Synthesis of homo- and hetero-polynuclear coinage metal complexes of 2-(diphenylphosphino)aniline

Article abstract of DOI:10.1039/b110398a

The reaction of the asymmetric ligand 2-(diphenylphosphino)aniline (PNH₂) with gold(I), silver(I) or copper(I) substrates in various molar ratios leads to the complexes [M(PNH₂)₂]A (M = Au, A = TfO (1); M = Ag, A = TfO (2), ClO₄ (3); M = Cu, A = TfO (4)), the homodinuclear derivatives [M(PNH₂)]₂A₂ (M = Ag, A = TfO (7), ClO₄ (8); M = Cu, A = TfO (9)) or [M(PNH₂)₃]A (M = Au, A = TfO (12); M = Ag, A = ClO₄ (13); M = Cu; A = TfO (14)). Reaction of [AuCl(PNH₂)] with AgClO₄ (1:1) in acetone causes the ligand to condense with the solvent, resulting in the synthesis of [Au(PN=CMe₂)]₂(ClO₄)₂ (5). Treatment of the gold(I) compound 1 with the same silver(I) or copper(I) starting materials as before gives the heteronuclear species [AuM(PNH₂)₂](TfO)₂ (M = Ag (10); M = Cu (11)). The optical properties of some of these complexes have been studied and the crystal structures of compounds 5, 10 and 12 have been determined by X-ray diffraction.

Full text of DOI:10.1039/b110398a

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Synthesis of homo- and hetero-polynuclear coinage metal
complexes of 2-(diphenylphosphino)aniline
Olga Crespo,a Eduardo J. Fernández,b Manuel Gil,b M. Concepción Gimeno,a Peter G. Jones,c
Antonio Laguna,*a José M. López-de-Luzuriagab and M. Elena Olmosb
a Departamento de Química Inorgánica, Instituto de Ciencia de Materiales de Aragón,
Universidad de Zaragoza-CSIC, E-50009, Zaragoza, Spain. E-mail: alaguna@posta.unizar.es
b Departamento de Química, Universidad de La Rioja, Grupo de Síntesis Química de La Rioja,
UA-CSIC, Madre de Dios 51, E-26006, Logroño, Spain
c Institut für Anorganische und Analytische Chemie der Technischen Universität, Postfach 3329,
D-38023 , Braunschweig, Germany
Received 13th November 2001, Accepted 28th January 2002
First published as an Advance Article on the web 12th March 2002
The reaction of the asymmetric ligand 2-(diphenylphosphino)aniline (PNH2) with gold(), silver() or copper()
substrates in various molar ratios leads to the complexes [M(PNH2)2]A (M = Au, A = TfO (1); M = Ag, A = TfO (2),
ClO4 (3); M = Cu, A = TfO (4)), the homodinuclear derivatives [M(PNH2)]2A2 (M = Ag, A = TfO (7), ClO4 (8); M =
Cu, A = TfO (9)) or [M(PNH2)3]A (M = Au, A = TfO (12); M = Ag, A = ClO4 (13); M = Cu; A = TfO (14)). Reaction
of [AuCl(PNH2)] with AgClO4 (1:1) in acetone causes the ligand to condense with the solvent, resulting in the
synthesis of [Au(PN᎐CMe )] (ClO ) (5). Treatment of the gold() compound 1 with the same silver() or copper()
᎐
2
2
4 2
starting materials as before gives the heteronuclear species [AuM(PNH2)2](TfO)2 (M = Ag (10); M = Cu (11)). The
optical properties of some of these complexes have been studied and the crystal structures of compounds 5, 10 and
12 have been determined by X-ray diffraction.
oxidizes to the copper() derivative. Their elemental analysis
Introduction
and physical and spectroscopic properties are in accordance
with the proposed stoichiometry. Their IR spectra show, among
others, the ν(N–H) stretching absorptions in the range 3230–
3430 cmϪ1. Their 31P{1H} NMR spectra at room temperature
show a singlet at 32.9 (1) or Ϫ11.7 ppm (4) or a multiplet at
Ϫ2.6 ppm (2 and 3) that splits into two doublets centered
at Ϫ3.6 ppm on cooling to 223 K, as expected for the presence
of equivalent phosphorus bonded to a silver atom [J(109Ag–P) =
574; J(107Ag–P) = 502 Hz]. The presence of TfO in 1, 2 and 4 is
confirmed by the presence of a single resonance in their 19F
Polynuclear P-, N- or S-donor ligands have been usually
employed in the synthesis of a broad diversity of polynuclear
species that, in the case of gold, may present interesting appli-
cations, such as chemotherapy, diagnostics, catalysis, electron
microscopy or surface technology.1–5 A number of complexes of
W, Ni, Pd, Pt, Rh, Os and Re containing the bidentate
P,N-donor ligand 2-(diphenylphosphino)aniline (PNH2) have
been described;6–11 in most of them PNH2 acts as a bidentate
chelating ligand, and the nitrogen atom is sometimes deproto-
nated. In contrast, only a few derivatives of PNH2 with group
11 metals have been reported to date,12 all of them being mono-
or homopolynuclear species in which the proposed geometry at
the metal ion is invariably linear for gold() or tetrahedral for
copper() or silver().
In this paper we describe the synthesis of some mononuclear
and homo- or hetero-polynuclear complexes of PNH2 with
group 11 metal centres that could display M–M or M–MЈ inter-
actions or a trigonal-planar geometry around the metal ion. It
should be borne in mind that metal–metal interactions or tri-
coordination have been shown to be responsible for interesting
optical properties, such as luminescence, in a large number of
gold() compounds13 and thus some of the complexes we have
synthesized might also be expected to be luminescent materials.
1
NMR while in their H NMR spectra, apart from the reson-
ances arising from the aromatic protons, the signal corre-
sponding to the aminic protons appears at ∼4.6 (1), 5.14 (2 and
3) or ∼4.9 ppm (4). Their mass spectra are also in accordance
with the proposed stoichiometry (see Experimental section).
