Mercury(II) and gold(III) derivatives of 2-phenyl pyridines and 2-phenyl-4-(methylcarboxylato)quinoline

Article abstract of DOI:10.1016/S0022-328X(99)00645-2

ortho-Mercurated derivatives of several substituted 2-phenylpyridines and of 2-phenyl-4-(methylcarboxylato)quinoline have been prepared and characterised. C,N-chelated gold(III) derivatives, [AuCl₂(C₆H₄C₅H₃RN)] (R = H, 3-Me, 3,5-Me₂, 4-Prⁿ, 4-Bu^t) are prepared more efficiently by trans-metallation reactions than by direct reaction of AuCl₄^- with the phenylpyridines. The new gold complexes were characterised spectroscopically and a variety of substitution reactions have been effected. As is usual with unsymmetrical bidentate ligands, the softer donor atom is found trans to the N-donor of the pyridine unit. Crystal-structure determinations are reported for [Au(OAc)(pmpy)(py)]ClO₄, [Au(ppy)(dpbt)]BPh₄, [Au(ppy)(S₂CNMe₂)]BPh₄ and AuCl(pqcm)₂ [Hppy = 2-phenylpyridine, Hpmpy = 2-phenyl-3-methylpyridine, Hpqcm = 2-phenyl-4-(methylcarboxylato)quinoline].

Full text of DOI:10.1016/S0022-328X(99)00645-2

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 596 (2000) 165–176
Mercury(II) and gold(III) derivatives of 2-phenyl pyridines and
2-phenyl-4-(methylcarboxylato)quinoline
R.V. Parish *, Jonathan P. Wright, Robin G. Pritchard
Department of Chemistry, UMIST, PO Box 88, Manchester M60 1QD, UK
Received 6 June 1999; received in revised form 12 October 1999
Abstract
ortho-Mercurated derivatives of several substituted 2-phenylpyridines and of 2-phenyl-4-(methylcarboxylato)quinoline have
been prepared and characterised. C,N-chelated gold(III) derivatives, [AuCl2(C6H4C5H3RN)] (R=H, 3-Me, 3,5-Me2, 4-Prn, 4-But)
are prepared more efficiently by trans-metallation reactions than by direct reaction of AuCl−4 with the phenylpyridines. The new
gold complexes were characterised spectroscopically and a variety of substitution reactions have been effected. As is usual with
unsymmetrical bidentate ligands, the softer donor atom is found trans to the N-donor of the pyridine unit. Crystal-structure
determinations are reported for [Au(OAc)(pmpy)(py)]ClO4, [Au(ppy)(dpbt)]BPh4, [Au(ppy)(S2CNMe2)]BPh4 and AuCl(pqcm)2
[Hppy=2-phenylpyridine, Hpmpy=2-phenyl-3-methylpyridine, Hpqcm=2-phenyl-4-(methylcarboxylato)quinoline]. © 2000 El-
sevier Science S.A. All rights reserved.
Keywords: Mercury(II); Gold(III); ortho-Metallation; 2-Phenylpyridines
1. Introduction
esting pharmacological properties [10,11] stimulated the
preparation of a wide range of analogues, of which
those derived from various 2-phenylpyridines and 2-
phenyl-4-(methylcarboxylato)quinoline are reported
here, together with some of their ligand-substitution
reactions.
Direct auration of aromatic ligands was first achieved
in 1931 by Kharasch [1], but it was not for a further 50
years that other concrete examples were obtained. In
1989, Constable and co-workers reported the ortho-
metallation of 2-phenyl-pyridine [2] and related materi-
als [3], giving stable five-membered C,N-chelates. More
recently various substituted pyridines have been shown
to undergo similar reactions, forming five- or six-mem-
bered chelates [4–6]. However, the yields in reactions of
this type can be low, and it is frequently better to
employ a transmetallation reaction from the ortho-mer-
curated derivative, a method well exploited by Vicente
and co-workers for the preparation of derivatives of
azobenzene [7] and dimethylbenzylamine [8].
There is developing interest in the use of gold com-
pounds in chemotherapy [9], and we have shown that
Constable’s original compound [AuCl2(ppy)] (I) showed
toxicity to and some discrimination between a variety
of cell lines [10]. Our observation that other C,N-
chelates of gold(III) (II, X=Cl, OAc) have more inter-
2. Results and discussion
Although it was possible to obtain the desired ortho-
metallated products by direct reaction between the lig-
and and [AuCl4]−, transmetallation from the mercury
derivatives was much more efficient, giving cleaner and
quicker reactions. It was therefore necessary to prepare
both the phenylpyridines and their ortho-mercurated
derivatives.
* Corresponding author. Fax: +44-161-200 4251.
E-mail address: r.v.parish@umist.ac.uk (R.V. Parish)
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00645-2

