Group 11 metal chemistry of a tetradentate ligand, Phenylene-1,4- diaminotetra(phosphonite), p-C6H4[N(P(OC6H 4OMe-o)2)2]2

Article abstract of DOI:10.1021/ic900085e

The Cu^I, Ag^I, and Au^I chemistry of a tetradentate ligand (phenylene-1,4-diaminotetra(phosphonite), p-C ₆H₄[N(P(OC₆H₄OMe-o) ₂)₂]₂ (P₂NΦ

Full text of DOI:10.1021/ic900085e

Inorg. Chem. 2009, 48, 3768-3782
Group 11 Metal Chemistry of a Tetradentate Ligand,
Phenylene-1,4-diaminotetra(phosphonite), p-C6H4[N{P(OC6H4OMe-o)2}2]2†
Chelladurai Ganesamoorthy and Maravanji S. Balakrishna*
Phosphorus Laboratory, Department of Chemistry, Indian Institute of Technology Bombay,
Mumbai 400 076, India
Joel T. Mague
Department of Chemistry, Tulane UniVersity, New Orleans, Louisiana 70118
Received January 16, 2009
The CuI, AgI, and AuI chemistry of a tetradentate ligand (phenylene-1,4-diaminotetra(phosphonite), p-C6H4[N{P(OC6H4OMe-
o)2}2]2 (P2NΦNP2) (1)) is described. The flexional conformations in 1 leads to interesting structural variations in transition-
metal complexes. The reaction of 1 with 4 equiv of CuX (where X ) Br and I) produce the tetranuclear complexes,
[{Cu2(µ-X)2(NCCH3)2}2(µ-P2NΦNP2)] (where X ) Br (2) or X ) I (3)) in quantitative yield. Treatment of 3 with an excess
of pyridine, 2-(piperazin-1-yl)pyrimidine, and pyrazole yielded the tetra-substituted derivatives, [{Cu2(µ-I)2(L)2}2(µ-P2NΦNP2)]
(where L ) pyridine (4), 2-(piperazin-1-yl)pyrimidine (5), or pyrazole (6)). Similar reactions of 3 with 1,10-phenanthroline
(phen) and 2,2′-bipyridine in a 1:2 molar ratio afford the disubstituted derivatives, [(Cu2(µ-I))2I2(phen)2(µ-P2NΦNP2)] (7)
and [(Cu2(µ-I))2I2(bipy)2(µ-P2NΦNP2)] (8). The o-methoxyphenoxy substituents on phosphorus in complexes 5 and 7
adopt approximately parallel planar conformations and contain lattice solvents. The reaction of 3 with 1,4-diaza-
bicyclo[2.2.2]octane (DABCO) in a 1:2 molar ratio in a dichloromethane-acetonitrile mixture leads to the formation of an
ionic complex [N(CH2CH2)3N+CH2Cl]2[(Cu2(Cl)(I)2)2(NCCH3)2(µ-P2NΦNP2)]2- (9), as a result of the chloromethylation of
DABCO. Treatment of 1 with 4 equiv of AgClO4 produces [{Ag2(µ-ClO4)2)2(C4H8O)2}2(µ-P2NΦNP2)] (10). Displace-
ment of perchlorate ions in 10 by PhN{P(OC6H4OMe-o)2}2 (PNP) or 2,2′-bipyridine yielded [(µ-PNP)2Ag2(µ-P2NΦNP2)Ag2-
(µ-PNP)2](ClO4)4 (11) and [{Ag2(bipy)2}2(µ-P2NΦNP2)](ClO4)4 (12), respectively. The similar reaction of 1 with 2 equiv of
AgOTf, in the presence of 4,4′-bipyridine, gave a three-dimensional AgI coordination polymer, [{Ag2(C10H8N2)2
(CH3CN)2}2(P2NΦNP2)]n(OTf)4n (13). The reactions of 1 with [AuCl(SMe2)], in appropriate ratios, afford the tetranuclear
and dinuclear complexes, [(Au2Cl2)2(µ-P2NΦNP2)] (14) and [(AuCl)2(P2NΦNP2)] (15). Complex 14 undergoes moisture-
assisted P-N bond cleavage in the presence of PhN{P(OC6H4OMe-o)2}2 to give [p-NH2C6H4N{P(OC6H4OMe-o)2}2Au2Cl2]
(17) and [PhN{P(OC6H4OMe-o)2}2Au2Cl2]. The structures of the complexes 5, 7-10, 12-15, and 17 are confirmed by
single-crystal X-ray diffraction studies.
Introduction
for the synthesis of supramolecular architectures through the
use of dynamic coordination chemistry4 and weak d10-d10
Recently, the synthesis and structural characterization of
Group 11 metal complexes in a +1 oxidation state have
attracted much attention, because of their potential application
in catalysis,1 biosystems,2 and photochemical areas.3 In
addition, Group 11 metals serve as versatile connecting nodes
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†
Dedicated to Prof. S. S. Krishnamurthy on the occasion of his 69th
birthday.
* Author to whom correspondence should be addressed. Tel.: +91 22
2576 7181. Fax: +91 22 2576 7152/2572 3480. E-mail: krishna@
chem.iitb.ac.in.
3768 Inorganic Chemistry, Vol. 48, No. 8, 2009
10.1021/ic900085e CCC: $40.75  2009 American Chemical Society
Published on Web 03/24/2009

Group 11 Metal Chemistry of a Tetradentate Ligand
metallophilic interactions.5 Several rigid N-donor ligands,
such as 4,4′-bipyridine, 4,4′-dibenzonitrile, pyrazine, and their
various derivatives have been extensively used to bridge these
metal ions to generate multidimensional, metal-organic
materials with diverse properties.6 Among these ligands, 4,4′-
bipyridine has served as an effective bridging group and
hundreds of interesting supramolecular architectures have
been reported.7 Instances of the use of rigid linear phos-
phines, analogous to 4,4′-bipyridine, in the synthesis of
polynuclear complexes are less extensive.8 Several phosphine
systems, including a variety of monophosphines (PR3) and
chelating bisphosphines (dppm, dcpm, dppa, etc.), have been
Chart 1
used extensively to investigate the coordinating ability of
CuI, AgI, and AuI centers.5d,9 In particular, bis(diphenylphos-
phino)methane (dppm) played a vital role as a bridging ligand
and its coordination chemistry has been thoroughly studied.10
Similar types of bis(phosphines) with an “RN<” spacer in
place of the methylene group (known as aminobis(phos-
phines) with a P-N-P framework) have been studied and
found to be thermally more stable, compared to dppm, and
sterically less rigid in comparison with P-O-P systems.11
Furthermore, the binding properties of these ligands can be
readily altered by changing the substituents on both the P
and N centers, and previous work has shown that such
changes can alter the P-N-P angle over the range of
110°-123°, thereby providing ligands capable of spanning
a considerable range of intermetallic distances.12
Recently, we have extended scope of this chemistry by
preparing the novel linear tetraphosphonite ligands {(X2P)2
NC6H4N(PX2)2} (where X ) Cl, F, OMe, OC6H4OMe-o)
(I).13 Interestingly, the compounds of type I can adopt several
conformations, depending on the orientation of the P-N-P
skeleton, with respect to the phenylene ring, as shown in
Chart 1. Furthermore, the lone pairs on P atoms can orient
in various directions, with respect to the R-N< bridge to
afford several geometrical conformations in metal com-
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Inorganic Chemistry, Vol. 48, No. 8, 2009 3769