Single crystals of 2 were obtained in order to determine its
crystal structure, but, unfortunately, serious disorder of the
nitrogen atoms of the ligands precluded satisfactory refine-
ment. It was however clear that the PNH2 molecules are acting
as monodentate P-bonded to the silver center instead of as
bidentate ligands as had been previously suggested.12c
One could expect that the same reactions carried out with
equimolecular amounts of the starting materials would lead
to the homodinuclear [M(PNH2)]22ϩ cations, but in the case of
gold this reaction results in the mononuclear [Au(PNH2)(tht)]ϩ
complex previously described.12a Thus, in order to obtain the
gold() dimer an alternative synthetic pathway was investigated
by reacting [AuCl(PNH2)] with AgClO4 (1:1) in acetone; this
Results and discussion
The reaction of the free ligand PNH2 with the appropriate M()
precursor (2 : 1 molar ratio) [Au(tht)2]TfO (tht = tetrahydro-
thiophene; TfO = trifluoromethylsulfonate), AgTfO, AgClO4 or
[Cu(NCMe)4]BF4 leads to the synthesis of the mononuclear
complexes [M(PNH2)2]A (M = Au, A = TfO (1); M = Ag, A =
TfO (2), ClO4 (3); M = Cu, A = TfO (4)) by coordination
or displacement of the weakly coordinated ligands. 1–3 are
obtained as air- and moisture-stable white solids while 4 slowly
surprisingly results in the formation of [Au(PN᎐CMe )] (ClO )
᎐
2
2
4 2
(5) instead of the expected product. This is an interesting result
that implies an unusual condensation process between the
amine group of the ligand and an acetone molecule at room
temperature. The analytical data and physical and spectro-
scopic properties agree with this formulation (see Experimental
section). The absorptions corresponding to the N–H bonds of
DOI: 10.1039/b110398a
J. Chem. Soc., Dalton Trans., 2002, 1319–1326
This journal is © The Royal Society of Chemistry 2002
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Table 1 Bond lengths [Å] and angles [Њ] for compound 5
In order to avoid the condensation process that takes place
when the reaction of AgClO4 and [AuCl(PNH2)] (1:1) is carried
out in acetone, we tested other possible solvents in which the
reaction could progress as desired, concluding that the best
results were obtained in a mixture of toluene/dichloromethane,
from which the complex [Au(PNH2)]2(ClO4)2 (6) was finally
isolated as a pure compound. The related silver and copper
species [M(PNH2)]2A2 (M = Ag, A = TfO (7), ClO4 (8); M = Cu,
A = TfO (9)) were more easily synthesized by treatment of the
free ligand with equimolecular amounts of AgTfO, AgClO4, or
[Cu(NCMe)4]TfO. An alternative synthetic procedure for these
three latter complexes consists of the treatment of the mono-
nuclear products 2–4 with the same silver() or copper() salts in
a 1:1 molar ratio (see Scheme 1). Complexes 6–8 are obtained as
white air- and moisture-stable solids, while the copper() center
in 9 slowly oxidizes to copper(). Their analytical, physical
and spectroscopic data are in accordance with the proposed
stoichiometry and they presumably present a head to tail
disposition of the ligands as commonly observed in homo-
dinuclear complexes containing asymmetric bridging ligands.15
Their IR spectra display ν(N–H) stretching absorptions in the
range 3202–3300 cmϪ1 and their 31P{1H} NMR spectra at room
temperature are similar to those registered for the mononuclear
derivatives 1–4, although in this case the broad signal observed
for the silver compounds 7 and 8 at room temperature is not
completely split on cooling. The 19F NMR spectra of the tri-
fluoromethylsulfonate derivatives display the single resonance
at Ϫ78.25 ppm corresponding to the anion. The resonances due
to the aminic protons appear in the 1H NMR spectra at 4.94 (6),
5.67 (7) and (8) or 5.1 ppm (9).
Au–N#1
Au–P
Au–Au#1
P–C(21)
P–C(1)
2.093(3)
2.2482(9)
2.8396(3)
1.813(3)
1.818(3)
P–C(11)
N–C(7)
N–C(6)
C(1)–C(6)
C(1)–C(2)
1.822(3)
1.295(5)
1.448(4)
1.395(5)
1.396(5)
N#1–Au–P
172.93(8)
90.74(7)
94.72(2)
106.36(15)
106.60(15)
107.05(15)
117.11(11)
112.41(11)
106.77(11)
119.8(3)
C(7)–N–Au#1
C(6)–N–Au#1
C(6)–C(1)–C(2)
C(6)–C(1)–P
122.0(2)
N#1–Au–Au#1
P–Au–Au#1
C(21)–P–C(1)
C(21)–P–C(11)
C(1)–P–C(11)
C(21)–P–Au
C(1)–P–Au
117.9(2)
118.5(3)
120.4(2)
121.0(3)
122.1(3)
118.2(3)
120.3(3)
119.6(2)
C(2)–C(1)–P
C(16)–C(11)–P
C(12)–C(11)–P
C(26)–C(21)–P
C(22)–C(21)–P
C(11)–P–Au
C(7)–N–C(6)
Symmetry transformations used to generate equivalent atoms: #1 Ϫx ϩ
1, Ϫy ϩ 1, Ϫz ϩ 1.
the PNH2 are not observed in its IR spectrum, while its 31P{1H}
NMR shows a unique resonance at 20.2 ppm. Furthermore, the
1H NMR spectrum of 5 displays (apart from the signals of the
aromatic protons) a broad signal at 2.06 ppm corresponding to
the methyl groups instead of any resonance due to aminic
protons.
Single crystals of 5 were obtained by slow diffusion of diethyl
ether into a chloroform solution of the complex and its crystal
structure was determined by X-ray analysis in order to confirm
this formulation. The cation of compound 5 (Fig. 1, Table 1)
Once the homodinuclear complexes 6–9 had been prepared,
we were interested in synthesizing the mixed Au–Ag, Au–Cu
and Ag–Cu dinuclear derivatives in order to analyze their
relative stabilities, structural differences and optical properties
compared to the homodinuclear species 6–9. Thus, when 6
reacts with AgTfO or [Cu(NCMe)4]BF4 (1:1) or [Au(tht)2]TfO
reacts with equimolecular amounts of 2 or 4, the hetero-
dinuclear complexes [AuM(PNH2)2](TfO)2 (M = Ag (10); M =
Cu (11)) are obtained, where the gold() centres are expected
to be coordinated through the phosphorus atoms as shown
in Scheme 1; this implies an isomerization process when the
starting material is [Au(tht)2]TfO, similar to that described by
us with other asymmetric ligands.16 In contrast, reaction of
[Ag(PNH2)2]TfO (2) with one equivalent of [Cu(NCMe)4]TfO
or reaction of [Cu(PNH2)2]TfO (4) with AgTfO in a 1:1 molar
ratio produces a mixture of the homodinuclear derivatives 7
and 9, as can be observed in solution by 31P{1H} NMR at 223
K, and as also previously observed with the asymmetric biden-
tate ligand PPh2CH2SPh.16 Complexes 10 and 11 were obtained
as white solids soluble in acetone and chlorinated solvents and
insoluble in diethyl ether and hexane. The ν(N–H) stretching
absorptions appear in their IR spectra at 3300 cmϪ1 and their
31P{1H} NMR spectra display a singlet at 31.1 (10) or 29.5 ppm
(11) confirming a head to head disposition of the ligands
Fig. 1 Molecular structure of 5. Hydrogen atoms are omitted for
clarity. Radii are arbitrary.
