The influence of alkane spacer of bis(diphenylphosphino)alkanes on the nuclearity of silver(I): Syntheses and structures of P,P′-bridged clusters and coordination polymers involving dithiophosphates

Article abstract of DOI:10.1016/j.jorganchem.2009.02.017

The effect of the length of alkane spacer in diphosphines on the nuclearity of Ag(I) complexes containing dialkyl dithiophosphates (dtp) ligands has been investigated. 1,1-Bis(diphenylphosphino)methane (dppm) yielded tetranuclear [Ag₄(dppm)

Full text of DOI:10.1016/j.jorganchem.2009.02.017

Journal of Organometallic Chemistry 694 (2009) 2134–2141
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
The influence of alkane spacer of bis(diphenylphosphino)alkanes on the
nuclearity of silver(I): Syntheses and structures of P,P0-bridged clusters
and coordination polymers involving dithiophosphates
a
b
b
b
c
C.W. Liu a, , Bijay Sarkar , Ben-Jie Liaw , Ya-Wen Lin , Tarlok S. Lobana , Ju-Chun Wang
*
a Department of Chemistry, National Dong Hwa University, Hualien 974, Taiwan
b Department of Chemistry, Chung Yuan Christian University, Chung-Li 320, Taiwan
c Department of Chemistry, Soochow University, Taipei 111, Taiwan, ROC
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 14 January 2009
Received in revised form 16 February 2009
Accepted 17 February 2009
Available online 28 February 2009
The effect of the length of alkane spacer in diphosphines on the nuclearity of Ag(I) complexes
containing dialkyl dithiophosphates (dtp) ligands has been investigated. 1,1-Bis(diphenylphos-
phino)methane (dppm) yielded tetranuclear [Ag4(dppm)2{S2P(OEt)2}4] (1), [Ag4(dppm)2{S2P(OiPr)2}4]
(3), trinuclear [Ag3(dppm)3{S2P(OEt)2}2](PF6) (2), and a dinuclear [Ag2(dppm)2{S2P(OiPr)}](PF6) (4).
The increase in spacer length from one methylene in dppm to two in 1,2-bis(diphenylphosphino)ethane
i
(dppe) resulted in the formation of polymeric, [Ag(dppe){S2P(OR)2}]1 (R = Et, 5a and 5a0; Pr, 5b), and
Keywords:
i
[Ag4(l
3-Cl)(dppe)1.5{S2P(OR)2}3] (R = Et, 6a; Pr, 6b). Compounds 5a, 5b, 6a and 6b were reported ear-
1
Silver complexes
Crystal structure
Coordination polymer
P donor ligands
S donor ligands
lier [C.W. Liu, B.-J. Liaw, L.-S. Liou, J.-C. Wang, Chem. Commun. (2005) 1983]. Further increase in the
chain length to four methylene units in 1,4-bis(diphenylphosphino)butane (dppb) yielded dppb-bridged
polymers, [Ag(dppb){S2P(OEt)2}] (7) and [Ag2(dppb){S2P(OEt)2}2] (8). In all the polynuclear com-
1
1
pounds, diphosphines acted as P,P0-bridging ligands, while the dtp ligands (S,S0-donors) adopted varie-
ties of coordination patterns: S,S0-chelating (5, 7), S,S0-bridging (4), bimetallic-triconnective, l2
(1, 3, 8), bimetallic-diconnective, l2
g2 (2, 3) and trimetallic-triconnective, l3 g1 (6). Some of the
:
g2 g1
,
:
: ,
g2
complexes exhibit argentophilicity with Agꢀ ꢀ ꢀAg distances in the range, 2.918–3.360 Å. Concomitant
bridging of two silver atoms either by dppm and dtp ligands (1, 3 and 4) or two dtp ligands (8) lead
to close silver-silver contacts. The diphosphines (dppe and dppb) with longer spacer appeared to favor
1D or 2D polymers due to the flexibility of the spacer within the diphosphine unit by adopting anti
conformation as opposed to syn conformation of the dppm linker is revealed in complexes.
Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction
coordination modes [12–15,17,18]. The study of metal–dtp inter-
actions has another perspective because of several applications of
The study of silver–silver short contact in complexes, less than
twice of van der Waal’s radii of silver atom (3.40 Å), has invited
attention of several research groups in the recent years [2–8], as
such interaction has led to generate interesting electrical conduct-
ing properties [9,10]. The sulfur donor ligands have played an
important role in the formation of such interactions due to their
ability to bring two or more metals in close contact in view of
angular flexibility at sulfur donor atoms [2–16]. Furthermore, sil-
ver–sulfur interactions are more covalent in nature due to the
soft–soft acid–base interactions, and such interactions enhance
the argentophilic character of silver atoms.
these ligands and their complexes as fungicides, pesticides, vulca-
nization accelerators, floating agents for mineral ores, additives to
lubricant oils, and solvent extraction reagents for metals [19–22].
However, there are only limited studies on silver-dtp chemistry
[12–15,17,18].
In this paper, formation of the complexes of Ag(I) with dialkyl
dithiophosphates in the presence of a series of diphosphines with
different spacer lengths and the influence of the spacer length in
the diphosphine on the nuclearity of silver(I) complexes have been
described. Some of the complexes disclose short silver–silver
contacts. Structural characterization reveal the formation of
tetranuclear, [[Ag4(dppm)2{S2P(OEt)2}4] (1), and [Ag4(dppm)2
{S2P(OiPr)2}4] (3)], trinuclear, [[Ag3(dppm)3 {S2P(OEt)2}2] (PF6)
(2)], and dinucelar [[Ag2(dppm)2{S2P(OiPr)2}] (PF6) (4)] complexes
in the presence of dppm with the shortest spacer. On the other
Dialkyl dithiophosphates ½fðROÞ2PSꢁ2 g; dtpꢂ, a class of ligand
having two sulfur donor atoms, are known to form a variety of
metal complexes with bite angle of ca. 75° exhibiting different
hand, 1D [[Ag(dppe){S2P(OR)2}] (R = Et, 5a and 5a0; iPr, 5b),
1
* Corresponding author. Fax: +886 3 8633570.
E-mail address: chenwei@mail.ndhu.edu.tw (C.W. Liu).
