Gold(I)-triphenylphosphine-arylazoimidazole: Synthesis and spectral (H, C, COSY, HMQC NMR) characterization

Article abstract of DOI:10.1134/S1070328407100120

The reaction of [Au(OSO₂CF₃)(PPh₃)] with arylazoimidazole in dichloromethane followed by NH₄PF₆ leads to [Au(RAaiR)(PPh₃)]PF₆ (RAaiR = p-R-N=N-C ₃H₂-NN-1-R), abbreviated as N,N/-chelator, where N (imidazole) and N (azo) represent N and N, respectively; R = H (a), Me (b), Cl (c), and R = Me (I), CH₂CH₃ (II), CH₂Ph (III)]. IR spectra of the complexes show -C=H- and -N=N-stretchings at 1590 and 1370 and at 1100, 755, 695, 545, and 505 cm^-1 due to the presence of the triphenylphosphine ring. The ¹H NMR spectral measurements suggest that methylene (-CH₂-) in (RAai)Et gives a complex of the AB type multiplet with a coupling constant of 7.6 Hz while in RAaiCH₂Ph it shows AB type quartets with coupling constant of av. 7.2 Hz. Considering the arylazoimidazole moity, there are different carbon atoms in the molecule giving different peaks in the ¹³C NMR spectrum of the complexes. In the ¹H-¹H COSY spectrum of the present complexes, the absence of any off-diagonal peaks extending from δ = 14.12 and 9.55 ppm confirms their assignment of no proton on N(1) and N(3), respectively. Contour peaks in the ¹H-¹³C HMQC spectrum in the present complexes, the absence of any contours at δ = 157.12, 160.76, 155.67, and 157.68-160.2 ppm assign them to the C(2), C(6), C(12), and C(PPh₃) carbon atoms, respectively. The solution structure and stereoretentive transformation in each step have been established from the ¹H NMR results.

Full text of DOI:10.1134/S1070328407100120

ISSN 1070-3284, Russian Journal of Coordination Chemistry, 2007, Vol. 33, No. 10, pp. 779–787. © Pleiades Publishing, Ltd., 2007.
Gold(I)–Triphenylphosphine–Arylazoimidazole: Synthesis
and Spectral (H, C, COSY, HMQC NMR) Characterization1
P. Byabartta and M. Laguna
Departmento de Quimica Inorganica-Instituto de Ciencia de Materiales de Aragon,
Universidad de Zaragoza-CSIC, Zaragoza–50009, Spain
E-mail: prithwis33@yahoo.com; Pribatta@rediffmail.com
Received May 2, 2006
Abstract—The reaction of [Au(OSO2CF3)(PPh3)] with arylazoimidazole in dichloromethane followed by
NH4PF6 leads to [Au(RAaiR')(PPh3)]PF6 (RAaiR' = p-R–N=N–C3H2–NN–1–R'), abbreviated as N,N'/-chela-
tor, where N (imidazole) and N (azo) represent N and N', respectively; R = H (a), Me (b), Cl (c), and R' = Me (I),
CH2CH3 (II), CH2Ph (III)]. IR spectra of the complexes show –C=N– and –N=N-stretchings at 1590 and 1370
and at 1100, 755, 695, 545, and 505 cm–1 due to the presence of the triphenylphosphine ring. The 1H NMR spectral
measurements suggest that methylene (–CH2–) in (RAai)Et gives a complex of the AB type multiplet with a cou-
pling constant of ~7.6 Hz while in RAaiCH2Ph it shows AB type quartets with coupling constant of av. 7.2 Hz.
Considering the arylazoimidazole moity, there are different carbon atoms in the molecule giving different peaks
1
in the 13C NMR spectrum of the complexes. In the H–1H COSY spectrum of the present complexes, the
absence of any off-diagonal peaks extending from δ = 14.12 and 9.55 ppm confirms their assignment of no pro-
ton on N(1) and N(3), respectively. Contour peaks in the 1H–13C HMQC spectrum in the present complexes,
the absence of any contours at δ = 157.12, 160.76, 155.67, and 157.68–160.2 ppm assign them to the C(2), C(6),
C(12), and C(PPh3) carbon atoms, respectively. The solution structure and stereoretentive transformation in
each step have been established from the 1H NMR results.