possesses an inversion center. The observed distortion from
linear geometry associated with the presence of gold ؒ ؒ ؒ gold
contacts (N#1–Au–P 172.93(8)Њ, Au–Au#1 2.8396(3) Å) is well
known in dinuclear derivatives of this type. The gold ؒ ؒ ؒ gold
interaction is shorter than that observed between the two
gold() centres in [Au(C6F5)2{PN(AuPPh3)2}]ClO4 12h (2.9749(3)
Å) and much shorter than that between gold centres of different
molecules in [Au{( )amp}]12b (3.1709(5) Å) (( )amp = ( )-
(2-aminophenyl)methylphenylphosphine). Similar Au–P dis-
1
with the gold atom bonded to the phosphorus centers. The H
NMR spectra of 10 and 11 show, besides the signals due to the
aromatic hydrogens, a singlet corresponding to the aminic
protons at 5.18 (10) or 5.47 ppm (11).
The crystal structure of 10 was determined by X-ray diffrac-
tion from single crystals obtained by slow diffusion of hexane
into a solution of the complex in dichloromethane. The cation
is shown in Fig. 2, with a selection of bond lengths and angles
in Table 3. Complex 10 cystallizes together with two half
molecules of dichloromethane, which are disordered. The
cation consists of a dinuclear mixed-metal unit with the
PPh2C6H4NH2 ligands bridging both metals. The gold atom is
linearly coordinated to the two phosphorus atoms of the
ligands with Au–P distances of 2.325(3) and 2.332(3) Å. These
values are similar to those found in bis(phosphine)gold com-
pounds such as [Au(PR3)2]ϩ (PR3 = PPh2Me, 2.316(4) Å; PCy3,
tances to those found in 5 (2.2482(9) Å) have been found in the
12a
derivatives [Au(SC4H8)(PNH2)]ClO4
(2.261(2) Å), [Au(C6-
F5)2{PN(AuPPh3)2}]ClO4 for the Au()–P bonds (2.2395(9),
2.2505(9) Å)12h or in [AuI(adp)]12b (2.260(4) Å) (adp = (2-amino-
phenyl)diphenylphosphine) and [Au{( )amp}]12b (2.262(2),
2.256(2) Å). The Au–N#1 distance (2.093(3) Å) is longer than
that found in [AuCl3(Hpm)]14 (Hpm = 2-pyridylmethanol)
(2.021(9) Å). Finally, a possible C–H ؒ ؒ ؒ O hydrogen bond is
found, involving an H ؒ ؒ ؒ O distance of 2.48 Å (see Table 2).
1320
J. Chem. Soc., Dalton Trans., 2002, 1319–1326

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Table 2 Hydrogen bonds [Å and Њ]
Compound 5
D–H ؒ ؒ ؒ A
d(D–H)
d(H ؒ ؒ ؒ A)
d(D ؒ ؒ ؒ A)
<(DHA)
144.2
C(26)–H(26) ؒ ؒ ؒ O(1)#1
0.95
2.48
3.299(5)
Compound 12
D–H ؒ ؒ ؒ A
d(D–H)
d(H ؒ ؒ ؒ A)
d(D ؒ ؒ ؒ A)
<(DHA)
N(1)–H(01) ؒ ؒ ؒ O(1)
N(1)–H(02) ؒ ؒ ؒ N(2)
N(2)–H(03) ؒ ؒ ؒ N(3)
N(2)–H(04) ؒ ؒ ؒ O(2)
N(3)–H(05) ؒ ؒ ؒ N(1)
N(3)–H(06) ؒ ؒ ؒ O(1)
N(1)–H(02) ؒ ؒ ؒ Au
N(2)–H(03) ؒ ؒ ؒ Au
N(3)–H(05) ؒ ؒ ؒ Au
0.83(2)
0.83(2)
0.83(2)
0.83(2)
0.83(2)
0.83(2)
0.83(2)
0.83(2)
0.83(2)
2.27(3)
2.64(4)
2.54(4)
2.11(3)
2.51(4)
2.53(4)
3.13(5)
2.91(5)
2.99(5)
2.997(6)
3.274(7)
3.195(7)
2.920(6)
3.193(6)
3.161(6)
3.366(4)
3.278(5)
3.426(5)
146(5)
134(4)
137(5)
163(5)
141(5)
134(5)
99(4)
109(4)
115(4)
[AuAg(PPh2CH2SPh)2](TfO)2 (2.3044(11) and 2.3103(11) Å)3
or [AuAg(PPh2py)2](ClO4)2 (2.296(2) and 2.297(2) Å).15b The
silver center is linearly coordinated to two nitrogen atoms with
an angle N–Ag–N of 175.2(3)Њ. The Ag–N bond distances,
2.244(9) and 2.262(9) Å, are longer than those found in other
linear silver complexes bonded to amine groups such as
Table 3 Selected bond lengths [Å] and angles [Њ] for compound 10
Au–P(2)
Au–P(1)
Au–Ag
2.325(3)
2.332(3)
2.9931(12)
2.244(9)
2.262(9)
1.823(12)
P(1)–C(6)
P(1)–C(21)
P(2)–C(51)
P(2)–C(12)
P(2)–C(41)
1.826(10)
1.854(11)
1.833(12)
1.836(11)
1.842(11)
Ag–N(2)
Ag–N(1)
P(1)–C(31)
[Ag(Ph C᎐NH) ]BF (2.113(2) Å)19 and smaller than those with
᎐
2
2
4
pyridine groups such as [AuAg(PPh2py)2](ClO4)2 (2.289(8) and
2.310(9) Å),15b although in this compound the silver also makes
covalent bonds to the perchlorate oxygens. The silver atom also
shows weak interactions with the oxygen atoms of the triflate
groups, Ag–O2 2.918, Ag–O3 2.821, Ag–O1# 2.765 Å, (# Ϫx ϩ
1, Ϫy ϩ 2, Ϫz ϩ 1). The Ag ؒ ؒ ؒ Au distance in 10 is 2.9931(12)
Å and can be considered as a bonding interaction, similar to
those found in other heteronuclear complexes such as [AuAg-
(PPh2CH2SPh)2](TfO)2 (2.9314(5) Å)16 or [Ag(µ-dppm)2{Au-
(mes)2}2]ClO4ؒ3CH2Cl2 (2.944(2) and 2.946(2) Å; dppm = bis-
(diphenylphosphino)methane; mes = mesityl)20 or [(AuPPh3)2-
P(2)–Au–P(1)
P(2)–Au–Ag
P(1)–Au–Ag
N(2)–Ag–N(1)
N(2)–Ag–Au
N(1)–Ag–Au
C(31)–P(1)–Au
167.90(10)
95.09(7)
94.91(7)
175.2(3)
86.8(2)
88.4(2)
116.7(4)
C(6)–P(1)–Au
C(21)–P(1)–Au
C(51)–P(2)–Au
C(12)–P(2)–Au
C(41)–P(2)–Au
C(1)–N(1)–Ag
C(11)–N(2)–Ag
109.8(3)
108.4(4)
113.8(4)
114.5(3)
107.6(3)
119.4(6)
117.0(6)
2.321(2) Å)17–18 although these values are slightly longer than
those in gold complexes with heterodifunctional ligands such
as [Au(PPh2CH2SPh)2]ClO4 (2.306(2) and 2.308(2) Å)16 or
Scheme 1 i) [Au(tht)2]TfO; ii) AgA; iii) [Cu(NCMe)4]TfO; iv) 2 [AuCl(tht)]; v) 2 AgClO4 in acetone; vi) 2 AgClO4 in CH2Cl2/toluene (1/1);
vii) 2 AgA; viii) 2 [Cu(NCMe)4]TfO; ix) AgTfO.
