Silver pyroarsonates obtained from Ag(I)-mediated in situ condensation of aryl arsonate ligands under solvothermal conditions

Article abstract of DOI:10.1021/ic301935g

Four new layered silver(I) organoarsonates, namely, [Ag₃(L ³)(CN)] (1) (H₂L³ = (PhAsO₂H) ₂O), [Ag₃(L⁴)(CN)] (2) (H₂L ⁴ = (2-NO₂-C₆H₄-AsO ₂H)₂O), [Ag₃(HL⁵)(H ₂L⁵)] (3) (H₃L⁵ = 3-NO ₂-4-OH-C₆H₃-AsO₃H₂) and [Ag₂(HL⁵)] (4), were synthesized under solvothermal conditions. During the preparations of 1 and 2, condensation of organoarsonate ligands (H₂L¹ = Ph-AsO₃H₂; H ₂L² = 2-NO₂-C₆H₄-AsO ₃H₂) and the decomposition of acetonitrile molecules to cyanide anions occurred. Single crystals of H₂L⁴ ligand and compounds 1-4 were isolated, and their crystal structures have been determined by single crystal X-ray diffraction studies. In 1, the one-dimensional (1D) chains based on Ag(I) ions and {L³}^2- anions are further interconnected by CN^- into two-dimensional (2D) layers. In 2, adjacent Ag(I) ions within the silver(I) organoarsonate layer are further bridged by μ₄-CN^- anions with very short Ag···Ag contacts. In 3, the hexanuclear {Ag ₆O₁₂} clusters are interconnected by bridging organoarsonate ligands into a silver(I) arsonate hybrid layer. In 4, the right-handed {Ag₄O₄} chains are further interconnected by organoarsonate ligands as well as additional Ag-O-Ag bridges into a novel silver(I) arsonate layer. Compounds 1 and 2 display red and orange-red emissions, respectively, which may be assigned to be an admixture of ligand-to-metal charge transfer (LMCT) and metal-centered (4d-5s/5p) transitions perturbed by Ag(I)···Ag(I) interactions. Upon cooling from room temperature to 10 K, compound 1 exhibits interesting temperature-dependent emissions.

Full text of DOI:10.1021/ic301935g

Article
pubs.acs.org/IC
Silver Pyroarsonates Obtained from Ag(I)-Mediated in Situ
Condensation of Aryl Arsonate Ligands under Solvothermal
Conditions
Xiang-Ying Qian,†,‡ Jun-Ling Song,† and Jiang-Gao Mao*,†
†State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences,
Fuzhou 350002, People’s Republic of China
‡Graduate School of the Chinese Academy of Sciences, Beijing, 100039, People’s Republic of China
S
* Supporting Information
ABSTRACT: Four new layered silver(I) organoarsonates, namely,
[Ag3(L3)(CN)] (1) (H2L3 = (PhAsO2H)2O), [Ag3(L4)(CN)] (2)
(H2L4 = (2-NO2-C6H4-AsO2H)2O), [Ag3(HL5)(H2L5)] (3) (H3L5 = 3-
NO2-4-OH-C6H3-AsO3H2) and [Ag2(HL5)] (4), were synthesized under
solvothermal conditions. During the preparations of 1 and 2,
condensation of organoarsonate ligands (H2L1 = Ph-AsO3H2; H2L2 = 2-
NO2-C6H4-AsO3H2) and the decomposition of acetonitrile molecules to
cyanide anions occurred. Single crystals of H2L4 ligand and compounds
1−4 were isolated, and their crystal structures have been determined by
single crystal X-ray diffraction studies. In 1, the one-dimensional (1D)
chains based on Ag(I) ions and {L3}2− anions are further interconnected
by CN− into two-dimensional (2D) layers. In 2, adjacent Ag(I) ions
within the silver(I) organoarsonate layer are further bridged by μ4-CN−
anions with very short Ag···Ag contacts. In 3, the hexanuclear {Ag6O12} clusters are interconnected by bridging organoarsonate
ligands into a silver(I) arsonate hybrid layer. In 4, the right-handed {Ag4O4} chains are further interconnected by organoarsonate
ligands as well as additional Ag−O−Ag bridges into a novel silver(I) arsonate layer. Compounds 1 and 2 display red and orange-
red emissions, respectively, which may be assigned to be an admixture of ligand-to-metal charge transfer (LMCT) and metal-
centered (4d-5s/5p) transitions perturbed by Ag(I)···Ag(I) interactions. Upon cooling from room temperature to 10 K,
compound 1 exhibits interesting temperature-dependent emissions.
various types of structures ranging from isolated clusters, one-
dimensional (1D) chains to two-dimensional (2D) layers.10
More interestly, when a flexible group of −NHCH2COOH was
attached to the arsonic ligand, a layered chiral zinc(II) arsonate
was obtained.11 Very recently, a series of lanthanide arsonates
had also been structurally characterized by our group.12
Silver-containing materials have received considerable
interest because of their remarkable luminescent and catalytic
properties for numerous chemical processes.13,14 So far, no
silver arsonate has been structurally characterized. Therefore,
we started a research program to systematically study the
structures and physical properties of silver organoarsonates.
