteeten et al. / Journal of Organometallic Chemistry 691 (2006) 4975–4981
steric interactions of the aryl hydrogens on C(17) and C(21)
with the Au(1)–Cl(2) bond, two enantiomeric conforma-
tions of 11 (with the aryl hydrogen above and below the
Cl(1)–Au(1)–Cl(2) plane) crystallized in the asymmetric
unit
lic complex of gold, and can even be purified by column
chromatography under aerobic conditions. Moreover, it
is thermally robust, showing little decomposition (relative
to an internal standard) by NMR spectroscopy after heat-
ing for 1 h at 100 ꢁC in THF-d8 in a sealed tube. This ther-
mal stability is in sharp contrast to that displayed by
(PR3)AuXMe2 complexes, which show rapid loss of ethane
at temperatures ranging from 45 to 75 ꢁC, depending on
the nature of Xꢀ and the nature of the phosphine ligand
[41–43]. Complex 3 (R = Me) also loses ethane at lower
temperatures (70 ꢁC) [61]. We speculate that the rigidity
of the 2-(3,5-diphenyl-1H-pyrrol-2-yl)pyridine ligand in
12 inhibits the dissociation of the pyridyl arm and the for-
mation of a three-coordinate intermediate, making 12 resis-
tant to reductive elimination reactions. This enhanced
stability, however, is not desirable for the catalysis outlined
in Scheme 1, as all attempts to effect Negishi, Kumada,
Sonogashira, and Stille cross-couplings with alkyl iodides
and bromides failed. Dimethyl gold(III) amido complexes
based on the ligands 6 and 7 are anticipated to be much
more coordinatively labile than those derived from 8, but
synthetic methods to prepare these derivatives still need
to be developed.
Ph
Ph
SnMe4
N
N
N
N
ð7Þ
Ph
Ph
THF
49 %
Au
Au
Me
Me
Cl
Cl
12
11
With amido complex 11 in hand, we were able to prepare
the dimethyl analogue 12 in moderate yields by transmetal-
lation with SnMe4 (Eq. (7)) [59]. Two distinct methyl
1
groups are observed in the H NMR spectrum at d 1.00
and 0.79 in CDCl3, as would be required for a non-flux-
ional square-planar complex. The X-ray structure (Fig. 5)
reveals that the Au–CH3 bond trans to the anionic ligand
˚
has a bond length of 2.135(6) A and is longer than Au–
˚
CH3 bond trans to the pyridyl nitrogen (2.051(9) A). Addi-
tionally, the bond between gold and the pyrrolyl nitrogen is
shorter than that between gold and the pyridyl nitrogen
˚
(2.064(7) vs. 2.149(7) A), reflecting the fact that gold forms
a stronger bond with the anionic donor. As with the dichlo-
ride complex 11, two enantiomeric conformations of 12
were observed in the unit cell, suggesting hindered rotation
around the C17–C18 bond (Fig. 5).
N
N
Pt
Structurally, the dimethyl complex 12 is an excellent
model of the isoelectronic pyridylindole platinum 13, which
is capable of oxidatively adding the C–H bonds of benzene
[60]. Complex 12 is also an exceedingly stable organometal-
Me Me
13
3. Concluding remarks
While a number of studies on the reductive elimination
of alkane from gold dialkyl complexes have been
reported, relatively little is known about the organometal-
lic chemistry of gold amido complexes. The synthetic
methods reported herein allow for the generation of a
structurally rigid bidentate amido dimethyl complex of
gold and an initial study of its thermal stability. It is
tempting to suggest that the elevated thermal stability of
12 is indicative of the fact that reductive elimination of
ethane for pyridyl amido complexes of gold follows the
same mechanism for (PR3)AuMe2X complexes and
requires initial dissociation of a ligand to form a three-
coordinate Au(III) intermediate. However, only when fur-
ther studies on 12 are performed along with studies on a
series of related pyridyl amido complexes will the mecha-
nism of reductive elimination for this class of gold amido
complexes be fully understood. Towards that endeavor,
two amino pyridyl complexes of gold containing more
floppy linkers have also been outlined in this report.