J. Chem. Soc., Dalton Trans., 2002, 1319–1326
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Table 4 Selected bond lengths [Å] and angles [Њ] for 12
{µ-C(PPh3)}(C5H4N){µ-Ag(O2NO)(OClO3)}] (2.926(1) and
3.006(1) Å)21 or slightly longer than those in [AuAg(PPh2-
py)2](ClO4)2 (2.820(1) Å).15b There is one short N–H ؒ ؒ ؒ O
hydrogen bond[N(2)–H(2b) ؒ ؒ ؒ O(4#) (# x, 1 + y, z) of 2.283 Å.
As mentioned above, the small number of compounds of
2-(diphenylphosphino)aniline with group 11 metals reported to
date were supposed to be linear for gold() or tetrahedral for
copper or silver, so we tried to prepare new species in which the
geometry could be different. Therefore, we treated PNH2 with
the same starting materials as before in a 3:1 molar ratio, a
reaction that led to the tris(phosphine) complexes [M(PNH2)3]A
(M = Au, A = TfO (12); M = Ag, A = ClO4 (13); M = Cu,
A = TfO (14)) (see Scheme 2). They were obtained as stable
white solids, except for the copper() derivative 14 that is slowly
oxidized to copper() with atmospheric oxygen. Complexes 12–
14 are soluble in chlorinated solvents and acetone and insoluble
in diethyl ether and hexane and they behave as 1 : 1 electrolytes
(see Experimental section). Their IR spectra show the charac-
teristic absorptions of the N–H bonds at ∼3325 cmϪ1 and also
Au–P(1)
Au–P(3)
Au–P(2)
2.3688(12)
2.3694(13)
2.3738(12)
N(1)–C(6)
N(2)–C(36)
N(3)–C(82)
1.383(6)
1.394(6)
1.388(6)
P(1)–Au–P(3)
P(1)–Au–P(2)
P(3)–Au–P(2)
C(1)–P(1)–Au
C(11)–P(1)–Au
C(21)–P(1)–Au
C(51)–P(2)–Au
C(31)–P(2)–Au
120.10(4)
C(41)–P(2)–Au
C(81)–P(3)–Au
C(71)–P(3)–Au
C(61)–P(3)–Au
N(1)–C(6)–C(5)
N(1)–C(6)–C(1)
C(35)–C(36)–N(2)
N(2)–C(36)–C(31)
116.53(15)
114.11(15)
117.93(14)
108.85(15)
119.0(5)
121.5(4)
119.6(4)
120.43(4)
119.34(4)
113.29(14)
110.37(14)
117.59(14)
109.35(15)
113.47(14)
121.7(4)
Finally, the crystal structure of the tricoordinated gold()
compound 12 was determined by X-ray diffraction methods
from single crystals obtained by slow diffusion of hexane into
a solution of 12 in dichloromethane. Compound 12 (Fig. 3,
Table 4) crystallizes with one dichloromethane molecule. It
exhibits trigonal geometry at the gold centre (P–Au–P angles
from 119.34(4) to 120.43(4)Њ). The metal atom is essentially
coplanar with the donor atoms P(1), P(2) and P(3). Au–P dis-
tances are very similar and range from 2.3688(12) to 2.3738(12)
Å. These values are in the range of those observed in [Au-
(PPh3)3]ϩ (three independent investigations (2.345–2.408 Å)24–26
or [Au(dppf )(PPh3)]ClO4 (2.343(2)–2.409(2) Å).27 Within the
those corresponding to the anions at ∼1100 (vs, br) and 623
Ϫ 22
cmϪ1 (m) for ClO4
or at ∼1260 (vs, br), 1153 (br), 1101 (br)
and 692 cmϪ1 (m) for TfOϪ.23 In the 31P{1H} NMR spectra of
12–14 a unique broad signal is observed at 26.0 (12), Ϫ3.6 (13)
or Ϫ9.1 ppm (14) at room temperature that is sharpened for 12
and 14 and splits into two doublets centered at Ϫ3.5 ppm for
the silver derivative 13 [J(109Ag–P) = 365; J(107Ag–P) = 320 Hz]
when they are registered at 223 K. Their 1H NMR spectra
display, besides the resonances corresponding to the aromatic
protons, a broad signal due to the aminic hydrogens at 4.74
(12), 4.72 (13) or 4.65 ppm (14) that appears as a singlet on
cooling.
Fig. 2 Molecular structure of the cation in 10. Hydrogen atoms
(except NH) are omitted for clarity. Radii are arbitrary.
Fig. 3 Molecular structure of the cation in 12. Hydrogen atoms
(except NH) are omitted for clarity. Radii are arbitrary.
Scheme 2 i) [Au(tht)2]TfO; ii) AgClO4; iii) [Cu(NCMe)4]TfO.
1322
J. Chem. Soc., Dalton Trans., 2002, 1319–1326

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asymmetric unit there are two short N–H ؒ ؒ ؒ O hydrogen
bonds (N1–H01 ؒ ؒ ؒ O1 and N2–H04 ؒ ؒ ؒ O2); several other
borderline interactions with H ؒ ؒ ؒ X (X = N or O) ca. 2.5 Å
could be interpreted as hydrogen bonds, and there are addition-
ally some short N–H ؒ ؒ ؒ Au contacts with H ؒ ؒ ؒ Au distances
of ca. 3 Å (Table 2), although the N–H ؒ ؒ ؒ Au angles are
around 100Њ.