[Ag(dppb){S2P(OEt)2}]1 (7), and [Ag2(dppb){S2P(OEt)2}2]1 (8)],
0022-328X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2009.02.017

C.W. Liu et al. / Journal of Organometallic Chemistry 694 (2009) 2134–2141
2135
RO
S
OR
S
RO
S
OR
S
RO
S
OR
S
RO
S
OR
S
RO
S
OR
S
P
P
P
P
P
M
M
M
M
M
M
M
M
M
M
I (5, 7)
IV (2, 3)
V(6)
II (4)
III (1, 3, 8 )
Chart 1.
and 2D honeycomb-shaped [[Ag4(
l3-Cl)(dppe)1.5{S2P(OR)2}3]1
be noted that silver clusters with formula [Ag4(l-
(R = Et, 6a; iPr, 6b)] polymers are obtained in the presence of dppe
and dppb with longer spacer in the diphosphine backbone. A part
of this work has been communicated earlier containing the
description of 5a, 5b, 6a and 6b [1]. The dtp ligands exhibited var-
ious bonding modes in the complexes 1–8 as depicted in Chart 1.
dppm)2{S2P(OEt)2}3]+ could be achieved by the reaction of
Ag(CH3CN)4X (where X = BF4, PF6), dppm, and dtp ligands in a ratio
2. Results and discussion
2.1. Synthesis
Simple stirring of Ag(I), dppm and dtp sources in 1:1:1 ratio at
RT in acetonitrile produces [Ag4(dppm)2{S2P(OEt)2}4] (1) and
[Ag3(dppm)3{S2P(OEt)2}2](PF6) (2) in 76% and 7% yield, respec-
tively. On the other hand, the same reaction in dichloromethane
results in [Ag4(dppm)2{S2P(OiPr)2}4] (3) in 75% yield. However,
the change in the molar ratio of Ag(I), dppm, and dtp sources to
2:2:1 in dichloromethane yields [Ag2(dppm)2{S2P(OiPr)2}](PF6)
(4). Again, mixing of Ag(I), dppe and dtp (R = Et) sources in
1:1:2.1 ratio produced 1D polymeric [Ag(dppe){S2P(OEt)2}] , 5a
1
and 2D honeycomb-shaped [Ag4(l3-Cl)(dppe)1.5{S2P(OEt)2}3]1
(6a) in 63% and 6% yield, respectively [1]. We have recently iso-
lated 5a’, a polymorph of 5a, when single crystal were grown from
acetone instead of dichloromethane. The similar reaction with iso-
propyl homolog of dtp results in [Ag(dppe){S2P(OiPr)2}]1 (5b) and
[Ag4(l
3-Cl)(dppe)1.5{S2P(OiPr)2}3]1 (6b) in 71% and 9% yield,
respectively [1]. When the bridging diphosphine ligand is changed
from dppm to dppb having a longer spacer, and the reaction condi-
Fig. 2. Thermal ellipsoid drawing (30% probability) of 2 (phenyl and ethyl groups
were omitted for clarity).
tions which produces
3 are maintained, a 1D polymeric
[Ag(dppb){S2P(OEt)2}] (7) in 73% yield is obtained. On the other
1
hand, a mixing of Ag(I), dppb and dtp sources in 2:1:2 ratio in
dichloromethane
gives
rise
to
1D
chain
of
[Ag2(dppb){S2P(OEt)2}2]1 (8). In this regard, it is highly worthy to
Fig. 1. Thermal ellipsoid drawing (30% probability) of 1 (phenyl and ethyl groups
Fig. 3. Thermal ellipsoid drawing (30% probability) of 3 (phenyl and isopropyl
were omitted for clarity).
groups were omitted for clarity).

2136
C.W. Liu et al. / Journal of Organometallic Chemistry 694 (2009) 2134–2141
Table 1
Bond lengths (Å) and angles (°) for compounds 1–4, 5a0, 7, and 8.
1a
Ag(1)–P(1)
Ag(1)–S(1)
Ag(1)–S(2)
Ag(1)–S(3)
Ag(1)ꢀ ꢀ ꢀAg(2)
P(1)–Ag(1)–S(1)
P(1)–Ag(1)–S(2)
S(1)–Ag(1)–S(2)
S(1)–Ag(1)–S(3)
2.408(1)
2.517(1)
2.902(1)
2.736(1)
3.1698(5)
Ag(2)–P(2)
Ag(2)–S(1A)
Ag(2)–S(3)
Ag(2)–S(4)
Ag(1)ꢀ ꢀ ꢀAg(2A)
S(3)–Ag(1)–S(2)
Ag(1)–S(1)–Ag(2A)
Ag(2)–S(3)–Ag(1)
2.401(1)
2.647(1)
2.514(1)
2.935(1)
4.125(5)
73.83(3)
106.01(3)
74.15(3)
139.05(3)
87.28(4)
109.05(4)
87.66(3)
2
Ag(1)–P(6)
Ag(1)–P(8)
Ag(2)–P(2)
Ag(2)–P(3)
2.495(1)
2.493(1)
2.441(1)
2.427(1)
2.476(1)
132.21(4)
108.62(3)
106.85(4)
110.52(3)
83.46(3)
Ag(3)–P(5)
Ag(1)–S(1)
Ag(1)–S(3)
Ag(2)–S(1)
2.508(1)
2.678(1)
2.747(1)
2.676(1)
2.608(1)
104.29(3)
102.91(4)
120.37(4)
136.32(4)
87.62(3)
Ag(3)–P(4)
Ag(3)–S(3)
P(8)–Ag(1)–P(6)
P(6)–Ag(1)–S(3)
P(6)–Ag(1)–S(1)
P(8)–Ag(1)–S(1)
S(1)–Ag(1)–S(3)
P(8)–Ag(1)–S(3)
P(2)–Ag(2)–S(1)
P(7)–Ag(2)–S(1)
P(7)–Ag(2)–P(2)
Ag(2)–S(1)–Ag(1)
3b
Ag(1)–P(3)
Ag(2)–P(4)
Ag(1)–S(3A)
Ag(1)–S(1)
Ag(2)–S(4)
P(1)–Ag(1)–S(1)
P(3)–Ag(1)–S(3A)
P(4)–Ag(2)–S(1)
P(4)–Ag(2)–S(3A)
P(4)–Ag(2)–S(4)
S(3A)–Ag(1)–S(1)
2.413(3)
2.406(3)
2.500(2)
2.660(3)
2.728(3)
131.40(9)
133.21(9)
132.22(1)
95.54(9)
107.43(9)
94.76(9)
Ag(2)–S(1)
Ag(2)–S(3)
2.518(3)
2.811(3)
3.063(1)
4.914(2)
Fig. 4. Thermal ellipsoid drawing (30% probability) of 4 (phenyl and isopropyl
groups were omitted for clarity).
Ag(1)ꢀ ꢀ ꢀAg(2)
Ag(1)ꢀ ꢀ ꢀAg(2A)
S(1)–Ag(2)–S(4)
S(1)–Ag(2)–S(3)
S(4)–Ag(2)–S(3)
Ag(2)–S(1)–Ag(1)
Ag(1A)–S(3)–Ag(2)
112.76(1)
95.54(9)
73.38(8)
72.46(8)
135.36(1)
of 4:2:3 in CH2Cl2 solution at ambient temperature in ꢃ75% yield
[23].