Ganesamoorthy et al.
Scheme 1. Synthesis of Copper(I) Halide Complexes
C2v conformation in I-III (see Chart 1) can bring the metals
in close proximity and, therefore, favor metal-metal bond-
ing. Barring C2v′ owing to steric crowding, there is a total
of 12 possible conformations (see Chart 1),14 which could
lead to the formation of different types of oligomers and
polymeric sheets with metals, the nature of which will be
dependent on the coordination geometry of the transition
metals and the possible conformations of the ligand.
As a part of our interest in phosphorus-based ligands15
and their applications in the synthesis of metalla-macromol-
ecules and polymers,16 we describe herein the synthesis and
structural characterization of several dinuclear and tetra-
nuclear Group 11 metal complexes of the phenylene-1,4-
diaminotetra(phosphonite), p-C6H4[N{P(OC6H4OMe-o)2}2]2
(P2NΦNP2) (1). This includes the formation of a three-
dimensional (3D) AgI coordination polymer.
lead to the formation of several mixed-ligand complexes with
additional hard donor sites on the periphery of the ligands
that can participate in ligation with hard metals to give
heteropoly metallic complexes. In this regard, the tetranuclear
iodo derivative 3 was used for reactions with strong Lewis
bases to give several mixed-ligand complexes, as shown in
Scheme 2. The substitution of the coordinated solvent
molecules in complex 3 with pyridine in acetonitrile or
dichloromethane did not take place, so that the desired
complex, [{Cu2(µ-I)2(C5H5N)2}2(µ-P2NΦNP2)] (4) was pre-
pared as a white crystalline solid by stirring 3 in an excess
of pyridine. Similarly, the treatment of complex 3 with an
excess of 2-(piperazin-1-yl)pyrimidine or pyrazole (1:6 mol
ratio) in dichloromethane/acetonitrile mixtures (1:1) afforded
[{Cu2(µ-I)2(L)2}2(µ-P2NΦNP2)] (where L ) 2-(piperazin-
1-yl)pyrimidine (5) or pyrazole (6)), as white crystalline
solids. The 31P NMR spectra of complexes 4, 5, and 6 show
single resonances at 104.2, 103.9, and 105.1 ppm, respec-
Results and Discussion
Copper(I) Complexes. Tetranuclear copper(I) halide
complexes, [{Cu2(µ-X)2(NCCH3)2}2(µ-P2NΦNP2)] (where X
) Br (2) and I (3)), have been prepared by reacting phen-
ylene-1,4-diaminotetra(phosphonite) p-C6H4[N{P(OC6H4OMe-
o)2}2]2 (P2NΦNP2) (1) with 4 equiv of CuX (where X ) Br
and I) in acetonitrile, as shown in Scheme 1.13 Compounds
2 and 3 are colorless, air-stable, white crystalline solids that
are moderately soluble in organic solvents.
Complexes 2 and 3 contain weakly coordinating solvent
molecules that can be easily replaced by strong Lewis bases
such as pyridine, pyrazole, 2,2′-bipyridine, 1,10-phenanthro-
line, and 2-(piperazin-1-yl)pyrimidine. These reactions would
1
tively. The H NMR spectrum of 4 shows single peaks at
7.11, 7.56, and 8.33 ppm, corresponding to the pyridyl
protons. In 5, the pyrimidyl protons appear as triplet and
doublet resonances, centered at 6.76 and 8.27 ppm, respec-
tively, with a 3JHH coupling of 4.8 Hz, whereas the piperazine
1
protons show a broad single resonance at 2.49 ppm. The H
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NMR spectrum of 6 shows broad single resonances at 6.15 and
7.14, corresponding to the pyrazole protons with a very broad
singlet at 10.35 ppm that corresponds to the “NH” protons. The
1H NMR and analytical data are consistent with the proposed
structures of compounds 4-6 and the structure of complex 5
was confirmed via an X-ray structure determination.
Treatment of complex 3 with 1,10-phenanthroline or 2,2′-
bipyridine in 1:2 molar ratios afforded the complexes [(Cu2
(µ-I))2I2(phen)2(µ-P2NΦNP2)] (7) and [(Cu2(µ-I))2I2(bipy)2
(µ-P2NΦNP2)] (8), as bright yellow crystalline solids in good
yield. In the formation of complexes 7 and 8, two acetonitrile
groups were replaced and one of the Cu-I-Cu bridges
was broken at each end of the molecule by the added
chelating ligand (bipy or o-phen) to give both tri- and
tetra-coordinated copper centers. Complexes 7 and 8 are
moderately stable toward air and partially dissolve in
acetonitrile and dimethyl sulfoxide. Although the two
phosphorus environments are entirely different in 7 and
8, the 31P NMR spectra of complexes 7 and 8 show single
broad peaks at 104.1 and 105.0 ppm, respectively,
suggesting interconversion of the terminal and bridging
iodides. The compositions of 7 and 8 as 1:2 complexes
of 3 and the bidentate N-donor ligands were verified by
elemental analysis, and the structures were confirmed
using single-crystal X-ray structure determinations.
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3770 Inorganic Chemistry, Vol. 48, No. 8, 2009

Group 11 Metal Chemistry of a Tetradentate Ligand
Scheme 2. Synthesis of Mixed-Ligand Copper(I) Complexes
The reaction of 3 with the potential intermolecular bridging
ligand 1,4-diazabicyclo[2.2.2]octane (DABCO) afforded a
product in moderate yield that proved to be [N(CH2CH2)3-
N+CH2Cl]2[(Cu2(Cl)(I)2)2(NCCH3)2(µ-P2NΦNP)]2- (9).
We rationalize this result by noting that 1,4-diazabicy-
clo[2.2.2]octane is known to undergo a nucleophilic addition
reaction with dichloromethane to give the R-chloro quaternary
ammonium salt [N(CH2CH2)3N+CH2Cl]Cl.17 This monoquat-
ernization reduces the basicity of the remaining nitrogen lone
pair by a factor of 106, and, because of this lower basicity of
the R-chloro quaternary ammonium salt, the substitution of
coordinated solvent molecules in 3 by [N(CH2CH2)3N+CH2Cl]
does not seem to have occurred, despite the existence of
considerable studies of the donor properties of the N-chlorom-
ethyl-dabconium ligand with Mn(II), Co(II), Zn(II), Fe(II),
Cu(II), and Ni(II) salts.18 Because of the poor solubility of
complex 9 in most suitable solvents, NMR spectroscopic studies
could not be performed; however, the molecular composition
was confirmed from elemental analysis data and the primary
structural features of complex 9 were established through a
single-crystal X-ray diffraction (XRD) study.
tion of a tetranuclear complex, [{Ag2(µ-ClO4)2(C4H8O)2}2(µ-
P2NΦNP2)] (10) in good yield. In complex 10, the AgI atoms
are bridged by a pair of perchlorate ions and a P2NΦNP2
ligand. The displacement of perchlorate ligands in 10 by 4
equiv of PhN(P(OC6H4OMe-o)2)2 (PNP) afforded a “manx-
ane”-like triply bridged tetranuclear complex, [(µ-PNP)2Ag2(µ-
P2NΦNP2)Ag2(µ-PNP)2](ClO4)4 (11), as shown in Scheme
3. Treatment of 10 with 4 equiv of 2,2′-bipyridine produces
a tetranuclear complex, [{Ag2(bipy)2}2(µ-P2NΦNP2)](ClO4)4
(12), whereas the similar reaction of 1 with 2 equiv AgOTf
in the presence of 4,4′-bipyridine affords a three-dimen-
sional AgI coordination polymer, [{Ag2(bipy)2(CH3CN)2}2
(P2NΦNP2)]n(OTf)4n (13) in quantitative yield. Complexes
10-12 are white crystalline solids that are only soluble in
DMSO; however, complex 13 is an insoluble white solid.
The 31P NMR spectra of complexes 10, 11, and 12 show
broad single resonances at 120.8, 120.1, and 125.7 ppm,
respectively. The spectral and analytical data are consistent
with the proposed structures of compounds 10-13, and the
structures of complexes 10 and 13 were confirmed by X-ray
structure determination.
Gold(I) Complexes. The reaction of 1 with [AuCl(SMe2)]
in a 1:4 molar ratio produces a tetranuclear complex,
[(Au2Cl2)2(µ-P2NΦNP2)] (14), with the ligand exhibiting the
bridging mode of coordination. A similar reaction of 1 with
[AuCl(SMe2)] in a 1:2 molar ratio furnishes a dinuclear
complex, [(AuCl)2(P2NΦNP2)] (15) along with a small
quantity of 14 (see Scheme 4). Treatment of complex 14
with PhN(P(OC6H4OMe-o)2)2 (PNP) in a 1:2 molar ratio did
not give the desired bridged tetranuclear complex [(µ-
PNP)Au2Cl2(µ-P2NΦNP2)Au2Cl2(µ-PNP)], even under re-
fluxing conditions. Instead, the reaction leads to the formation
of 15 and [PhN(P(OC6H4OMe-o)2)2AuCl] (16) in high yields,
Silver(I) Complexes. The reaction of 1 with AgClO4 in a
1:4 molar ratio in tetrahydrofuran (THF) leads to the forma-
(17) (a) Gustafsson, B.; Hakansson, M.; Jagner, S. Inorg. Chim. Acta 2005,
358, 1309–1312. (b) Banks, R. E.; Besheesh, M. K.; Mohialdin-
Khaffaf, S. N.; Sharif, I. J. Chem. Soc., Perkin Trans. I 1996, 2069–
2076. (c) Abdul-Ghani, M.; Banks, R. E.; Besheesh, M. K.; Sharif, I.;
Syvret, R. G. J. Fluorine Chem. 1995, 73, 255–257. (d) Almarzoqi,
B.; George, A. V.; Isaacs, N. S. Tetrahedron 1986, 42, 601–607. (e)
Vallarino, L. M.; Goedken, V. L.; Quagliano, J. V. Inorg. Chem. 1973,
12, 102–107.
(18) (a) Vallarino, L. M.; Goedken, V. L.; Quagliano, J. V. Inorg. Chem.
1972, 11, 1466–1469. (b) Quagliano, J. V.; Banerjee, A. K.; Goedken,
V. L.; Vallarino, L. M. J. Am. Chem. Soc. 1970, 92, 482–488. (c)
Garrett, B. B.; Goedken, V. L.; Quagliano, J. V. J. Am. Chem. Soc.
1970, 92, 489–493. (d) Goedken, V. L.; Quagliano, J. V.; Vallarino,
L. M. Inorg. Chem. 1969, 8, 2331–2337.
Inorganic Chemistry, Vol. 48, No. 8, 2009 3771