The solvothermal reaction of AgNO3 with phenylarsonic acid
(H2L1 = PhAsO3H2) or 2-nitrophenylarsonic acid (H2L2 = 2-
NO2-C6H4-AsO3H2) in acetonitrile resulted in [Ag3(L3)(CN)]
(1) (H2L3 = (PhAsO2H)2O) and [Ag3(L4)(CN)] (2) (H2L4 =
(2-NO2-C6H4-AsO2H)2O), respectively, in which unexpected
dimerization of the arsonate ligands (Scheme 1) and the
decomposition of acetonitrile molecules into cyanide anions
INTRODUCTION
■
Metal phosphonates have attracted tremendous research
interest in the past 20 years because of their potential
applications in optics, ion-exchange, catalysis, and sensors,
and so forth.1,2 Metal arsonates are expected to display a similar
structural chemistry to those of metal phosphonates, but the
larger ionic radius of As(V) than that of P(V) could possibly
lead to some different architectures with different physical
properties. So far, studies on metal arsonates are still limited. A
variety of polyoxometalate clusters of vanadium, molybdenum,
and tungsten capped by arsonate ligands have been
reported.3−6 A heteropoly-13-palladium(II) cluster of phenyl-
arsonate ligand has also been isolated.7 By using the
solvothermal approach, Ma’s group have prepared a series of
organo oxo tin clusters of organoarsonates and several
organotin arsonates with infinite ladders or chains.8 By
introducing an O-donor second metal linker of 5-sulfoisoph-
thalic acid monosodium salt or 1,3,5-benzenetricarboxylic acid,
three novel mixed-ligand lead(II) carboxylate-arsonates had
been isolated by our group.9 Using an N-donor chelating
auxiliary ligand such as phen, 2,2′-bipy, or terpy led to the
isolation of a series of divalent transition metal arsonates with
Received: September 4, 2012
Published: February 6, 2013
© 2013 American Chemical Society
1843
dx.doi.org/10.1021/ic301935g | Inorg. Chem. 2013, 52, 1843−1853

Inorganic Chemistry
Article
Scheme 1. Free Ligands of H2L1, H2L2, H3L5 and the Corresponding Condensation Ligands of H2L3 and H2L4
Table 1. Summary of Crystal Data and Structure Refinements for H2L4 and Compounds 1−4
compound
formula
fw
H2L4
1
2
3
4
C12H10As2N2O9
476.06
C13H10Ag3As2NO5
733.67
C13H8Ag3As2N3O9
823.67
C12H9Ag3As2N2O12
846.66
C12H8Ag4As2N2O12
953.52
space group
a [Å]
Pbcn
P1
P21/c
P1
P21
̅
̅
8.436(5)
7.843(5)
23.140(14)
90
5.939(3)
11.086(5)
12.822(6)
84.902(9)
87.198(11)
84.968(9)
836.9(6)
2
15.988(5)
15.673(4)
7.460(2)
90
6.680(3)
8.387(3)
17.250(7)
79.226(11)
87.677(10)
79.746(9)
934.1(6)
2
10.409(11)
5.664(6)
16.460(19)
90
b [Å]
c [Å]
α [deg]
β [deg]
γ [deg]
V [Å3]
Z
Dcalcd [g·cm−3
μ(Mo Kα) (mm−1
GOF on F2
90
93.839(5)
90
94.059(19)
90
90
1531.1(15)
4
1865.2(9)
4
968.1(18)
2
]
2.065
2.911
2.933
3.010
3.271
)
4.419
7.422
6.697
6.700
7.448
1.045
0.955
1.030
1.104
1.039
a
R1, wR2 [I > 2σ(I)]
0.0349, 0.0835
0.0410, 0.0870
0.0320, 0.0564
0.0425, 0.0603
0.0454, 0.0940
0.0626, 0.1035
0.0513, 0.0824
0.0693, 0.0915
0.0668, 0.1256
0.0988, 0.1453
a
R1, wR2 (all data)
a
R1 = ∑||Fo| − |Fc||/∑|Fo|, wR2 = {∑w[(Fo)2 − (Fc)2]2/∑w[(Fo)2]2}1/2
.
to a Parr Teflon-lined autoclave (23 mL) and heated at 140 °C for 6
days. Crystals of 1 were obtained as the major phase with a small
amount of unidentified yellow impurity. The impurity was removed
through ultrasound vibration and sieving. The crystals were recovered
in about 54% yield (based on phenylarsonic acid), and the purity of
the sample was confirmed by powder XRD (Supporting Information,
occurred. By selecting 4-hydroxy-3-nitrophenylarsonic acid as
the arsonic ligand and Ag(CH3COO) as the Ag+ source,
[Ag3(HL5)(H2L5)] (3) (H3L5 = 3-NO2-4-OH-C6H3-AsO3H2)
and [Ag2(HL5)] (4) were isolated. They form four different
types of layered structures. Herein, we report their syntheses,
crystal structures, and luminescent properties.
Figure S1). Elem. anal. calcd (%) for C13H10O5NAs2Ag3 (Mr
=
733.67): C, 21.28; H, 1.37; N, 1.91. Found: C, 21.10; H, 1.55; N, 2.06.
IR data for 1 (KBr, cm−1): 3054(m), 2343(m), 2139(w), 1600(m),
1484(w), 1438(s), 1385(w), 1221(m), 1095(m), 906(s), 738(s),
693(m), 474(m).
EXPERIMENTAL SECTION
■
Materials and Methods. All chemicals except that of acetonitrile
were obtained from commercial sources and used without further
purification. Acetonitrile was dried with a 4 Å molecular sieve prior to
use. Elemental analyses were performed on a German Elementary
Vario EL III instrument. The FT−IR spectra were recorded on a
Nicolet Magna 750 FT−IR spectrometer using KBr pellets in the
range of 4000−400 cm−1. Thermogravimetric analyses were carried
out on a NETZSCH STA 449F unit at a heating rate of 10 °C/min
under an oxygen atmosphere. X-ray powder diffraction (XRD)
patterns (Cu−Kα) were collected on a Rigaku MiniFlex II
diffractometer. Photoluminescence studies for compounds 1 and 2
were performed on an Edinburgh FLS920 fluorescent spectrometer.
Synthesis of [Ag3(L3)(CN)] (1). A mixture of AgNO3 (0.3 mmol)
and phenylarsonic acid (0.2 mmol) in 2 mL of acetonitrile was sealed
Synthesis of [Ag3(L4)(CN)] (2) and H2L4. A mixture of AgNO3
(0.2 mmol) and 2-nitrophenylarsonic acid (0.1 mmol) in 2 mL of
acetonitrile was sealed to a Parr Teflon-lined autoclave (23 mL) and
heated at 120 °C for 2 days, then cooled to room temperature (RT)
slowly. A mixture of two types of single crystals, [Ag3(L4)(CN)] and
H2L4, were obtained. When the reaction time was prolonged to 6 days,
pure plate-like crystals of compound 2 were collected in a yield of
about 59% (based on 2-nitrophenylarsonic acid). Its purity was
confirmed by powder XRD study (Supporting Information, Figure
S1). Elem. anal. calcd (%) for C13H8O9N3As2Ag3 (Mr = 823.67): C,
18.96; H, 0.98; N, 5.10. Found: C, 19.20; H, 1.13; N, 5.25. IR data for
2 (KBr, cm−1): 3066(w), 2735(m), 2321(m), 2140(w), 1599(m),
1844
dx.doi.org/10.1021/ic301935g | Inorg. Chem. 2013, 52, 1843−1853

Inorganic Chemistry
Article
Table 2. Important Bond Lengths (Å) for H2L4 and
Compounds 1−4
Information, Figure S1). Elem. anal. calcd (%) for C12H9O12N2As2Ag3
(Mr = 846.66): C, 17.02; H, 1.07; N, 3.31. Found: C, 17.27; H, 1.17;
N, 3.39. IR data for 3 (KBr, cm−1): 3432(s), 2318(w), 1610(s),
1532(s), 1410(w), 1326(m), 1248(s), 1153(m), 1094(m), 897(w),
832(w), 773(w), 624(w), 546(w).