DOI: 10.1134/S1070328407100120
1
Transition metal complexes of diimine and related sional structures [9–11]. The underlying “aurophilic”
ligands have attracted much attention [1–4]. Running bonding has been analyzed in theoretical studies, which
years have witnessed a great deal of interest in the syn- have confirmed the experimental results and gave an
thesis of the complexes of gold with α-diimine-type of explanation for the finding that the “metallophilic”
bonding is strongest and, therefore, most obvious for
heavy metals in general and for gold complexes in par-
ticular [1–3]. Notwithstanding, there has also been
growing evidence for weak metallophilic bonding
between low-coordinate silver atoms [3] and, as a logi-
cal consequence, for gold–silver metallophilicity [5, 6,
8, 12–15].
In this article we present new and noteworthy exam-
ples taken from the important class of gold triphe-
nylphosphines. Gold phosphine compounds have inter-
esting photophysical properties [2] and are relevant to
homogeneous gold catalysis [1] and gold/silver thin
film technology [3]. Recently, we have developed the
arylazoimidazole chemistry of ruthenium and have
synthesized dichloro compounds [RuCl2(RAaiR')2] and
diaquo species [Ru(OH2)2(RAaiR')2]2+ (RAaiR' = p-R–
C6H4–N=N–C3H2–NN–1-R', R = H, Me, Cl and R' =
Me, CH2CH3, CH2Ph abbreviated as N,N'-chelator,
where N (imidazole) and N (azo) represent N and N',
respectively). Syntheses of hetero-tris-chelates,
[Ru(Bipy)n(RAaiR')3 – n](ClO4)2 (Bipy = 2.2'-bipyri-
dine; n = 1, 2) from the solvento complexes
[Ru(OH2)2(Bipy)2]2+/[Ru(OH2)2 (RAAIR'‘)2]2+ con-
ligands because of their photochemical and catalytic
properties [5], energy conversion, and the ability to
serve as building blocks in supramolecular arrays [6].
Researchers have been engaged in modifying the prop-
erties of Au–pyridine complexes by replacing the
ligands of other donor centers, altering the steric and
electronic properties of the ligands, differently substi-
tuted polypyridine mixed donor heterocycles. The
search for a suitable precursor to synthesize azoimine
complexes is a challenging domain, and the compounds
are found to be useful in this context [7]. The concept
of “metallophilic bonding” has added a new range of
intermolecular interactions to the spectrum of chemical
bonding in supramolecular aggregates [8]. A small
number of scattered observations in the early structural
chemistry of gold(I) complexes [1–4, 7, 9, 10] has
grown into a wealth of reports on related phenomena in
the last two decades, which finally provided a clear pat-
tern of the conditions under which direct interactions
between closed-shell gold(I) centers can contribute sig-
nificantly to the stability of molecular and multidimen-
1
The article was submitted by the authors in English.
779

780
BYABARTTA, LAGUNA
taining labile reaction centers are reported [4, 7, 9–11, collected by filtration, washed thoroughly with hexane
16, 17]. Syntheses of molybdenum-bis-chelates with to remove excess ligand, and then dried in vacuo using
carbonyl containing these ligand centers are reported a pump overnight. Analytically pure complex was
from Ankermann’s laboratory. A. Chakravorty has obtained after chromatography on an alumina (neutral)
unfolded its rhenium chemistry on this ligand system. column on eluting the red band with toluene–acetoni-
However the gold chemistry with 1D, 2D NMR spec- trile (4 : 1, vol/vol) and evaporating slowly in air. The
troscopy of this ligand system is totally unexplored. In yield was 0.088 g (80%).
this paper, we examined the reaction of RAaiR' with
The complexes [Au(RAaiR/)(PPh3)]PF6, were pre-
gold(I) triphenylphosphine derivatives, and the prod-
pared similarly for Ib, using as ligand RAaiR/(R' = Me,
ucts were isolated. The complexes are well character-
R = H (Ia), Cl (Ic); R' = Et, R = H (IIa), Me (IIb), Cl
(IIc); R' = Bz, R = H (IIIa), Me (IIIb), Cl (IIIc).
ized by IR, 1H, 13C NMR, 1H–1H COSY NMR, 1H–13C
HMQC, and ESI mass spectrometry.
