Synthesis and characterisation of some azo-containing phosphine complexes of Au(I): Crystal and molecular structure of [Au(CCPh){6-P(Ph)2-1-(4-Me2N-C6H 4N2)-C10H5-2-OH}]·CHCl <su

Article abstract of DOI:10.1016/S0022-328X(01)00841-5

Reduction of Na[AuCl₄] followed by in situ addition of a stoichiometric amount of L{L=1-(4-R-C₆H₄)-2-OR′-6-Ph₂P-C ₁₀H₅; R′=H, R=Me (I); R=NMe₂ (II); R=NO₂ (III); R′=C(

Full text of DOI:10.1016/S0022-328X(01)00841-5

Journal of Organometallic Chemistry 629 (2001) 153–159
www.elsevier.com/locate/jorganchem
Synthesis and characterisation of some azo-containing phosphine
complexes of Au(I): crystal and molecular structure of
[Au(CꢀCPh){6-P(Ph)2-1-(4-Me2NꢁC6H4N2)ꢁC10H5-2-OH}]·CHCl3
Mark J. Alder, Kevin R. Flower *, R.G. Pritchard
Department of Chemistry, UMIST, P.O. Box 88, Manchester M60 1QD, UK
Received 28 February 2001; accepted 4 April 2001
Abstract
Reduction of Na[AuCl4] followed by in situ addition of a stoichiometric amount of L{L=1-(4-RꢁC6H4)-2-OR%-6-Ph2PꢁC10H5;
R%=H, R=Me (I); R=NMe2 (II); R=NO2 (III); R%=C(O)Me; R=Me (IV); R=NMe2 (V)} affords the Au(I) complexes
[LAuCl] 1a–1e (L=I, 1a; II, 1b; III, 1c; IV, 1d; V, 1e) in good yield. Treatment of 1a–1c with two molar equivalents of LiCꢀCR¦
(R¦=Ph, nBu) affords the acetylide containing complexes [Au(CꢀCR%%)L] 2a–2f {R=Ph, L=I, 2a, L=II, 2b, L=III, 2c;
R=nBu, L=I, 2d, L=II, 2e, L=III, 2f} in good yield. The reaction of 1d or 1e with LiCꢀCPh affords 2a and 2b, respectively,
in which reaction of the acetylide ion with the complex takes place both at the metal centre and the ester group of the phosphine
ligand. All of the compounds have been fully characterised by spectroscopic techniques and 2b·CHCl3 by a single crystal X-ray
diffraction study. The solid state structure of 2b·CHCl3 shows a close Cl3CH···CꢀC p-interaction and no Au···Au interaction.
© 2001 Elsevier Science B.V. All rights reserved.
Keywords: Gold; Alkynyl; Crystal structure
describe the preparation of a series of azo-containing
phosphine complexes of gold(I).
1. Introduction
The first reported alkynyl gold compound dates from
1900 [1] and since that date many compounds have
been prepared [2]. Current interest in Au(I) compounds
2. Results and discussion
derives from the observation of close Au···Au interac-
2.1. Preparation of azo-containing phosphine–gold(I)
tions [3] which have recently led to the synthesis, in
chloride complexes
association with AuꢁS interactions, to homoleptic gold
thiolate catenanes [4]. Other gold-containing catenane
The azo-containing phosphines
L
{L=1-(4-
systems are known and are derived from acetylide
based systems [5] and strategies for synthesising large
rings have been described [6], and some of the com-
pounds prepared show luminescent properties. In addi-
tion to the interest in Au···Au interactions a series of
alkynylgold phosphine complexes have been prepared
and their non-linear optical properties assessed [7].
We recently reported the synthesis of a series of
azo-containing phosphines [8] and have been investigat-
ing their coordination chemistry [9]. In this paper, we
RꢁC6H4)-2-OR%-6-Ph2PꢁC10H5; R%=H, R=Me (I);
R=NMe2 (II); R=NO2 (III); R%=C(O)Me; R=Me
(IV); R=NMe2 (V)} Fig. 1, were added, dissolved in
CHCl3, to a reduced solution of Na[AuCl4] using the
* Corresponding author. Tel.: +44-161-200-4538.
E-mail address: k.r.flower@umist.ac.uk (K.R. Flower).