a
H2L4
As(1)−O(1)
As(1)−O(2)
N(1)−O(4)
N(1)−C(2)
1.636(2)
1.677(2)
1.220(4)
1.470(4)
As(1)−O(3)
As(1)−C(1)
N(1)−O(5)
1.7588(14)
1.920(3)
1.221(3)
Synthesis of [Ag2(HL5)] (4). A mixture of Ag(CH3COO) (0.2
mmol) and 4-hydroxy-3-nitrophenylarsonic acid (0.1 mmol) in 2 mL
of acetonitrile was sealed to a Parr Teflon-lined autoclave (23 mL) and
heated at 100 °C for 4 days. Very thin plate-like crystals of 4 were
recovered in about 73% yield (based on 4-hydroxy-3-nitrophenylar-
sonic acid). It is worthy to note that when the reaction temperature
was raised to 120 °C, compound 3 will be obtained. The purity of 4
was confirmed by powder XRD studies (Supporting Information,
Figure S1). Elem. anal. calcd (%) for C12H8O12N2As2Ag4 (Mr =
953.52): C, 15.12; H, 0.84; N, 2.94. Found: C, 15.28; H, 0.97; N, 2.97.
IR data for 4 (KBr, cm−1): 3412(vs), 2920(w), 2323(w), 1610(s),
1542(m), 1442(w), 1363(w), 1334(m), 1262(s), 1152(m), 1095(w),
903(w), 874(w), 832(m), 714(m), 627(w), 533(w).
Compound 1
Ag(1)−O(1)
Ag(1)−O(5)#1
Ag(1)−N(1)
2.236(3)
2.519(3)
2.105(4)
2.149(3)
2.035(5)
2.248(4)
2.334(3)
2.494(3)
As(1)−O(1)
As(1)−O(2)
As(1)−O(3)
As(2)−O(5)
As(2)−O(4)
As(2)−O(3)
N(1)−C(13)
1.656(3)
1.655(3)
1.757(3)
1.654(3)
1.661(3)
1.767(3)
1.136(6)
Ag(2)−O(2)
Ag(2)−C(13)#2
Ag(3)−O(5)#1
Ag(3)−O(4)
Ag(3)−O(2)#3
X-ray Crystallography. Data collections were performed on either
a Rigaku Saturn 724 CCD diffractometer (for 1 and 2) or a Rigaku
Mercury CCD diffractometer (for H2L4, 3 and 4). Both
diffractometers were equipped with graphite-monochromated Mo−
Kα radiation (λ = 0.71073 Å). Intensity data for all four compounds
were collected by the narrow frame method at 293 K. The five data
sets were corrected for Lorentz and polarization factors as well as for
absorption by the Multiscan method.15a All five structures were solved
by the direct methods and refined by full-matrix least-squares fitting on
F2 using SHELX-97.15b All non-hydrogen atoms were refined with
anisotropic thermal parameters except that O6, O9 in complex 2 and
O1, O3, O6, O7 in complex 4 were refined with ISOR restraints.
Without these restraints, these atoms will be nonpostive-definite when
refined anistropically. All hydrogen atoms associated with phenyl ring
and hydroxyl groups were located at geometrically calculated positions
and refined with isotropic thermal parameters. The structures were
also checked for possible missing symmetry with PLATON.15c The
refined Flack parameter of chiral compound 4 is 0.02(5), indicating
the correctness of its absolute structure. The refinements of compound
4 are not so good because of the poor quality of its single crystals with
a thin plate shape, though several data sets were collected on several
different crystals, results showed little improvement. Crystallographic
data and structural refinements for compounds 1−4 as well as H2L4
are summarized in Table 1. Important bond lengths are listed in Table
2. More details on the crystallographic studies are given as Supporting
Information.
Compound 2
Ag(1)−C(13)#1
Ag(1)−O(4)#2
Ag(1)−O(1)
Ag(1)−O(2)#3
Ag(2)−C(13)#4
Ag(2)−O(2)
Ag(2)−N(3)
Ag(2)−O(4)#5
Ag(3)−O(5)
2.124(7)
2.284(4)
2.365(5)
2.505(4)
2.221(6)
2.286(4)
2.318(6)
2.434(5)
2.250(5)
2.254(4)
Ag(3)−N(3)#5
Ag(1)−Ag(2)#2
As(1)−O(1)
As(1)−O(2)
As(1)−O(3)
As(2)−O(5)
As(2)−O(4)
As(2)−O(3)
N(3)−C(13)
2.479(6)
2.7674(9)
1.637(4)
1.648(4)
1.752(5)
1.641(4)
1.655(4)
1.757(4)
1.145(8)
Ag(3)−O(1)#6
Compound 3
Ag(1)−O(1)
Ag(1)−O(7)
2.195(5)
2.205(5)
2.517(5)
2.524(5)
2.271(5)
2.381(5)
2.444(5)
2.470(5)
2.221(5)
Ag(3)−O(9)
Ag(3)−O(2)#4
As(1)−O(1)
As(1)−O(2)
As(1)−O(3)
As(2)−O(7)
As(2)−O(8)
As(2)−O(9)
2.291(5)
2.385(5)
1.684(5)
1.665(5)
1.721(5)
1.679(5)
1.672(5)
1.709(5)
Ag(1)−O(8)#1
Ag(1)−O(3)#2
Ag(2)−O(2)#1
Ag(2)−O(8)#3
Ag(2)−O(7)
Ag(2)−O(8)#1
Ag(3)−O(1)#2
Compound 4
Ag(1)−O(3)
2.175(12)
2.230(10)
2.468(12)
2.262(12)
2.292(11)
2.411(13)
2.492(12)
2.166(11)
2.213(11)
2.414(12)
Ag(4)−O(1)#3
Ag(4)−O(8)#2
Ag(4)−O(9)
Ag(4)−O(7)#1
As(1)−O(1)
As(1)−O(2)
As(1)−O(3)
As(2)−O(7)
As(2)−O(8)
As(2)−O(9)
2.195(11)
2.209(10)
2.410(13)
2.508(11)
1.682(11)
1.664(12)
1.671(14)
1.670(10)
1.677(13)
1.656(11)
Ag(1)−O(7)#1
Ag(1)−O(2)#2
Ag(2)−O(3)
Ag(2)−O(9)#3
Ag(2)−O(2)#3
Ag(2)−O(1)#2
Ag(3)−O(8)#1
Ag(3)−O(2)
RESULTS AND DISCUSSION
■
Compounds 1−4 have been synthesized in acetonitrile under
solvothermal condition. They represent the first structurally
Ag(3)−O(7)#4
a
Symmetry transformations used to generate equivalent atoms: For 1:
#1, −x+1, −y, −z+1; #2, −x, −y−1, −z+1; #3, −x, −y, −z+1. For 2:
#1, x, −y+1/2, z−1/2; #2, x, y, z−1; #3, −x+2, −y, −z+1; #4, x, −y
+1/2, z+1/2; #5, −x+2, −y, −z+2; #6, x, −y−1/2, z+1/2. For 3: #1,
−x, −y, −z+1; #2, −x, −y+1, −z+1; #3, x+1, y, z; #4, −x−1, −y+1, −z
+1. For 4: #1, −x+1, y+1/2, −z; #2, x, y+1, z; #3, −x+2, y+1/2, −z;
#4, −x+1, y−1/2, −z.