166
R.V. Parish et al. / Journal of Organometallic Chemistry 596 (2000) 165–176
2.1. Preparation of ligand precursors
2.2. Preparation and characterisation of
organomercurials
The 2-phenylpyridines IV–VII were prepared by the
established method [12] of reaction of the substituted
pyridine with phenyllithium (Scheme 1). 2-Phenylquino-
line 4-carboxylic acid (XVII) was prepared from ben-
zaldehyde and pyruvic acid (Scheme 2) [13]. These
materials were characterised by NMR (Tables 1 and 2)
and used immediately.
Mercuration was achieved by direct reaction of the
2-phenylpyridines with mercury(II) acetate in ethanol
[14,15] followed by replacement of the acetate by chloride
(Schemes 1 and 2). Yields were modest (30–40%), and
considerable quantities of insoluble by-products were
always formed. This has been observed previously during
the reaction of 2-phenylpyridine[12] and attributed to the
formation of bis-mercurated derivatives [16].
The organomercury compounds VIII–XII were char-
acterised by chemical analysis, IR and NMR (Tables 1
and 2). In the far infrared, all showed bands in the regions
413–422 cm−1 [w(Hg–C)] and 332–337 cm−1 [w(Hg–
Cl)]. The latter are consistent with linear two-coordina-
tion [13]. The pyridine C–N deformation bands (ca. 1600
cm−1) were at frequencies very similar to those of the
parent phenylpyridines, indicating lack of coordination
of the pyridine nitrogen atom.
Scheme 1.
Table 1
1H-NMR data for substituted pyridines (HL), [HgCl(L)] and [AuCl2(L)] (CDCl3 solutions)
Compound
Phenyl
H3
Pyridine/quinoline
Other
H4
H5
H6
H8
H9
H10
H11
Hppy (III)
Hpmpy (IV)
Hpmmpy (V)
Hpppy (VI)
7.93
7.43
7.32
7.92
7.84
8.05
8.60
8.56
8.35
8.24
8.53
8.01
9.52
9.61
8.44
7.29
7.28
7.19
7.30
7.22
7.31
7.92
–
7.29
7.28
7.19
7.30
7.22
7.31
7.81
7.86
7.42
-
7.29
7.28
7.19
7.30
7.22
7.31
8.60
8.56
8.35
8.24
8.53
7.39
9.52
9.61
7.19
7.49
–
7.41
7.51
–
8.20
8.00
7.74
7.66
7.80
8.04
8.59
7.97
8.24
8.60
7.49
7.43
7.12
–
–
–
7.44
7.47
7.39
7.28
7.43
–
7.48
7.72
–
7.01
7.02
–
8.58
8.41
8.16
8.48
8.40
7.41
H1 7.93
H1 7.43, CH3 2.21
H1 7.32, CH3 2.30
H1 7.92, CH3 0.85, CH2 1.57
H1 7.84
6.89
6.96
8.05
7.42
7.47
7.39
7.28
7.43
7.54
7.38
7.62
8.15
Hpbpy (VII)
Hpcqm (XVII)
HgCl(ppy) (VIII)
HgCl(pmpy) (IX) b
HgCl(pmmpy) (X)
HgCl(pppy) (XI)
HgCl(pbpy) (XII)
HgCl(pcqm) (XVIII)
AuCl2(ppy) (I) b
AuCl2(pppy) (XV) b
AuCl2(pqcm) (XIX)
H12 7.56. H13 8.37, CH3 3.81
7.51 a
7.74 c
7.50 d
7.28 e
7.55 f
7.06
7.81
8.14
8.15
CH3 2.48
CH3 2.35, 2.48
CH3 0.88, CH2 1.59, 2.48
CH3 1.26
H12 8.43, H13 8.37, CH3 4.01
–
7.53
7.80
7.39
8.40
–
7.39
8.40
7.89
7.50
CH3 1.21, CH2, 2.00, 3.08
H12 8.00, H13 8.86, CH3 4.35
7.80
a JHg 211 Hz.
b In (CD3)2SO.
c JHg 218 Hz.
d JHg 207 Hz.
e JHg 211 Hz.
f JHg 211 Hz.

R.V. Parish et al. / Journal of Organometallic Chemistry 596 (2000) 165–176
167
n-propylpyridinyl and quinolyl complexes, XV and
XIX. Downfield shifts of all the pyridine ring carbon
signals confirm that the nitrogen is coordinated. The
FAB mass spectra did not give strong parent-ion peaks,
but signals corresponding to the loss of one and both
chlorine atoms were seen, as well as those of the free
phenylpyridines. Strong peaks corresponding to the
bis-aryl compounds are also seen.
There is thus no doubt that these compounds have
the now-conventional C,N-chelated structures shown in
the Schemes.
2.4. Substitution chemistry of the gold complexes
The chloride ligands are readily substituted by a
range of other, softer, ligands and we have used a
variety of anionic sulfur-based materials. Substitution
by a hard ligand requires assistance from silver ion.
These reactions are summarised in Scheme 3.
Scheme 2.
The NMR assignments shown in Tables 1 and 2 were
made from consideration of the values of the 199Hg
coupling constants and 13C DEPT(135°) of all the
compounds, and from complete (1H–1H) and (1H–13C)
COSY studies of the t-butyl-substituted compound XII
[17]. As observed previously [12,18], mercuration gives
a strong (ca. 22 ppm) downfield shift for C1, and the
coupling constants appear in the expected order [19].
For X, XI and XVIII, the FAB mass spectra show
parent ions with the correct isotopic patterns. Peaks
corresponding to the phenylpyridines and, in two cases,
to the loss of a chlorine atom are also seen. The bis-aryl
disproportionation products are also observed.
Complexes XIII, XIV and XVI reacted readily with
silver acetate, provided light was excluded. The prod-
ucts, XX–XXII, were the expected di-acetato com-
plexes, obtained as white, air- and moisture-stable,
light-sensitive crystalline solids, with good solubility in
common solvents. NMR data for these complexes are
given in Tables 3 and 4 (COSY and NOE data are
given in Ref. [17]). The two sets of 13C signals for the
acetato groups have not only different chemical shifts
but different intensities: the higher-shifted signals are
broadened considerably. We first observed this effect
for [Au(OAc)2(damp)] [damp=2-(dimethylamino-
methyl)phenyl] [21], and showed that it was due to
rapid exchange of the group trans to carbon with small
amounts of adventitious water in the solvent.
2.3. Preparation and characterisation of gold complexes
Our efforts to prepare the unsubstituted [AuCl2(ppy)]
on a relatively large scale by the direct auration route
always gave low yields (ca. 20%) and considerable
quantities of metallic gold. Similar problems have been
found by other workers for 2-benzoylpyridine [5] and
6-phenyl-2,2%-bypyridine [20], even when silver ion was
used to facilitate removal of chloride ligands from the
intermediate [AuCl3(pyridine)] complexes. Comparable
difficulty was met here with the substituted phenyl-
pyridines. However, the transmetallation reaction of the
mercury derivatives with [AuCl4]− in acetonitrile
worked cleanly and rapidly, and gave good yields (60–
80%).
The new compounds XIII–XVI, XIX were character-
ised by chemical and spectroscopic analysis (Tables 1
and 2). In the infrared (IR) spectrum, an increase in
w(C–N) of the pyridine rings indicates that the pyridine
is coordinated, and Au–Cl stretching modes at 360–
380 and 300–310 cm−1 are consistent with chloride
ligands trans to nitrogen and to carbon, respectively.
Several of the compounds exhibited rather low solu-
bility, and NMR spectra were obtained only for the
The IR spectra (Table 5) show two distinct sets of
C–O stretching frequencies, both consistent with
monodentate bonding of the acetate groups. As dis-
cussed previously [7,22] the lower frequencies corre-
spond to the acetato group trans to the phenyl ligand.
Complex XX reacts with pyridinium perchlorate to
give substitution of one acetato group by pyridine. The
product is very light sensitive but stable to air and
moisture. Similar compounds reported by Vicente et al.
were thought, on the basis of IR data, to have struc-
tures analogous to XXIII (Scheme 3) [23,24]. This is
now confirmed by X-ray diffraction for crystals of
XXIII, the cation of which is shown in Fig. 1. Selected
bond distances and angles are given in Table 6. The
coordination of the gold atom is almost ideally planar,
and the two different pyridine units are trans to each
other. The Au–N(py) distance found here is rather
shorter than those reported [22] for [Au(py)2(damp)]-
,
(ClO4)2 [2.016(7), 2.155(9) A]. The carbonyl-group
stretching frequencies of all these compounds are simi-
lar to those of the groups trans to carbon in the
diacetato complexes (Table 5).