Fig. 1. Azo-containing phosphines L. R%=H, R=Me (I), NMe2 (II),
NO2 (III); R%=C(O)Me, R=Me (IV), NMe2 (V).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00841-5

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M.J. Alder et al. / Journal of Organometallic Chemistry 629 (2001) 153–159
Table 1
Physical a and analytical data b for complexes 1a–1e and 2a–2f
Compound
Colour
Yield
m.p. (°C)
Microanalysis ((%))
C
H
N
1a·0.5CHCl3
1b
1c
1d
Red
Red
Black
Red
Black
Red
Red
Black
Red
Red
Black
83
73
85
72
59
64
93
78
71
94
59
256
258
210
236
222
218
180
196
150
232
262
48.4 (48.0)
50.1 (50.9)
47.4 (47.3)
52.5 (51.6)
52.0 (52.3)
53.0 (52.8)
53.6 (53.6)
55.4 (55.8)
55.1 (54.6)
51.3 (50.9)
52.5 (52.4)
2.9 (3.2)
3.4 (3.7)
3.7 (3.0)
3.2 (3.5)
4.0 (3.8)
3.4 (3.4)
2.8 (3.6)
3.7 (3.3)
3.5 (4.1)
3.1 (3.7)
3.5 (3.8)
3.6 (3.8)
5.2 (5.9)
6.2 (6.2)
3.5 (3.9)
5.0 (5.7)
2.7 (3.2)
4.7 (4.7)
4.4 (5.3)
3.7 (3.6)
5.1 (4.8)
4.8 (5.3)
1e
2a·CHCl3
2b·0.8CHCl3
2c
2d·0.5CHCl3
2e·CHCl3
2f·0.25CHCl3
a All compounds soften before melting.
b Calculated values in parentheses.
Table 2
31P{1H}-NMR a and proton b data for complexes 1a–1e and 2a–2f
Complex
31P (l ppm)
1H (l ppm)
1a
34.1
16.1 (s, 1H, OH); 8.7 (dd, [JHH=8.5 Hz, JHH=2.3 Hz], 1H, aryl-H); 7.9 (dd, [JPH=14.8 Hz, JHH=1.5 Hz],
1H, aryl-H); 7.7–7.3 (bm, 16H, aryl-H); 7.1 (d, [JHH=9.1 Hz], 1H, aryl-H); 2.4 (s, 3H, CH3)
16.2 (s, 1H, OH); 8.4–7.4 (bm, 18H, aryl-H); 6.7 (d, [JHH=9.8 Hz], 1H, aryl-H)
16.0 (s, 1H, OH); 8.6 (d, [JHH=6.5 Hz], 1H, aryl-H); 7.9–7.5 (bm, 17H, aryl-H); 7.0 (d, [JHH=9.5 Hz], 1H,
aryl-H); 3.2 (s, 6H, CH3)
1b
1c
34.1
34.2
1d
1e
34.1
33.3
8.7 (d, [JHH=6.8 Hz], 1H, aryl-H); 8.2 (d, [JPH=15.6 Hz], 1H, aryl-H); 7.9–7.8 (bm, 3H, aryl-H); 7.6–7.3 (bm,
14H, aryl-H); 2.5 (s, 3H, CH3); 2.3 (s, 3H, CH3)
8.7 (dd, [JHH=8.7 Hz, JHH=2.0 Hz], 1H, aryl-H); 8.1 (d, [JPH=14.3 Hz], aryl-H); 7.9–7.3 (bm, 12H, aryl-H);
6.8 (d, [JHH=9.3 Hz], 2H, aryl-H); 3.1 (s, 6H, CH3); 2.3 (s, 3H, CH3)
2a
2b
43.3
43.3
16.2 (s, 1H, OH); 8.7 (d, [JHH=8.3 Hz], 1H, aryl-H); 8.1–7.0 (bm, 24H, aryl-H); 2.4 (s, 3H, CH3)
16.0 (s, 1H, OH); 8.5 (d, [JHH=7.0 Hz], 1H, aryl-H); 8.3 (d, [JHH=8.5 Hz], 1H, aryl-H); 7.9–6.9 (bm, 21H,
aryl-H); 6.8 (d, [JHH=9.5 Hz], 1H, aryl-H)
2c
2d
43.6
30.8
15.7 (s, 1H, OH); 8.9 (d, [JHH=7.3 Hz], 1H, aryl-H); 8.7 (d, [JHH=6.8 Hz], 1H, aryl-H); 8.2–7.2 (bm, 21H,
aryl-H 6.8 (dd, [JHH=9.3 Hz, JHH=2.0 Hz], 1H, aryl-H); 3.1 (s, 6H, CH3)
16.1 (s, 1H, OH); 8.7 (dd, [JHH=8.4 Hz, JHH=2.0 Hz], 1H, aryl-H); 7.9 (d, [JPH=14.0 Hz], 1H, aryl-H);
7.7–7.3 (bm, 16H, aryl-H); 7.0 (d, [JHH=8.6 Hz], 1H, aryl-H); 2.4 (s, 3H, CH3); 2.4 (t, [JHH=7.0 Hz], 2H,