31P{1H} NMR, ppm of Ia, 30.234; ESI mass, M
(% abundance), 790 (90) [M+], 645 (34) [M – PF6], 721
31
(10) [Au(PPh3)2)]+; P{1H} NMR, ppm of Ib, 30.28;
ESI mass, M (% abundance), 804 (70) [M+], 659 (31)
[M –PF6], 721 (13) [Au(PPh3)2)]+; 31P{1H} NMR, ppm
of Ic, 30.44; ESI mass, M (% abundance), 824.5 (45)
[M+], 679.5 (34) [M – PF6], 721 (16) [Au(PPh3)2)]+;
31P{1H} NMR, ppm of IIa, 30.98; ESI mass, M (%
abundance), 804 (70) [M+], 659 (31) [M – PF6], 721 (13)
EXPERIMENTAL
Published methods were used to prepare RAaiR'
[10, 11, 16], [AuCl(PPh3)] [5, 6, 8, 12–15]. All other
chemicals and organic solvents used were of reagent
grade (SRL, Sigma, Alhrich). The purification of
MeCN used as solvent and other solvents were done
following the literature method [6, 8, 11–13, 16, 17].
Microanalytical data (C, H, N) were collected using a
Perkin Elmer 2400 CHN instrument. IR spectra were
obtained using a Perkin Elmer spectrophotometer
(using KBr disks, 4000–400 cm–1). The 1H NMR spec-
tra in CDCl3 were obtained on a Bruker 400 MHz FT
NMR spectrometer using SiMe4 as internal reference.
Mass spectra were recorded on a VG Autospec ESI
mass spectrometeter using 3-nitrobenzyl as matrix.
31
[Au(PPh3)2)]+; P{1H} NMR, ppm of IIb, 29.98; ESI
mass, M (% abundance), 818 (70) [M+], 673 (31) [M –
PF6], 721 (11) [Au(PPh3)2)]+; 31P{1H} NMR, ppm of
IIc, 30.28; ESI mass, M (% abundance), 839.5 (70)
[M+], 694.5 (31) [M – PF6], 721 (13) [Au(PPh3)2)]+;
31P{1H} NMR, ppm of IIIa, 31.02; ESI mass, M (%
abundance), 866 (55) [M+], 721 (13) [M – PF6], 721 (6)
[Au(PPh3)2)]+; 31P{1H} NMR, ppm of IIIb, 30.28; ESI
mass, M (% abundance), 880 (67) [M+], 735 (31) [M –
PF6], 721 (3) [Au(PPh3)2)]+; 31P{1H} NMR, ppm of
IIIc, 31.01; ESI mass, M (% abundance), 901.5 (45)
[M+], 756.5 (31) [M – PF6], 721 (10) [Au(PPh3)2)]+.
Synthesis
of
[{1-methyl-2-(p-tolylazo)imida-
zole}(triphenylphosphine)aurate(I)]hexafluorophos-
phate, [Au(MeAAIMe)(PPh3)]PF6 (Ib). A yellow
dichloromethane solution of 1-methyl–2-(p-toly-
lazo)imidazole (0.039 g, 0.20 mmol) was slowly, drop-
wise, added to a dichloromethane colorless solution
(15 ml) of [Au(OSO2CF3)(PPh3)] (0.941 g, 0.20 mmol)
and the mixture was stirred at 343–353 K for 12 h. The
RESULTS AND DISCUSSION
The complexes [Au(RAaiR/)(PPh3)]PF6 (Ia–Ic, IIa–
red solution that resulted was concentrated (4 ml) and IIc, and IIa–IIIc), were prepared by removing OSO2CF3
kept in a refrigerator overnight. The addition of hexane from [Au(OSO2CF3)(PPh3)], with RAaiR under stirring
followed by ammonium hexafluorophosphate salt to at 343–353 K in dichloromethane solution in good
the above red solution gives a precipitate, which was yield (65–85%). The synthetic routes are shown below:
4 5
1
3
Ph P Au N
N R'
3
2
N
CH2Cl2
–Cl
+NH4PF6
+
+
RAaiR'
[AuCl(PPh )]
[Ag(OSO CF )]
PF6
3
2
3
N
11
10
7