Table 2
13C{1H}-NMR data for substituted pyridines (HL), [HgCl(L)] and [AuCl2(L)] (numbers in parentheses are JHg (Hz))
Compound
Phenyl
C1
Pyridine
C7
Other
C2
C3
C4
C5
C6
C8
C9
C10
C11
Hppy (III) a,b,c
Hpmpy (IV) c
Hpmmpy (V) c
Hpppy (VI) c
Hpbpy (VII) c
Hpqcm (XVII) c
127.1
128.4
127.9
127.0
127.1
127.5
139.6
140.6
140.4
139.6
140.0
138.8
127.1
128.4
127.9
127.0
127.1
127.5
128.7
129.0
128.8
128.7
128.4
129.2
129.0
127.9
126.9
127.2
128.5
129.0
128.7
129.0
128.8
128.7
128.4
129.2
156.7
158.7
155.7
157.3
160.6
156.6
119.9
130.8
129.9
120.7
117.4
120.3
136.2
138.5
138.5
152.1
157.4
124.1
121.5
122.1
131.2
122.4
119.7
125.5
149.1
147.0
147.2
149.4
149.6
130.8
/
CH3 20.1
CH3 17.7, 19.7
CH3 13.7, CH2 23.5, 37.4
CH3 30.7, CMe3 34.7
C12 130.1, C13 130.2, C14 135.5,
C15 149.3, CO2 166.8, CH3 52.7
HgCl(ppy) (VIII) a,d,e
HgCl(pmpy) (IX) e
HgCl(pmmpy) (X) e
HgCl(pppy) (XI) c
HgCl(pbpy) (XII) c
HgCl(pqcm) XVIII c
147.9
157.9
152.1
148.3
148.5
148.3
141.3
148.0
143.7
141.4
142.3
140.9
127.1
132.0 [181]
127.6
126.8 [151]
127.0 [158]
128.3
129.2
131.1 [30]
130.1
128.6 [24]
128.6 [28]
129.3
128.2
137.8
155.9
163.6
155.6
155.8
162.4
155.0
120.9
135.4
131.1
120.0
117.5
110.9
138.3
143.7
141.1
155.1
155.7
124.9
123.4
126.8
132.7
123.7
120.8
125.6
149.1
150.7
147.3
147.5
147.9
131.1
133.5 [151]
128.5 [211]
129.6 [211]
129.7 [214]
128.6
141.2 [113]
137.0 [128]
137.8 [132]
137.9 [133]
138.3
CH3 24.3
CH3 17.9, 20.9
CH3 13.7, CH2 23.5, 37.6
CH3 30.6, CMe3 35.2
C12 128.2, C13 130.9, C14 136.7,
C15 147.9, CO2 166.5, CH3 53.1
AuCl2(ppy) (I) a,e
AuCl2(pppy) (XV) e
AuCl2(pqcm) (XIX)
156.2
n.o.
151.0
152.0
146.8
141.7
130.7
130.5
131.8
134.0
133.9
133.6
133.3
135.2
132.1
135.6
135.4
135.3
167.9
164.3
160.9
126.2
125.9
126.9
146.9
156.0
126.5
129.3
129.0
128.8
147.9
151.1
133.9
59696
CH3 9.9
C12 132.3, C13 133.7, C14 138.1,
C15 143.7, CO2 169.2, CH3 56.8
(2000)2000)
16565
a ppy=2-(2-pyridyl)phenyl.
b Ref. [38].
17676
c In CDCl3.
d Ref. [14].
e In (CD3)2SO.