The study of luminescent gold() compounds has received
great attention and developed rapidly in the last years. Particu-
larly interesting are the multimetallic systems that show metal–
metal interactions, because the study of their photophysical
and photochemical properties, apart from the fundamental
interest, has potential applications in synthesis, energy con-
version and pharmacology.28 The luminescence in gold()
derivatives is usually: a) related to the presence of metal–metal
interactions, b) conditioned by the ligands in internal transi-
tions or in charge transfers, or c) related to a trigonal planar
geometry around the gold center. Thus, we have registered the
excitation and emission spectra of the gold products described
here, which could present such optical properties.
All the spectra recorded in solution show a common feature:
a broad emission band at high energy in the range 429–441 nm
(excitation: 382–384 nm) that can be assigned to ligand transi-
tions probably located in the π orbitals of the rings. High
energy values of intraligand transitions have been reported
in related systems29 and the solution spectrum of the ligand
shows an emission at similar values of energy. Thus, the
emission spectra of solutions of the dinuclear gold() species
[AuM(PNH2)2]2ϩ (M = Au (6), Ag (10), Cu (11)) show this
emission at 441 (6), 430 (10) or 431 nm (11). Nevertheless, a
more detailed analysis of these spectra reveals the presence of
a second transition that appears as a shoulder in the emission
spectrum of the homonuclear gold derivative 6 (see Fig. 4) at
spectrum at 500 nm, a value that is in accordance with a
phosphorescent transition in the metal promoted by the trico-
ordination. When the spectrum is recorded in acetone solution
only the band corresponding to the intraligand transitions is
observed. In the cases of the silver and copper derivatives only a
weak luminescence of the ligand is observed either in solution
or in the solid state, a fact that could be interpreted as possible
tetracoordination around the metal centers.
Experimental
Reagents
AgClO4 and AgTfO were purchased from Aldrich and used
as received. The compounds PNH2,32 [Au(tht)2]TfO,33 [Cu-
(NCMe)4]TfO,34 [AuCl(PNH2)]12a were prepared by literature
methods.
Caution! perchlorate salts with organic cations may be
explosive.
General procedure
Infrared spectra were recorded in the range 4000–200 cmϪ1 on a
Perkin-Elmer FT-IR Spectrum 1000 spectrophotometer using
Nujol mulls between polyethylene sheets. Conductivities were
measured in ca. 5 × 10Ϫ4 M acetone solutions with a Jenway
4010 conductimeter. C, H, N, S analyses were carried out with a
Perkin-Elmer 240C microanalyser. Mass spectra were recorded
on a VG Autospec using the LSIMS techniques and nitrobenzyl
alcohol as the matrix and on a HP59987 A electrospray. 1H, 19
F
and 31P NMR spectra were recorded on a Bruker ARX 300 in
CDCl3 or hexadeuteroacetone (HDA) solutions. Chemical
shifts are quoted relative to SiMe4 (1H, external), CFCl3
(19F, external) and H3PO4 (85%) (31P, external). Excitation and
emission spectra were recorded on a Perkin-Elmer LS-50B
luminescence spectrometer. Acetone for photophysics was
distilled over potassium permanganate and degassed before
use. All the experiments were carried out under nitrogen
atmosphere using Schlenk techniques and at room temperature.
Synthesis of the complexes
[Au(PNH2)2]TfO (1). To a dichloromethane solution (20 mL)
of [Au(tht)2]TfO (0.25 mmol, 0.13 g) was added PNH2
(0.5 mmol; 0.14 g) and after 15 min of stirring the solvent was
evaporated to ca. 5 mL. Addition of diethyl ether (20 mL)
led to precipitation of complex 1 as a white solid. Yield: 80%.
Mass spectrum: [M]ϩ at m/z = 751 (100%). Anal. Calcd. for:
C37H32AuF3N2O3P2S (1): C, 49.35; H, 3.6; N, 3.1; S, 3.55.
Found: C, 49.5; H, 3.4; N, 3.25; S, 3.6%. 31P{1H} NMR
(CDCl3), δ: 32.9 (s). 19F NMR (CDCl3), δ: Ϫ78.25 (s). 1H NMR
(CDCl3), δ: 6.49–7.61 [m, 28H, aromatic protons], ∼4.6 [m,
Fig. 4 Excitation and emission spectra of complexes 6, 10 and 11 in
solution at room temperature.
4H, NH2]. ΛM = 72 ΩϪ1 cm2 molϪ1
.
∼500 nm (excitation: ∼350 nm). The absence of this transition in
the other dinuclear complexes allows us to assign tentatively its
origin in the interactions between the gold() centres. Besides,
similar values have also been reported for other dinuclear
gold() derivatives30 and assigned as phosphorescence from a
triplet excited state. In contrast, these complexes are only very
weakly luminescent in the solid state.
[Ag(PNH2)2]A (A ؍ TfO (2), ClO4 (3)). To a solution of
0.25 mmol of AgA (A = TfO, 0.06 g; A = ClO4, 0.05 g) in 20 mL
of diethyl ether was added PNH2 (0.5 mmol; 0.14 g) and a white
precipitate immediately began to form. After 2 h of stirring
the precipitation was complete and the white solid was then
filtered off. Yield: 80 (2), 94% (3). Mass spectra: [M]ϩ at m/z =
661 (100%, 2 and 3). Anal. Calcd. for: C37H32AgF3N2O3P2S (2):
C, 54.75; H, 3.95; N, 3.45; S, 3.95. Found: C, 54.5; H, 3.95;
N, 3.45; S, 3.95%. C36H32AgClN2O4P2 (3): C, 56.75; H, 4.25;
N, 3.7. Found: C, 56.45; H, 4.45; N, 3.45%. 31P{1H} NMR
(HDA): 298 K, δ: (2) Ϫ2.7 (m); (3) Ϫ2.6 (m); 223 K, δ: (2)
Ϫ3.6 [J(109Ag–P) = 574; J(107Ag–P) = 502 Hz]; (3) Ϫ3.6
[J(109Ag–P) = 574; J(107Ag–P) = 502 Hz]. 19F NMR (HDA),
It has been shown31 that tricoordination around a d10 ion in
phosphino complexes produces a reduction of the HOMO–
LUMO gap that allows the appearance of luminescent transi-
tions. Thus, the experimental studies of this type of complex in
the solid state show emissions ranging between 481 and 533 nm
and they are assigned to a phosphorescent emission. In the case
of complex 12, when the excitation and emission spectra are
recorded at room temperature only a transition at 440 nm
assigned to the ligand is observed, but when the temperature is
lowered to 77 K an additional band appears in the emission
1
δ: (2) Ϫ78.25 (s). H NMR (HDA), 223 K, δ: (2) 6.56–7.60
[m, 28H, aromatic protons], 5.62 [s, 4H, NH2]; (3) 6.74–7.61 [m,
28H, aromatic protons], 5.14 [s, 4H, NH2]. ΛM = 68 (2); 78 ΩϪ1
cm2 molϪ1 (3).