R' = Me, R = H(Ia), Me(Ib), Cl(Ic)
R' = Et, R = H(IIa), Me(IIb), Cl(IIc)
R' = Bz, R = H(IIIa), Me(IIIb), Cl(IIIc)
8
9
R
The composition of the complexes is supported by viz., acetone, acetonitrile, chloroform, and dichlo-
microanalytical results (Table 1). The red-orange romethane but are insoluble in H2O, methanol, and
complexes are soluble in common organic solvents, ethanol.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 33 No. 10 2007

GOLD(I)–TRIPHENYLPHOSPHINE–ARYLAZOIMIDAZOLE
781
Table 1. Data of elemental analysis and IR spectra of the complexes Ia–Ic, IIa–IIb, and IIIa–IIIc
Contents (found/calcd), %
IR
ν(N=N), ν(C=N), ν(PPh3)
7.80/7.90 1370, 1590
1100, 750, 690, 550, 505
7.71/7.80 1373, 1594
1106, 756, 695, 557, 515
7.50/7.90 1370, 1590
1100, 750, 690, 550, 505
7.71/7.80 1373, 1594
1106, 756, 695, 557, 515
7.61/7.70 1373, 1599
1102, 753, 694, 550, 510
7.41/7.50 1371, 1594
1106, 756, 695, 557, 515
7.10/7.20 1373, 1590
1106, 750, 695, 550, 515
7.10/7.20 1373, 1590
1106, 750, 695, 550, 515
6.90/6.80 1370, 1590
1100, 750, 690, 550, 510
Compound
C
H
N
Cl
P
[Au(HAaiMe)(PPh3)]PF6, 42.59/42.58 3.18/3.08 7.18/7.2
C28H25F6N4AuP2 (Ia)
[Au(MeAaiMe)(PPh3)]PF6 43.39/43.58 3.38/3.28 6.97/6.99
C29H27F6N4AuP2 (Ib)
[Au(ClAaiMe)(PPh3)]PF6 40.59/40.58 2.88/2.88 6.80/7.0
C28H24F6N4AuClP2 (Ic)
4.30/4.40
[Au(HAaiEt)(PPh3)]PF6
C29H27F6N4AuP2 (IIa)
43.39/43.58) 3.38/3.28 6.97/6.99
[Au(MeAaiEt)(PPh3)]PF6 44.03/44.05 3.80/3.70 6.77/6.90
C30H29F6N4AuP2 (IIb)
[Au(ClAaiEt)(PPh3)]PF6 41.39/41.58 3.13/3.18 6.70/6.90
C29H26F6N4AuClP2 (IIc)
4.20/4.30
3.90/4.01
[Au(HAaiBz)(PPh3)]PF6 47.30/47.50 3.30/3.28 6.70/6.50
C34H29F6N4AuP2 (IIIc)
[Au(MeAaiBz)(PPh3)]PF6 47.37/47.50 3.50/3.80 6.40/6.50
C35H31F6N4AuP2 (IIIb)
[Au(ClAaiBz)(PPh3)]PF6 45.30/45.50 3.10/3.20 6.90/6.80
C34H28F6N4AuClP2 (IIIc)
The population of gas phase ions generated by ESI
often closely reflects that in solution. Hence, we used
ESI-MS to verify the solution and gas-phase stability of
the complexes and to structurally characterize such iso-
meric thermally labile complexes via ESI-MS. The ESI
mass spectrum of a MeCN solution in the positive ion
mode is structurally enlightening, since it displays a
series of characteristic singly. The ESI-MS mass spec-
trum of one complex [Au(ClAaiBz)(PPh3)]PF6 (IIIc)
was recorded in a MeCN medium. The maximum
molecular peak of IIIc is observed at m/z 901.5 (50%),
which corresponds to the molecular ion, where calcu-
IR spectra of the complexes [Au(RAaiR/)(PPh3)]PF6
are given in Table 1; they show a 1 : 1 correspondence
to the spectra of the chloro analogs, [AuCl(PPh3)],
except the appearance of intense stretching at 1365–
1370 and 1570–1580 cm–1 with concomitant loss of
ν(Au–Cl) at 320–340 cm–1. They are assigned to
ν(N=N) and ν(C=N) appear at 1365–1380 and 1570–
1600 cm–1, respectively.