CH2); 1.5 (m, [JHH=7.0 Hz], 4H, CH2); 0.6 (t, [JHH=6.8 Hz], 3H, CH3)
2e
2f
30.1
29.8
16.0 (s, 1H, OH); 8.5 (d, [JHH=8.3 Hz], 1H, aryl-H); 8.3 (d, [JHH=9.0 Hz], 1H, aryl-H); 7.7–7.4 (bm, 16H,
aryl-H); 6.8 (d, [JHH=9.8 Hz], 1H, aryl-H); 2.4 (t, [JHH=5.8 Hz], 2H, CH2); 1.5 (m, [JHH=6.0 Hz], 4H, CH2);
0.6 (t, [JHH=6.0 Hz], 3H, CH3)
15.6 (s, 1H, OH); 8.8 (d, [JHH=8.3 Hz], 1H, aryl-H); 8.6 (d, [JHH=10.5 Hz], 1H, aryl-H); 8.2–7.2 (bm, 16H,
aryl-H); 6.8 (dd, [JHH=9.3 Hz, JHH=2.3 Hz], 1H, aryl-H); 3.1 (s, 6H, CH3); 2.4 (t, [JHH=7.0 Hz], 2H, CH2);
1.5 (m, [JHH=4.5 Hz], 4H, CH2); 0.6 (t, [JHH=6.8 Hz], 3H, CH3)
a Spectra recorded in CDCl3 (298 K) and referenced to 85% H3PO4.
b Spectra recorded in CDCl3 (298 K) and referenced to CHCl3, J=Hz; s=singlet, d=doublet, t=triplet, m=multiplet, b=broad.
distinctive sharp singlet at ca. 16 ppm which disappears
on addition of D2O and is indicative of the strongly
hydrogen-bonded OH proton; whereas, compounds
1d–1e display a singlet resonance at 2.3 ppm indicative
of the methyl group of acetyl ester.
All of the compounds showed a sharp singlet ca. 34
ppm in their 31P{1H}-NMR spectrum which is at sig-
nificantly higher frequency than the parent phosphines
[8] and comparable to that observed for [AuCl(PPh3)]
[11].
method of Parish et al. [10]. After stirring for 2 h and
recrystallisation [AuCl(L)] 1a–1e (L=I, 1a; II, 1b; III,
1c; IV, 1d; V, 1e) were obtained in good yield. All of
the compounds were characterised by elemental analy-
sis (C, H, N) (Table 1); 1H-, 31P{1H}-NMR spec-
troscopy (Table 2); 13C{1H}-NMR spectroscopy (Table
3); and UV–vis spectroscopy (Table 4).
The H-NMR spectra for 1a–1e are little perturbed
from those observed for the free azo-containing phos-
phines [8]. For example, compounds 1a–1c show a
1

M.J. Alder et al. / Journal of Organometallic Chemistry 629 (2001) 153–159
155
The 13C{1H}-NMR spectra have all been fully as-
signed with the aid of DEPT 135 data, the assigned
spectra of I–V [8], published substituent effects [12] and
the spin coupling to 31P, see Fig. 2 for the numbering
scheme. It is apparent from the data that the position
of the hydroxyazo-ketohydrazone tautomerisation, that
takes place in these phosphine ligands is little perturbed
on complexation to the Au(I) centre in 1a–1c. This can
be deduced from the position of the resonance assigned
to C(2) which is sensitive to the position of the equi-
librium [8a,13] and this is consistent with observations
made on complexation of these ligands to other metal
centres [9]. For 1d–1e resonances at 169.4 and 20.9
ppm are observed for the (CO) and (CH3) groups of the
ester moiety, respectively.