J. Chem. Soc., Dalton Trans., 2002, 1319–1326
1323

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[Cu(PNH2)2]TfO (4). To an acetonitrile solution (20 mL) of
[Cu(NCMe)4]TfO (0.25 mmol; 0.09 g) was added PNH2
(0.5 mmol; 0.14 g) and after 15 min of stirring the solvent was
evaporated to ca. 5 mL. Addition of diethyl ether (20 mL)
led to precipitation of complex 4 as a white solid. Yield: 61%.
Mass spectrum: [M]ϩ at m/z = 617 (100%). Anal. Calcd. for:
C37H32CuF3N2O3P2S (4): C, 57.95; H, 4.2; N, 3.65; S, 4.2.
Found: C, 57.75; H, 4.05; N, 3.95; S, 4.3%. 31P{1H} NMR
C38H32Cu2F6N2O6P2S2 (9): C, 46.6; H, 3.3; N, 2.85; S, 6.55.
Found: C, 46.7; H, 3.25; N, 2.75; S, 6.7%. 31P{1H} NMR
1
(CDCl3) δ: Ϫ10.8 (s). 19F NMR (CDCl3), δ: Ϫ78.25 (s). H
NMR (CDCl3), δ: 6.68–7.47 [m, 28H, aromatic protons],
∼5.1 [m, 4H, NH2]. ΛM = 124 ΩϪ1 cm2 molϪ1
.
[AuM(PNH2)2](TfO)2 (M ؍ Ag (10), Cu (11)). Method 1. A
dichloromethane solution of complex 1 (0.2 mmol, 0.18 g) was
added to a solution of 0.2 mmol of AgTfO (0.05 g) in diethyl
ether (10) or [Cu(NCMe)4]TfO (0.07 g) in acetonitrile (11).
After 15 min of stirring at room temperature the solvent was
evaporated to ca. 5 mL and addition of diethyl ether (20 mL)
led to precipitation of complexes 10 or 11 as white solids. Yield:
83 (10); 86% (11).
1
(CDCl3), δ: Ϫ11.7 (s). 19F NMR (CDCl3), δ: Ϫ78.25 (s). H
NMR (CDCl3), δ: 7.13–7.4 [m, 28H, aromatic protons], ∼4.9
[m, 4H, NH2]. ΛM = 70 ΩϪ1 cm2 molϪ1
.
[Au(PN᎐CMe )] (ClO ) (5). To a solution of AgClO (0.25
᎐
2
2
4
2
4
mmol; 0.05 g) in acetone was added [AuCl(PNH2)] (0.25 mmol;
0.13 g). After 3 h of stirring the AgCl formed was filtered
off and the resulting solution was concentrated in vacuum.
Addition of 20 mL of diethyl ether led to precipitation of 5 as a
white solid. Yield: 86%. Anal. Calcd. for: C42H40Au2Cl2N2O8P2
(5): C, 41.1; H, 3.3; N, 2.3. Found: C, 40.9; H, 3.35; N, 2.3%.
Method 2. To a solution of [Au(tht)2]TfO (0.2 mmol, 0.10 g)
in 20 mL of dichloromethane was added 0.2 mmol of 4 (0.15 g)
or 2 (0.16 g). The solution was stirred for 15 min and then
concentrated in vacuum. Addition of diethyl ether (20 mL) led
to the precipitation of complexes 10 or 11 as white solids. Yield:
90 (10); 78% (11). Anal. Calcd. for: C38H32AgAuF6N2O6P2S2
(10): C, 39.45; H, 2.8; N, 2.4; S, 5.55. Found: C, 39.55; H, 2.65;
N, 2.45; S, 5.65%. C38H32AgCuF6N2O6P2S2 (11): C, 41.0; H, 2.9;
N, 2.5; S, 5.75. Found: C, 40.7; H, 2.95; N, 2.85; S, 5.65%.
31P{1H} NMR (CDCl3): δ: (10) 31.1 (s); (11) 29.5 (s). 19F NMR
1
31P{1H} NMR (HDA), δ: 20.5 (s). H NMR (HDA), δ: 7.13–
7.93 [m, 28H, aromatic protons], 2.06 [m, 12H, Me]. ΛM
=
125 ΩϪ1 cm2 molϪ1
.
[Au(PNH2)]2(ClO4)2 (6). To a solution of AgClO4 (0.25
mmol; 0.05 g) in dichloromethane/toluene (1/1) was added
[AuCl(PNH2)] (0.25 mmol; 0.13 g). After 3 h of stirring the
AgCl formed was filtered off and the resulting solution was
concentrated in vacuum. Addition of 20 mL of diethyl ether led
to precipitation of 6 as a white solid. Yield: 95%. Anal. Calcd.
for: C36H32Au2Cl2N2O8P2 (6): C, 37.7; H, 2.8; N, 2.45. Found:
C, 37.75; H, 2.9; N, 2.5%. 31P{1H} NMR (CDCl3), δ: 17.1 (s).
1H NMR (CDCl3), δ: 6.45–7.72 [m, 28H, aromatic protons],
1
(CDCl3), δ: (10 and 11) Ϫ78.25 (s). H NMR (CDCl3), δ: (10)
6.73–7.65 [m, 28H, aromatic protons], 5.18 [s, 4H, NH2]; (11)
6.74–7.59 [m, 28H, aromatic protons], 5.47 [s, 4H, NH2]. ΛM
=
124 (10); 105 ΩϪ1 cm2 molϪ1 (11).