Figure 1. View of H2L4 with 50% probability displacement ellipsoids.
H atoms are shown as small spheres of arbitrary radii. Symmetry codes
for the generated atoms: (a) −x, y, −z + 3/2.
1530(s), 1430(w), 1347(s), 1295(m), 1167(w), 1114(m), 1053(w),
918(s), 864(s), 826(m), 789(m), 747(m), 688(w), 484(w), 419(w).
Synthesis of [Ag3(HL5)(H2L5)] (3). A mixture of Ag(CH3COO)
(0.3 mmol) and 4-hydroxy-3-nitrophenylarsonic acid (0.2 mmol) in 3
mL of acetonitrile was sealed to a Parr Teflon-lined autoclave (23 mL)
and heated at 100 °C for 4 days. Yellow plate-like crystals were
recovered in about 84% yield (based on 4-hydroxy-3-nitrophenylar-
sonic acid). Its purity was confirmed by powder XRD (Supporting
characterized Ag(I) arsonates. For compounds 1 and 2, the new
arsonate ligands with As−O−As linkages were formed by
condensation of two corresponding arsonate ligands with the
release of one mole of water (Scheme 1). It is noted that the
1845
dx.doi.org/10.1021/ic301935g | Inorg. Chem. 2013, 52, 1843−1853

Inorganic Chemistry
Article
Figure 2. View of the 2D layered hydrogen bonding network of H2L4 (a) and the packing structure of H2L4 along b axis (b). The hydrogen bonding
interactions are represented by dashed lines.
As linkage, the reaction of phenylarsonic acid (or 2-nitro-
phenylarsonic acid) in the presence of small amounts of AgNO3
produced the condensed product, confirming that the
polyarsonate ligands were formed in a metal-mediated
thermally induced process. Furthermore, the CN− anions in
compounds 1 and 2 formed by in situ decomposition of the
acetonitrile molecules. A similar process had been reported
during the preparation of the metal pyrophosphonates.16,17 So
far, only two examples of metal pyroarsonates have been
reported in the literature.18
Syntheses. The reaction conditions for complexes 1−4
have been listed in Supporting Information, Table S1.
Additional experiments have been also performed to explore
the effects of Ag+ source, the amount of acetonitrile,
temperature, and reaction time on the compositions and
structures of the final products formed.
Figure 3. ORTEP representation of the selected unit in compound 1.
The thermal ellipsoids are drawn at 50% probability level. Symmetry
codes for the generated atoms: (a) −x+1, −y, −z+1; (b) −x, −y−1, −z
+1; (c) −x, −y, −z+1.
For 1, when Ag(CH3COO) was used as the Ag+ source,
crystals of 1 can be isolated along with a lot of black impurities.
Using AgNO3 as the Ag+ source led to the isolation of the pure
phase of 1. It is also found that elongation of the reaction time
helps to enhance the yield. 2 can be synthesized under shorter
reaction time, lower temperature, and higher yield compared
reaction of phenylarsonic acid (or 2-nitrophenylarsonic acid)
alone under the same condition yields no species with As−O−
1846
dx.doi.org/10.1021/ic301935g | Inorg. Chem. 2013, 52, 1843−1853

Inorganic Chemistry
Article
Scheme 2. Coordination Modes of the Ligands in Compounds 1(a), 2(b), 3(c), and 4(d)
with those of 1. When Ag(CH3COO) was used as Ag+ source,
the crystals of 2 could not be isolated. For the syntheses of 3
and 4, the metal/ligand molar ratios applied and reaction
temperatures are important. At 100 °C, when the metal/ligand
molar ratio is 3:2, the resulting product will be 3; when the
metal/ligand molar ratio is 2:1, the resulting product will be 4.
At a higher reaction temperature of 120 °C, 3 will be obtained
regardless if the Ag(CH3COO)/H3L5 molar ratio is 3:2 or 2:1.
The amount of acetonitrile added affects the yield and
morphology of the crystals of 3. When AgNO3 was used as
Ag+ source in these reactions, only unknown red-brown power
was obtained. According to our experiments, it is best to
control the amount of acetonitrile to be 2−3 mL for all four
complexes.
distance of the As−O(3)−As bridge is significantly larger than
those of the four terminal As−O bonds. O(2) is protonated
hence As(1)−O(2) is significantly longer than that of As(1)−
O(1). As shown in Figure 2, each independent H2L4 unit
connects with 4 neighboring H2L4 molecules through strong
O−H···O hydrogen bonds (Supporting Information, Table S2)
to form a 2D sheet (Figure 2a). The interlayer distance is close
́
to 11.6 Å (half of the c-axis). These 2D layers are further cross-
linked by weak π···π interactions between the phenyl rings
(Figure 2b).