free phosphines [8a] and the molar absorption coeffi-
cients for both the hydrazone- and azo-tautomer were
calculated from the relative position of the equilibrium
using the equation: K=[{l80−lC(2)}/lC(2)−
{lC(2)−lC(2)ester+11}] [8a]. An additional band at
ca. 290 nm observed for 1a–1c has been assigned to a
s(Au’P)“p*(Np) (Np=naphthalene) transition and
is consistent with the assignment of similar absorption
bands in a series of ethynylgold(I) naphthylphosphine
complexes [14b].
2.2. Preparation of azo-containing phosphine–gold(I)
alkynyl complexes
The compounds 2a–2f were prepared from the
chlorogold(I) precursors 1a–1c on reaction with two
The UV–vis spectra of 1a–1e all displayed absorp-
tion bands in similar positions to those observed for the
n
molar equivalents of LiCꢀCR¦ (R¦=Ph or Bu). It was
Table 3
13C{1H}-NMR data a for compounds 1a–1e and 2a–2f
Compound
b
1a
166.0 (s, C(2)); 144.2 (s, C(15)); 139.9 (s, C(18)); 137.5 (s, C(4)); 135.8 (d, [J=16.0 Hz], C(5)); 134.1 (d, [J=13.8 Hz], C(12));
132.0 (s, C(17)); 131.7 (d, [J=11.6 Hz], C(7)); 130.4 (s, C(14)); 129.3 (d, [J=11.6 Hz], C(13)); 124.4 (s, C(3)); 122.7 (d, [J=10.9
Hz], C(8)); 120.0 (s, C(16)); 20.4 (s, CH3)
178.3 (s, C(2)); 147.7 (s, C(18)); 145.1 (s, C(1)); 142.5 (s, C(4)); 135.3 (d, [J=16.7 Hz], C(5)); 134.0 (d, [J=14.5 Hz], C(12));
133.3 (d, [J=12.4 Hz], C(7)); 129.2 (d, [J=10.9 Hz], C(13)); 128.6 (s, C(14)); 126.9 (s, C(3)); 125.6 (s, C(17)); 122.8 (d, [J=10.2
Hz], C(8)); 117.2 (s, C(16))
157.2 (s, C(2)); 152.1 (s, C(18)); 139.4 (s, C(15)); 136.0 (d, [J=15.3 Hz], C(5)); 134.1 (d, [J=13.8 Hz], C(12)); 133.4 (s, C(4));
132.1 (d, [J=10.2 Hz], C(7)); 131.9 (d, [J=2.9 Hz], C(14)); 129.2 (d, [J=11.6 Hz], C(13)); 123.6 (s, C(16)); 123.1 (d, [J=11.6
Hz], C(8)); 122.5 (s, C(3)); 112.0 (s, C(17)); 40.3 (s, CH3)
169.4 (s, CO); 151.3 (s, C(15)); 142.8 (s, C(18)); 139.1 (s, C(1)); 138.4 (s, C(2)); 135.9 (d, [J=15.9 Hz], C(5)); 134.1 (d, [J=13.8
Hz], C(12)); 132.1 (d, [J=2.2 Hz], C(14)); 131.6 (d, [J=13.1 Hz], C(7)); 131.4 (s, C(9)); 131.1 (s, C(4)); 129.3 (d, [J=11.6 Hz],
C(13)); 125.6 (d, [J=10.9 Hz], C(8)); 122.8 (s, C(16)); 119.7 (s, C(3)); 21.5 (s, CH3); 20.9 (s, CH3)
169.4 (s, CO); 153.0 (s, C(18)); 144.5 (s, C(2)); 139.2 (s, C(15)); 138.8 (s, C(1)); 135.7 (d, [J=15.3 Hz], C(5)); 134.1 (d, [J=13.8
Hz], C(12)); 132.1 (d, [J=10.2 Hz], C(10)); 131.8 (d, [J=2.2 Hz], C(14)); 131.5 (d, [J=13.8 Hz], C(7)); 129.4 (s, C(4)); 129.2
(d, [J=11.8 Hz], C(13)); 125.8 (d, [J=10.9 Hz], C(8)); 123.6 (s, C(16)); 122.4 (s, C(3)); 111.4 (s, C(17)); 40.3 (s, CH3); 20.9
(s, CH3)
1b b