1
The H NMR spectra of complexes I–III demon-
strated by complexes IIa and IIb were unambiguously
assigned (Table 2, Figs. 1, 2) on comparing with
[AuCl(PPh3)] and the free ligand (RAaiR') [6, 10, 11].
lated molecular weight is 901.03. A very careful exam- The aryl protons (H(7)–H(11)) of (7–9) are downfield
shifted by 0.1–0.7 ppm as compared to those of the par-
ent derivatives [10, 11, 16]. They are affected by substi-
tution; H(8) and H(10) are severely perturbed due to
changes in the electronic properties of the substituents
in the C(9)-position. The proton movement upon R(9)
substitution is corroborated with the electromeric effect
of R. The aryl protons H(7) or H(7') and H(11) or
H(11') resonate asymmetrically indicative of a magnet-
ically anisotropic environment [10, 16] even in the
solution phase. The R'(1) (R' = Me, CH2CH3, CH2(Ph))
exhibits usual spin-spin interaction. Me(1) appears as a
singlet at 2.02 ppm for [Au(RAaiMe)(PPh3)]PF6; the
methylene protons of 1-CH2–(CH3) show the AB type
quartet (ca. 4.4, 4.6 ppm, J = 10–12 Hz) and
(1-CH2)CH3 gives a triplet at 1.5 ppm (8.0 Hz) for
[Au(RAaiCH2CH3)(PPh3)]PF6; 1-CH2(Ph) protons appear
at AB tipy quartets (ca. 5.5, 5.7 ppm) with a geminal
coupling constant of 10 Hz on the average. Imidazole
ination of the fragmentation pattern of the ESI mass
spectrum reveals the stepwise elimination of the
hexafluorophosphate ion (m/z at 756.1 (40%)
[Au(ClAaiBz)(PPh3)]PF6) and the diphosphinoaurate
molecule (m/z at 721 (30%) [Au(PPh3)2)]+. The maxi-
mum molecular peak of Ia is observed at m/z 790
(50%), which corresponds to the molecular ion, and the
fragmentation pattern of the ESI mass spectrum reveals
the stepwise elimination of PF6 (m/z, 645 (40%)), the
diphosphinoaurate molecule (m/z at 721 (40%)
[Au(PPh3)2)]+); The maximum molecular peak of IIIa is
observed at m/z 866 (50%), which corresponds to the
molecular ion, and the fragmentation pattern of the ESI
mass spectrum reveals the stepwise elimination of the
PF6-ion (m/z at 721 (40%) [Au(HaaiMe)(PPh3)]) and
the diphosphinoaurate molecule (m/z at 721 (09%)
[Au(PPh3)2)]+).
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 33 No. 10 2007

782
BYABARTTA, LAGUNA
1
Table 2. H NMR spectral data (δ, ppm (J, Hz)) of the complexes Ia–Ic, IIa–IIc, and IIIa–IIIc in CDCl3
Compound
H(4)c
H(5)c
H(11)c
H(7)c
H(8.10)
N–CH3
N–CH2
Iaa
Ibb
7.15 (7.5)
6.98 (7.5)
7.13 (8.1)
7.14 (7.5)
7.33 (8.1)
7.34 (8.1)
7.06 (7.8)
6.97 (8.1)
7.06 (7.5)
6.86 (7.5)
7.02 (8.1)
7.00 (7.5)
7.24 (8.1)
7.36 (8.1)
6.98 (7.8)
6.99 (8.1)
7.02 (7.8)
8.03 (8.1)
8.17 (8.1)
8.15 (7.8)
8.01 (7.8)
8.11 (7.5)
8.04 (7.5)
8.08 (8.1)
8.21 (8.1)
7.99 (8.1)
8.04 (8.1)
7.95 (7.8)
7.85 (7.8)
8.04 (7.5)
7.54 (7.5)
8.00 (8.1)
8.10 (8.1)
8.05 (8.1)
7.45 (8.1)d 2.09f
7.34 (8.1)c
7.55 (7.8)c
2.17f
2.16f
Ic
IIaa
IIbb
IIc
IIIaa, h
IIIbb, h
IIIch
7.45 (8.1)d 1.52 (8.1)d
4.42, 4.55 (10.0)e
4.54, 4.56 (10.0)e
4.54, 4.53 (11.0)e
5.48, 5.73 (15.0)g
5.46, 5.73 (17.0)g
7.52 (7.5)c
7.46 (7.5)c
7.48 (8.1)d
7.10 (8.1)c
7.58 (8.1)c
1.58 (8.1)d
1.55 (8.1)d
7.11 (7.8)
8.15 (8.1)
5.44, 5.70 (18.0)g
a
b
c
d
e
f
g
δ
7.60 ppm (m.);
δ
; doublet; triplet; AB type quartet, geminal coupling constant;
δ
, singlet; AB type quartet, gem-
H(9)
Me(9)
Me(1)
h
inal coupling constant; δ 7.5–7.9 (P–Ph , 15H); Phenyl – H of N–Bz. δ 7.5–7.6.