Structure of [Ag3(L3)(CN)] (1). Compound 1 crystallizes in
the triclinic space group P1 and features a 2D wave-like layer
̅
parallel to the ab plane. Its asymmetric unit consists of three
Ag(I) ions, one {L3}2− and one CN− anions. As shown in
Figure 3, Ag1 is three-coordinated by two arsonate oxygen
atoms from two different {L3}2− anions, and one nitrogen atom
from a CN− anion. Ag2 is two-coordinated by one arsonate
oxygen atom and one carbon atom from a CN− anion. Ag3 is
three-coordinated by three arsonate oxygen atoms from three
different {L3}2− anions. Both Ag1 and Ag3 are in a trigonal
coordination geometry. The Ag−O distances are in the range of
2.149(3)−2.519(3) Å, which are comparable to those reported
in Ag(I) phosphonates.16,19 Each {L3}2− anion connects six
Ag(I) ions. O2 and O5 are bidentate bridging whereas O1 and
O4 is unidentate, O3 forms a As−O−As bridge and it is not
coordinated to the silver ion (Scheme 2a). Each CN− anion
bridges two Ag(I) ions by using its nitrogen and carbon atoms,
with the angles of Ag1−C−N and C−N−Ag2 of 173.7(4)° and
172.7(5)°, respectively. The Ag1−C−N−Ag2 is almost in a
straight line.
It is also interesting to note that the condensation reactions
of the arsonate ligands occurred for 1 and 2 but not for 3 and 4.
We suspect it may be due to the number and nature of the
substituents on the benzene rings of the arsonate ligands. The
Ph-AsO3H2 has only one -AsO3 group on its benzene ring and
2-NO2-C6H4-AsO3H2 contains an additional ortho-nitro group
whereas the benzene ring of 3-NO2-4-OH-C6H3-AsO3H2
contains additional meta-nitro and para-OH groups. It is
known that the nitro group is electron withdrawing whereas the
hydroxyl group is electron donating. Furthermore the nitro
group on the ortho-position can withdraw eletrons more
effectively than that of meta-position. An electron withdrawing
group will enhance the reactivity of the organic ligand whereas
an electron donating group lowered the reactivity of an organic
ligand. Hence the reactivities of the three arsonate ligands have
the following order: 2-NO2-C6H4-AsO3H2 > Ph-AsO3H2 > 3-
NO2-4-OH-C6H3-AsO3H2. Therefore the condensation reac-
tion for 3-NO2-4-OH-C6H3-AsO3H2 does not occur easily.
Structure of H2L4. H2L4 crystallizes in the orthorhombic
space group Pbcn, and its crystal structure features a 2D
hydrogen bonded supramolecular sheet. Its asymmetric unit
contains half of the H2L4 molecule (Figure 1). The As−O
The interconnection of Ag(I) ions by chelating {L3}2− anions
resulted in an infinite chain along the a axis. Within the 1D
chain, six coplanar Ag(I) ions are bridged by two arsonate
ligands into a hexanuclear cluster unit with moderate Ag···Ag
interactions [3.144(1)−3.262(1) Å] (Figure 4a). Neighboring
1D chains are further interconnected by CN− anions via the
coordination of the nitrogen and carbon atoms with the Ag(I)
́
distances range from 1.632(2) to 1.759(2) Å. The As−O
1847
dx.doi.org/10.1021/ic301935g | Inorg. Chem. 2013, 52, 1843−1853

Inorganic Chemistry
Article
Figure 4. View of the infinite chain of Ag(I) ions by chelating {L3}2− anions and a six-membered ring of Ag(I) ions in one plane within the chain (a),
and the packing structure of 1 along a axis (b). All H atoms are omitted for clarity.
Structure of [Ag3(L4)(CN)] (2). Compound 2 crystallizes in
the monoclinic space group P21/c and features a 2D wave-like
layer paralell to the bc plane. Its asymmetric unit consists of
three Ag(I) ions, one {L4}2− and one CN− anions. As shown in
Figure 5, Ag1 is four-coordinated by three arsonate oxygen
atoms from three different {L4}2− anions, and one carbon atom
from a CN− anion. Ag2 is four-coordinated by two arsonate
oxygen atoms from two {L4}2− anions, one carbon and one
nitrogen atom from two different CN− anions. Ag3 is three-
coordinated by two arsonate oxygen atoms from two different
{L4}2− anions and one nitrogen atom from a CN− anion. Ag1
and Ag2 adopt distorted tetrahedral geometry whereas Ag3
adopts a trigonal geometry. The Ag−O, Ag−N, and Ag−C
Figure 5. ORTEP representation of the selected unit in compound 2.
The thermal ellipsoids are drawn at 50% probability level. Symmetry
codes for the generated atoms: (a) x, −y+1/2, z−1/2; (b) x, y, z−1;
(c) −x+2, −y, −z+1; (d) x, −y+1/2, z+1/2; (e) −x+2, −y, −z+2; (f)
x, y, z+1; (g) x, −y−1/2, z+1/2; (h) x, −y−1/2, z−1/2.
́
bond distances are in the ranges of 2.250(5)−2.505(4) Å,
́
́
2.318(6)−2.479(6) Å, and 2.124(7)−2.221(6) Å, respectively.
Each {L4}2− anion connects 7 Ag(I) ions. Three of the arsonate
oxygens, O1, O2, and O4, are bidentate and each bridges with
two Ag(I) ions. O5 is unidentate and bonds with a Ag(I) ion
whereas O3 of the As−O−As involves no metal coordination
(Scheme 2b). The coordination mode of CN− is very different
from that of compound 1. Each CN− anion bridges with four
Ag(I) ions, both nitrogen and carbon atoms are bidentate.
ions from neighboring chains into a wave-like layer with the
phenyl groups orientated toward the interlayer space (Figure
4b).
1848
dx.doi.org/10.1021/ic301935g | Inorg. Chem. 2013, 52, 1843−1853

Inorganic Chemistry
Article
Figure 6. View of the 2D hybrid layer of 2 paralell to the bc plane (a), the packing structure of 2 along b axis (b). All H atoms are omitted for clarity.
bc plane. The interconnection of the Ag(I) ions by bridging
{L4}2− anions form the main skeleton of the layer with Ag3As3
rings which are filled by the CN− anions (Figure 6a). The
Ag···Ag contact of 2.7674(9) Å for the Ag−C−Ag bridge is
significantly shorter than the Ag···Ag separation of 2.88 Å in the
metallic state.20 The overall structure can be described as wave-
like layers stacking along the a axis, with the phenyl groups and
noncoordination nitro groups oriented toward the interlayer
space (Figure 6b).