The initial studies indicate that during the preparation
gold complexes containing ligands 6 and 7, the formation
Fig. 5. ORTEP diagram of 12. Ellipsoids shown at the 50% level. Selected
bond lengths (A): Au(1)–C(2) 2.051(9), Au(1)–N(2) 2.064(7), Au(1)–C(1)
˚
2.135(6), Au(1)–N(1) 2.149(7), N(1)–C(7) 1.346(11), N(1)–C(3) 1.347(11),
N(2)–C(17) 1.372(10), N(2)–C(8) 1.402(10). Selected bond angles (ꢁ): C(2)–
Au(1)–N(2) 98.6(3), C(2)–Au(1)–C(1) 87.1(4), N(2)–Au(1)–C(1) 174.2(3),
C(2)–Au(1)–N(1) 173.4(4), N(2)–Au(1)–N(1) 77.6(3), C(1)–Au(1)–N(1)
96.8(3), N(2)–C(8)–C(7) 114.9(7).

S. Schouteeten et al. / Journal of Organometallic Chemistry 691 (2006) 4975–4981
4979
of salts containing AuCl4 counter-ions must be avoided in
order to both increase yields of gold amino complexes
and to provide more versatile precursors to their respec-
tive amido derivatives.
(0.104 g, 0.275 mmol) in degassed water (5 ml). A yellow
solid precipitated immediately. After 50 min the solid was
filtered and washed with water. A bright yellow solid was
recovered and dried over vacuum (0.102 g, 49%). 1H
NMR (CD3CN, 270 MHz, 300 K): d 9.14 (dd, J = 6.2,
0.8 Hz, 1H), 8.38 (dt, J = 7.9, 1.3 Hz, 1H), 7.93 (d,
J = 7.7 Hz, 1H), 7.83 (dt, J = 6.9, 1.3 Hz, 1H), 5.05 (d,
J = 17.5 Hz, 1H), 4.73 (d, J = 17.5 Hz, 1H), 3.86 (septet,
J = 6.4 Hz, 1H), 1.32 (d, J = 6.6 Hz, 6H). 13C NMR
(CD3CN, 300 MHz, 300 K): d 147.1, 145.2, 126.9, 124.4,
59.3, 57.2, 29.9. Anal. Calc. for C9H14Au2Cl6N2: C 14.28,
H 1.86. Found: C 14.59, H 1.83%.
4. Experimental
4.1. General considerations
All manipulations were performed using standard
Schlenk techniques or in a nitrogen-filled glovebox, unless
otherwise noted. Solvents were distilled from appropriate
drying agents before use, and deionized water was used
for aqueous reactions. All reagents were used as received
from commercial vendors unless otherwise noted. Elemen-
tal analyses were performed by Desert Analytics. 1H NMR
spectra were recorded at ambient temperature on a JEOL
270 MHz and a Bruker 300 MHz spectrometer and refer-
enced to residual proton solvent peaks. A Rigaku MSC
Mercury/AFC8 diffractometer was used for X-ray
structural determinations. The ligands N-isopropyl-N-2-
methylpyridine [62], N-isopropyl-N-2-ethylpyridine [63],
and 2-(3,5-diphenyl-1H-pyrrol-2-yl)pyridine [64] were pre-
pared by previously published methods.
4.3. Preparation of complex 10
To an aqueous solution of NaAuCl4 Æ 2H2O (0.200 g,
0.503 mmol) was added 5.03 ml of a 0.1 M water solution
of N-isopropyl-N-2-ethylpyridine (0.082 g, 0.503 mmol).
A yellow solid precipitated immediately and was filtered
and washed with water. The solid was then recrystallized
via vapor diffusion from acetonitrile with diethyl ether to
give bright yellow crystals (0.093 g, 24%). 1H NMR
(CD3CN, 300 MHz, 300 K): d 9.01 (d, J = 6.2 Hz, 1H),
8.35 (dt, J = 7.7, 1.5 Hz, 1H), 7.89 (d, J = 7.9 Hz, 1H),
7.82 (dt, J = 6.4, 1.6 Hz, 1H), 3.78 (dsept, J = 6.8,
3.0 Hz, 1H), 3.55 (m, 2H), 3.3–3.2 (m, 1H), 2.87–2.75 (m,
1H), 1.22 (d, J = 6.6 Hz, 3H), 1.23 (d, J = 6.6 Hz, 3H).