Ganesamoorthy et al.
Scheme 3. Synthesis of Silver(I) Complexes
Scheme 4. Synthesis of Gold(I) Complexes: Reaction of 1 To Produce
14 and 15
Crystal and Molecular Structures of 5, 7-10,
12-15, and 17. Perspective views of the molecular structures
of compounds 5, 7–10, 12–15, and 17, with atom numbering
schemes, are shown in Figures 1–10, respectively. Crystal
data and the details of the structure determinations are given
in Tables 1 and 2, while selected bond lengths and bond
angles are given in Tables 3-6. The molecular structure of
compound 5 consists of two discrete Cu2I2 cores with the
copper(I) centers tetrahedrally coordinated by a P atom, two
bridging iodides, and a solvent molecule. As observed in
complexes 2 and 3, the Cu2I2 core adopts a butterfly shape
with the I atoms at the wingtips.13 The eight Cu-I bond
lengths differ significantly from each other but can be seen
(Table 3) to fall roughly into a “longer” pair and a “shorter”
pair, with each Cu atom forming a “long” and a “short” Cu-I
bond. The distances between the two copper centers
Cu1 · · · Cu2 and Cu3 · · · Cu4 are 2.715 and 2.762 Å, respec-
tively, which indicate the presence of ligand-supported
Cu · · · Cu interactions.16c The Cu(I) centers exhibit distorted
tetrahedral coordination geometries, as indicated by the
interligand angles, which range from 134.3(2)° to 87.8(2)°.
The average Cu-P distance and Cu-I-Cu angle are 2.168
Å and 61.46°, respectively. As is evident from Figure 1, the
conformations of the 2-(piperazin-1-yl)pyrimidine ligands
and the relatively short backbone of the phosphonite ligand
constrain the o-methoxyphenoxy substituents on phosphorus
to adopt approximately parallel planar conformations which
generates a “pocket” on either side of the ligand backbone.
These are occupied by the solvent acetonitrile molecules,
which participate in weak C-H· · ·O hydrogen bonding with
some of the phenoxy O atoms.
with a small quantity of 14 remaining, as shown in Scheme
5. Complexes 15 and 16 were separated by fractional
crystallization in a dichloromethane/n-hexane (2:1) mixture.
Several attempts were made to prepare the bridged tetra-
nuclear complex [(µ-PNP)Au2Cl2(µ-P2NΦNP2)Au2Cl2(µ-
PNP)], and, in one instance, the entry of trace amount of
moisture to the reaction mixture prompted the P-N bond
cleavage in 14, which leads to the transfer of two Au-Cl
units to PhN(P(OC6H4OMe-o)2)2 to give the stoichiometric
mixture of [H2NC6H4{N{P(OC6H4OMe-o)2}2}2Au2Cl2] (17)
and [Ph{N{P(OC6H4OMe-o)2}2}2Au2Cl2], as indicated by the
31P NMR data and the XRD studies.
The 31P NMR spectrum of 14 consists of a single peak at
114.3 ppm, whereas 15 shows two doublets, centered at 110.5
and 132.2 ppm, with a large 2JPP coupling of 348 Hz.14d-f,19
The 1H NMR spectrum of 14 shows single resonance
corresponding to the ortho-methoxy groups at 3.81, whereas
15 shows two resonances at 3.60 and 3.63 ppm for ortho-
methoxy groups present on uncoordinated and coordinated
P atoms, respectively. The structures of complexes 14, 15,
and 17 were confirmed using X-ray structure determinations.
In complex 7, the Cu1 is tetra-coordinated [one P, one I,
and two N (from the o-phen moiety) atoms], whereas the
Cu2 center is tricoordinated being bound to one phosphorus
(19) (a) Keat, R. J. Chem. Soc., Dalton Trans. 1972, 2189–2192. (b)
Rudolph, R. W.; Newmark, R. A. J. Am. Chem. Soc. 1970, 92, 1195–
1199. (c) Nixon, J. F. J. Chem. Soc. A 1969, 1087–1089.
3772 Inorganic Chemistry, Vol. 48, No. 8, 2009

Group 11 Metal Chemistry of a Tetradentate Ligand
Scheme 5. Synthesis of Gold(I) Complexes: Reaction of 14 To Produce 15-18
and two iodine centers. The molecule has crystallographically
imposed centrosymmetry so that the two Cu atoms chelated
by 1,10-phenanthroline are required to adopt a trans disposi-
tion. The two Cu-P distances differ significantly (Cu1-P1
) 2.1630(6) Å, Cu2-P2 ) 2.1875(6) Å), as do the Cu-I
distances to the bridging I atom (Cu2-I1 ) 2.5702(3) Å
and Cu1-I1 ) 2.5943(3) Å) with the shorter Cu-P distance
to the 4-coordinated Cu atom. The Cu-N bond lengths
(Cu1-N2 ) 2.0749(2) Å and Cu1-N3 ) 2.065(2) Å) are
approximately equal, whereas the terminal Cu2-I1 bond
distance is 2.5178(4) Å. The distance between two copper
centers is 2.957 Å. The I1-Cu2-I2 angle is 119.48(1)°,
whereas the Cu1-I1-Cu2 angle is 69.87(1)°. These angles
obviously indicate a distortion of the copper coordination
sphere, which is occasioned primarily by the small bite angle
of the 1,10-phenanthroline (N2-Cu1-N3 ) 81.39(8)°). As
with 5, the o-methoxyphenoxy substituents on phosphorus
adopt approximately parallel planar conformations (Figure
2) and the lattice solvent acetonitrile resides in the “pockets”
thus created.
Complexes 7 and 8 have several similar structural features.
In both complexes, the structures, the chelating moiety, and
the terminal I atom are displaced to the same side of the
Cu2P2 plane while the Cu(µ-I)Cu bridge is folded away from
the terminal I atom. Furthermore, the Cu(µ-I)Cu bridge and
terminal I atoms are pointed away from each other. However,
in 8, which has no crystallographically imposed symmetry,
the two 2,2′-bipy moieties are on the same side in contrast
to the trans orientation of 7. Furthermore, in 8, the oxygen
atom O4 (or O26) of the methoxy group of one of the
Figure 1. Molecular structure of 5. All H atoms and lattice solvents have been omitted for clarity. Displacement ellipsoids are drawn at the 30% probability
level.
Inorganic Chemistry, Vol. 48, No. 8, 2009 3773

Ganesamoorthy et al.
Figure 2. Molecular structure of 7. All H atoms and lattice solvent have been omitted for clarity. Displacement ellipsoids are drawn at the 50% probability
level.
Figure 3. Molecular structure of 8. All H atoms and lattice solvents have been omitted for clarity. Displacement ellipsoids are drawn at the 50% probability
level. Only one orientation is shown for each of the disordered moieties.
phenoxy substituents makes a close approach to Cu1 (or Cu7)
(Cu1 · · · O4 ) 2.818 Å; Cu7 · · · O26 ) 2.790 Å). Because
Cu1 is formally 3-coordinated and, at this distance, is less
than the sum of the van der Waals radii of O and Cu (2.90
Å), it is likely that this represents a weak bonding interaction
with the copper center.20 The patterns of bond lengths and
bond angles in 8 are similar to those in 7; however, unlike
that in the former, not all of the o-methoxyphenoxy substit-
uents on phosphorus adopt the parallel plane arrangement.
The molecular structure of 9 consists of an anionic [Cu4(µ-
I)2(µ-X)2X2(NCCH3)2(µ-P2NΦNP2)]2- (where X ) Cl, I)
core with two chloromethylated units (1,4-diazabicyclo[2.2.2]-
octane, [N(CH2CH2)3N+CH2Cl]) as countercations. During
the course of the refinement, it became clear that a partial
incorporation of chloride into sites shown as I1 (bridging,
ca. 70%) and I3 (terminal, ca. 30%) had occurred in the
crystal that was used for the data collection. As a result,
metrical parameters that involve these atoms have noticeably
higher errors than for the remainder of the structure.21 The
anion has crystallographically imposed centrosymmetry and
the Cu2X2 core adopts a butterfly-shaped structure with the
(21) Although the elemental analyses data taken for the crystalline sample
clearly show the partial replacement of iodide by chloride, it is not
entirely clear how the exchange takes place. Attempts to react DABCO
with 3 in acetonitrile resulted in the formation of an insoluble
precipitate that could not be further analyzed or crystallized to
obtain X-ray quality crystals. X-ray quality crystals were obtained
only when a dichloromethane solution of DABCO was added to 3
in acetonitrile.
(20) Bondi, A. J. Phys. Chem. 1964, 68, 441–451.
3774 Inorganic Chemistry, Vol. 48, No. 8, 2009

Group 11 Metal Chemistry of a Tetradentate Ligand
Figure 4. Molecular structure of 9. All H atoms and the lattice solvent have been omitted for clarity. Displacement ellipsoids are drawn at the 50%
probability level. Only one orientation is shown for the disordered portion of the cation, and only the iodine positions are shown for I1 and I3, where partial
replacement by chloride occurred.
Figure 5. Molecular structure of 10. All H atoms and lattice solvents have been omitted for clarity. Displacement ellipsoids are drawn at the 30% probability
level.
halogen atoms at the wingtips. Both of the copper(I) centers
are tetrahedrally coordinated by a P atom, two bridging
halogen atoms, and a terminal halogen atom on Cu1 and a
solvent molecule on Cu2. The four bridging Cu-I bond
lengths vary from 2.52(2) Å to 2.764(1) Å. The terminal
Cu-I bond distance is 2.568(1) Å. The distance between
the two copper centers is Cu1 · · · Cu2 ) 2.789 Å, which is
slightly longer that that observed in 2, 3, and 5. In 9, the
two independent Cu-P distances are virtually the same
[P1-Cu1 ) 2.190(1) Å and P2-Cu2 ) 2.184(1) Å], whereas
the I-Cu-I angles [I1-Cu1-I2 ) 101.7(4)° and I1-Cu2-I2
) 105.9(4)°] show distortion in the tetrahedral environment
around copper.
atoms exhibit distorted tetrahedral geometry with an
Ag1· · ·Ag2 distance of 3.090 Å. One of the perchlorate ions
coordinates in a bridged bidentate fashion to both of the Ag
atoms while the other forms an almost-symmetrical µ-oxo
bridge between the two metals. The complex has two slightly
different Ag-P bonds (2.3378(1) and 2.3431(1) Å) and the
P1-N-P2 bond angle (121.47(2)°) is smaller than that
observed in complexes 2 and 3.
In complex 12, the Ag(I) atoms have a trigonal planar
geometry and are surrounded by two N atoms and a P atom.
The sums of the angles around the Ag1, Ag2, Ag3, and Ag4
centers are 359.6°, 359.7°, 357.2°, and 359.9°, respectively.
The Ag-P bond distances vary from 2.3109(1) Å to
2.3326(1) Å and are shorter than those observed in 10. The
Ag-N bond distances vary from 2.241(3) Å to 2.292(3) Å
and the bite angles created by the 2,2′-bipyridines at the
Ag1, Ag2, Ag3, and Ag4 centers are 73.10(1)°, 72.57(1)°,
The crystals of 10 suitable for XRD analysis were grown
by keeping the saturated THF solution of 10 at room
temperature for several days (in darkness). The molecule has
crystallographically imposed centrosymmetry and the Ag(I)
Inorganic Chemistry, Vol. 48, No. 8, 2009 3775