Structure of [Ag3(HL5)(H2L5)] (3). The structure of 3
features a Ag(I) arsonate 2D layer. As shown in Figure 7, its
asymmetric unit consists of three Ag(I) ions, one {HL5}2−, and
one {H2L5}− anions. Ag1 is four-coordinated by four arsonate
Figure 7. ORTEP representation of the selected unit in compound 3.
The thermal ellipsoids are drawn at 50% probability level. Symmetry
oxygen atoms from two {HL5}2− and two {H2L5}− anions
codes for the generated atoms: (a) −x, −y, −z+1; (b) −x, −y+1, −z
whereas Ag2 is four-coordinated by four arsonate oxygen atoms
+1; (c) x+1, y, z; (d) −x−1, −y+1, −z+1; (e) x−1, y, z.
from three {HL5}2− and one {H2L5}− anions, and Ag3 is three-
coordinated by three arsonate oxygen atoms from two {HL5}2−
The Ag(I) ions are interconnected by bridging {L4}2− and
CN− anions into a complicated 2D hybrid layer paralell to the
and one {H2L5}− anions. The Ag−O distances are in the range
of 2.195(5)−2.524(5) Å, which are comparable to those
1849
dx.doi.org/10.1021/ic301935g | Inorg. Chem. 2013, 52, 1843−1853

Inorganic Chemistry
Article
Figure 8. View of the hexanuclear {Ag6O12} clusters interconnected by bridging arsonic groups into a silver(I) arsonate hybrid layer in compound 3
(a), view of the packing structure of 3 along a axis (b). All H atoms are omitted for clarity.
anion acts as hexadentate metal linker, O7, O8, and O9 bridge
with two, three, and one Ag(I) ions, respectively (Scheme 2c).
As shown in Figure 8a, the three types of Ag(I) ions are
interconnected by bridging arsonate oxygens, resulting in the
formation of hexanuclear {Ag6O12} clusters. Such hexanuclear
clusters are further interconnected by arsonate groups into a
2D silver(I) arsonate layer. The organic groups are orientated
toward the interlayer space (Figure 8b). Intralayer hydrogen
bonds are formed between the −OH and −NO2 groups in both
{HL5}2− and {H2L5}− anions (Supporting Information, Table
S2).
Structure of [Ag2(HL5)] (4). Compound 4 crystallizes in
the monoclinic space group P21 and features a Ag(I) arsonate
layer as well. The structure of 4 differs significantly from that of
compound 3. As shown in Figure 9, there are four different
Figure 9. ORTEP representation of the selected unit in compound 4.
Ag(I) atoms in each asymmetric unit. Both Ag1 and Ag3 are
The thermal ellipsoids are drawn at 50% probability level. Symmetry
three-coordinated by three arsonate oxygen atoms from three
codes for the generated atoms: (a) −x+1, y+1/2, −z; (b) x, y+1, z; (c)
different {HL5}2− anions, adopting trigonal geometries, whereas
−x+2, y+1/2, −z; (d) −x+2, y−1/2, −z; (e) −x+1, y−1/2, −z; (f) x,
Ag2 and Ag4 are four-coordinated by four different {HL5}2−
y−1, z.
anions in a distorted tetrahedral geometry. The Ag−O
distances are in the range of 2.18(1)−2.49(1) Å. There are
two {HL5}2− anions in each asymmetric unit. Both of them
bridge with seven Ag(I) ions, two of the arsonate oxygens are
bidentate whereas the third one is tridentate (Scheme 2d). The
hydroxyl and nitro groups are not involved in metal
coordination.
reported in Ag(I) phosphonates.19 The two arsonate ligands are
different in charge and coordination mode. The {HL5}2− anion
containing As(2) is −2 in charge whereas the {H2L5}− anion
containing As(1) is −1 in charge. The O3 atom is protonated
and exhibits a longer As−O distance. Both {HL5}2− and
{H2L5}− anions contain a hydroxyl group on the phenyl ring.
The {H2L5}− anion is pentadentate, O1 and O2 are bidentate
bridging, and the protonated O3 is monodentate. The {HL5}2−,
The Ag(I) ions are interconnected by bidentately and
tridentately bridging arsonate oxygens into right-handed
{Ag4O4} chains. These chains are further interconnected by
1850
dx.doi.org/10.1021/ic301935g | Inorg. Chem. 2013, 52, 1843−1853

Inorganic Chemistry
Article
Figure 10. View of the right-handed {Ag4O4} chains interconnected by Ag−O−Ag bridges and arsonate ligands into a silver(I) arsonate layer in
compound 4 (a), a view of the layers of 4 stacking along b axis (b).
but form a dihedral angle of 52.5°. Similar to that in compound
3, an intra ligand hydrogen bond is formed between hydroxyl
and nitro groups (Figure 10b).
TGA Study. The thermal gravimetric analyses (TGA) of
compounds 1−4 were carried out at a heating rate of 10 °C/
min under an air atmosphere (Figure 11). Compound 1 is
stable to about 280 °C, then it exhibits two main steps of
weight losses, corresponding to the combustion of organo
arsonate and CN− ligands. Compounds 2−4 exhibit a small
weight loss before 210 °C, which is probably attributed to the
release of the small amount of surface water present in the
samples. Compound 2 exhibits a very rapid weight loss from
250 to 500 °C, which corresponds to the combustion of {L4}2−
and CN− ligands. The decomposition profiles for 3 and 4 are
similar in the 280−800 °C region, consisting of two main
Figure 11. TGA curves for compounds 1−4.
weight losses attributed to the decomposition of organo
arsonate ligands. Compounds 1−4 exhibit the final plateau
almost at the same temperature of about 500 °C, and all the
final residues shine with a metallic luster. These residues are
assumed to be silver metal, and the observed weights of final
products (45.8% for 1, 40% for 2, 41.3% for 3 and 48.9% for 4)
are close to the calculated values (44.1% for 1, 39.8% for 2,
38.2% for 3, and 45.3% for 4).
organoarsonate ligands as well as additional Ag−O−Ag bridges
into novel silver(I) arsonate layers (Figure 10a). The phenyl
groups, hydroxyl and nitro substitute groups on the phenyl
rings of the arsonate ligands are oriented toward the interlayer
region. Unlike the paralell arrangements in compound 3, these
phenyl groups in compound 4 are not paralell to each other,
1851
dx.doi.org/10.1021/ic301935g | Inorg. Chem. 2013, 52, 1843−1853

Inorganic Chemistry
Article
noteworthy that the luminescence intensity of compound 1 is
much stronger than that of 2 (Complex 2 exhibits no emission
at RT.) and a band with higher emission energy is observed for
2. This may be mainly attributed to the substituent of -NO2 in
compound 2, which results in a smaller π-conjugated system in
the ligand and a larger gap between the highest occupied
molecular orbital (HOMO) and the lowest unoccupied
molecular orbital (LUMO).24
More interestly, 1 shows a temperature-dependent emission.