2.2. Structural studies
2.2.1. Structure of clusters, 1–4
4
Clusters 1–3 crystallize in the P21/n (monoclinic), Pbca and
Pna21 (orthorhombic), respectively, whereas the dinuclear 4 crys-
tallizes in the monoclinic space group P21/c. Figs. 1–4 depict the
structures of compounds 1–4 and the selected metric data are gi-
ven in Table 1. The tetranuclear cluster 1 contains a crystallograph-
ically imposed center of symmetry (Fig. 1). Besides four Ag atoms,
it is composed of two P,P0-bridging dppm ligands with averaged
Ag–P lengths of 2.405 Å, and four dtp ligands which bind to the
Ag atoms via both chelating and bridging fashion by the sulfur
Ag(1)–P(2)
Ag(1)–P(4)
Ag(1)–S(1)
Ag(2)–S(2)
P(2)–Ag(1)–P(4)
P(2)–Ag(1)–S(1)
P(5)–Ag(2)–S(2)
P(3)–Ag(2)–S(2)
2.442(2)
2.498(2)
2.589(2)
2.575(2)
143.82(6)
120.81(6)
122.35(7)
92.50(6)
Ag(2)–P(3)
Ag(2)–P(5)
Ag(1)ꢀ ꢀ ꢀAg(2)
2.521(2)
2.428(2)
2.918(1)
P(4)–Ag(1)–S(1)
P(1)–S(1)–Ag(1)
P(5)–Ag(2)–P(3)
95.27(6)
110.23(10)
145.05(6)
5a0
Ag(1)–P(2)
Ag(1)–P(3)
P(2)–Ag(1)–S(1)
P(2)–Ag(1)–S(2)
P(3)–Ag(1)–S(1)
2.4774(12)
2.4615(12)
112.64(5)
108.48(6)
114.95(5)
Ag(1)–S(2)
Ag(1)–S(1)
P(3)–Ag(1)–S(2)
S(2)–Ag(1)–S(1)
P(2)–Ag(1)–P(3)
2.7038(16)
2.6641(16)
113.06(6)
77.21(6)
atoms (l2: ,g
g2 1; mode III). It is interesting to point out that the
eight-membered ring formed by Ag4S4 core remains in chair con-
formation. All Ag–S distances alternating in length across the ring
are in the range, 2.514(1)–2.736(1) Å, and the terminal Ag–S dis-
tances are longer, 2.902(1)–2.935(1) Å. The lengthening of terminal
distances may be due to the lower S–Ag–S bite angle (ca. 73°), and
a strain imposed by the bridging requirement. There are two differ-
ent Agꢀ ꢀ ꢀAg distances observed in 1: two short at 3.1698(5) Å, and
two long at 4.125(5) Å. The longer distances are between the silver
atoms bridged only by sulfur atom of a dtp whereas the simulta-
neous bridging of two Ag by S atom from a dtp and P,P0-bridging
dppm ligand shortens the silver–silver distances (Ag1ꢀ ꢀ ꢀAg2 and
Ag1Aꢀ ꢀ ꢀAg2A). The observed Agꢀ ꢀ ꢀAg distance of 3.17 Å, is less than
twice of van der Waal’s radii of Ag, 3.40 Å, and this is comparable
to the average Agꢀ ꢀ ꢀAg distances 3.13 and 3.14 Å in [Ag4(SPh)4
(PPh3)4] [24] and [Ag2(sac)2(MeCN)2] (sacH = 1,1-dioxo-1,2-ben-
zothiazol-3-one) [25], respectively. Overall each silver atom is
coordinated by a P and three S atoms in a distorted tetrahedral
geometry.
121.74(4)
7
Ag(1)–P(2)
Ag(1)–P(3)
P(2)–Ag(1)–S(1)
P(2)–Ag(1)–S(2)
P(3)–Ag(1)–S(1)
2.489(2)
2.470(2)
115.92(8)
109.53(8)
115.87(8)
Ag(1)–S(2)
Ag(1)–S(1)
P(3)–Ag(1)–S(2)
P(2)–Ag(1)–P(3)
S(2)–Ag(1)–S(1)
2.681(2)
2.697(2)
122.31(7)
112.62(7)
76.10(8)
8c
Ag(1A)–P(2A)
Ag(1A)–S(1A)
2.425(1)
2.530(1)
2.964(1)
134.77(2)
119.56(2)
104.10(2)
101.54(2)
Ag(1A)–S(2A)
S(1A)–Ag(1B)
Ag(1A)ꢀ ꢀ ꢀAg(1B)
2.694(1)
2.964(1)
3.360(1)
Ag(1A)–S(1AA)
P(2)–Ag(1)–S(1)
P(2A)–Ag(1A)–S(2A)
P(2A)–Ag(1A)–S(1AA)
S(1A)–Ag(1A)–S(2A)
S(2A)–Ag(1A)–S(1AA)
S(1A)–Ag(1A)–S(1AA)
Ag(1A)–S(1A)–Ag(1B)
73.49(2)
105.04(2)
74.96(2)
Symmetry transformations used to generate equivalent atoms: aA: ꢁx + 2, ꢁy,
ꢁz + 1; bA: ꢁx + 1, ꢁy, ꢁz + 1; cA: ꢁx, ꢁy + 2, ꢁz + 1; B: ꢁx + 1, ꢁy + 2, ꢁz + 1.
The cation of trinuclear cluster 2 contains three silver atoms
bridged by three dppm units to form a 12-membered ring, and fur-
one dangling S atom. P–Ag–P angles are the largest around the me-
tal centers as usual. The coordination mode for the dtp ligands is
ther each of the two ‘dtp’ ligands binds to two Ag atoms via
l2-S
bimetallic–biconnective (l2
:g
2, mode IV). The average Agꢀ ꢀ ꢀAg dis-
from opposite sides of the metallacycle (Fig. 2). This results in
two Ag atoms with distorted trigonal planar geometry {ca. 103–
136°, Ag(2); ca. 110–126°, Ag(3)}, and a Ag atom in distorted tetra-
hedral geometry (ca. 104–132°) and leaves each dtp ligand with
tance of 3.8 Å, is much longer than that reported (3.3 Å) in
[Ag3(dppm)3{SC(O)R}2](ClO4) (R = Me, Ph) [26]. Although S(1)
bridges Ag(2) and Ag(1) atoms almost symmetrically, S(3) bridges

C.W. Liu et al. / Journal of Organometallic Chemistry 694 (2009) 2134–2141
2137
Ag(1) and Ag(3) unsymmetrically with Ag(3)–S(3) being the short-
est among all Ag–S distances [2.608(1)–2.747(1) Å]. The averaged
Ag–P distance is 2.473 Å, which is not unusual.
compounds under discussion. The Ag–S and Ag–P distances are
comparable to those observed in other clusters 1–3. The P–Ag–P
angle is the largest, and S–Ag–P, the smallest angle; with geometry
around each Ag atom in distorted T-shaped.