R.V. Parish et al. / Journal of Organometallic Chemistry 596 (2000) 165–176
169
Scheme 3. (i) AgOAc, CH2Cl2. (ii) pyHClO4, CH2Cl2. (iii) HSCH2CH2SH, Et3N, MeOH. (iv) HSCH(CH2CO2H)CO2H, Me2CO. (v, vi)
HSCH2CH2NH2, Et3N, MeOH. (vii) Ph2PC6H4SH, THF. (viii, ix) NaS2CNR2, Me2CO; Au complex, MeCN.
Table 3
1H-NMR data for substituted gold complexes [in (CD3)2SO]
Compound
Phenyl
H3
Pyridine
H8 H9
7.58 7.29 7.14 7.21 CH3 2.21, 2.33; CH3 (OAc) 2.11, 2.64
Other diagnostic signals
H4
–
H5
H6
–
H10
H11
Au(OAc)2(pmpy) a (XXI)
Au(OAc)2(bmpy) a (XXII)
Au(OAc)2(bmpy) (XXII)
Au(pmpy)(edt2) a (XXIV)
Au(pmmpy)(msa) (XXVII)
Au(ppy)(mea) (XXIX)
8.34
8.33 7.75
8.51 8.43
7.74
–
–
7.30 7.58 7.21 7.01 7.01 CH3 1.34; CH3 (OAc) 2.09, 2.19
7.86 8.23 7.59 7.44 7.21 CH3 1.55; CH3 (OAc) 2.12, 2.28
8.88 7.86 7.92 7.28 7.78 7.28 7.28 7.62 CH2 2.86, 3.40
9.10 7.89 7.79 7.31 7.20 7.60 CH3 2.30, 2.61; CH2 2.81, CH 4.58
8.91 8.55 8.48 7.88 8.15 7.52 7.40 7.61 CH2 2.91, 3.31, NH2 6.24 b
9.05 8.53 8.45 7.60 8.21 7.43 7.12 7.12
–
–
Au(ppy)(ppbt) (XXX)
[Au(ppy)(S2CNMe2)]PF6 (XXXI)
[Au(ppy)(S2CNEt2)]BPh4 (XXXII)
Au(pbpy)(S2CNMe2)2 (XXXIII)
8.60 8.38 8.38 7.60 7.98 7.42 7.23 6.90 CH3 3.41, 3.42
8.71 8.42 8.42 7.68 8.05 7.49 7.32 7.02 CH3 1.42, 3.91
8.53 7.72
–
7.52 8.00 7.15 7.15 7.15 CH3 1.25 (But), 3.21 (dtc)
a In CDCl3.
[Au(msa)(damp)] [10]. With HS(CH2)2NH2, the inter-
mediate mono-substitution product XXVIII was also
isolated. The far-IR spectrum of this contains bands at
316 and 386 cm−1, which presumably correspond to
w(Au–Cl) and w(Au–S). On the grounds that (a) in
all other monosubsituted derivatives of type [Au-
Cl(Y)(C,N)] the incoming soft ligand Y is found trans
to N rather than to C [25], and (b) the higher frequency
Reactions of the parent dichloro complexes have
been carried out with a range of bidentate thiols
(Scheme 3). In the case of ethanedithiol, there is no
ambiguity, and the products must have structures
XXIV, XXV. The other thiols are all mixed-donor
ligands. We presume that the derivatives from mercap-
tosuccinic acid (Hmsa), XXVI and XXVII, have the
same configuration as that which we found for

Table 4
13C{1H}-NMR data for substituted gold complexes [in (CD3)2SO]
Compound
Phenyl
Pyridine
Other diagnostic
signals
/
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
C11
Au(Oac)2(pmmpy) a (XXI)
Au(Oac)2(pbpy) a (XXII)
Au(Oac)2(pbpy) (XXII)
143.1
145.4
144.3
141.4
141.8
145.0
127.8
128.5
130.2
128.7
128.8
133.0
129.2
129.3
133.1
145.9
130.7
135.1
159.4
168.3
172.7
133.3
117.4
123.1
129.8
164.0
167.1
133.5
117.8
126.3
147.1
147.0
151.4
H3C 21.7, 22.2; H3CO 26.1, 40.0;
OOC 175.2, 176.9
H3C 30.0; Me3C 36.0; H3CO 22.2, 36.0;
OOC 175.2, 177.0
H3C 33.6; Me3C 40.0; H3CO 26.1, 28.4;
OOC 177.6, 179.1
CH2 33.2, 44.5
Au(ppty)(edt) a (XXIV)
Au(pmmpy)(msa) (XXVII)
162.8
153.8
143.5
148.4
125.6
131.5
127.3
132.5
132.6
133.1
141.2
149.0
165.4
160.5
120.8
137.3
132.9
133.9
124.4
138.0
149.8
150.8
CH3 21.7, 26.1; CH2 44.5, CH 46.0;
CO2 176.0, 177.3
Au(ppy)(mea) (XXIX)
[Au(ppy)(S2CNMe2)]PF6 (XXXI)
[Au(ppy)(S2CNEt2)]BPh4 (XXXII)
150.8
155.4
154.5
148.0
148.9
n.o.
130.8
131.3
130.6
132.5
132.1
131.3
135.8
133.3
132.5
147.1
147.9
147.1
165.5
167.3
166.4
125.6
126.6
125.8
136.7
136.4
135.6
129.5
130.3
129.5
152.7
153.8
153.0
CH2 36.9, 53.9
CH3 44.6, 46.1; NCS2 196.9
CH3 15.4, 15.8; CH2 50.3, 51.8;
NCS2 196.1
59696
(2000)2000)
[Au(pqcm)(S2CNMe2)]PF6 (XXXIV)
Au(pbpy)(S2CNMe2)2 (XXXIII) a
156.0
143.9
148.2
142.7
133.7
126.1
133.3
129.1
130.9
129.2
137.5
134.1
168.9
160.8
123.3
120.1
128.7
159.7
129.2
116.6
138.0
148.6
C12 146.7, C13 149.6; CO2 170.4,
CH3 57.8; CH3 (dtc) 47.0, 45.2
CH3 (But) 36.0; CH3 (dtc) 30.4, 45.4;
NCS2 201.9
16565
17676
a In CDCl3.