Ganesamoorthy et al.
Figure 6. Molecular structure of 12. All H atoms, perchlorate ions, and lattice solvents have been omitted for clarity. Displacement ellipsoids are drawn at
the 50% probability level.
73.50(1)°, and 72.17(1)°, respectively. The four bipyridyl
rings are parallel to each other and show offset or slipped
stacking π-π alignment with the minimum distance between
the bipyridyl rings being 3.506 Å.22
interactions.23 The Au-P and Au-Cl bond distances are
∼2.20 and ∼2.28 Å, respectively. The P1-N-P2 bond angle
is 124.84(14)°. In the crystal identified as 17, there are
two independent molecules of [RC6H4{N{P(OC6H4OMe-
o)2}2}2Au2Cl2] (where R ) H, NH2) in the asymmetric unit
that differ only slightly in geometry and conformation. In
the unit that contains Au1 and Au2, ∼30% of the R group
is NH2 and ∼70% of the R group is H, whereas in the unit
that contains Au3 and Au4, 70% of the R group is NH2 and
30% of the R group is H. The P-Au-Cl units are
cis-oriented with an average intramolecular Au · · ·Au distance
of 3.1119(4) Å.
As observed from the nuclear magnetic resonance (NMR)
spectroscopic data, the molecular structure of 15 has alternat-
ing coordinated and uncoordinated P atoms with a discrete
[(AuCl)(P2NΦNP2)(AuCl)] core. The complex has crystal-
lographically imposed centrosymmetry and the unique Au(I)
center adopts an approximately linear geometry with a
P-Au-Cl angle of 176.62(4)°. The structure did not show
any intermolecular or intramolecular Au · · · Au interactions.
The Au-P and Au-Cl bond distances are 2.205(1) Å and
2.282(1) Å, respectively, whereas the P1-N-P2 bond angle
is 118.8(2)°. In all of the structures of complexes of 1,
the bridging phenylene ring is almost perpendicular to the
P-N-P planes, with the torsion angles varying from
74.8(4)° to 103.5(4)°.
The colorless crystals of 13 were obtained from a
dichloromethane-acetonitrile mixture at room temperature.
The molecular structure of compound 13 consists of repeating
[(P2NΦNP2)Ag4] and 4,4′-bipyridine units with Ag atoms
disposed approximately in a plane. The 4,4′-bipyridine units
are distributed above and below the P-N-P skeleton to form
a bowl-shaped molecule. Each bowl is joined to neighboring
bowls by four Ag atoms to form a 54-membered macrocyclic
cage that encapsulates two CH2Cl2 molecules and a triflate
ion. The observed minimum and maximum distances be-
tween the Ag atoms are 6.078(1) Å and 23.318(3) Å,
respectively (see Figure 7c). The coordination geometry
around the Ag(I) atom is tetrahedral and consists of two N
atoms of two 4,4′-bipyridine ligands, one P atom of 1, and
one N atom of an acetonitrile molecule. The molecule has
two different Ag-P bonds, with bond distances of 2.338(2)
and 2.397(2) Å. The molecule did not show any metal-metal
interactions, because of the twisted conformations of the
Ag-P vectors, which make an angle of ∼103° with each
other. The Ag-N bond distances to the bipyridyl moieties
vary from 2.292(7) Å to 2.361(8) Å and are shorter than
those observed for the coordinated acetonitrile molecules
(2.395(8) Å and 2.407(9) Å). The P1-N4-P2 angle is
125.2(3)°.
Conclusion
The molecular structure of 14 consists of a discrete
[(AuCl)2(µ-P2NΦNP2)(AuCl)2] species having crystallo-
graphically imposed centrosymmetry. The two independent
Au(I) centers adopt approximately linear geometries with
P-Au-Cl angles of 169.97(3)° and 168.37(3)°. The
P-Au-Cl units are cis-oriented with an intramolecular
Au · · · Au distance of 3.102 Å. This is well within the
Au · · ·Au distances that are considered to represent aurophilic
Although several polydentate phosphorus ligands are
known in the literature, many of them have restricted
coordination behavior, often forming either chelating or
polycyclic cagelike complexes. In this context, the tetra-
phosphonite 1 is unique and can be compared to two 4,4′-
bipyridine units fused sideways containing both electronically
(23) (a) Schmidbaur, H.; Schier, A. Chem. Soc. ReV. 2008, 37, 1931–1951.
(b) Schmidbaur, H. Gold Bull. 2000, 33, 3–10. (c) Pyykko¨, P.;
Mendizabal, F. Inorg. Chem. 1998, 37, 3018–3025. (d) Pyykko¨, P.
Chem. ReV. 1997, 97, 597–636.
(22) (a) Roesky, H. W.; Andruh, M. Coord. Chem. ReV. 2003, 236, 91–
119. (b) Janiak, C. J. Chem. Soc., Dalton Trans. 2000, 3885–3896.
3776 Inorganic Chemistry, Vol. 48, No. 8, 2009

Group 11 Metal Chemistry of a Tetradentate Ligand
Figure 7. (a) The repeating unit of 13. All H atoms, triflate ions, and lattice solvents have been omitted for clarity. Displacement ellipsoids are drawn at
the 30% probability level. Only one orientation of the disordered phenoxy group is shown. (b) Portion of three-dimensional view of 13. All H atoms, triflate
ions, and lattice solvents have been omitted for clarity. (Symmetry operations: (i) 1 - x, 1 - y, 1 - z; (ii) 2 - x, 2 - y, 1 - z; (iii) 1 - x, 2 - y, -z; (iv)
-x, 1 - y, -z; (v) 1 - x, 2 - y, 1 - z.) (c) Distribution of Ag atoms in macrocyclic cage.
and sterically tunable phosphorus donor centers. The tetra-
phosphonite 1 has the advantage of being rigid and, at the
same time, is able to offer various conformations as shown
in Chart 1. Such conformational fluxionality in 1 can lead
to interesting structural variations in transition-metal com-
plexes. For instance, the formation of a three-dimensional
(3-D) polymer 13 is associated with the rotation of phos-
phorus lone pairs, with respect to phosphorus substituents,
to give twisted AgI complex and that must have occurred
through the pre-formation of [(OTf)2Ag2(µ-P2NΦNP2)-
Ag2(OTf)2], followed by the reaction with 4,4′-bipyridine.
The different orientations of phosphorus substitutions can
induce unique behavior to the complexes as observed in 5
and 7. o-Methoxyphenoxy substituents on phosphorus in 5
and 7 adopt approximately parallel planar conformations and
generate a “pocket” on either side of the ligand backbone to
give sufficient space to house lattice solvents. Simple
substitution reactions of 2, 3, and 10 with several bipyridyls
clearly indicate that these complexes could serve as efficient
tectons for the construction of several “conglomerates” with
the assistance of bipyridyls and linear phosphorus ligands.
Furthermore, complex 14 is a potential precursor for the
preparation of several polynuclear gold(I) complexes, because
of the presence of highly polar Au-Cl bonds. We have
actively focused on these two latter aspects to create several
“conglomerates” with different properties.
(24) Armarego, W. L. F.; Perrin, D. D. Purification of Laboratory
Chemicals, 4th ed.; Butterworth-Heinemann: Oxford, U.K., 1996.
Inorganic Chemistry, Vol. 48, No. 8, 2009 3777