The cluster 3, with isopropoxyl groups in the dtp ligand, exhib-
its different structural characteristics in comparison to those re-
vealed in 1 (Fig. 3). Two sorts of connection patterns for the dtp
ligands, bridging-chelating (mode III) and bridging–dangling
(mode IV), are identified in 3, whereas only the mode III is dis-
played for the dtp ligands in 1. The Ag–S distances lie in the range,
2.500(2)–2.811(3) Å; the longest bond is formed by the bridging S
atom of dtp ligand which adopts mode III. Similar to 1, cluster 3
also exhibits Ag–S distances alternating in length across the
eight-membered ring formed by the Ag4S4 core. All Ag–P distances
are similar to those observed in 1. Two different Agꢀ ꢀ ꢀAg distances
are present in 3: two short [3.0630(12) Å] and two long
[4.914(2) Å]; the distances between silver atoms bridged by a sul-
fur atom only are longer. Thus the simultaneous bridging of
Agꢀ ꢀ ꢀAg by both a S atom from dtp and P,P0-bridging ligand short-
ens the silver–silver distance in the same way as in 1. The cluster 3
reveals two three-coordinated Ag atoms with angles in the range,
ca. 95–133°, and two four-coordinated Ag atoms with angles in
the range, 73–132°; the lowest angle represents the bite angle
(S–Ag–S) of the chelating dtp ligand.
2.2.2. Structure of polymers, 5–8
The increase in spacer length of diphosphine from –CH2– in
dppm to –(CH2)2– in dppe induces more flexibility in terms of pos-
sible bonding modes of the PPh2 units as the P,P0-bridging ligand
which leads to form polymeric 1D chains (5a, 5a’ and 5b), and
2D honeycomb-shaped layers (6a–b) instead of oligomeric cluster
compounds viz. 1–4 [1]. A newly isolated, polymeric 5a’, a poly-
morph of 5a, exhibits the same bonding patterns as those reported
for 5a [1]. Each silver atom bonded to one dtp ligand in chelating
manner (mode I) is connected to two Ag atoms with dppe as the
bridge to form a 1D chain. The S(1)–Ag(1)–S(2) bite angle in 5a0
(77.21°) is comparable to that in 5a (76.97°). Both Ag–P
[2.4615(12), 2.4774(12) Å] and Ag–S [2.6641(16), 2.7038(16) Å]
distances in 5a0 are in normal range for a four-coordinated silver(I)
center [27,28]. The linker, dppe, adopts anti conformation while
connecting silver atoms and this trend continues to favor 1D zigzag
chain rather than ring formation. Besides, the chelating dtp ligands
are arranged in an alternating up and down fashion along the zig-
zag chain. Similar polymeric chain [Ag(dppe)(S2PPh2)] involving
dppe and a dtp ligand was reported by Fenske and co-workers
[29]. The characteristics of iso-structural polymers 6a and 6b were
described in the previous communication [1].
The cation of dimer 4 consists of two Ag atoms bridged by two
dppm and a dtp ligand adopting mode II, and thus each trigonally
coordinated Ag has a P2S coordination environment (Fig. 4). The
Agꢀ ꢀ ꢀAg distance, 2.918(1) Å, is the shortest among all the
Fig. 5. Thermal ellipsoid drawing (30% probability) of 7.
Fig. 6. Thermal ellipsoid drawing (30% probability) of 8. Ethyl groups were omitted for clarity.

2138
C.W. Liu et al. / Journal of Organometallic Chemistry 694 (2009) 2134–2141
P
P
R
R
P
R
P
S
S
P
S
Ag
Ag
R
S
P
2
R
S
S
R
R
Ag
Ag
S
R
P
S
S
P
S
P
S
R
Ag
Ag
P
R
A
P
R
R
S
P
S
R
4
Ag+
P
P
2
P
4
+
+
R
S
1
(R =OEt )
dppm
dtp
P
R
P
S
Ag
R
P
R
P
P
R
Ag
S
S
R
S
S
P
P
S
2
R
P
R
Ag
Ag
S
S
R
S
S
P
S
Ag
P
Ag
R
P
S
R
R
B
R
P
3 (R =OiPr)
P
P
R
P
P
Ag
P
S
S
R
Ag
Ag
S
P
x= y=2
z =1
x=y=3
z =2
P
P
Ag+
+
P
Ag
S
y
z R
P
P +
dppm
S
x
R
R
P
S
P
R
R
S
dtp
R
S
P
Ag
P
P
4 ( R=OiPr)
2 (R=OEt)
Scheme 1.
The increase in chain length of diphosphine from –(CH2)2– in
dppe to –(CH2)4– in dppb, produces two types of polymers depend-
ing on the molar ratio used; a zigzag chain, 7 (Fig. 5), in which dppb
bridges two Ag(dtp) units having a similar bonding pattern that
observed in dppe polymer 5a, 5a0 and [Cu(dppe){S2P(OR)2}]1
[30], and the other zigzag chain 8 in which the dppb ligands bridge
dimeric Ag2(dtp)2 units (Fig. 6). In polymer 7, Ag–P and Ag–S bond
lengths are similar to that in polymer 5a0, and angles around silver
vary in the range, ca. 76–122° with the smallest angle being the
bite angle of chelating dtp. The P–Ag–P bond angle in 7 is similar
to that in 5a0, and thus Ag atoms have distorted tetrahedral geom-
etry. In polymer 8, two PS2 fragments, each from a dtp, and two Ag
atoms form a fused eight-membered tricyclic ring which remains
in chair form; however the central Ag2S2 core is a perfect parallel-
ogram with Ag–S distances of 2.530(1) and 2.964(1) Å. Also the an-
gles in Ag2S2 core are comparable to similar cores observed in the
R
R
R
R
P
P
P
P
C
S
n
P
S
Ag
R
S
S
Ag
S
Ag
P
S
P
P
P
R
x=y=z=1
C
i
5a 5b
5a'
= dppe; R = OEt, and ; O Pr,
= dppb;
P
P
P
P
R = OEt, 7
S
R
R
x
Ag+
y
P
P
+ z
+
P
S
dppe
or
dppb
dtp
R
R
R
R
P
R
R
P
S
S
P
S
S
P
P
S
Ag
y=1
S
x=z=2
Ag
nD
P
Ag
S
Ag
Ag
S
P
P
Ag
P
S
S
P
S
P
P
S
R
R
R
D
R
R
R
= dppb;R=OEt, 8
P
P
Scheme 2.