13C NMR (CD3CN, 300 MHz, 300 K): d 150.5, 145.2,
128.8, 126.5, 59.5, 41.4, 38.9, 20.3, 19.3. Anal. Calc. for
C10H16Au2Cl6N2: C 15.58, H 2.09. Found: C 15.81, H
2.36%.
4.2. Preparation of complex 9
A solution of N-isopropyl-N-2-methylpyridine (0.041 g,
0.275 mmol) in degassed water (5 ml) was adjusted to pH
6 by addition of dilute hydrochloric acid solution and then
added dropwise to a stirred solution of KAuCl4 hydrate
Table 1
Crystal data and structure refinement parameters for all new compounds.
Compound
9
10
11
12
Chemical formula
Formula weight
Crystal dimensions (mm)
Color, habit
C9H14Au2Cl6N2
756.86
0.45 · 0.40 · 0.25
Gold, prism
Triclinic
0.71070
17.563
ꢀ
P, 2
7.912(14)
10.141(16)
11.17(3)
92.62(6)
97.75(6)
97.16(6)
879(3)
C10H16Au2Cl6N2
770.88
0.30 · 0.20 · 0.10
Gold, prism
Triclinic
0.71070
17.089
ꢀ
P, 2
8.149(9)
10.06(3)
11.732(17)
8.149(9)
10.06(3)
11.732(17)
904(3)
C21H15AuCl2N2
563.22
C23H21AuN2
522.38
0.30 · 0.20 · 0.10
Gold, prism
Monoclinic
0.71070
0.4 · 0.2 · 0.2
Gold, prism
Monoclinic
0.71070
7.985
Crystal system
˚
Wavelength (A)
l (cmꢀ1
)
7.739
Space group, Z
P21, 4
P21/n, 4
12.379(3)
9.617(2)
15.986(4)
90
90.594(6)
90
1903.0(8)
1.823
˚
a (A)
6.5109(15)
15.618(4)
18.865(6)
90
95.026(7)
90
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
Vol (A )
qcalc (g cmꢀ1
3
˚
1910.9(9)
1.958
)
2.858
2.832
Temperature (ꢁC)
R indices [I > 2r(I)]
R indices [all data]
Goodness of fit
ꢀ100
ꢀ100
25
ꢀ100
0.0397, 0.0948
0.0457, 0.0970
1.037
0.0328, 0.0849
0.0378, 0.0872
1.105
0.0459, 0.1018
0.0622, 0.1139
1.066
0.0590, 0.1302
0.0761, 0.1441
1.125
h Range (ꢁ)
1.84–27.99
17972
4247
1.79–28.0
18568
4367
2.53–28.00
19143
7294
2.07–28.00
19051
4593
Number of data collected
Number of unique data
Rint
0.0866
0.0523
0.0556
0.0707

4980
S. Schouteeten et al. / Journal of Organometallic Chemistry 691 (2006) 4975–4981
4.4. Preparation of complex 11
of the data can be obtained free of charge on application
to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK
[fax: +44 1223 336 033; e-mail: deposit@ccdc.cam.ac.uk].
Supplementary data associated with this article can be
found, in the online version, at doi:10.1016/j.jorganchem.
2006.08.083.
To a solution of NaAuCl4 Æ 2H2O (0.113 g, 0.284 mmol)
in 6 mL of degassed water was added a solution of 2-(3,5-
diphenyl-1H-pyrrol-2-yl)pyridine (0.084 g, 0.284 mmol) in
3 mL of acetonitrile. The mixture became cloudy and then
a brown precipitate was formed. The mixture was allowed
to stir overnight at room temperature. After filtration a
brown solid was recovered (0.148 g, 92%). 1H NMR
(CDCl3, 270 MHz, 300 K): d 9.02 (d, J = 6.4 Hz, 1H),
7.58 (t, J = 7.9 Hz, 1H), 7.51 (m, 2H), 7.45 (m, 5H), 7.35
(m, 4H), 6.99 (t, J = 6.4 Hz, 1H), 6.42 (s, 1H). Anal. Calc.
for C21H15AuCl2N2: C 44.78, H 2.68. Found: C 44.98, H
2.84%.
References
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