Ganesamoorthy et al.
foil. All the solvents were purified by conventional procedures and
distilled prior to use.24 The compounds p-C6H4[N{P(OC6H4OMe-
o)2}2]2,13 PhN{P(OC6H4OMe-o)2}2,25 CuBr,26 and AuCl(SMe2)27
were prepared according to the published procedures. AgX (where
X ) OTf and ClO4), 1,10-phenanthroline, 2-(piperazin-1-yl)pyri-
midine, pyrazole, 2,2′-bipyridine, and 4,4′-bipyridine were pur-
chased from Aldrich Chemical Company and used as such without
further purification. [Caution! Perchlorate salts of metal complexes
with organic ligands are potentially explosiVe. A small amount was
used in all the reactions and handled with great caution. Except
for 10, all perchlorate compounds were determined to be resistant
to shock.] Other chemicals were obtained from commercial sources
and purified prior to use.
Instrumentation. The 1H and 31P{1H} NMR (δ in ppm) spectra
were recorded using a Varian VXR 300 or VXR 400 spectrometer
operating at the appropriate frequencies using tetramethylsilane
(TMS) and 85% H3PO4, as internal and external references,
respectively. The microanalyses were performed using a Carlo Erba
Model 1112 elemental analyzer. The melting points were observed
in capillary tubes and are uncorrected.
Figure 8. Molecular structure of 14. All H atoms have been omitted for
clarity. Displacement ellipsoids are drawn at the 50% probability level.
Synthesis of [{Cu2(µ-I)2(py)2}2(µ-P2NΦNP2)] (4). To 5 mL of
pyridine, compound 3 (0.050 g, 0.023 mmol) was added and the
mixture stirred at room temperature for 3 h. The resulting yellow
solution was taken to dryness under vacuum, and the residue was
dissolved in dichloromethane, layered with petroleum ether, and
stored at -30 °C to give white crystals of 4. Yield: 91% (0.049 g).
Anal. Calcd. for C82H80N6O16P4Cu4I4: C 42.98, H 3.52, N 3.67.
Found: C 42.87, H 3.43, N, 3.60. mp >250 °C. 1H NMR (400 MHz,
CDCl3, 25 °C, TMS): δ ) 8.33-6.58 (m, 56H; Ph, Py), 3.50 (s,
24H; OCH3). 31P{1H} NMR (162 MHz, CDCl3, 25 °C, H3PO4): δ
) 104.2 (br s).
Synthesis of [{Cu2(µ-I)2(C8H12N4)2}2(µ-P2NΦNP2)] (5). A
solution of 1-(2-pyrimidyl)piperazine (0.008 g, 0.050 mmol) in
dichloromethane (5 mL) was added dropwise to a solution of 3
(0.018 g, 0.008 mmol) in acetonitrile (5 mL), and the reaction
mixture was stirred at room temperature for 4 h. The resulting clear
solution was concentrated and kept at room temperature for 1 day
to give analytically pure white crystals of 5. Yield: 72% (0.016 g);
mp 194-196 °C (dec). Anal. Calcd. for C94H108N18O16P4Cu4I4: C
Figure 9. Molecular structure of 15. All H atoms have been omitted for
clarity. Displacement ellipsoids are drawn at the 50% probability level.
1
42.90, H 4.13, N 9.58. Found: C 42.87, H 4.08, N 9.72. H NMR
(400 MHz, CDCl3, 25 °C, TMS): δ ) 8.27 (d, 8H; C4H3N2), 6.76
3
(t, J(H, H) ) 4.8 Hz, 4H; C4H3N2), 7.65-6.46 (m, 36H; C6H4),
3.67 (s, 24H; OCH3), 2.49 (br s, 32H; C4H8N2). 31P{1H} NMR (162
MHz, CDCl3, 25 °C, H3PO4): δ ) 103.9 (br s).
Synthesis of [{Cu2(µ-I)2(C3H4N2)2}2(µ-P2NΦNP2)] (6). This
compound was synthesized using a procedure similar to that of 5,
using 3 (0.070 g, 0.033 mmol) and pyrazole (0.013 g, 0.198 mmol).
Yield: 81% (0.060 g). mp 196-198 °C (dec). Anal. Calcd. for
C74H76N10O16P4Cu4I4: C 39.55, H 3.41, N 6.23. Found: C 39.50, H
3.36, N 6.16. 1H NMR (400 MHz, CDCl3, 25 °C, TMS): δ ) 10.35
(br s, 4H; NH), 7.99-6.15 (m, 48H; Ar, C3H3N2), 3.55 (s, 24H;
OCH3). 31P{1H} NMR (162 MHz, CDCl3, 25 °C, H3PO4): δ ) 105.1
(br s).
Synthesis of [(Cu2(µ-I))2I2(C12H8N2)2(µ-P2NΦNP2)] (7). A
solution of 1,10-phenanthroline (0.012 g, 0.058 mmol) in the same
solvent (5 mL) was added dropwise to a solution of 3 (0.062 g,
0.029 mmol) in acetonitrile (10 mL), and the reaction mixture was
Figure 10. Molecular structure of 17. All H atoms have been omitted for
clarity. Displacement ellipsoids are drawn at the 50% probability level.
(25) Balakrishna, M. S.; George, P. P.; Mague, J. T. J. Organomet. Chem.
2004, 689, 3388–3394.
Experimental Section
(26) Furniss, B. S.; Hannaford, A. J.; Smith, P. W. G.; Tatchell, A. R.
Vogel’s Textbook of Practical Organic Chemistry, 5th ed.; Longman
Scientific and Technical: Harlow, England, 1989; pp 428-429.
(27) Brandys, M.-C.; Jennings, M. C.; Puddephatt, R. J. J. Chem. Soc.,
Dalton Trans. 2000, 4601–4606.
General Procedures. All manipulations were performed under
rigorously anaerobic conditions using Schlenk techniques. The
gold(I) and silver(I) complexes were prepared with minimum
exposure to light by wrapping the reaction vessel with aluminum
3778 Inorganic Chemistry, Vol. 48, No. 8, 2009

Group 11 Metal Chemistry of a Tetradentate Ligand
Table 1. Crystallographic Information for Compounds 5 and 7-10
complex 5
complex 7
complex 8
complex 9
complex 10
empirical formula
C98H114Cu4I4N20O16P4 C90H82Cu4I4N8O16P4
C86H81.50Cu4I4N8O16P4 C84H100Cl4Cu4I4N10O16P4 C104H132Ag4Cl4N2O43P4
formula weight, Fw
cryst. system
space group
a
b
c
2713.73
2417.28
2368.73
triclinic
P1 (No. 2)
2533.18
triclinic
P1 (No. 2)
2795.28
triclinic
P1(No. 2)
monoclinic
P21/c (No. 14)
33.029(2) Å
10.4259(6) Å
36.587(2) Å
90°
monoclinic
P21/c (No. 14)
11.5637(6) Å
24.811(1) Å
17.2689(8) Å
90°
j
j
j
17.484 (1) Å
24.135(2) Å
25.987(2) Å
112.878(1)°
100.200(1)°
105.222(1)°
9255.7(12) Å3
2
11.8672(9) Å
11.9366(9) Å
18.003(1) Å
96.277(1)°
103.143(1)°
95.784(1)°
2447.6(3) Å3
1
13.743(2) Å
15.530(2) Å
16.198(2) Å
109.135(2)°
110.464(2)°
90.280(2)°
3032.0(7) Å3
1
R
ꢀ
112.337(1)°
90°
108.182 (1)°
90°
γ
V
11653.6(12) Å3
4
4707.2(4) Å3
2
Z
Fcalc
µ (Mo KR)
F (000)
1.547 g/cm3
1.901 mm-1
5432
1.706 g/cm3
2.339 mm-1
2388
1.700 g/cm3
2.377 mm-1
4678
1.719 g/cm3
2.359 mm-1
1258
1.531 g/cm3
0.861 mm-1
1430
T
100 K
100 K
100 K
100 K
100 K
2θ range
total number of reflns
2.1°-27.5°
190140
2.0°-29.2°
84294
2.3°-25.6°
133988
2.2°-28.0°
42641
2.3°-26.6°
81438
number of indep reflns 26841 [Rint ) 0.080]
12414 [Rint ) 0.045] 34555 [Rint ) 0.054]
11706 [Rint ) 0.062]
1.03
0.0450
23267 [Rint ) 0.083]
0.93
0.0579
GOF (F2)
1.07
0.0675
0.1538
b
1.02
1.04
a
R1
0.0276
0.0641
0.0488
0.1440
b
wR2
0.1059
0.1686
a R1 ) ∑|F0|-|Fc|/∑|F0|. R2 ) {[∑w(F0 - Fc2)/∑w(F0 )2]}1/2 and w ) 1/[σ2(F0 ) + (xP)2] (where P ) (F0 + 2Fc2)/3).
2
2
2
2
Table 2. Crystallographic Information for Compounds 12-15, and 17
complex 12
complex 13
complex 14
complex 15
complex 17
empirical formula
C105H98Ag4Cl6N10O32.50P4 C113.5H102Ag4ClF12N14O29P4S4 C62H60Au4Cl4N2O16P4 C62H60Au2Cl2N2O16P4 C34H32.75Au2Cl2N1.50O8P2
Fw
2787.99
triclinic
P1 (No. 2)
3073.19
triclinic
P1 (No. 2)
2142.67
monoclinic
P21/n (No. 14)
10.7400(8) Å
12.1116(8) Å
25.674(2) Å
90°
1677.84
monoclinic
P21/c (No. 14)
11.933(5) Å
15.241(6) Å
17.673(7) Å
90°
1117.10
cryst. system
space group
a
b
monoclinic
P21/n (No. 14)
19.815(2) Å
18.739(2) Å
20.610(2) Å
90°
j
j
19.399(1) Å
16.586(1) Å
19.374(1) Å
96.091(1)°
99.812(1)°
88.538(1)°
6107.6(6) Å3
1
13.465(2) Å
15.172(2) Å
18.297(2) Å
103.965(2)°
103.251(2)°
104.149(2)°
3348.4(8) Å3
1
c
R
ꢀ
92.880(1)°
90°
107.117(7)°
90°
106.594(1)°
90°
γ
V
3335.4(4) Å3
2
3072(2) Å3
2
7334.1(13) Å3
4
Z
Fcalc
µ (Mo KR)
F (000)
T
1.516 g/cm3
0.893 mm-1
2816
1.524 g/cm3
0.797 mm-1
1550
2.134 g/cm3
9.094 mm-1
2036
1.814 g/cm3
5.033 mm-1
1652
2.023 g/cm3
8.277 mm-1
4266
100 K
100 K
100 K
100 K
100 K
2θ range
2.1°-28.4°
1.2°-24.8°
39668
2.3°-28.3°
57943
2.2°-29.6°
54500
2.0°-26.0°
107386
total number of reflns 108634
number of indep reflns 30072 [Rint ) 0.047]
11319 [Rint ) 0.048]
1.06
0.0669
8256 [Rint ) 0.033]
1.06
0.0219
8208 [Rint ) 0.038]
1.04
0.0313
14416 [Rint ) 0.069]
1.04
0.0343
GOF (F2)
1.06
a
R1
0.0516
0.1508
b
wR2
0.2023
0.0564
0.0845
0.0818
b
a R1 ) ∑|F0| - |Fc|/∑|F0|. R2 ) {[∑w(Fo - Fc2)/∑w(F0 )2]}1/2 and w ) 1/[σ2(F0 ) + (xP)2] (where P ) (F0 + 2Fc2)/3).
2
2
2
2
stirred at room temperature for 4 h. The resulting yellow solution
was concentrated and kept at room temperature for 1 day to give
analytically pure bright yellow crystals of 7. Yield: 83% (0.056
g). mp 194-196 °C (dec). Anal. Calcd. for C86H76N6O16P4Cu4I4:
C 44.23, H 3.28, N 3.60. Found: C 44.14, H 3.21, N 3.68. 1H NMR
(400 MHz, [d6] DMSO, 25 °C, TMS): δ ) 8.06-6.70 (m, 52H;
Ph, C12H8N2). 31P{1H} NMR (162 MHz, [d6] DMSO, 25 °C,
H3PO4): δ ) 104.1 (br s).
Synthesis of (C6H12N2CH2Cl)2[(Cu(Cl)(I2))2(NCCH3)2(µ-P2NΦ-
NP2)] (9). A solution of 3 (0.030 g, 0.014 mmol) in acetonitrile (3
mL) was added dropwise to a solution of 1,4-diazabicyclo[2.2.2]octane
(0.0032 g, 0.028 mmol) in dichloromethane (3 mL). The resulting
solution was kept undisturbed at room temperature for 3-4 days, to
give analytically pure white crystals of 9. Yield: 60% (0.022 g). mp
174-176 °C (dec). Anal. Calcd. for C84H100N10Cl4O16P4Cu4I4: C 39.87,
H 3.98, N 5.53. Found: C 39.40, H 4.06, N 5.44.
Synthesis of [(Cu2(µ-I))2I2(C10H8N2)2(µ-P2NΦNP2)] (8). This
compound was synthesized using a procedure similar to that of 7,
using 3 (0.071 g, 0.033 mmol) and 2,2′-bipyridine (0.005 g, 0.066
mmol). Yield: 89% (0.068 g). mp 230-232 °C (dec). Anal. Calcd.
for C82H76N6O16P4Cu4I4: C 43.06, H 3.35, N 3.67. Found: C 43.14,
H 3.41, N 3.74. 1H NMR (400 MHz, [d6] DMSO, 25 °C, TMS): δ
) 8.22-6.66 (m, 52H; Ph, C10H8N2). 31P{1H} NMR (162 MHz,
[d6] DMSO, 25 °C, H3PO4): δ ) 105.0 (br s).
Synthesis of [{Ag2(µ-ClO4)2(C4H8O)2}2(µ-P2NΦNP2)] (10). A
solution of 1 (0.073 g, 0.060 mmol) in THF (10 mL) was added
dropwise to a suspension of AgClO4 (0.054 g, 0.240 mmol) also
in THF (5 mL) with constant stirring. The reaction mixture was
subjected to stirring at room temperature for 4 h. The resulting
solution was concentrated to 4 mL under vacuum and kept at
room temperature overnight to give analytically pure product
10 as white crystals. Yield: 90% (0.126 g). mp: 154-156 °C
Inorganic Chemistry, Vol. 48, No. 8, 2009 3779