[Au(PNH2)3]ClO4 (12). To
a dichloromethane solution
(20 mL) of [Au(tht)2]ClO4 (0.2 mmol, 0.10 g) was added PNH2
(0.6 mmol; 0.17 g) and after 30 min of stirring at room tempera-
ture the solvent was evaporated to ca. 5 mL. Addition of diethyl
ether (20 mL) led to precipitation of complex 12 as a white
solid. Yield: 77%. Anal. Calcd. for: C55H48AuF3N3O3P3S (12):
C, 56.1; H, 4.1; N, 3.55; S, 2.7. Found: C, 54.8; H, 4.4; N, 3.35;
S, 2.6%. 31P{1H} NMR (CDCl3), 298 K, δ: 26.0 (m); 223 K,
δ: 28.8 (s). 19F NMR (CDCl3), δ: Ϫ78.25 (s). 1H NMR (CDCl3),
δ: 6.57–7.37 [m, 42H, aromatic protons], 4.74 [m, 6H, NH2].
4.94 [s, 4H, NH2]. ΛM = 120 ΩϪ1 cm2 molϪ1
.
[Ag(PNH2)]2A2 (A ؍ TfO (7), ClO4 (8)). Method 1. To a
diethyl ether solution (20 mL) of 0.5 mmol of AgA (A = TfO,
0.13 g; A = ClO4, 0.14 g) was added PNH2 (0.5 mmol, 0.14 g)
and a white precipitate immediately started to form. After 2 h
of stirring at room temperature the precipitation was complete;
complexes 7 and 8 were obtained as white solids that were then
filtered off. Yield: 72 (7), 97% (8).
ΛM = 73 ΩϪ1 cm2 molϪ1
.
[Ag(PNH2)3]ClO4 (13). To a solution of 0.2 mmol of AgClO4
(0.04 g) in 20 mL of diethyl ether was added PNH2 (0.6 mmol;
0.17 g); a white precipitate immediately appeared. After 3 h of
stirring the precipitation was complete and the white solid was
filtered off. Yield: 88%. Anal. Calcd. for: C54H48AgClN3O4P3
(13): C, 62.4; H, 4.65; N, 4.05. Found: C, 61.7; H, 5.05;
N, 3.85%. 31P{1H} NMR (HDA): 298 K, δ: Ϫ3.6 (m); 223 K,
Method 2. To a solution of 0.2 mmol of AgA (A = TfO, 0.05
g; A = ClO4, 0.04 g) in acetone was added 0.2 mmol of 2 (0.16 g)
(7) or 3 (0.15 g) (8). After 15 min of stirring the solution was
concentrated in vacuum and addition of 20 mL of diethyl ether
led to the precipitation of complexes 7 and 8 as white solids.
Yield: 70 (7), 85% (8). Mass spectra: [M A]ϩ at m/z = 919 (6%,
ؒ
7); 869 (6%, 8). Anal. Calcd. for: C38H32Ag2F6N2O6P2S2 (7): C,
42.7; H, 3.0; N, 2.6; S, 6.0. Found: C, 42.6; H, 3.15; N, 2.35;
S, 6.05%. C36H32Ag2Cl2N2O8P2 (8): C, 44.6; H, 2.35; N, 2.9.
Found: C, 44.35; H, 3.25; N, 3.1%. 31P{1H} NMR (HDA): 298
K, δ: (7) Ϫ0.8 (m); (8) Ϫ0.8 (m); 223 K, δ: (7) Ϫ2.10 (broad
doublet); (8) Ϫ2.4 (broad doublet). 19F NMR (HDA), δ: (7)
Ϫ78.25 (s). 1H NMR (HDA), 223 K, δ: (7) 6.71–7.66 [m,
28H, aromatic protons], 5.67 [s, 4H, NH2]; (8) 6.72–7.64
[m, 28H, aromatic protons], 5.68 [s, 4H, NH2]. ΛM = 128 (7);
117 ΩϪ1 cm2 molϪ1 (8).
1
δ: Ϫ3.5 [J(109Ag–P) = 365; J(107Ag–P) = 320 Hz]. H NMR
(HDA), δ: 6.75–7.51 [m, 42H, aromatic protons], 4.72 [s, 6H,
NH2]. ΛM = 81 ΩϪ1 cm2 molϪ1
.
[Cu(PNH2)3]TfO (14). To an acetonitrile solution (20 mL)
of [Cu(NCMe)4]TfO (0.2 mmol, 0.07 g) was added PNH2
(0.6 mmol; 0.17 g) and after 30 min of stirring the solvent was
evaporated to ca. 5 mL. Addition of diethyl ether (20 mL) led to
precipitation of complex 14 as a white solid. Yield: 70%. Anal.
Calcd. for: C55H48CuF3N3O3P3S (14): C, 63.25; H, 4.65; N, 4.0;
S, 3.05. Found: C, 63.0; H, 4.35; N, 3.75; S, 2.85%. 31P{1H}
NMR (CDCl3), 298 K, δ: Ϫ9.1 (m); 223 K, δ: Ϫ8.3 (s). 19F
[Cu(PNH2)]2(TfO)2 (9). Method 1. To an acetonitrile solution
(20 mL) of [Cu(NCMe)4]TfO (0.5 mmol; 0.19 g) was added
PNH2 (0.5 mmol; 0.14 g). After 15 min of stirring at room
temperature the solvent was evaporated to ca. 5 mL and
addition of diethyl ether (20 mL) led to precipitation of 9 as a
white solid. Yield: 70%.
Method 2. To a solution of [Cu(NCMe)4]TfO (0.2 mmol,
0.07 g) in acetonitrile was added 0.2 mmol of 4 (0.15 g). After
15 min of stirring the solution was concentrated in vacuum
and addition of 20 mL of diethyl ether led to the precipitation
of complex 9 as a white solid. Yield: 65%. Anal. Calcd. for:
1
NMR (CDCl3), δ: Ϫ78.25 (s). H NMR (CDCl3), δ: 6.64–7.31
[m, 42H, aromatic protons], 4.65 [m, 6H, NH2]. ΛM = 73 ΩϪ1
cm2 molϪ1
.