C.W. Liu et al. / Journal of Organometallic Chemistry 694 (2009) 2134–2141
2139
R
P
R
P
P
R
R
R
S
P
Ag
S
S
R
Ag
S
S
S
P
P
S
R
S
R
Ag
Cl
Ag
Ag
Ag+
Cl-
P
Ag
Ag
P
P
S
S
P
S
S
P
P
R
R
R
R
S
S
R
R
E
Ag+
P
3
P
P
+
3
+
3
+
R
P
R
R
E
Ag
nE
R
P
S
S
E
E
P
S
Ag
S
Cl
Ag
E
E
Ag
P
P
S
S
E
E
E
P
R
R
E
E
E
E
E
E
= dppe
P
P
R= OEt, 6a; OiPr, 6b
Scheme 3.
literature [31]. The Agꢀ ꢀ ꢀAg distance of 3.360(1) Å is longer than
that in 4. The geometry around each Ag atom in 8 is distorted tet-
rahedral, similar to those in polymers 5 and 7.
dppm and two dtp ligands. Three dppm bridge three silver ions in
syn manner to form a 12-membered ring and further two dtp li-
gands bridge these silver ions. The formation of dimer 4 involves
the reaction of two Ag+ ions with two dppm and one dtp ligand,
which is the same as the mixing ratio of reactants. In all these com-
plexes, the dppm ligand which acted as P,P0-bridge and remained
in syn conformation, favored the formation of clusters (1–4) in-
stead of polymeric compounds.
2.3. NMR spectroscopy
The 1H NMR data of compounds 1–8 show peaks attributed to
ethyl and isopropyl groups of dtp, as well as methylene and phenyl
groups of dppm, dppe and dppb in their characteristic regions as
listed in the Section 4. In 31P NMR spectroscopy, dtp ligands show
In the formation process of the polymers, which involves either
dppe or dppb as the P,P0-bridging ligand, presumably a Ag(I) is che-
lated by a dtp to form a neutral species {Ag(dtp)}, being coordin-
atively unsaturated, get polymerized with the help of either dppe
or dppb as the linker to produce 5a, 5a0, or 7, respectively (Scheme
2). The ratio of the Ag(I), dtp and dppe (or dppb) present in the
polymers is 1:1:1, same as the mixing ratio of the reactants. How-
ever to rationalize the formation of 8, it is assumed that two Ag+
and two dtp ligands combined to yield Ag2(dtp)2 which is further
connected to dppb to form the repeating unit D of the polymer 8.
The molar ratio of Ag:dtp:dppb (2:2:1) in 8, leads us to postulate
that use of lower amount of dppb might favor the formation of
Ag2(dtp)2 species, followed by bridging by dppb. The P,P0-bridging
ligands, dppe and dppb, remained in anti conformation in 5a, 5a0, 7
and 8 which facilitated the formation of the polymer species.
The formation of 6a, the honeycomb-shaped network, is unu-
sual in which three dtp ligands assembled to bridge three Ag atoms
which generates a 12-membered metallacycle, and each of the Ag
atoms is further bonded to one P atom of dppe with the second P
atom remained dangling. Coordination of one more Ag(I) to three
S atoms of three bridging dtp ligands, and abstraction of a Clꢁ, pre-
sumably from the solvent CH2Cl2, by three Ag atoms might lead to
produce the repeating unit E (Scheme 3). This repeating unit led to
the formation of 2D layer 6a which was obtained as the minor
product from the reaction mixture of polymer 5a.
upfield coordination shifts (
D
d = dcomplex ꢁ dligand(S2P), which lie in
the range, ca. ꢁ4 to ꢁ9 ppm. The high field shift might be caused
by the electromeric effect of both alkoxy groups and S donors at-
tached to the P atom which would have resulted in net shielding
of P nucleus in the complexes. The PPh2 groups of diphosphines
show one broad signal in low field region relative to the free li-
gands with coordination shifts (
D
d = dcomplex ꢁ dligand(Ph2P)), in the
range, ca. 14–26 ppm. The dimer 4 exhibits the highest shift while
the cluster 3 shows the lowest. The broad signals suggest possibil-
ities of either more than one species co-existed in solution, which
was confirmed from the isolation of some minor products (2 and 6)
from the reaction mixtures of 1 and 5, respectively, or the intrinsic
lability of Ag–P bond. However, the exact nature is not well
understood.
2.4. Rationalization of the reaction pathway
Although several possible binding modes of dtp ligands favor a
variety of species being existed in solution in equilibrium, the
structural characterization of species 1–8 prompts us to rationalize
their formation pathways in order to get a better understanding of
these types of ligands for further research. Schemes 1–3 depict a
rationale of the formation of the complexes. The formation of 1
and 3 involve the reaction of Ag+, dtp and dppm in 2:2:1 ratio
which may yield a dimeric intermediate A or B and further dimer-
ization of them results in 1 and 3, respectively. It is noted that the
ratio of reactants used in these two reactions was 1:1:1. Although,
we could not isolate any by-product from reaction mixture of 3;
however, cluster 2 is obtained as the minor product from the
reaction mixture of 1, by the reaction of three Ag+ ions with three
3. Conclusions
Diphosphines adopted P,P0-bridging mode in silver(I)-dtp chem-
istry; the shorter alkane spacer in dppm favors complexes with low
nuclearity, the longer spacer as in dppe or dppb favors 1D and/or
2D polymers. The difference is attributed to the higher flexibility

2140
C.W. Liu et al. / Journal of Organometallic Chemistry 694 (2009) 2134–2141
of alkane spacers in dppe or dppb, which adopted anti conforma-
tion in the complexes vs. syn conformation adopted by dppm.
The dtp exhibited several coordination modes in the complexes
and it demonstrates larger angular flexibility on sulfur atom which
can tune itself to local environments for a given metal center. That
two silver atoms are concomitantly bridged by both phosphorus
and sulfur donors of the dppm and dtp ligands led to short sil-
ver-silver contacts thus enhancing argentophilicity in cluster 1, 3,
and 4. On the other hand, polymeric 8 also showed short Agꢀ ꢀ ꢀAg
contacts as they were bridged by two S from two dtp ligands.
for C74H100Ag4O8S8P8 ꢀ CH3OH: C, 43.20; H, 5.03; S, 12.30. Found: C,
43.15; H, 5.01; S, 12.01%. 1H NMR (CDCl3): d 1.23 (m, 24H, CH3),
3.07 (br s, 4H, CH2 of dppm), 4.75 (m, 8H, CH), 7.08–7.43 (m,
40H, Ph). 31P {1H} NMR (CDCl3): d 106.75 {s, P(OiPr)2}, ꢁ5.75 (br
s, PPh2).