1c b
1d b
1e b
2a b
2b b
2c b
166.8 (s, C(2)); 143.9 (s, C(15)); 139.7 (s, C(18)); 137.8 (s, C(4)); 136.0 (d, [J=17.4 Hz], C(5)); 134.2 (d, [J=14.5 Hz], C(12));
132.4 (s, C(21)): 132.1 (d, [J=13.5 Hz], C(7)); 131.6 (s, C(17)); 130.3 (s, C(14)); 130.1 (s, C(1)); 129.2 (d, [J=11.6 Hz], C(13));
127.9 (s, C(22)); 126.8 (s, C(23)); 124.8 (s, C(20)); 124.8 (s, C(3)); 122.6 (d, [J=10.6 Hz], C(8)); 119.8 (s, C(16)); 21.3 (s, CH3)
178.0 (s, C(2)); 147.8 (s, C(18)); 145.3 (s, C(1)); 142.0 (s, C(4)); 135.5 (d, [J=16.7 Hz], C(5)); 134.2 (d, [J=14.5 Hz], C(12));
133.6 (d, [J=10.2 Hz], C(7)); 132.4 (s, C(21)); 129.3 (d, [J=10.9 Hz], C(13)); 127.9 (s, C(22)); 127.2 (s, C(23)); 126.8 (s, C(3));
125.7 (s, C(17)); 124.7 (s, C(20)); 123.0 (d, [J=10.2 Hz], C(8)); 117.4 (s, C(16)); 104.3 (bs, C(19))
156.9 (s, C(2)); 152.0 (s, C(18)); 139.4 (s, C(15)); 136.0 (d, [J=16.0 Hz], C(5)); 134.4 (d, [J=17.4 Hz], C(12)); 133.6 (s, C(4));
133.1 (s, C(9)); 132.4 (s, C(21)); 132.0 (d, [J=8.8 Hz], C(7)); 132.0 (d, [J=2.2 Hz], C(14)); 129.1 (d, [J=11.6 Hz], C(13)); 127.9
(s, C(22)); 126.8 (s, C(23)); 124.8 (s, C(20)); 123.5 (s, C(16)); 122.9 (d, [J=10.2 Hz], C(8)); 122.2 (s, C(3)); 104.0 (bs, C(19)); 40.2
(s, CH3)
166.4 (s, C(2)); 143.8 (s, C(15)); 139.6 (s, C(18)); 137.5 (s, C(4)); 135.7 (d, [J=16.4 Hz], C(5)); 134.0 (d, [J=13.5 Hz], C(12));
131.9 (d, [J=15.4 Hz], C(7)); 131.7 (s, C(17)); 130.2 (s, C(14)); 129.8 (s, C(1)); 129.5 (d, [J=15.5 Hz], C(13)); 124.7 (s, C(3));
122.5 (d, [J=10.5 Hz], C(8)); 119.7 (s, C(16)); 105.7 (bs, C(19)); 30.4 (s, C(21), CH2); 21.8 (s, C(22), CH2); 21.3 (s, CH3); 18.2
(s, C(20), CH2); 13.7 (s, C(23), CH3)
178.6 (s, C(2)); 147.7 (s, C(18)); 145.2 (s, C(1)); 142.4 (s, C(4)); 135.6 (d, [J=15.5 Hz], C(5)); 134.1 (d, [J=13.5 Hz], C(12));
133.7 (d, [J=9.7 Hz], C(7)); 132.3 (d, [J=2.5 Hz], C(14)); 129.3 (d, [J=12.6 Hz], C(13)); 127.1 (s, C(3)); 125.7 (s, C(17)); 123.1
(d, [J=10.6 Hz], C(8)); 117.3 (s, C(16)); 29.6 (s, C(21)); 22.2 (s, C(22), CH2); 18.2 (s, C(20), CH2); 13.1 (s, C(23), CH3)
157.0 (s, C(2)); 152.1 (s, C(18)); 139.4 (s, C(15)); 136.0 (d, [J=15.3 Hz], C(5)); 134.1 (d, [J=13.8 Hz], C(12)); 133.6 (s,
C(4));132.1 (d, [J=10.2 Hz], C(7)); 131.8 (s, C(14)); 129.6 (s, C(1)), 129.2 (d, [J=11.6 Hz], C(13)); 129.2 (d, [J=43.6 Hz],
C(6)); 123.6 (s, C(16)); 123.1 (d, [J=11.6 Hz], C(8)); 122.4 (s, C(3)); 112.0 (s, C(17)); 40.3 (s, CH3); 31.5 (s, C(21), CH2); 22.6
(s, C(22), CH2); 19.2 (s, C(20), CH2); 14.1 (5, C(23), CH2)
2d b,c
2e b,c
2f b
a Spectra recorded in CDCl3 (293 K) and referenced to CDCl3 (l 77.0); s=singlet, d=doublet.