Upon cooling to 10 K, a blue shift of 16 nm for the higher-
energy (HE) emission and a blue shift of 67 nm for the lower-
energy (LE) emission are observed compared with those
measured at RT (Figure 12a). The excitation maximum
remains almost unchanged during cooling (375 nm at RT
and 372 nm at 10 K). Similar blue shifts of emissions at low
temperature have been found in other d10 transition metal
complexes.25a−d It has been reported that the slight distortion
of coordination geometry of the central metal ions and
shrinkage of the unit cell at low temperatures might cause
significant changes for the emission bands (blue shift or red
shift).25b−f In the absence of crystallographic data for 1 at 10 K,
we can only assume that in complex 1, the blue shifts of these
emissions may result from the distortion of the coordination
geometry of Ag(I) ions and the slight changes in the average
geometry of the complex during cooling. In addition, the
enhancement of emission is found to be more obvious in the
LE emission band than that in the HE one at 10 K. The HE
emission appears to depend on the ligand being π-unsaturated
while the more intense LE band originates from the Ag(I)
cluster-based centers. As temperature decreased, the rigidity of
the ligands should be enhanced,25b,c thereby the radiationless
decay of the intraligand (π···π*) excited state is reduced and
the delocalization of electron transitions increases. As a result,
the LMCT in complex 1 becomes more efficient at low
temperature and then the LE emission is much more enhanced
than that of the HE emission.
Figure 12. Solid-state emission spectra of compounds 1 (a) and 2 (b)
at 10 K and RT.
CONCLUSIONS
■
Luminescent Properties. The solid-state photolumines-
cent spectra of compounds 1−4 as well as the free ligands were
measured at room temperature (RT) and 10 K. Compound 1
exhibits a sharp red light emission band at 618 nm and a weak
peak at 446 nm (λex = 372 nm) at 10 K, and compound 2
displays a broad orange-red light emission band at 583 nm (λex
= 434 nm) at 10 K (Figure 12b). The luminescences for 3 and
4 are too weak to be observed. The solid-state lifetimes are 9
and 0.5 ns, respectively for 1 and 2, suggestive of their
fluorescent characters. Compared with the emission of free
phenylarsonic acid (λex = 280 nm, λem = 475 nm) and 2-
nitrophenylarsonic acid (no obvious luminescence) in the solid
state at 10 K, the luminescence of 1 and 2 can be attributed to
the Ag(I) cluster-based centers therein.14,21,22 Given the
oxidizing nature of Ag(I), a approprite assignment for the
origin of the emission involves excited states derived from
ligand-to-metal charge transfer (LMCT) transitions mixed with
d-s/d-p character. Furthermore, the shortest Ag(I)···Ag(I)
distance in 1 is 3.144(1) Å and only 2.7674(9) Å in 2, which
indicate strong Ag(I)···Ag(I) interactions. Since the lumines-
cence of d10 systems has a demonstrated sensitivity to metal−
metal interactions, the existence of Ag(I)···Ag(I) interactions is
expected to play a role in the solid state emission, which are
likely responsible for the low energies of the luminescence
bands of compounds 1 and 2.14,22b,23 In addition, it is
In summary, four new types of Ag(I)-mediated organoarsonates
were obtained under solvothermal conditions. The structures of
compounds 1−2 were constructed by in situ generated
{RAsO2(O)O2AsR}2− and CN− anions, indicating the
occurrence of in situ C−C bond cleavages of the acetonitrile
molecules. Both 1 and 2 feature a 2D wave-like layer with short
Ag(I)···Ag(I) contacts. Compounds 3 and 4 feature a Ag(I)
arsonate 2D layer as well, but compound 4 results in a chiral
generation. Complexes 1−2 display unusual photoluminescent
properties in the red/orange-red region at the low temperature
of 10 K, which may be assigned to be an admixture of LMCT
and metal-centered (4d-5s/5p) transitions perturbed by
Ag(I)···Ag(I) interactions. In addition, upon cooling from RT
to 10 K, compound 1 exhibits interesting temperature-
dependent emissions. Further work on pyroarsonates generated
in situ will continue in our laboratory.
ASSOCIATED CONTENT
■
S
* Supporting Information
X-ray crystallographic files in CIF format, simulated and
experimental XRD powder patterns, IR spectra, morphologies
and detailed data for hydrogen bonds. This material is available
free of charge via the Internet at http://pubs.acs.org.
1852
dx.doi.org/10.1021/ic301935g | Inorg. Chem. 2013, 52, 1843−1853

Inorganic Chemistry
Article
́
(13) (a) Alvarez-Corral, M.; Munoz-Dorado, M.; Rodríguez-García, I.
̃
AUTHOR INFORMATION
Corresponding Author
*E-mail: mjg@fjirsm.ac.cn. Fax: (+86)591-83714946.
Notes
■
Chem. Rev. 2008, 108, 3174. (b) Naodovic, M.; Yamamoto, H. Chem.
Rev. 2008, 108, 3132.
(14) (a) Ford, P. C.; Vogler, A. Acc. Chem. Res. 1993, 26, 220.
(b) Yam, V. W. W.; Lo, K. K. W. Chem. Soc. Rev. 1999, 28, 323.
(15) (a) CrystalClear, version 1.3.5; Rigaku Corp.: Woodlands, TX.,
1999. (b) Sheldrick, G. M. SHELXTL, Crystallographic Software
Package, SHELXTL Version 5.1; Bruker-AXS: Madison, WI, 1998.
(c) Spek, A. L. J. Appl. Crystallogr. 2003, 36, 7.
(16) (a) Guo, L. R.; Bao, S. S.; Li, Y. Z.; Zheng, L. M. Chem.
Commun. 2009, 2893. (b) Guo, L. R.; Tong, J. W.; Liang, X.; Kohler,
J.; Nuss, J.; Li, Y. Z.; Zheng, L. M. Dalton Trans. 2011, 40, 6392.