R.V. Parish et al. / Journal of Organometallic Chemistry 596 (2000) 165–176
171
Table 5
C–O stretching frequencies for acetato complexes
Compound
trans to C
trans to N
w(C–O)asym
w(C–O)asym
w(C–O)sym
Dw
w(C–O)sym
Dw
Au(OAc)2(pmpy) (XX)
Au(OAc)2(pmmpy) (XXI)
Au(OAcO2(pbpy) (XIX)
[Au(OAc)2(damp)] a
1634
1631
1620
1620
1629
1626
1610
1620
1308
1306
1324
1315
1310
1308
–
326
325
296
305
319
318
1665
1665
1667
1670
1665
1366
1367
1367
1370
1360
299
298
300
300
305
[Au(OAc)2(pap)] b
[Au(OAc)(pmpy)(py)]ClO4 (XX)
a
[Au(OAc)(py)(damp)]ClO4
b
[Au(OAc)(py)(pap)]ClO4
1300
320
a damp=2-C6H4CH2NMe2 [8]
b pap=2-C6H4NꢀNPh [23].
is too high for w(Au–Cl) and must therefore be w(Au–
S), we assign structure XXVIII in which the incoming
thiolate is bound trans to nitrogen. Unfortunately, the
corresponding bands for the chelated product XXIX are
obscured. The NMR spectra (Tables 3 and 4) are
consistent with the suggested structures. We have re-
cently found the analogous configuration for a C,P-
chelated system, [Au(Ph2PC6H4CHCH2OMe)(SCH2-
CH2NH2) [26].
groups, and both the IR and NMR spectra indicate
lack of coordination of the pyridine unit. On the other
hand, only single sets of NMR signals (1H and 13C) are
found for the dithiocarbamates: this is most probably
due to a rapid equilibrium between the two forms as
shown in Scheme 3. Such exchanges between mono-
and bi-dentate dithiocarbamate have been observed
previously for [Au(damp)(S2CNEt2)2] [10] and in the
ylide complex [Au(CH2P(SPPh2)(S2CNEt2)2] [29].
For the phosphine-thiol Ph2PC6H4SH, it is less easy
to predict the structure of the chelated product XXX,
since it is not obvious which donor atom is the softer or
the better nucleophile. Fortunately, we were able to
crystallise this product and to solve the X-ray diffrac-
tion pattern. There was some ambiguity (see Section 4)
owing to the difficulty of distinguishing the phenyl and
pyridine groups. The most satisfactory configuration is
shown in Fig. 2 (bond lengths and distances are in
Table 6), and has the phosphine group trans to N,
suggesting that Ph2P is softer than ArS−.
Finally, [AuCl2(pqcm)] (XIX) reacts with a further
molar equivalent of HgCl(pqcm) to give [AuCl(pqcm)2],
XXXVII. X-ray crystal analysis (Fig. 4, Table 6) confi-
rms that this material is analogous to similar di-aryl
gold(III) complexes reported by Vicente et al. [22,
30,31]: one of the aryl ligands is monodentate, the other
is chelated, and the two Au–C bonds are mutually cis.
This is a further example [10,30,32,33] where a fifth
ligand is poised above the gold atom but at a relatively
,
large distance [Au···N=2.93(1) A].
Reaction of the parent dichloro complex with one
molar equivalent of a dithiocarbamate gave displace-
ment of both chlorides and formation of the cationic,
di-chelated complexes XXXI and XXXII; [AuCl2-
(pqcm)] (XIX) reacts similarly to give [Au(pqcm)S2CN-
Me2]PF6 (XXXIV). Chelation of the dithiocarbamates is
confirmed by the C–N stretching frequencies (1557 and
1561 cm−1, respectively), which are very similar to
those of other chelated gold(III) derivatives [8,27,28]
and by the non-equivalence in the NMR of the methyl
and ethyl signals (Table 4). Final confirmation was
obtained by X-ray analysis of XXXI, giving the struc-
ture shown in Fig. 3 (bond lengths and distances are in
Table 6).
When two molar equivalents of dithiocarbamate are
used, the disubstituted complex XXXIII is formed. This
appears in all respects to be similar to the correspond-
ing damp complex we reported earlier [10]: in the IR,
the C–N and C–S stretching modes suggest the pres-
ence of both mono- and bidentate dithiocarbamate
Fig. 1. Structure of the cation [Au(OAc)(pmpy)(py)]+. Significant
bond lengths and angles are given in Table 6.

172
R.V. Parish et al. / Journal of Organometallic Chemistry 596 (2000) 165–176
Table 6
,
Selected bond lengths (A) and angles (°)
Compound
[Au(OAc)(pmpy)(py)]ClO4
(XXIII)
[Au(ppy)(dpbt)]BPh4
[Au(ppy)(S2CNEt2)]BPh4
(XXXI)
AuCl(pqcm)2
(XXXV)
(XXX) a
Bond lengths
Au–C
1.96(3)
2.02(5)
1.93(5) (N)
2.13(3) (O)
1.88(1), 2.10(2)
2.20(3), 2.02(3)
2.24(1), 2.31(1)
2.32(1), 2.31(1)
2.036(17)
2.058(11)
2.291(4) (S)
2.376(4) (S)
2.033(11)
2.223(9)
2.007(10) (C)
2.388(3) (Cl)
Au–N b
c
Au–L1
d
Au–L2
Bond angles
C–Au–N
C–Au–L1
L2–Au–N
L1–Au–L2
87.0
92.0
94.0
87.0
78.0(7), 84.0(8)
106.3(2), 98.0(8)
88.3(8), 90.8(7)
87.4(4), 87.3(4)
82.2(5)
99.0(4))
103.7(3)
75.19(14)
81.0(4)
88.2(5)
105.2(3)
85.8(3)
a There are two independent cations in the crystal; data for both are given.
b N of phenylpyridine/quinoline.
c L1 is the ligand trans to the N of the phenylpyridine/quinoline.
d L2 is the ligand trans to the C of the phenylpyridine/quinoline.
Fig. 3. Structure of the cation [Au(ppy)(S2CNEt2)]+. Significant bond
lengths and angles are given in Table 6.
5PC Fourier transform IR spectrometer in Nujol mulls
Fig. 2. Structure of the cation [Au(ppy)(Ph2PC6H4S)]+. Significant
bond lengths and angles are given in Table 6.
1
between KBr plates. H- and 13C-NMR spectra were
recorded on a Bruker AC-300 spectrometer at respec-
tively 200 and 50.3 MHz in CDCl3 or (CD3)2SO at
25°C using TMS as internal standard. 31P{1H}-NMR
spectra were obtained on a Bruker AC-200 spectrome-
ter; chemical shifts are recorded relative to 85%
aqueous H3PO4.
3. Conclusions
The chemistry of 2-pheylpyridines orthometallated
by gold(III) has been extended. It appears to be very
similar to that of the corresponding aurated benzyl-
amine, in that the C,N-coordination is tightly held
during substitution. In other cases, such as the metal-
lated azobenzene [6,7] and aromatic Schiff-base deriva-
tives [34,35], the N-donor is displaced by for example, a
tertiary phosphine.
4.1. Substituted phenylpyridines (IV–VII)
The pyridine (0.10 mol) in ether (30 cm3) was added
dropwise to a refluxing solution of phenyl lithium
(0.1 mol) in ether (30 cm3). The solvent was removed
under reduced pressure, being replaced by freshly
distilled toluene (100 cm3). Refluxing was continued
for 8 h, after which the mixture was cooled and water
(35 cm3) was added cautiously and with continuous
stirring. The aqueous layer was separated and extracted
repeatedly with ether. The extracts were added to
the toluene layer, the whole was dried (KOH) and
4. Experimental
Elemental analyses were carried out by the UMIST
Chemistry Department Microanalytical Service. IR
spectra (4000–300 cm−1) were recorded on a Nicolet