3
Table 3. 13C NMR spectral data of of the complexes Ia–Ic, IIa–IIc, and IIIa–IIIc in CDCl3
Com-
pound
C(2) C(6) C(4) C(5) C(7.11) C(8.10) C(9)
P–C P–Cortho P–Cpara P–Cmeta R'(9)–C N–Me(Et, Bz)
Ia
140.87 139.89 120.21 122.76 130.98 128.98 127.56 140.87 130.98 135.66 134.99 30.98
Ib 141.87 139.89 122.21 122.76 131.98 127.98 126.56 140.87 132.98 135.66 134.99 24.45 31.98
Ic
140.87 139.89 120.21 122.76 130.98 128.98 137.56 141.87 130.98 135.66 134.99
30.08
IIa 141.87 139.89 121.21 123.76 131.98 127.98 127.56 140.87 131.98 134.66 134.99
30.98, 41.12
IIb 140.87 139.89 120.21 122.76 130.98 128.98 127.56 141.87 130.98 135.66 134.99 23.33 31.98, 42.09
IIc 141.87 139.89 122.21 122.76 131.98 128.98 126.56 141.87 131.98 135.66 134.99
IIIa 140.87 139.89 120.21 122.76 130.98 128.98 127.56 140.87 130.98 135.66 134.99
30.98, 42.65
31.98, 128–132
IIIb 141.87 138.89 121.21 122.76 131.98 128.98 125.56 141.87 131.98 135.66 135.99 22.33 30.98, 128–137
IIIc 140.87 139.89 120.21 122.76 130.98 128.98 127.56 140.87 130.98 135.66 134.99 30.98, 129–138
H(4) and H(5) appear as a doublet at the lower fre- The signals of the carbon atoms neighboring the nitro-
quency side of the spectra (7.0–7.2 for H(4); gen atom are shifted downfield due to an increased
6.9−7.1 ppm for H(5)). The aryl-Me (R = Me) in electron density resulting from the presence of the elec-
[Au(MeAaiR/)(PPh3)]PF6 appears as a single signal at tronegative nitrogen atom and π-electron delocalization
2.30 ppm.
31P{1H} NMR spectra are very much informative
in the magnetic environment. The signals non-proto-
nated carbon atoms at C(2) and C(6) of the arylazoimi-
dazole moiety are shifted farthest downfield in the spec-
trum (δ = 170.12 and 168 ppm) affected by the mag-
netic interection of two bulky phenyl rings environment
and the methyl-, ethyl-, benzyl-substituted imidazole
rings and the π-electron delocalization on = N–CC =
N– and = N-CC = CC–. Similarly, the ipso-carbon atom
of the triphenylphosphine molecule in the complex res-
onance at a lower field of 145 ppm resulting in the con-
jugative effect of the phenyl ring with more electroneg-
ative π-conjugated system. The methyl carbon atom of
the imidazole ring resonate at 40 ppm, which is com-
pared to the other carbon atoms resonance.
for the present series of complexes. Due to the presence
of the azoimine function, which is π-acidic in nature,
the gold(I) oxidation state is stabilized giving a value of
31.23, where the parent chloro complex shows the peak
at 33.78. Changing the substitution at R, R' on the
ligand, there is a slight chemical shift changes of these
complexes [5, 13].