Ganesamoorthy et al.
Table 3. Selected Bond Distances and Bond Angles for Complexes 5, 7, and 8
Complex 5 Complex 7
Complex 8
bond
distance (Å)
bond
angle (°)
bond
bond
angle (°)
bond
bond distance (Å)
bond
angle (°)
bond
bond
bond distance (Å)
bond
bond
P1-N9
1.680(5)
1.695(5)
1.685(5)
1.690(5)
2.173(2)
2.159(2)
2.166(2)
2.174(2)
2.039(6)
2.077(6)
P1-N9-P2
119.8(3)
P3-N10-P4 121.2(3)
P1-N1
P2-N1
1.681(2)
1.690(2)
P1-N1-P2
120.35(10) P1-N1
1.681(5)
1.685(5)
1.687(5)
1.672(5)
2.181(2)
2.145(2)
2.165(2)
2.159(2)
2.047(7)
2.054(5)
2.066(5)
2.071(7)
2.516(1)
2.593(1)
2.586(1)
2.497(1)
2.564(1)
2.637(1)
P1-N1-P2
P3-N4-P4
N2-Cu2-N3 80.9(2)
N5-Cu4-N6 80.4(3)
Cu1-I2-Cu2 69.93(3)
Cu3-I4-Cu4 71.41(3)
120.1(3)
121.1(3)
P2-N9
N2-Cu1-N3 81.39(8) P2-N1
P3-N10
P4-N10
Cu1-P1
Cu2-P2
Cu3-P3
Cu4-P4
Cu1-N1
Cu2-N5
Cu1-I1-Cu2
Cu1-I2-Cu2
Cu3-I3-Cu4
Cu3-I4-Cu4
I1-Cu1-I2
I1-Cu2-I2
I3-Cu3-I4
I3-Cu4-I4
I1-Cu1-P1
I2-Cu1-P1
61.11(2) Cu1-P1
60.78(2) Cu2-P2
63.12(2) Cu1-N2 2.075(2)
60.81(2) Cu1-N3 2.065(2)
100.47(3) I1-Cu1
101.71(3) I1-Cu2
102.23(3) I2-Cu2
102.69(3)
118.27(5)
109.40(5)
111.61(5)
115.84(5)
2.1630(6) Cu1-I1-Cu2 69.87(1) P3-N4
2.1875(6) I1-Cu2-I2
119.48(1) P4-N4
P1-Cu1-N2 112.82(6) Cu1-P1
P1-Cu1-N3 116.72(6) Cu2-P2
2.5943(3) I1-Cu1-P1 118.66(2) Cu3-P3
I1-Cu1-I2
I3-Cu3-I4
112.26(4)
115.75(4)
2.5702(3) I1-Cu1-N2 105.90(6) Cu4-P4
2.5178(4) I1-Cu1-N3 114.54(6) Cu2-N2
P2-Cu2-N2 112.27(17)
P2-Cu2-N3 111.44(17)
P4-Cu4-N5 122.81(19)
P4-Cu4-N6 114.2(2)
P2-Cu2-I2 122.93(7)
P4-Cu4-I4 120.50(6)
P1-Cu1-I1 130.21(6)
P1-Cu1-I2 117.17(6)
P3-Cu3-I3 125.84(7)
P3-Cu3-I4 118.04(7)
I1-Cu2-P2 121.18(2) Cu2-N3
I2-Cu2-P2 119.08(2) Cu4-N5
Cu3-N11 2.066(6)
Cu4-N15 2.051(6)
Cu4-N6
Cu1-I1
Cu1-I2
Cu2-I2
Cu3-I3
Cu3-I4
Cu4-I4
I1-Cu1
I1-Cu2
I2-Cu1
I2-Cu2
I3-Cu3
I3-Cu4
I4-Cu3
I4-Cu4
2.7207(8) I1-Cu2-P2
2.6178(9) I2-Cu2-P2
2.6557(9) I3-Cu3-P3
2.7109(9) I4-Cu4-P4
2.5886(9) P1-Cu1-N1 120.31(18)
2.6847(9) P2-Cu2-N5 124.47(19)
2.7821(9) P3-Cu3-N11 134.36(18)
2.6711(9) P4-Cu4-N15 121.64(18)
110.97(5)
106.22(5)
Table 4. Selected Bond Distances and Bond Angles for Complexes 9, 10, and 12
Complex 9 Complex 10
bond
bond distance (Å)
Complex 12
bond
angle (°)
bond
distance (Å)
bond
angle (°)
bond
bond
angle (°)
bond
bond
bond
bond
distance (Å)
bond
P1-N1
1.693(3)
1.675(4)
2.190(1)
2.184(1)
2.60(2)
P1-N1-P2 119.8(2)
I1-Cu1-I2 101.7(4)
I1-Cu2-I2 105.9(4)
I1-Cu1-I3 111.35(1) Ag2-P2
I2-Cu1-I3 108.74(3) P1-O1
P1-N1
P2-N1
Ag1-P1
1.665(4)
1.679(4)
2.338(1)
2.343(1)
1.615(3)
1.618(3)
1.612(3)
1.609(3)
2.434(4)
P1-N1-P2
121.47(18) P1-N5
116.27(11) P2-N5
1.684(3)
1.661(3)
1.680(3)
1.668(3)
2.311(1)
2.322(1)
2.304(1)
2.333(1)
2.261(4)
2.258(3)
2.281(3)
2.262(4)
2.267(3)
2.241(3)
2.292(3)
P1-N5-P2
P3-N6-P4
120.65(18)
120.51(18)
P2-N1
P1-Ag1-O9
P1-Cu1
P2-Cu2
Cu1-I1
Cu1-I2
Cu1-I3
Cu2-I1
Cu2-I2
Cu2-N2
N3-C42
P1-Ag1-O13 123.12(10) P3-N6
P1-Ag1-O18 135.22(10) P4-N6
P2-Ag2-O10 125.07(11) Ag1-P1
P2-Ag2-O13 129.74(9) Ag2-P2
P2-Ag2-O17 138.65(8) Ag3-P3
Ag1-P1-N1
Ag2-P2-N1
O9-Ag1-O13
O9-Ag1-O18
P1-Ag1-N1 142.88(9)
P1-Ag1-N2 143.67(9)
P2-Ag2-N3 147.80(9)
P2-Ag2-N4 139.30(9)
P3-Ag3-N7 139.66(9)
P3-Ag3-N8 144.06(8)
P4-Ag4-N9 147.24(9)
P4-Ag4-N10 140.52(9)
Ag1-P1-N5 122.19(11)
Ag2-P2-N5 119.55(11)
Ag3-P3-N6 120.95(11)
Ag4-P4-N6 119.39(12)
2.764(1)
I1-Cu2-N2 106.7(5)
I2-Cu2-N2 107.05(10) P2-O5
P2-O7
2.6928(6) P1-Cu1-I2 112.07(4) Ag1-O9
P1-O3
2.568(1)
2.524(19) P1-Cu1-I1 105.1(4)
119.07(13) Ag4-P4
120.14(12) Ag1-N1
95.65(15) Ag1-N2
87.43(14) Ag2-N3
1.993(4)
1.486(7)
P2-Cu2-I1 114.1(4)
Ag1-O13 2.468(4)
P2-Cu2-I2 106.36(3) Ag1-O18 2.259(4)
P1-Cu1-I3 116.80(4) Ag2-O10 2.400(5)
P2-Cu2-N2 116.08(11) Ag2-O13 2.589(4)
C42-Cl1 1.778(7)
O13-Ag1-O18 88.51(13) Ag2-N4
O10-Ag2-O13 75.17(16) Ag3-N7
O10-Ag2-O17 79.87(15) Ag3-N8
Cu1-I1-Cu2 65.9(5)
Cu1-I2-Cu2 61.45(2) Ag1-Ag2 3.0900(8) O13-Ag2-O17 85.31(11) Ag4-N9
Ag2-O17 2.285(3)
N1-Ag1-N2
N3-Ag2-N4
73.10(12)
72.57(12)
73.50(12)
Ag4-N10 2.265(3)
Ag1-Ag2 3.0907(5) N7-Ag3-N8
Ag3-Ag4 2.9954(4) N9-Ag4-N10 72.17(12)
Table 5. Selected Bond Distances and Bond Angles for Complexes 13 and 14
Complex 13
Complex 14
bond
bond distance (Å)
bond
bond angle (°)
bond
bond distance (Å)
bond
bond angle (°)
P1-N4
1.687(7)
1.686(7)
1.616(6)
1.613(6)
1.602(7)
1.613(6)
2.338(2)
2.397(2)
2.312(8)
2.292(7)
2.407(9)
2.361(8)
2.336(7)
2.395(8)
P1-N4-P2
125.2(3)
97.9(3)
87.7(3)
95.1(3)
96.8(2)
P1-N1
1.674(2)
1.676(2)
1.603(2)
1.589(2)
1.600(2)
1.589(2)
2.1981(8)
2.2003(8)
2.2657(8)
2.2852(9)
3.1019(8)
P1-N1-P2
124.84(1)
169.97(3)
168.37(3)
113.39(9)
118.83(9)
118.44(9)
112.26(9)
119.82(8)
117.33(9)
P2-N4
N1-Ag1-N2
N1-Ag1-N3
N2-Ag1-N3
N5-Ag2-N6
N5-Ag2-N7
N6-Ag2-N7
P1-Ag1-N1
P1-Ag1-N2
P1-Ag1-N3
P2-Ag2-N5
P2-Ag2-N6
P2-Ag2-N7
P2-N1
P1-Au1-Cl1
P2-Au2-Cl2
Au1-P1-O1
Au1-P1-O3
Au1-P1-N1
Au2-P2-O5
Au2-P2-O7
Au2-P2-N1
P1-O1
P1-O1
P1-O3
P1-O3
P2-O5
P2-O5
P2-O7
93.5(3)
P2-O7
Ag1-P1
Ag2-P2
Ag1-N1
Ag1-N2
Ag1-N3
Ag2-N5
Ag2-N6
Ag2-N7
101.9(3)
131.0(2)
122.7(2)
112.2(2)
120.7(2)
122.2(2)
116.4(2)
P1-Au1
P2-Au2
Au1-Cl1
Au2-Cl2
Au1-Au2
(dec). [Caution! Compound 10 explodes Violently at 170 °C. In
all cases, 1-2 mg of perchlorate complexes have been used to
note the melting point.] Anal. Calcd. for C78H92Cl4N2O36P4Ag4:
C 40.19, H 3.98, N 1.20. Found: C 40.25, H 3.92, N 1.21. H
NMR (400 MHz, [d6] DMSO, 25 °C, TMS): δ ) 7.73-6.69
(t, 16H; CH2). 31P{1H} NMR (162 MHz, [d6] DMSO, 25 °C,
H3PO4): δ ) 120.8 (br s).
Synthesis of [{(µ-PNP)2Ag2}2(µ-P2NΦNP2)](ClO4)4 (11). A
solution of PhN(P(OC6H4OMe-o)2)2 (PNP) (0.104 g, 0.162 mmol)
in THF (10 mL) was added dropwise to a solution of 10 (0.094 g,
0.040 mmol) also in THF (10 mL) with constant stirring. The
1
(m, 36H; Ph), 3.74 (s, 24H; OCH3), 3.62 (t, 16H; OCH2), 1.77
3780 Inorganic Chemistry, Vol. 48, No. 8, 2009