R.V. Parish et al. / Journal of Organometallic Chemistry 596 (2000) 165–176
173
%Hg; w(Hg–C) (cm−1), w(Hg–Cl) (cm−1), l(C–N)py
(cm−1)): VIII, 34.2 (33.9), 2.0 (2.1), 3.8 (3.6), 9.1 (9.1),
n.o.; n.o., 320, 1586: IX, 35.7 (35.7), 2.4 (2.5), 3.7 (3.5),
n.o., 49.6 (49.0); 419, 335, n.o.: X, 37.3 (37.4), 2.8 (2.9),
3.6 (3.4), 7.9 (8.5), 47.6 (47.9); 419, 336, n.o: XI, 37.1
(37.2), 3.3 (3.4), 3.5 (3.3), 8.3 (8.4), 46.3 (46.0); 417, 332,
1599: XII, 40.4 (40.4), 3.6 (3.5), 3.1 (3.1), 7.9 (8.0), 44.9
(45.3); 423, 337, 1599: XVIII, 40.8 (41.0), 2.1 (2.3), 2.5
(2.6), 13.7 (13.4), n.o; 428, 335b, n.o.]
4.4. 2-(Substituted-2-pyridyl)phenyl]dichlorogold(III)
(XIII–XVI)
The chloromercury derivative (0.5 mmol) in di-
chloromethane 15 cm3) was added to a solution of
sodium tetrachloroaurate dihydrate (0.20 g, 0.5 mmol)
in acetonitrile (15 cm3), and the mixture was stirred for
about 1 h. An off-white or yellow solid separated and
was washed with acetonitrile (20 cm3) and dried. Re-
crystallisation was effected from dichloromethane.
The pqcm-derivative XIX was obtained analogously.
[Analytical and spectroscopic data (%C, %H, %N, %Cl;
w(Au–C) (cm−1), w(Au–Cl) (cm−1), l(C–N)py
(cm−1)): I, 31.1 (31.3), 1.7 (1.9), 2.9 (3.3), 16.5 (16.8);
412, 363 and 310, 1607: XIII, 33.3 (33.1), 2.1 (2.3), 3.6
(3.2), 15.9 (16.3); 420, 366 and 302, n.o.: XIV, 34.9
(34.9), 2.4 (2.7), 3.2 (3.1), 15.5 (15.8); 415, 380, n.o.:
XV, 35.9 (36.2), 2.7 (3.0), 3.1 (3.0), 15.4 (15.3); 414, 366
and 307, 1618: XVI, 37.7 (38.0), 3.4 (3.3), 2.9 (2.9), 14.8
(14.7); 415, 368 and 307, 1620: XIX, 33.1 (33.2), 2.4
(2.5), 4.1 (3.9), 9.1 (8.9).]
Fig. 4. Structure of [AuCl(pqcm)2]. Significant bond lengths and
angles are given in Table 6.
distilled; clear oils were obtained after two to three
redistillations.
4.2. 2-Phenyl-4-(methylcarboxylate)quinoline (XVII)
2-Phenylquinoline-4-carboxylic acid was prepared by
the method of Ref. [12]. This acid (32.7 g, 0.125 mol)
was refluxed gently with thionyl chloride (14.6 cm3, 0.2
mol) on a water bath for ca. 45 min. The excess thionyl
chloride was removed under reduced pressure and the
residue was washed with diethyl ether (30 cm3). The
crude 2-phenyl-4-benzoylquinoline was recrystallised
from dichloromethane (20 cm3). To the whole yield (27
g, 0.10 mol), kept at 0°C, methanol (15 cm3) was added
dropwise over 30 min. The resulting solution was
refluxed for 2 h and then evaporated to dryness. The
residue was extracted repeatedly with dichloromethane
(portions of 30 cm3) and the combined extracts were
combined, dried (MgSO4) and reduced to about 15 cm3.
White needles of XVII separated during the
evaporation.
4.5. 2-(Substituted-2-pyridyl)phenyl]diacetatogold(III)
(XX–XXII)
Solid silver acetate (0.17 g, 1.0 mmol) was stirred
with a suspension of XIII, XIV or XVI (0.5 mmol) in
dichloromethane (30 cm3) for about 1 h in the absence
of light. The solution was filtered and the residue
extracted with dichloromethane (2 or 3×25 cm3). The
combined dichloromethane solutions were evaporated
to dryness and the residue recrystallised from di-
chloromethane. [Analytical and spectroscopic data
(%C, %H, %N, %X (X=S or Cl); w(Au–C) (cm−1):
39.5 (39.8), 3.2 (3.3), 2.9 (2.9); 415: XXI, 40.9 (41.1), 3.6
(3.7), 2.7 (2.8); 415: XXII, 42.9 (43.5), 3.6 (4.2), 2.7
(2.7); 414: XXII 42.9 (43.5), 3.6 (4.2), 2.7 (2.7); 414.]
4.3. 2-(Substituted-2-pyridyl)phenyl]chloromercury
(VIII–XII)
The phenylpyridine (0.1 mol) in ethanol (50 cm3) was
added slowly to a stirred solution of mercury(II) acetate
(32.0 g, 0.1 mol) in ethanol (100 cm3). The mixture was
refluxed for 12 h and filtered (hot) into a solution of
lithium chloride (6.0 g, 0.14 mol) in methanol (20 cm3).
This mixture was refluxed for a further hour and al-
lowed to cool overnight. The precipitate was filtered
off, washed with water (50 cm3) and ethanol (50 cm3,
0°C) and recrystallised from dichloromethane (30 cm3).
The pqcm-derivative XVIII was obtained similarly.
[Analytical and spectroscopic data (%C, %H, %N, %Cl,
4.6. Acetato(2-2-methylpyridylphenyl)(pyridine)gold(III)
perchlorate (XXIII)
Solid pyridinium perchlorate (0.09 g, 0.5 mmol) was
added to a solution of XXI (0.23 g, 0.5 mmol) in
dichloromethane (20 cm3). The mixture was stirred for
1 h and concentrated to 10 cm3. Addition of ether (5
cm3) gave a white solid, which was recrystallised from