b One or more resonances partially obscured due to overlap.
c Spectrum recorded at 100.6 MHz; see Fig. 2 for numbering scheme.

156
M.J. Alder et al. / Journal of Organometallic Chemistry 629 (2001) 153–159
Table 4
takes place. It appears, qualitatively at least, that the
rates of the two competing reactions are comparable as
on addition of a stoichiometric amount of lithium
acetylide a 50:50 mixture of starting material and
product are obtained; reprotonation of the hydroxyl
group was effected by stirring with a saturated aqueous
solution of NH4Cl.
UV–vis a data for complexes 1a–1e and 2a–2f
Complexes
Hydrazone-form Azo-form
s(Au’P)“p*(Np)
c
c
c
u
b/m
u
b/m
u
b/m
1
2
3
4
491.5/18371
485.0/21258
412.0/17659 299.5/10591
282.0/13833
489.5/19561 280.0/17628
351.5/9017
483.0/2436
442.5/10485
d
Similar reactions of 1d and 1e with a stoichiometric
n
amount LiCꢀCR¦ (Rh¦=Ph, Bu) does not lead to an
d
5
alkynylgold(I) species, rather compounds 1a and 1b are
isolated. This presumably results from preferential
acetylide attack on the ester moiety. In an attempt to
prepare the ester containing alkynylgold(I) complexes
compounds 2a and 2b were each reacted with one mole
equivalent of NaH to generate the naphthalide anion,
which imparted a deep red colouration to the solution,
and then reacted with acetyl chloride; once again only
1a and 1b were isolated and this suggested that the gold
complex acts as an efficient alkynylating agent and that
complexes containing the ester-functionalised azo-con-
taining phosphines are intrinsically unstable. This was
simply confirmed by adding IV to 2a and observing the
formation of I, 1a and PhCCC(O)Me [15]. Another
example of Au(I) alkynyl complexes behaving in this
manner is the reaction between [Au(CꢂCPh)(PPh3)] and
HgCl2 to give [Hg(CꢀCPh)2] [16].
6
7
8
9
10
11
490.5/16553
485.0/10204
414.5/15237 296.5/11897
282.0/13833
504.0/11778 280.0/17150
412.0/14771 291.0/12493 (sh)
280.0/11184 (sh)
491.0/15285
484.5/11000
504.0/16564 276.0/16898
a Spectra recorded in CHCl3.
b umax=nm.
c m=dm3 mol−1 cm−1
.
d Band obscured; sh=shoulder.
All of the compounds 2a–2f were characterised by
1
elemental analysis (C, H, N) (Table 1); H-, 31P{1H}-
NMR spectroscopy (Table 2); 13C{1H}-NMR spec-
troscopy (Table 3); and UV–vis spectroscopy (Table 4).
The H-NMR spectra for 2a–2f are little perturbed
1
Fig. 2. Numbering scheme for 13C{1H}-NMR data.
from those observed for the free azo-containing phos-
phines [8a]. For example, all of the compounds show a
distinctive sharp singlet at ca. 16 ppm which disappears
on addition of D2O and is indicative of the strongly
hydrogen-bonded OH proton. The resonances at-
found that two molar equivalents of the lithium
acetylide were required as deprotonation of the hy-
droxyl group as well as metathesis of the AuꢁCl bond
Fig. 3. ORTEP representation of 2c showing the atomic numbering scheme.