Crystal structure determinations
The crystals were mounted in inert oil on a glass fibre and
transferred to the cold gas stream of a Siemens P4 or Siemens-
Smart 1000-CCD (5) diffractometers. Data were collected using
monochromated Mo Kα radiation (λ = 0.71073 Å). Absorption
1324
J. Chem. Soc., Dalton Trans., 2002, 1319–1326

View Article Online
Table 5 Details of data collection and structure refinement for complexes 5, 10 and 12
Compound
5
10ؒ2×1/2CH2Cl2
12ؒCH2Cl2
Chemical formula
Crystal habit
Crystal size/mm
Crystal system
C42H40Au2Cl2N2O8P2
Colourless tablet
0.18 × 0.08 × 0.06
Triclinic
C39H34AgAuCl2F6N2O6P2S2
Colourless prism
0.50 × 0.30 × 0.20
Triclinic
C56H50AuCl2F3N3O3P3S
Colourless tablet
0.20 × 0.14 × 0.14
Triclinic
¯
¯
¯
Space group
P1
P1
P1
a/Å
b/Å
c/Å
α/Њ
8.5581(8)
11.2666(12)
11.8309(12)
70.274(3)
78.216(3)
80.113(3)
1044.61(18)
1
12.027(3)
12.451(3)
16.605(4)
76.38(1)
72.23(2)
87.81(1)
2299.8(10)
2
11.5579(18)
12.209(2)
20.646(3)
101.310(12)
92.877(14)
103.841(12)
27593(7)
2
β/Њ
γ/Њ
U/Å3
Z
Dc/g cmϪ3
1.951
1.794
1.520
M
F(000)
1227.53
592
1242.48
1212
1262.83
1264
T /ЊC
2θmax/Њ
Ϫ130
56
7.274
0.928–0.708
14295
Ϫ100
50
3.958
0.242–0.505
9296
Ϫ100
50
2.943
0.681–0.876
11619
µ(Mo-Kα)/mmϪ1
Transmission
No. of reflections measured
No. of unique reflections
Rint
5166
7998
9641
0.0436
0.0251
0.0543
5166
264
65
0.0481
0.0601
0.1589
7998
605
349
0.0255
0.0350
0.0665
9641
662
195
Ra(F > 4σ(F))
wRb(F 2, all refl.)
No. of reflections used
No. of parameters
No. of restraints
Sc
0.990
1.716
1.031
2.87
0.911
0.832
Max. ∆ρ/e ÅϪ3
2
2
2
2
a R(F) = Σ Fo| Ϫ |Fc /Σ|Fo|. b wR(F 2) = [Σ{w(Fo Ϫ Fc2)2}/Σ{w(Fo )2}]0.5; wϪ1 = σ2(Fo ) ϩ (aP)2 ϩ bP, where P = [Fo ϩ 2Fc2]/3 and a and b are
constants adjusted by the program. c S = [Σ{w(Fo2 Ϫ Fc2)2}/(n Ϫ p)]0.5, where n is the number of data and p the number of parameters.
(b) C. Redshaw, V. C. Gibson, W. Clegg, A. J. Edwards and B. Miles,
J. Chem. Soc., Dalton Trans., 1997, 3343.
7 L. Crociani, F. Tisato, F. Refosco, G. Bandoli and B. Corain, Eur. J.
Inorg. Chem., 1998, 1689.
8 (a) U. Casellato, P. Guerriero, S. Tamburini and P. A. Vigato, Inorg.
Chim. Acta, 1997, 260, 1; (b) S. Chatterjee, D. C. R. Hockless,
G. Salem and P. Waring, J. Chem. Soc., Dalton Trans., 1997, 38;
(c) S. Chatterjee, D. C. R. Hockless, G. Salem and P. Waring,
J. Chem. Soc., Dalton Trans., 1997, 3889.
9 (a) G. J. Organ, M. K. Cooper, K. Henrick and M. Mc Partlin,
J. Chem. Soc., Dalton Trans., 1984, 2287; (b) M. K. Cooper,
G. J. Organ, P. A. Duckworth, K. Henrick and M. Mc Partlin,
J. Chem. Soc., Dalton Trans., 1988, 2287.
corrections were based on ψ-scans (10, 12) or multiple scans
(program SADABS (5)).35 The structures were refined on F 2
using the program SHELXL-97.36 All non-hydrogen atoms
were refined anisotropically. H atoms were included using a
riding model or rigid methyl groups (exceptions see below).
Special features of refinement: for all compounds, restraints to
light atom U value components and to local ring symmetry
were employed to improve the stability of the refinement. The
solvent molecules in complex 10 (two half molecules of dichloro-
methane) are disordered over inversion centres. The aminic
hydrogens of compound 12 were located in difference syntheses
and refined with fixed U values and restrained N–H distances.
Further crystallographic details are given in Table 5.
10 C. J. Adams, M. I. Bruce, P. A. Duckworth, P. A. Humphrey,
O. Kuhl, E. R. T. Tiekink, W. R. Cullen, P. Braunstein, S. C. Cea,
B. W. Skelton and A. H. White, J. Organomet. Chem., 1994, 467, 251.
11 C. Bolzati, F. Tisato, F. Refosco, G. Bandoli and A. Dolmella, Inorg.
Chem., 1996, 35, 6221.
CCDC reference numbers 176612–176614.
See http://www.rsc.org/suppdata/dt/b1/b110398a/ for crystal-
lographic data in CIF or other electronic format.
12 (a) J. M. López-de-Luzuriaga, A. Schier and H. Schmidbaur, Chem.
Ber., 1997, 130, 647; (b) P. Papathanasiou, G. Salem, P. Waring and
C. Willis, J. Chem. Soc., Dalton Trans., 1997, 3435; (c) L. Crociani,
R. Anacardio, P. Traldi and B. Corain, Inorg. Chim. Acta, 1998,
282, 119; (d ) F. Tisato, G. Pilloni, F. Refosco, G. Bandoli, C. Corvaja
and B. Corain, Inorg. Chim. Acta, 1998, 275, 401; (e) E. R. T.
Tiekink, J. Coord. Chem., 1993, 28, 233; ( f ) B. L. Shaw, N. Iranpoor,
S. D. Perera, M. Thornton-Pett and J. D. Vessey, J. Chem. Soc.,
Dalton Trans., 1998, 1885; (g) A. M. Z. Slavin and M. B. Smith, New
J. Chem., 1999, 23, 777; (h) E. J. Fernández, M. Gil, M. E. Olmos,
O. Crespo, A. Laguna and P. G. Jones, Inorg. Chem., 2001, 40, 3018.
13 J. M. Forward, J. P. Fackler, Jr. and Z. Assefa, in Optoelectronic
Properties of Inorganic Compounds, ed. D. M. Roundhill and
J. P. Fackler, Jr., Plenum Press, New York, 1999, pp. 195–226.
14 B. Bruni, M. Ferranzoni, P. Orli and G. Speroni, Acta Crystallogr.,
Sect. C, 1996, 52, 1423.
15 (a) E. J. Fernández, J. M. López-de-Luzuriaga, M. Monge,
M. A. Rodríguez, O. Crespo, M. C. Gimeno, A. Laguna and
P. G. Jones, Inorg. Chem., 1998, 37, 6002; (b) M. E. Olmos, A. Schier
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Acknowledgements
We thank the Dirección General de Investigación (M. C. T.)
(no. BQU2001-2409), University of La Rioja (API-01/B14), the
Fonds der Chemischen Industrie, and the Caja the Ahorros de
la Inmaculada for financial support.
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