174
R.V. Parish et al. / Journal of Organometallic Chemistry 596 (2000) 165–176
dichloromethane–ether. [%C, %H, %N, w(AuC)
(cm−1)=35.0 (34.9), 2.5 (2.9), 4.2 (4.1), 414.]
4.10. (2-2-Pyridylphenyl)(2-diphenylphosphino-
phenylthiolato)gold(III) tetraphenylboronate (XXX)
A solution of 2-diphenylphosphinobenzenethiol (0.15
g, 0.5 mmol) in THF (20 cm3) was added dropwise to a
stirred suspension of dichlorogold complex I (0.21 g,
0.5 mmol) in THF (20 cm3). The mixture was stirred for
about 1 h, giving a clear solution that was then concen-
trated (15 cm3). Addition of sodium tetraphenyl-
boronate (0.19 g, 0.55 mmol) in methanol (20 cm3) gave
an immediate yellow precipitate of the product, which
was washed with methanol (20 cm3) and di-
chloromethane (20 cm3) and recrystallised from dmf–
ether. [%C, %H, %N, %S, w(Au–C) (cm−1), w(Au–S)
(cm−1)=65.8 (66.1), 3 (4.4), 3.9 (3.8), 3.7 (3.3), 413,
310.]
4.7. 2-(Substituted-2-pyridyl)phenyl](1,2-
ethanedithiolato)gold(III) (XXIV, XXV)
A solution of 1,2-ethanedithiol (42 ml, 0.5 mmol) in
methanol (10cm3) was treated with triethylamine (0.14
cm3, 1.0 mmol) and added dropwise to a suspension of
the dichlorogold complex I or XIII (0.5 mmol) in
methanol (20 cm3). The mixture was stirred for about 3
h and evaporated to dryness. The residue was recrys-
tallised from dichloromethane. [Analytical and spectro-
scopic data (%C, %H, %N, %S, w(Au–C) (cm−1),
w(Au–S) (cm−1): XXIV, 35.3 (35.2), 2.9 (2.7), 3.4 (3.2),
14.8 (14.5), 408, 327 and 373: XXV, 38.2 (37.9), 3.2
(3.4), 2.9 (3.0), 13.6 (13.6), n.o., 322 and 374.]
4.11. (2-2-Pyridylphenyl)(dialkydithiocarbamato)-
gold(III) salts (XXXI, XXXII)
4.8. 2-(Substituted-2-pyridyl)phenyl]-
(thiomalato)gold(III) (XXVI, XXVII)
A solution of sodium dialkyldithiocarbamate (0.5
mmol) in acetone (5 cm3) was added dropwise to a
solution of the dichloro complex I (0.5 mmol) in ace-
tonitrile (20 cm3), giving an orange coloration. After 30
min stirring, the mixture was filtered and a solution of
sodium hexafluorophosphate or tetraphenylboronate
(0.55 mmol) in methanol (5 cm3) was added. The
mixture was stirred for a further 30 min and the
precipitated product was filtered off, washed with ace-
tone (10 cm3) and recrystallised from dmf–ether. The
pqcm-derivative XXXIV was obtained similarly. [Ana-
lytical and spectroscopic data (%C, %H, %N, %S,
w(Au–C) (cm−1, w(Au–S) (cm−1): XXXI, 25.8 (25.8),
1.9 (2.6), 4,1 (4.3), 9.8 (9.8), 413, 327 and 376: XXXII,
58.7 (58.4), 4.7 (5.0), 3.4 (3.3), 7.8 (8.4), 412, 354b and
375: XXXIV, 33.1 (33.2), 2.4 (2.5), 4.1 (3.9), 9.1 (8.9,
n.o., n.o.]
Solid mercaptosuccinic acid (80 mg, 0.5 mmol)
was added to a stirred solution of the dichlorogold
complex I or XIII (0.5 mmol) in acetone (15 cm3).
The pale yellow precipitate which formed immediately
was filtered off, washed with water, ethanol and
ether, and dried. [For XXVII, %C, %H, %N, %S,
w(Au–C) (cm−1): 36.3 (36.8), 2.9 (2.9), 2.6 (2.7), 6.2
(6.1), 419.]
4.9. (2-2-Pyridylphenyl)(2-aminoethylthiolato)-
chlorogold(III) (XXVIII) and (2-2-pyridylphenyl)-
(2-aminoethylthiolato)gold(III) tetraphenylboronate
(XXIX)
2-Mercaptoethylamine hydrochloride (60 mg, 0.5
mmol) in methanol (10 cm3) was treated with triethyl-
amine (70 ml, 0.5 mmol), filtered, and added with
stirring to a solution of dichlorogold complex I (0.21 g,
0.5 mmol) in methanol (20 cm3). A yellow precipitate
formed immediately, which was filtered off, washed
with water, ethanol and ether, dried, and characterised
as complex XXVIII. [%C, %H, %N, %S, w(Au–C)
(cm−1), w(Au–S) (cm−1)=33.8 (34.5), 3.1 (3.3), 6.1
(6.3), 6.9 (7.3), 411, 316 and 386.]
4.12. [2-(t-Butyl-2-pyridyl)phenyl]bis(dimethyldithio-
carbamato)-gold(III) (XXXIII)
A solution of sodium dimethyldithiocarbamate (1.0
mmol) in acetone (15 cm3) was added dropwise to a
solution of the dichloro complex XVI (0.5 mmol) in
acetonitrile (20 cm3), giving an intense orange col-
oration. The mixture was stirred for 1 h and filtered.
The filtrate was evaporated to dryness, and the residue
extracted with dichloromethane (10 cm3). Slow evapo-
ration of the extract gave the crystalline product. [%C,
%H, %N, %S, w(Au–C) (cm−1=38.8 (39.0), 4.3 (4.4),
6.4 (6.5), 20.6 (19.8), 414.]
Dropwise addition of sodium tetraphenylboronate
(0.19g, 0.55 mmol) in methanol (10 cm3) to the above
solution gave precipitation of a pale yellow solid, which
was filtered off and washed with ethanol and ether.
Recrystallisation
from
dimethylformamide–ether
4.13. Crystallography
yielded dark yellow crystals of XXIX. [%C, %H, %N,
%S, w(Au–C) (cm−1), w(Au-S) (cm−1)=59.3 (59.6),
4.8 (4.6), 3.9 (3.8), 4.7 (4.3), 411, obsc.]
Details of the crystal data, data-collection, and least-
square parameters are summarised in Tables 7 and 8.