M.J. Alder et al. / Journal of Organometallic Chemistry 629 (2001) 153–159
157
tributable to the n-butyl moiety of the acetylide ligand
appear where expected based upon substituent effects
[17].
compounds tenaciously hold onto CHCl3 on recrystalli-
sation. The relevance of these types of interactions
arises from the mode of electrophilic attack on the CꢀC
bond, i.e. the addition of HX to an alkyne, in which the
first step is believed to be the formation of a weakly
H-bound complex with a T-shaped configuration. Crys-
tallographically characterised examples of these types
of complex have been previously reported [14,19] and
this structure offers another example.
The compounds 2a–2c showed a sharp singlet ca. 43
ppm which is at higher frequency than the chloro–
phosphine complex and comparable to the value 43.1
ppm reported by Humphrey et al. for the analogous
complex [Au(CꢀCPh)(PPh3)] [7]. The nBu–acetylide
complexes all show a resonance around 30 ppm which
is at lower frequency than the parent chloro-containing
complex and suggests that the nature of the acetylide
affects the 31P{1H}-NMR resonant frequency, whereas
the R-groups on the 4-R-phenyl-azo groups appear to
have no influence.
3. Conclusions
A collection of new gold(I) azo-containing phosphine
complexes have been prepared and characterised. The
alkynyl-containing complexes have been shown to act
as alkynylating agents towards the ester functional
group in the ligated azo-containing phosphines.
The 13C{1H}-NMR spectra have all been assigned in
a manner similar to that for the chloro-containing
complexes 1a–1e. The aurated C-atom of the acetylide-
ligand was not observed for any of the compounds and
this is presumably due to the quadrapolar broadening
effect of the 197Au (100%) nucleus. The non-aurated
carbon C(19) for 2a–2c appears ca. 104 ppm which is
comparable to that observed in [Au(CꢀCPh)(PPh3)] [7].
The UV–vis spectra seem little affected on exchange
of the chloride by acetylide and the molar extinction
coefficients for the two tautomers were calculated as-
suming the position of the ketohydrazone/hydroxyazo
tautomerisation was unaffected, by the chloride–
acetylide exchange. This assumption is justifiable as the
C(2) resonances for 2a–2f are in the same position
observed for the parent chloro-compounds 1a–1c [8a].
4. Experimental
All solvents were dried by refluxing over an appropri-
ate drying agent and distilled prior to use. All other
chemicals were obtained from commercial sources and
used as received except for Na[AuCl4] which was
loaned by Johnson Matthey. Melting points were mea-
sured on a Griffin Melting Point apparatus and are
uncorrected. 1H-NMR (200.2 MHz) and 31P{1H}-NMR
(81.3 MHz) spectra were recorded on a Bruker DPX
200 spectrometer and 13C{1H}-NMR (75.6 or 100.6
MHz) spectra were recorded on either a Brucker DPX
300 or Brucker DPX 400 spectrometer. 1H- and
13C{1H}-NMR spectra were referenced to CHCl3 (l=
7.26) and CHCl3 (l=77.0) and 31P{1H}-NMR was
referenced externally to 85% H3PO4. Elemental analyses
were performed by the Microanalytical Service, Depart-
ment of Chemistry, UMIST; solvates of crystallisation
were confirmed by repeated elemental analysis. UV–vis
spectra were recorded on a Shimadzu UV20101 PC
spectrophotometer in CHCl3 in 1 cm cuvettes. The
syntheses of all complexes were carried out under a
dinitrogen atmosphere using standard Schlenk tech-
niques. Work-ups were generally carried out in the
open unless otherwise stated.