The 13C NMR spectrum provides direct information
about the carbon skeleton of the molecule. Assignment
of different resonant peaks to respective carbon atoms
was done on nine complexes, and the data are given in
Table 3 (Figs. 1–3). Considering arylazoimidazole moi-
1
The COSY spectrum reveals the H–1H coupling
eties, there are different carbon atoms in the molecule interections in the molecule. It is usually plotted as
giving corresponding peaks in the 13C NMR spectrum. three dimentional contours, where the conventional
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 33 No. 10 2007

GOLD(I)–TRIPHENYLPHOSPHINE–ARYLAZOIMIDAZOLE
783
(a)
500
0
12.66
ppm 8.0
(b)
7.0
6.0
5.0
4.0
3.0
2.0
1.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
ppm
ppm
8.0
(c)
7.0
6.0
5.0
4.0
3.0
2.0
1.0
200
150
100
50
0
ppm 200
150
100
50
0
1
1
1
13
Fig. 1. Spectra of complexes: (a) H NMR – 2b, (b) H– H COSY – 2b, (c) C NMR – 2b.
spectrum is represented along the diagonal (Figs. 1, 4). tion in the spectrum. For instance, in the COSY spec-
The cross peaks along both the sides of the diagonal trum of the present complexes, the absence of any off-
identify the nuclei that are coupled to each other. On the diagonal peaks extending from δ = 14.12 and 9.55 ppm
contrary, the protons that are decoupled from the adja- confirm their assignment of no proton on N(1) and
cent ones due to the lack of α-protons show no correla- N(3), respectively. However, extending horizontal and
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 33 No. 10 2007

784
BYABARTTA, LAGUNA
(a)
700
600
500
400
300
200
100
0
–100
8.0
ppm
7.0
6.0
5.0
4.0
3.0
2.0
300
250
200
150
100
50
(b)
0
–50
ppm 200
(c)
150
100
0
50
100
150
ppm
ppm
10.0
5.0
1
13
1
13
Fig. 2. Spectra of complexes: (a) H NMR – 2a, (b) C NMR – 2c, (c) H– C HMQC – 3c.
vertical lines from δ = 8.32 (C(a)H) and 868 ppm C(4)H and C(5)H protons of the imidazole moity are
(C(b)H) encounter cross peaks at δ = 7.12 and 7.23 ppm, shown by the poorly resolved cross peaks at δ = 7.32
where the C(7)H and C(11)H resonances are merged and 7.33 ppm. This also helps to accurately assign phe-
into multiplets along with the phenyl ring proton reso- nyl and imidazole moity protons to their respective val-
nances. The comperatively weaker coupling interec- ues, which is contrary to the expected more downfield
tions of C(8)H and C(10)H with the far apart positioned shift of C(11)H (δ = 7.92 ppm) of the RaaiR’ molecule.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 33 No. 10 2007

GOLD(I)–TRIPHENYLPHOSPHINE–ARYLAZOIMIDAZOLE
785
(a)
0
50
100
150
ppm
ppm
8.0
(b)
7.0
6.0
5.0
4.0
3.0
2.0
1.0
1000
500
0
40.0
ppm
35.0
30.0
25.0
20.0
15.0
(c)
90
80
70
60
50
40
30
20
10
ppm 200
150
100
50
0
1
13
31
13
Fig. 3. Spectra of complexes: (a) H– C HMQC – 2b, (b) P NMR – 2b, (c) C NMR – 3b.
The COSY spectrum also turns out to be very helpful in COSY, only the resultant interections are plotted as
the accurate assignment of proton resonance in the aro-
matic region. The doublet of the C(7)H and C(11)H
protons show a coupling interection with the doublet at
δ = 7.12 and 7.68 ppm (C(8)H and C(10)H).
contour peaks in the HMQC spectrum (Figs. 2, 3). In
the present complexes, the absence of any contours at
δ = 147.12, 160.76, 155.67, and 157.68 ppm assign
them to the C(2), C(6), C(12), and C(C–PPh3) carbon
atoms, respectively. This is because they belong to the
non-protonated carbon atoms on the imidazole, phenyl,
and aryl rings. So, they unable to show any direct
The 1H–13C heteronuclear multiple-quantum coher-
ence (HMQC) spectrum provides inforamation regard-
ing the interection between the protons and carbon
atoms to which they are directly attached. Contrary to 1H−13C heteronuclear multiple-quantum coherence.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 33 No. 10 2007

786
BYABARTTA, LAGUNA
(a)
5
10
ppm
ppm
10
5
(b)
5
10
ppm
ppm
10
(c)
5
0
1
2
3
4
5
6
7
8
ppm
8
7
6
5
4
3
2
1
0
ppm
1
1
1
1
1
1
Fig. 4. Spectra of complexes: (a) H– H COSY – b, (b) H– H COSY – 1b, (c) H– H COSY – 1c.