D
d = dComplex ꢁ dLigand(S2P) = ꢁ4.63 ppm;
D
d = dComplex
ꢁ
dLigand(PPh2) = 13.75 ppm.
4.2.3. [Ag2(dppm)2{S2P(OiPr)2}](PF6) (4)
Dichloromethane (30 mL) was added to a 100 mL flask contain-
ing [Ag(CH3CN)4](PF6) (0.30 g, 0.72 mmol), dppm (0.27 g,
0.72 mmol) and NH4[S2P(OiPr)2] (0.08 g, 0.36 mmol). The solution
mixture was stirred for 24 h at ambient temperature and filtered
to remove any solid. The filtrate was then washed with water
and the dichloromethane extract was allowed to evaporate to get
a white solid. This solid was re-dissolved in dichloromethane and
layered with hexane which afforded crystalline material of 4. Yield:
68% (0.16 g). Anal. Calc. for C56H58Ag2O2S2P6F6: C, 50.09; H, 4.35; S,
4.78. Found: C, 49.98; H, 4.57; S, 4.83%. 1H NMR (CDCl3): d 1.16 (m,
6H, CH3), 3.60 (br s, 4H, CH2 of dppm), 4.58 (br s, 1H, CH), 7.00–
7.65 (m, 40H, PPh). 31P {1H} NMR (CDCl3): d 102.17 {s, P(OiPr)2},
4. Experimental
4.1. Materials and instruments
All the reactions were performed in oven-dried Schlenk glass-
ware by using standard inert-atmosphere techniques. Solvents
were purified following standard method prior to use.
Ag(CH3CN)4(PF6) [32], Ag2(
l
-dppm)2(CH3CN)2(PF6)2 [33], Ag2(
l-
dppe)2(CH3CN)2(PF6)2 [34], Ag2(
l-dppb)2(PF6)2 [35] and the
ammonium dialkyldithiophosphates [36] were either procured or
prepared according to the literature methods. Compounds 5a–b
and 6a–b were reported previously [1]. All other reagents obtained
from commercial sources, were used as received. NMR spectra
were recorded on a Bruker Advance-300 FT spectrometer which
operates on 300 MHz for 1H NMR and on 121.49 MHz for 31P
NMR. The 31P{1H} NMR spectrometer is referenced externally
against 85% H3PO4. The elemental analyses (C, H, S) were done
using a Perkin–Elmer 2400 Analyzer.
6.62 (br, PPh2).
dLigand(PPh2) = 26.12 ppm.
D
d = dComplex ꢁ dLigand(S2P) = ꢁ9.21 ppm;
D
d = dComplex
ꢁ
4.2.4. [Ag(dppe){S2P(OEt)2}] (5a0)
1
The compoound was prepared in a similar proceedure described
in case of 5a. [Ag2(dppe)2(CH3CN)2](PF6)2 (0.50 g, 3.60 mmol) and
NH4[S2P(OEt)2] (0.15 g, 7.20 mmol) were taken in a 100 mL flask
and 50 mL of CH2Cl2 was added and stirred for 24 h at ambient
temperature. After this it was filtered to remove the solid formed
and the dichloromethane solution was washed with 2 ꢄ 50 mL of
water. The organic layer was dried over MgSO4 and evaporated
to dryness to get a white solid. The solid was washed by MeOH
using sonication to get compound 5a or 5a0. Crystals of 5a0 were
obtained from slow evaporation of acetone solution of this solid
whereas crystals of 5a could be obtained by diffusing hexane into
dicholomethane solution of the isolated solid. Thus 5a and 5a0 are
polymorph. Yield: 63% (0.32 g). Anal. Calc. for C30H34AgO2S2P3: C,
52.10; H, 4.95; S, 9.27. Found: C, 52.40; H, 5.00; S, 9.17%. 1H
NMR (CDCl3): d 1.13 (m, 6H, CH3), 2.44 (br s, 4H, CH2 of dppm),
3.93 (m, 4H, CH2), 7.08–7.79 (m, 40H, Ph). 31P {1H} NMR (CDCl3):
4.2. Syntheses
4.2.1. [Ag4(dppm)2{S2P(OEt)2}4] (1), and
[Ag3(dppm)3{S2P(OEt)2}2](PF6) (2)
Acetonitrile (30 mL) was added to
a
flask containing
Ag2(dppm)2(CH3CN)2(PF6)2 (0.29 g, 0.2 mmol) and NH4[S2P(OEt)2]
(0.09 g, 0.4 mmol). It was stirred for 24 h at ambient temperature,
and then filtered to remove any solid remained there. The filtrate
was allowed to evaporate at room temperature, until white solid
was obtained. The white solid was re-dissolved in CH3OH
(20 mL) and crystals of 2 were formed in 7% yield. After separation
of the crystals of 2, the filtrate was evaporated using rotavapor, and
the solids obtained were re-dissolved in chloroform (20 mL) and
layered with hexane (10 mL) which afforded crystalline material
of 1. Compound 2 was washed well with CHCl3 to remove any
traces of 1.
d
105.78 {s, P(OiPr)2}, 2.87 (br, PPh2).
dLigand(S2P) = 9.02 ppm;
d = dComplex ꢁ dLigand(PPh2) = 17.07 ppm.
D
d = dComplex
ꢁ
D
4.2.5. [Ag(dppb){S2P(OEt)2}] (7)
1
The method is the same as for 1, except using dichloromethane
as solvent with [Ag2(dppb)2(CH3CN)2](PF6)2 as starting material.
Crystals were grown from CH2Cl2/C2H5OH mixed solvent. Yield:
73% (0.21 g). Anal. Calc. for C32H38AgO2S2P3 ꢀ 1/2CH2Cl2: C, 51.22;
H, 5.16; S, 8.42. Found: C, 50.58; H, 5.16; S, 8.07%. 1H NMR (CDCl3),
d 1.28 (m, 6H, CH3), 1.75 (br s, 4H, CH2 of dppb), 2.15 (br s, 4H, CH2
of dppb), 4.06 (m, 4H, CH2), 7.24–7.78 (m, 20H, Ph). 31P {1H} NMR
Compound 1: Yield: 76% (0.30 g). Anal. Calc. for C66H84A-
g4O8S8P8: C, 40.84; H, 4.36; S, 13.21. Found: C, 40.76; H, 4.54; S,
13.05%. 1H NMR (CDCl3): d 1.18 (m, 24H, CH3), 3.39 (s, br; 4H,
CH2 of dppm), 4.07 (m, 16H, CH2), 7.02–7.42 (m, 40H, Ph); 31P
{1H} NMR (CDCl3): d 108.21 {s, P(OEt)2}, 1.00 (br s, PPh2).