2.3. Molecular structure of
[Au(CꢀCPh){6-P(Ph)2-1-(4-Me2NꢁC6H4N2)-
C10H5-2-OH}]·CHCl3 (2c)
Little comment can be made about the solid state
structure of 2c due to the poor quality of the data, see
Fig. 3 for the atomic numbering scheme. The structure
confirms the spectroscopic data and shows that there
are no close Au···Au interactions: the closest approach
,
is 8.9 A. The structure also confirms the CHCl3 solvate
of crystallisation and offers some explanation as to why
the alkynyl-containing complexes 2a–2f tenaciously
hold onto chloroform. The chloroform solvate was
located directly above the CꢀC triple bond effecting a
Cl3CH···CꢀC p-interaction. Although the H atom was
not located the orientation of the three CꢁCl bonds and
the distance of the C(39) of the CHCl3 solvate to C(31)
4.1. [AuCl{6-P(Ph)2-1-(4-MeꢁC6H4N2)ꢁC10H5-2-OH}]
(1a)
,
and C(32)-atoms of the CꢀC bond of 3.45 A is com-
To Na[AuCl4]·2H2O (0.27 g, 0.67 mmol) dissolved in
H2O (30 cm3) at 0°C was added 2,2%-thiodiethanol (0.25
g, 2.0 mmol) over 15 min. After stirring for 1 h, I (0.3
g, 0.67 mmol), dissolved in CHCl3 (10 cm3), was added
at 0°C and stirred for a further 1 h. CHCl3 (30 cm3)
was then added to the mixture and the organic layer
was separated and dried over anhydrous MgSO4. After
parable to that reported by Mingos et al. in the crystal
structure of [{{Np(Ph)2P}Au}2(CꢀC)] [14]. Calculations
reported by Mingos et al. suggest that interactions of
this nature have energies of ca. 25 kJ mol−1 and are
comparable in strength to hydrogen-bonded systems
[18] and offers a good explanation as to why these

158
M.J. Alder et al. / Journal of Organometallic Chemistry 629 (2001) 153–159
filtration and removal of the solvent under reduced
pressure, recrystallisation of the crude material from
CHCl3–hexane afforded 1a·0.25CHCl3 as a red solid
(0.38 g, 83%). In an analogous manner, complexes 1b,
1c, 1d and 1e were obtained; see Table 1 for physical
and analytical data.
101.75(3), i=92.85(5), k=91.03(2)°, Z=2. The ꢀ/2q
scan technique was used with an ꢀ scan width of
(0.9°+0.35 tan q) to collect reflections with 2q550°.
The intensities were corrected for Lorenz polarisation
and absorption (4.386 mm−1). The SHELX-97 suite of
programs [20] were used to solve the structure by direct
methods and refined using full-matrix least-squares
based on F2, hydrogen atoms were constrained to
chemically reasonable positions: R [I\2|(I)], R1=
0.1138, wR2=0.2135; R (all data), R1=0.2365, wR2=
0.2742.
4.2. [Au(CꢀCPh){6-P(Ph)2-1-(4-MeꢁC6H4N2)ꢁ
C10H5-2-OH}] (2a)
To phenylethyne (0.1 cm3, 0.88 mmol) dissolved in
dry THF (10 cm3), with continuous stirring under an
n
atmosphere of dry dinitrogen, at 0°C was added BuLi
(0.35 cm3, 2.5 M in hexanes, 0.88 mmol). After stirring
for 10 min, 1a (0.2 g, 0.29 mmol) was added and the
mixture stirred for a further 2 h at 0°C. Saturated
NH4Cl(aq) solution (5 cm3) was then added to the
mixture and the solvent was removed in vacuo. The
residue was extracted into CH2Cl2 (10 cm3) and dried
over anhydrous MgSO4. Filtration followed by removal
of the solvent under reduced pressure and recrystallisa-
tion from CHCl3–hexane afforded 2a·CHCl3 as a red
solid (0.14 g, 64%). In an analogous manner, complexes
2b·0.8CHCl3 and 2c were prepared; see Table 1 for
physical and analytical data. Single crystals of 2a used
in the diffraction study were grown by diffusion of
hexane into a saturated solution of 2a in CHCl3.
5. Supplementary material
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC no. 158667. Copies of this infor-
mation may be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge CB2
1EZ, UK (Fax: +44-1223-336033; e-mail: deposit@
ccdc.cam.ac.uk or www: http://www.ccdc.cam.ac.uk).
Acknowledgements
M.J.A. would like to thank the EPSRC for the award
of postgraduate studentship. We also thank Johnson
Matthey for the loan of Na[AuCl4].
4.3. [Au(CꢀCnBu){6-P(Ph)2-1-(4-MeꢁC6H4N2)ꢁ
C10H5-2-OH}] (2d)
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