1
The peaks observed at δ = 134.12, 131.76, 135.67, and splitting of ethyl substitution. In the H–1H COSY
137.68 ppm assign them to the C(9), C(8), C(7), C(11),
and C(10) carbon atoms respectively, due to their inter-
ection with H resonance at δ = 7.42, 7.55, 7.82, 7.80,
and 7.38 ppm. The evidence of the presence of pro-
tons attached to the different types of carbon atoms
spectrum of the present complexes, the absence of any
off-diagonal peaks extending from δ = 14.12 and
9.55 ppm confirms their assignment of no proton on
N(1) and N(3), respectively. The contour peaks in the
1H–13C HMQC spectrum in the present complexes, and
the absence of any contours at δ = 147.12, 160.76,
155.67, and 157.68 ppm assign them to the C(2), C(6),
1
in the spectrum is obtained from the H–13C HMQC
spectrum.
This
work
describes
the
isolation
of
[Au(RaaiR/)(PPh3)]PF6 and their spectral and elemen-
C(12) and C(13)–C(17) carbon atoms, respectively.
1
31
tal characterization. H NMR study suggests quartet The P{H} NMR spectrum is very much informative
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 33 No. 10 2007

GOLD(I)–TRIPHENYLPHOSPHINE–ARYLAZOIMIDAZOLE
787
6. Chakravarty, A.R. and Chakravorty, A., Dalton Trans.,
1983, p. 961.
7. Saha, A., Das, C., Goswami, S., and Peng, S.M., Indian
J. Chem, 2001, vol. 40A, p. 198.
8. Murray, H.H., Iwen, W.I., Sherman, S.E., et al., Ang.
Chem., 1995, vol. 34, p. 841.
9. Mondal, B., Paul, H., Puranik, V.G., and Lahiri, G.K.,
Dalton Trans., 2001, p. 481.
10. Hansongnern, K., Saeteaw, V., Cheng J., et al., Acta
Crystallogr., 2001, vol. 57C, p. 895.
11. Chattopadhyay, S., Ghosh, K., Pattanayak, S., and
Chakravorty, A., Dalton Trans., 2001, p. 1259.
12. Cerrada, E., Fernandez, E.J., Gimeno, M.C., et al., J. Or-
ganomet., Chem., 1995, vol. 492, p. 105.
and show the sharp signals at higher field than the sig-
nals of the parent complex.
ACKNOWLEDGMENTS
We are grateful to C. Sinha, L. Falvello, M. Thomas,
and E. Cerrada for valuable comments on this work.
This work was supported by the Ministerio De Cien-
cia y Technologia (Spain) (project no. CTQ2005-
08099-CO3-01) and P.B. (grant no. SB2004–0060).
REFERENCES
1. Synthetic Coordination and Ogranometallic Chemistry,
Garnovskii, A.D. and Kharisov, B.I., Eds., New York– 13. Uson, R., Laguna, A., and Laguna, M., Inorg. Synth.,
Basel: Marcel Dekker, 2003.
1989, vol. 26, p. 85.
2. Gimeno, C. and Laguna, A., In: Comprehensive Coordi- 14. Uson, R., Laguna, A., Laguna, M., et al., Dalton Trans.,
nation Chemistry II, McCleverty, J.A. and Meyer, T.J.,
Eds., Oxford–New York: Elsevier–Pergamon, 2003,
vol. 6, p. 911.
1990, p. 3457.
15. Contel, M., Jimenez, L, Jones, P.G., et al., Dalton
Trans., 1994, p. 2515.
3. Dryden, N.H., Shapter, J.G., Coatesworth, L.L., et al.,
Chem. Mater., 1992, vol. 4, p. 979.
4. Ulman, A., Chem. Rev., 1996, vol. 96, p. 1533.
5. Uson, R., Laguna, A., Laguna, M., et al., Inorg. Chim.
Acta, 1990, vol. 168, no. 1, p. 89.
16. Jemmis, E.D., Subramanian, G., Nowek, A., et al.,
J. Mol. Struct., 2000, vol. 556, p. 315.
17. Cotton, F.A., Wilkinson, G. Murillo, C.A., and Boch-
mann, M., Advances Inorganic Chemistry, Wiley-Inter-
science, 1999, 1355 p.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 33 No. 10 2007