Group 11 Metal Chemistry of a Tetradentate Ligand
Table 6. Selected Bond Distances and Bond Angles for Complexes 15 and 17
Complex 15
Complex 17
bond distance (Å)
bond
bond distance (Å)
bond
bond angle (°)
bond
bond
bond angle (°)
P1-N1
P2-N1
P1-O1
P1-O3
P2-O5
P2-O7
P1-Au1
Au1-Cl1
N1-C16
1.656(4)
1.741(3)
1.596(3)
1.594(3)
1.624(3)
1.633(3)
2.205(1)
2.282(1)
1.446(5)
P1-N1-P2
P1-Au1-Cl1
Au1-P1-O1
Au1-P1-O3
Au1-P1-N1
N1-P1-O1
N1-P1-O3
O1-P1-O3
N1-P2-O5
N1-P2-O7
O5-P2-O7
118.75(19)
176.62(4)
118.50(11)
117.44(11)
112.37(12)
104.88(16)
103.37(16)
98.18(15)
94.25(15)
100.79(16)
98.69(14)
P3-N2
1.664(6)
1.681(6)
1.595(5)
1.608(6)
1.585(6)
1.599(5)
2.198(2)
2.198(2)
2.264(2)
2.272(2)
3.0975(4)
P3-N2-P4
122.7(4)
170.16(8)
175.57(7)
115.3(2)
113.33(19)
120.8(2)
120.3(2)
114.6(2)
114.8(2)
P4-N2
P3-Au3-Cl3
P4-Au4-Cl4
Au3-P3-O9
Au3-P3-O11
Au3-P3-N2
Au4-P4-O13
Au4-P4-O15
Au4-P4-N2
P3-O9
P3-O11
P4-O13
P4-O15
P3-Au3
P4-Au4
Au3-Cl3
Au4-Cl4
Au3-Au4
reaction mixture was subjected to stirring at room temperature for
2 h. The resulting solution was concentrated to 4 mL, layered with
3 mL of n-hexane, and kept at room temperature for one day to
give analytically pure white microcrystals of 11. Yield: 65% (0.121
g). mp 132-134 °C (dec). Anal. Calcd. for C198H192N6O64P12Ag4Cl4:
C 51.42, H 4.18, N 1.82. Found: C 51.40, H 4.15, N 1.84. 1H NMR
(400 MHz, [d6] DMSO, 25 °C, TMS): δ ) 7.31-6.52 (m, 120H;
Ph), 3.77 (br s, 72H; OCH3). 31P{1H} NMR (162 MHz, [d6] DMSO,
25 °C, H3PO4): δ ) 120.1 (br s).
subjected to stirring at room temperature for 8 h. The resulting
solution was concentrated to 5 mL, layered with 3 mL of n-hexane,
and kept at -30 °C for one day to give analytically pure white
crystals of 15 in the first crop. Yield: 76% (0.043 g).
Method 2. A solution of AuCl(SMe2) (0.039 g, 0.132 mmol) in
THF (5 mL) was added dropwise to a solution of 1 (0.080 g, 0.066
mmol) that also was in THF (8 mL). The reaction mixture was
refluxed for 6 h and then cooled to room temperature. The solution
was concentrated to 5 mL, layered with 3 mL of n-hexane, and
kept at -30 °C for one day to give analytically pure white crystals
of 15. Yield: 88% (0.098 g). mp 188-190 °C (dec). Anal. Calcd.
for C62H60N2O16P4Au2Cl2: C 44.38, H 3.60, N 1.67. Found: C 44.42,
H 3.50, N 1.61.1H NMR (400 MHz, CDCl3, 25 °C, TMS): δ )
7.64-6.63 (m, 36H; Ph), 3.60 (br s, 12H; OCH3), 3.63 (br s, 12H;
OCH3). 31P{1H} NMR (162 MHz, CDCl3, 25 °C, H3PO4): δ ) 132.2
Synthesis of [{Ag2(C10H8N2)2}2(µ-P2NΦNP2)](ClO4)4 (12). A
solution of 1 (0.051 g, 0.042 mmol) in CH2Cl2 (6 mL) was added
dropwise to a suspension of AgClO4 (0.038 g, 0.167 mmol) also
in CH2Cl2 (8 mL) with constant stirring. The reaction mixture was
stirred for 2 h and then a solution of 2,2′-bipyridine (0.026 g, 0.167
mmol) in CH2Cl2 (3 mL) was added dropwise. The resulting
solution was concentrated to 4 mL, layered with 2 mL of n-hexane,
and stored at -30 °C for 3 days to give white crystals of 12. Yield:
70% (0.078 g). mp 176-178 °C (dec). Anal. Calcd. for C102H92
N10O32P4Ag4Cl4: C 45.93, H 3.48, N 5.25. Found: C 46.01, H, 3.40,
2
(d, J(P,P) ) 348 Hz), 110.5 (d).
X-ray Crystallography. A crystal of each of the compounds 5,
7-10, 12-14, 15, and 17 suitable for X-ray crystal analysis was
mounted in a Cryoloop with a drop of Paratone oil and placed in
the cold nitrogen stream of the Kryoflex attachment of a Bruker
APEX CCD diffractometer. Full spheres of data were collected
using 606 scans in ω (0.3° per scan) at φ ) 0°, 120°, and 240°
(13) or a combination of three sets of 400 scans in ω (0.5° per
scan) at ꢁ ) 0°, 90°, and 180° plus two sets of 800 scans in ꢁ
(0.45° per scan) at ω ) -30° and 210° (5, 7-10, 12, 14, 15, and
17) under the control of the SMART software package28a (10, 12,
and 14) or the APEX2 program suite28b (5, 7-9, 13, 15, and 17).
The raw data were reduced to F2 values using the SAINT+
software29 and global refinements of unit-cell parameters using
1448-9967 reflections chosen from the full data sets were
performed. Multiple measurements of equivalent reflections pro-
vided the basis for empirical absorption corrections, as well as
corrections for any crystal deterioration during the data collection
(SADABS,30 for all but 10 and 13). In the cases of 10 and 13,
initial attempts to obtain a unit cell were unsuccessful and further
analysis of 1280 and 2110 reflections, respectively, with I/σ(I) g
15 with CELL_NOW,31 suggested that the crystal of 10 had a
triclinic cell twinned by a 180° rotation about the reciprocal
direction 1,0,1/2, whereas for 13, the large majority of the crystal
consisted of a triclinic cell twinned by a 180° rotation about the
real axis 1,1,0. Processing of the raw intensity data for these
structures was accomplished with the multicomponent version of
SAINT,28 under the control of the two-component input file
1
N 5.28. H NMR (400 MHz, [d6] DMSO, 25 °C, TMS): δ )
8.22-6.92 (m, 68H; Ph, C10H8N2), 3.68 (s, 24H; OCH3). 31P{1H}
NMR (162 MHz, [d6] DMSO, 25 °C, H3PO4): δ ) 125.7 (br s).
Synthesis of [{Ag2(C10H8N2)2(CH3CN)2}2(µ-P2NΦNP2)]n(OTf)4n
(13). A solution of 1 (0.035 g, 0.029 mmol) in CH2Cl2 (6 mL) was
added dropwise to a suspension of AgOTf (0.030 g, 0.117 mmol)
also in CH2Cl2 (8 mL) with constant stirring. The reaction mixture
was allowed to stir at room temperature for 2 h and then was layered
with an acetonitrile (3 mL) solution of 4,4′-bipyridine (0.018 g,
0.117 mmol). Analytically pure white crystals of 13 formed after
the mixture was allowed to stand at room temperature for several
days. Yield: 54% (0.048 g). mp 160-162 °C (dec). Anal. Calcd.
for C114H104F12N14O28P4S4Ag4: C 45.19, H 3.46, N 6.47, S 4.23.
Found: C 45.25, H 3.40, N 6.52, S 4.20.
Synthesis of [(Au2Cl2)2(µ-P2NΦNP2)] (14). A solution of 1
(0.031 g, 0.026 mmol) in CH2Cl2 (5 mL) was added dropwise to a
solution of AuCl(SMe2) (0.030 g, 0.102 mmol) also in CH2Cl2 (5
mL). The reaction mixture was subjected to stirring at room
temperature for 4 h. The resulting solution was concentrated to 3
mL, followed by the addition of n-hexane, to give a white precipitate
of 14. White crystals were obtained upon recrystallization from a
1:1 dichloromethane/n-hexane mixture at -30 °C. Yield: 87%
(0.048 g). mp 204-206 °C (dec). Anal. Calcd. for C62H60N2O16
P4Au4Cl4: C 34.75, H 2.82, N 1.31. Found: C 34.64, H 2.75, N
1
1.29. H NMR (400 MHz, CDCl3, 25 °C, TMS): δ ) 7.97-6.72
(28) (a) SMART, Version 5.625; Bruker-AXS: Madison, WI, 2000. (b)
APEX2, Version 2.1-0; Bruker-AXS: Madison, WI, 2006.
(29) SAINT+, Versions 6.35A and 7.34A; Bruker-AXS: Madison, WI, 2002,
2006.
(30) Sheldrick, G. M. SADABS, Versions 2.05 and 2007/2; University of
Go¨ttingen: Go¨ttingen, Germany, 2002, 2007.
(m, 36H; Ph), 3.81 (s, 24H; OCH3). 31P{1H} NMR (162 MHz,
CDCl3, 25 °C, H3PO4): δ ) 114.3 (s).
Synthesis of [(AuCl)2(P2NΦNP2)] (15). Method 1. A solution
of PhN(P(OC6H4OMe-o)2)2 (0.044 g, 0.068 mmol) in CH2Cl2 (5
mL) was added dropwise to a stirred solution of 14 (0.073 g, 0.034
mmol) that also was in CH2Cl2 (7 mL). The reaction mixture was
(31) Sheldrick, G. M. CELL_NOW; University of Go¨ttingen: Go¨ttingen,
Germany, 2005.
Inorganic Chemistry, Vol. 48, No. 8, 2009 3781