D
d =
dComplex ꢁ dLigand(S2P) = ꢁ6.59 ppm;
Dd = dComplex ꢁ dLigand(PPh2) = 20.5
ppm.
(CDCl3): d 105.96 {m, P(OEt)2}, 0.33 (m, PPh2).
D
d = dComplex
ꢁ
Compound 2: Yield: 7% (0.02 g). Anal. Calc. for C83H86A-
g3O4S4P9F6 ꢀ CHCl3: C, 47.78; H, 4.15; S, 6.07. Found: C, 47.76; H,
4.54; S, 6.05%. 1H NMR (CDCl3): d 1.13 (m, 12H, CH3), 3.56 (br s,
6H, CH2, dppm), 3.86 (m, 8H, CH2), 7.05–7.37 (m, 60H, Ph); 31P
{1H} NMR (CDCl3): d 106.03 {s, P(OEt)2}, ꢁ0.20 (br s, PPh2).
dLigand(S2P) = ꢁ8.82 ppm; d = dComplex ꢁ dLigand(PPh2) = 19.83 ppm.
D
4.2.6. [Ag2(dppb){S2P(OEt)2}2]1 (8)
It was prepared by the same method as for 4 by reacting
[Ag(CH3CN)4](PF6), dppb and NH4[S2P(OEt)2] in 2:1:2 molar ratio.
Yield: 68% (0.25 g). Anal. Calc. for C36H48Ag2O4S4P4: C, 42.70; H,
4.78; S, 12.67. Found: C, 43.15; H, 4.93; S, 12.36%. 1H NMR (CDCl3):
d 1.20 (m, 12H, CH3), 1.58 (br s, 4H, CH2 of dppb), 2.07 (br s, 4H,
CH2 of dppb), 4.00 (m, 4H, CH), 7.20–7.53 (m, 20H, PPh). 31P {1H}
D
d = dComplex ꢁ dLigand(S2P) = ꢁ8.77 ppm;
Dd = dComplex – dLigand(PPh2) =
19.30 ppm.
4.2.2. [Ag4(dppm)2{S2P(OiPr)2}4] (3)
It was prepared by the method as used for 1, except using
dichloromethane as solvent and NH4S2P(OiPr)2 as ligand. After
isolation, 3 were subjected to thorough washing with CH3OH to
remove any species analogous to 2. Yield: 75% (0.18 g). Anal. Calc.
NMR (CDCl3): d 107.53 {s, P(OEt)2}, 1.02 (br s, PPh2).
D
d =
dComplex ꢁ dLigand(S2P) = ꢁ7.30 ppm;
D
d = dComplex ꢁ dLigand(PPh2)
=
20.52 ppm.

C.W. Liu et al. / Journal of Organometallic Chemistry 694 (2009) 2134–2141
2141
Table 2
Crystallographic data for compounds 1–4, 5a0, 7 and 8.
1
2
3
4
5a0
7 ꢀ CH2Cl2 ꢀ C2H5OH
8
Formula
C33H42Ag2O4S4P4
970.53
Monoclinic
P21/n
14.1504(11)
17.8787(13)
16.4680(10)
90
90.700(6)
90
C83H86Ag3O4S4P9F6
1992.10
Orthorhombic
Pna21
32.2003(16)
18.5101(9)
14.5405(7)
90
90
90
8666.6(7)
4
1.527
C74H100Ag4O8S8P8
2053.26
Orthorhombic
Pbca
17.2672(17)
22.7228(17)
23.462(2)
90
C56H58Ag2F6O2P6S2
1342.70
Monoclinic
P21/c
10.4045(13)
36.563(5)
16.043(2)
90
105.644(3)
90
5877.2(13)
4
C30H34AgO2P3S2
691.47
C35H46AgCl2O3P3S2
850.52
C18H24AgO2P2S2
506.30
Formula weight
Crystal system
space group
a (Å)
b (Å)
c (Å)
Triclinic
Triclinic
Triclinic
ꢀ
ꢀ
ꢀ
P1
P1
P1
11.1168(17)
11.640(2)
13.4236(12)
99.904(11)
91.219(11)
106.036(15)
1640.2(4)
2
12.4844(17)
13.410(3)
14.4970(18)
102.387(10)
107.825(9)
109.245(13)
2042.7(5)
2
9.6616(13)
10.5348(14)
11.5849(16)
67.726(2)
86.002(3)
86.095(3)
1087.4(3)
2
a
(°)
b (°)
90
90
c
(°)
V (Å3)
4165.9(5)
4
1.547
9205.5(14)
4
1.482
Z
qcalc (g cmꢁ3
)
1.517
1.400
1.383
1.546
k (Mo K
l
a
)
) (Å)
0.71073
1.053
0.71073
0.994
0.71073
1.206
0.71073
0.960
0.71073
0.913
0.71073
0.875
0.71073
1.275
(mmꢁ1
T (K)
298(2)
0.0358
0.0936
298(2)
0.0365
0.0916
293(2)
0.0659
0.1473
298(2)
0.0682
0.1572
293(2)
0.0470
0.1165
293(2)
0.0585
0.1513
298(2)
0.0241
0.0600
R1a
wR2b
a
R1 = ||Fo| ꢁ |Fc||/|Fo|.
2
2 1=2
wR2 ¼ ½wðF2o ꢁ Fc2Þ ꢂ=½wðF2oÞ ꢂ
.
b
[6] J.P. Fackler Jr., C.A. Lopez, R.J. Stapies, S. Wang, R.E.P. Winpenny, R.P. Lattimer,
Chem. Commun. (1992) 146.
4.3. X-ray crystallography
[7] C.W. Liu, B.-J. Liaw, J.-C. Wang, T.-C. Keng, Inorg. Chem. 39 (2000) 1329.
[8] L.S. Ahmed, J.R. Dilworth, J.R. Miller, N. Wheatley, Inorg. Chim. Acta 278 (1998)
229.
[9] W.-P. Su, M.-C. Hong, J.-B. Weng, R. Cao, S.-F. Lu, Angew. Chem., Int. Ed. Engl. 39
(2000) 2911.
[10] W.-P. Su, M.-C. Hong, J.-B. Weng, Y.-C. Liang, Y.-J. Zhao, R. Cao, Z.-Y. Zhou,
Inorg. Chim. Acta 331 (2002) 8.
[11] E.S. Raper, Coord. Chem. Rev. 165 (1997) 475.
[12] I. Haiduc, D.B. Sowerby, Polyhedron 14 (1995) 2469.