R.V. Parish et al. / Journal of Organometallic Chemistry 596 (2000) 165–176
175
Table 7
Crystallographic details for XXIII and XXX
Table 8
Crystallographic details for XXXIII and XXXV
Compound
Au(OAc)(pmpy)- [Au(ppy)(Ph2PC6H4S)]-
(py)ClO4 (XXIII) BPh4 (XXX)
Compound [Au(ppy)(S2CNEt2)]- AuCl(pqcm)2
BPh4 (XXXIII)
CCDC Reference No. 121692
(XXXV)
CCDC Reference No. 121694
121693
121695
Empirical formula
Formula weight
Temperature (K)
C20H20AuCl3N2O6 C53H42AuBNPS
Empirical formula
Formula weight
Temperature (K)
Wavelength
Crystal system,
space group
C40H38AuBN2S2
818.62
293(2)
0.71069
Monoclinic,
Cc
C34H24AuClN2O4
756.97
293(2)
0.71069
Triclinic,
687.70
963.68
293(2)
291(2)
,
Wavelength (A)
0.71069
Monoclinic,
P21/n
0.71069
Orthorhombic,
Pna21
Crystal system,
(
space group
Unit cell dimensions
P1
Unit cell dimensions
,
a
b
c
10.7054(10)
13.163(2)
16.958(2)
91.40(2)
31.577(5)
9.742(2)
27.611(3)
a (A)
11.499(2)
33.114(4)
9.439(2)
11.946(2)
12.022(2)
10.9394(10)
96.46(2)
99.43(2)
62.28(2)
1406.1(4)
2, 1.788
5.370
,
b (A)
,
c (A)
i
h (°)
i (°)
k (°)
3
,
Volume (A )
2388.9(5)
8494(2)
8, 1.507
102.06(2)
Z, calculated density 4, 1.912
(Mg m−3
)
Volume (A )
3514.6
4, 1.547
3
,
Absorption
6.532
3.589
Z, Dcalc (Mg m−3
)
coefficient (mm−1
)
Absorption coefficient 4.335
(mm−1
F(000)
Crystal size (mm)
q range for data
collection (°)
F(000)
1328
0.25×0.25×0.15
2.27–25.04
3856
0.3×0.25×0.25
1.47–23.97
)
Crystal size (mm)
q range for data
collection (°)
1632
0.30×0.15×0.15
1.23–24.96
740
0.30×0.25×0.20
2.50–25.00
Index ranges
−125h512,
05k515,
05l520
−365h5−10,
−115k50,
−75l5−31
4216/4117
Index ranges
05h513,
05k539,
−115l510
−145h514,
−145k514,
05l512
Reflections collected/ 4116/4116
unique
Completeness to
2q=25.04
[Rint=0.0000]
92.8%
[Rint=0.01211]
60.6%
Reflections collected/ 3208/3208
4791/4791
[Rint=0.0000]
96.7%
unique
[Rint=0.0000]
Completeness to
2q=25.04
49.4%
Refinement method
Full-matrix least- Full-matrix least-
squares on F2
4116/0/290
squares on F2
4117/165/490
Refinement method
Full-matrix least-
squares on F2
3208/2/415
Full-matrix least-
squares on F2
4791/0/382
Data/restraints/
parameters
Data/restraints/
Goodness-of-fit on F2 1.038
1.015
parameters
Final R indices
[I\2|(I)]
R indices (all data)
R1=0.0787,
R1=0.0673,
wR2=0.1138
R1=0.0949,
wR2=0.1272
0.00004(3)
Goodness-of-fit on F2 1.001
1.046
R1=0.0482,
WR2 =0.1210
R1=0.0870,
wR2=0.1348
0.0003(2)
wR2=0.1576
R1=0.1606,
wR2=0.2080
Final R indices
[I\2|(I)]
R indices (all data)
R1=0.0318,
wR2=0.0748
R1=0.00878,
wR2=0.0934
Extinction coefficient 0.0005(2)
Largest difference
peak and hole
1.007 and −2.324 0.760 and −0.704
Extinction coefficient
Largest difference
0.590 and −1.069
1.816 and −1.405
(e A−3
)
peak and hole
3
,
(e A )
refinements were made, on the assumption that the
pyridine was trans to the phosphine or to the thiol
group. The former model was chosen since it gave
slightly lower residuals and more consistent bond dis-
tances and vibrational parameters. The R-values were
Data were collected on a Rigaku/MSC AFC6S (for
XXIII, XXXV and XXXIII) or an Enraf–Nonius
CAD4 diffractometer (XXX), both with monochro-
,
mated Mo–Ka radiation (u=0.71069 A). All structures
2
2
were solved by direct methods [36] and refined versus
defined as R1=ꢀꢁꢁFoꢁ−ꢁFcꢁ /ꢀꢁFoꢁ
and wR2=
F2
(SHELXL-97) [37]. All non-hydrogen atoms were
[ꢀ(w(Fo2 −Fc2)2/ꢀwFo4]1/2
.
refined anisotropically. A riding model starting from
calculated positions was employed for the hydrogen
atoms. In structure XXX each asymmetric unit com-
prises two formula units. The chemically and conforma-
tionally identical ions were constrained so that their
bond lengths and second-neighbour distances (angles)
5. Supplementary material
Further details of the crystal structure determinations
may be obtained from The Director, CCDC, 12, Union
Road, Cambridge CB2 1EZ, UK (fax: +44-1223-336-
,
were equal within standard deviations of 0.02 A. Two

176
R.V. Parish et al. / Journal of Organometallic Chemistry 596 (2000) 165–176
[16] E.C. Constable, T.A. Leese, J. Organomet. Chem. 335 (1987)
293.
[17] J.P. Wright, PhD Thesis, Manchester, 1995.
[18] P.-A. Bonnardel, R.V. Parish, J. Organomet. Chem. 515 (1996)
221.
033) or e-mail: deposit@ccdc.cam.ac.uk or http://
www.ccdc.cam.ac.uk, quoting the reference numbers in
Tables 7 and 8.
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