Ganesamoorthy et al.
generated by CELL_NOW. The empirical absorption correction was
performed with TWINABS,32 which also provided a one-component
reflection set that was used to solve the structures and perform the
initial refinement. The structures were solved by direct methods
(for 5, 7-10, 12, 13, and 17) or the positions of the heavy atoms
were obtained from a sharpened Patterson function (for 14 and 15).
All structures were refined by full-matrix least-squares procedures
using the SHELXTL program package.33 H atoms were placed in
calculated positions and included as riding contributions with
isotropic displacement parameters tied to those of the attached
non-H atoms. For 8, the o-methoxyphenoxy substituents built on
C52 and C59 were each disordered over two resolvable sites, as
was the THF molecule coordinated to silver; in 13, the o-
methoxyphenoxy substituent built on C32 is disordered over two
sites; and in 12, the perchlorate ion containing Cl4 is disordered
over two sites with two O atoms in common. All of these were
refined subject to the restraints that both orientations of each group
have equivalent geometry and that these approximate ideal geom-
etry. In the case of 9, inspection of difference maps in the vicinity
of atoms initially assigned as I1 and I3, as well as the equivalent
isotropic displacement parameters for these two atoms, suggested
partial occupancy of these ligating sites by chloride. The evidence
consisted of the appearance of partially resolved peaks in the
difference map slightly closer to the metal atoms and equivalent
isotropic displacement parameters for I1 and I3 significantly larger
than that for I2, which appeared well-behaved. Assignment of the
partially resolved peaks as Cl and refinement of the occupancy
factors of Cl and I in both bridging and terminal sites subject to
their sum at each location being 1.0 led to the values presented in
the Results and Discussion section. In addition, the entire cation
seems to be disordered to some extent, but because the only well-
resolved part of the disorder involved the Cl atom, this was the
only part of this disorder that was modeled. In 17, there are two
independent R-C6H4N(P(OR′)2AuCl)2 (where R ) H, NH2 and
R′ ) o-C6H4OMe) moieties in the asymmetric unit, each of which
is a mixture of the R ) H and R ) NH2 complexes. Based on
inspection of difference maps and trial refinements of occupancy
parameters for the nitrogen of the R ) NH2 substituent, there
seemed to be a 70:30 mixture in the first site and a 30:70 mixture
in the other.
Acknowledgment. We are grateful to the Department of
Science and Technology (DST), New Delhi, for financial
support (through Grant No. SR/S1/IC-02/007). C.G. thanks
CSIR, New Delhi for Senior Research Fellowship (SRF).
We also thank SAIF, Mumbai, Department of Chemistry
Instrumentation Facilities, Bombay, for spectral and analyti-
cal data and J.T.M. thanks the Louisiana Board of Regents
for purchase of the CCD diffractometer and the Chemistry
Department of Tulane University for support of the X-ray
laboratory.
Supporting Information Available: X-ray crystallographic files
in CIF format for the structure determinations of 5, 7-10, 12-14,
15, and 17. This material is available free of charge via the Internet
at http://pubs.acs.org.
(32) Sheldrick, G. M. TWINABS, Version 2007/5; University of Go¨ttingen:
Go¨ttingen, Germany, 2007.
(33) (a) SHELXTL, Version 6.10; Bruker-AXS: Madison, WI, 2000. (b)
Sheldrick, G. M. SHELXS97 and SHELXL97; University of Go¨ttingen:
Go¨ttingen, Germany, 1997.
IC900085E
3782 Inorganic Chemistry, Vol. 48, No. 8, 2009