[13] D.-L. Long, S. Shi, X.-Q. Xin, B.-S. Luo, L.-R. Chen, X.-Y. Huang, B.-S. Kang, J.
Chem. Soc., Dalton Trans. (1996) 2617.
[14] C.W. Liu, J.T. Pitts, J.P. Fackler Jr., Polyhedron 16 (1997) 3899.
[15] K. Matsumoto, R. Tanaka, R. Shimomura, Y. Nakao, Inorg. Chim. Acta 304
(2000) 293.
The crystal structures of 1–4, 5a0, 7, and 8 were obtained by sin-
gle crystal X-ray diffraction technique. Crystals were mounted on
the tips of glass fibers with epoxy resin. Data for compounds 3,
5a0, and 7 were collected at 298 K on a Siemens P4 diffractometer
equipped with Mo K
lected using 2h– scan technique. Crystal data for compounds1, 2,
4, and 8 were collected at 293 K on a Siemens SMART CCD diffrac-
tometer. Data were measured with scans of 0.3° per frame for
90 s. Cell parameters were retrieved with SMART software [37] and
refined with SAINT software on all observed reflection (I > 10 (I)).
a radiation (k = 0.71073 Å). The data were col-
x
x
r
Data reduction was performed with SAINT [38], which corrects for
Lorentz and polarization effects. An empirical absorption correc-
tion was applied for all compounds. The structure was solved by
the use of direct methods, and refinement was performed by the
least-squares methods on F2 with the SHELXL-97 package [39], incor-
porated in SHELXTL/PC V5.10 [40]. Selected crystal data for the com-
pounds are summarized in Table 2. Compounds 5a and 5a0, with a
different unit cell, are polymorphs. Structures of 5a, 6a, and 6b
(CCDC 254826—254828) were reported in the previous communi-
cation [1].
[16] E.-S. Raper, Coord. Chem. Rev. 165 (1997) 475.
[17] M.G.B. Drew, R.J. Hobson, P.P.E.M. Munba, D.A. Rice, Inorg. Chim. Acta 142
(1988) 301.
[18] H.-G. Zheng, W.-L. Tan, M.K.L. Low, W. Ji, D.-L. Long, W.-T. Wong, K.B. Yu, X.-Q.
Xin, Polyhedron 18 (1999) 3115.
[19] D. Coucouvanis, Prog. Inorg. Chem. 26 (1979) 301.
[20] P.J. Nieuwenhuizen, A.W. Ehlers, J.G. Haasnoot, S.R. Janse, J. Reedijk, E.J.
Baerends, J. Am. Chem. Soc. 121 (1999) 163.
[21] P.J. Nieuwenhuizen, S. Timal, J.G. Haasnoot, A.L. Spek, J. Reedijk, Chem. Eur. J. 3
(1997) 1846.
[22] M.A. Hossain, J. Llinares, D. Powell, K. Bowman-James, Inorg. Chem. 40 (2001)
2936.
[23] C.W. Liu, B.-J. Liaw, L.-S. Liou, Inorg. Chem. Commun. 7 (2004) 868.
[24] T.C. Deivaraj, J.J. Vittal, J. Chem. Soc, Dalton Trans. (2001) 322.
[25] V.T. Yilmaz, S. Hamamci, C. Kazak, J. Organomet. Chem. 693 (2008) 3885.
[26] T.C. Deivaraj, J.J. Vittal, J. Chem. Soc., Dalton Trans. (2001) 329.
[27] D. Coucouvanis, N.C. Benzinger, S.M. Johnson, Inorg. Chem. 13 (1974) 1191.
[28] D.D. Heinrich, J.P. Fackler Jr., P. Lahuerta, Inorg. Chim. Acta 116 (1986) 15.
[29] M. Shafaei-Fallah, C.E. Anson, D. Fenske, A. Rothenberger, Dalton Trans. (2005)
2300.
Acknowledgements
We thank the National Science Council of Taiwan (NSC 97-
2113-M-259-007) for the financial support.
[30] B.-J. Liaw, T.S. Lobana, Y.-W. Lin, J.-C. Wang, C.W. Liu, Inorg. Chem. 44 (2005)
9921.
Appendix A. Supplementary material
[31] T.S. Lobana, A. Castineiras, Polyhedron 21 (2002) 1603. and references cited
therein.
[32] K. Nelsson, A. Oskarsson, Acta Chem. Scand. Ser. A 38 (1984) 79.
[33] J. Diaz, M.P. Gamasa, J. Gimeno, A. Tiripicchio, M.T. Camellini, J. Chem. Soc.,
Dalton Trans. (1987) 1275.
[34] J.V. Effendy, F. Hanna, D. Marchetti, C. Martini, C. Pettinari, R. Pettinari, B.W.
Skelton, A.H. White, Inorg. Chim. Acta 357 (2004) 1523.
[35] R.-N. Yang, Y.-M. Hou, B.-Y. Xue, D.-M. Wang, D.-M. Jin, Transition Met. Chem.
21 (1996) 28.
[36] J.J. Dickert, C.N. Rowe, J. Org. Chem. 32 (1967) 647.
[37] SMART V4.043: Software for the CCD Detector System, Bruker Analytical X-ray
System, Madison, WI, 1995.
CCDC 293322, 293323, 293324, 293325, 293326, 293327, and
293328 contain the supplementary crystallographic data for com-
pounds 1, 2, 3, 4, 5a0, 7, and 8. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif. Supplementary data associ-
ated with this article can be found, in the online version, at
doi:10.1016/j.jorganchem.2009.02.017.
References
[38] SAINT V4.043: Software for the CCD Detector System, Bruker Analytical X-ray
System, Madison, WI, 1995.
[39] G.M. Sheldrick, SHELXL-97: Program for the Refinement of Crystal Structure,
University of Göttingen, Göttingen, Germany, 1997.
[40] SHELXL 5.10 (PC Version): Program Library for Structure Solution and Molecular
Graphics, Bruker Analytical X-ray System, Madison, WI, 1998.
[1] C.W. Liu, B.-J. Liaw, L.-S. Liou, J.-C. Wang, Chem. Commun. (2005) 1983.
[2] R. Uson, M.A. Uson, S. Herrero, Inorg. Chem. 36 (1997) 5959.
[3] H.-J. Haupt, O. Seewald, U. Florke, V. Buss, T. Weyhemuller, J. Chem. Soc.,
Dalton Trans. (2001) 3329.
[4] T. Komuro, T. Malsuo, H. Kawaquchi, K. Tatsumi, Inorg. Chem. 42 (2003) 5340.
[5] P. Perez-Lourido, J.A. Garcia-Vazquez, J. Romero, A. Sousa, E. Block, K.P.
Maresca, J. Zubieta, Inorg. Chem. 38 (1999) 538.