(17) (a) Guo, L. R.; Bao, S. S.; Li, Y. Z.; Zheng, L. M. Chem.
Commun. 2009, 2893. (b) Guo, L. R.; Tong, J. W.; Liang, X.; Kohler,
J.; Nuss, J.; Li, Y. Z.; Zheng, L. M. Dalton Trans. 2011, 40, 6392.
(18) (a) Salta, J.; Chang, Y. D.; Zubieta, J. J. Chem. Soc., Chem.
Commun. 1994, 1039. (b) Mason, M. R.; Matthews, R. M.; Mashuta,
M. S.; Richardson, J. F. Inorg. Chem. 1997, 36, 6476.
(19) (a) Sagatys, D. S.; Dahlgren, C.; Smith, G.; Bott, R. C.; White, J.
M. J. Chem. Soc., Dalton Trans. 2000, 3404. (b) Singleton, R.; Bye, J.;
Dyson, J.; Baker, G.; Ranson, R. M.; Hix, G. B. Dalton Trans. 2010, 39,
6024. (c) Zavras, A.; Fry, J. A.; Beavers, C. M.; Talbo, G. H.; Richards,
A. F. CrystEngComm 2011, 13, 3551.
(20) (a) Zheng, S. L.; Zhang, J. P.; Wong, W. T.; Chen, X. M. J. Am.
Chem. Soc. 2003, 125, 6882. (b) Wang, C. M.; Wu, Y. Y.; Chang, Y.
W.; Lii, K. H. Chem. Mater. 2008, 20, 2857.
(21) (a) Yang, J. H.; Zheng, S. L.; Yu, X. L.; Chen, X. M. Cryst.
Growth Des. 2004, 4, 831. (b) Yan, C.; Chen, L.; Feng, R.; Jiang, F.;
Hong, M. CrystEngComm 2009, 11, 2529. (c) Hu, M.; Zhang, Q.;
Zhou, L. M.; Fang, S. M.; Liu, C. S. Inorg. Chem. Commun. 2010, 13,
1548.
(22) (a) Allendorf, M. D.; Bauer, C. A.; Bhakta, R. K.; Houk, R. J. T.
Chem. Soc. Rev. 2009, 38, 1330. (b) Jin, J. C.; Wang, Y. Y.; Zhang, W.
H.; Lermontov, A. S.; Lermontova, E.; Shi, Q. Z. Dalton Trans. 2009,
10181.
(23) (a) Che, C. M.; Tse, M. C.; Chan, M. C. W.; Cheung, K. K.;
Phillips, D. L.; Leung, K. H. J. Am. Chem. Soc. 2000, 122, 2464.
(b) Omary, M. A.; Patterson, H. H. J. Am. Chem. Soc. 1998, 120, 7696.
(c) Hou, L.; Li, D. Inorg. Chem. Commun. 2005, 8, 128. (d) Sun, D.;
Liu, F. J.; Huang, R. B.; Zheng, L. S. Inorg. Chem. 2011, 50, 12393.
(e) Catalano, V. J.; Munro, L. B.; Strasser, C. E.; Samin, A. F. Inorg.
Chem. 2011, 50, 8465.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This work was supported by the National Natural Science
Foundation of China (Nos. 20973170 and 20825104), the
major project from FJIRSM (SZD09001).
REFERENCES
■
(1) (a) Clearfield, A. Metal Phosphonate Chemistry; John Wiley &
Sons, Inc.: New York, 2007; pp 371−510. (b) Mao, J. G. Coord. Chem.
Rev. 2007, 251, 1493. (c) Matczak-Jon, E.; Videnova-Adrabinska, V.
Coord. Chem. Rev. 2005, 249, 2458. (d) Maeda, K. Microporous
Mesoporous Mater. 2004, 73, 47.
(2) (a) Ngo, H. L.; Lin, W. J. Am. Chem. Soc. 2002, 124, 14298.
(b) Zhu, J.; Bu, X. H.; Feng, P. Y.; Stucky, G. D. J. Am. Chem. Soc.
2000, 122, 11563. (c) Cheetham, A. K.; Ferey, G.; Loiseau, T. Angew.
Chem., Int. Ed. 1999, 38, 3268. (d) Rao, C. N. R.; Natarajan, S.;
Vaidhyanathan, R. Angew. Chem., Int. Ed. 2004, 43, 1466.
(3) (a) Burkholder, E.; Zubieta, J. Inorg. Chim. Acta 2004, 357, 301.
(b) Burkholder, E.; Wright, E.; Golub, V.; O’Connor, C. J.; Zubieta, J.
Inorg. Chem. 2003, 42, 7460. (c) Barkigia, K. M.; Rajkovic-Blazer, L.
M.; Pope, M. T.; Quicksall, C. O. Inorg. Chem. 1981, 20, 3318.
(d) Johnson, B. J. S.; Geers, S. A.; Brennessel, W. W.; Young, V. G.;
Stein, A. Dalton Trans. 2003, 4678. (e) Liu, B.; Ku, Y.; Wang, M.;
Zheng, P. Inorg. Chem. 1988, 27, 3868.
(4) (a) Matsumoto, K. Y. Bull. Chem. Soc. Jpn. 1978, 51, 492. (b) Liu,
B. Y.; Xie, G. Y.; Ku, Y. T.; Wang, X. Polyhedron 1990, 9, 2023.
(c) Khan, M. I.; Zubieta, J. Angew. Chem., Int. Ed. 1994, 33, 760.
(d) Khan, M. I.; Chang, Y.; Chen, Q.; Hope, H.; Parking, S.; Goshorn,
D. P.; Zubieta, J. Angew. Chem., Int. Ed. 1992, 31, 1197. (e) Johnson, B.
J. S.; Schroden, R. C.; Zhu, C. C.; Young, V. G.; Stein, A. Inorg. Chem.
2002, 41, 2213.
(5) (a) Kwak, W.; Rajkovic, L. M.; Stalick, J. K.; Pope, M. T.;
Quicksall, C. O. Inorg. Chem. 1976, 15, 2778. (b) Chang, Y. D.;
Zubieta, J. Inorg. Chim. Acta 1996, 245, 177. (c) Johnson, B. J. S.;
Schroden, R. C.; Zhu, C. C.; Stein, A. Inorg. Chem. 2001, 40, 5972.
(d) Liu, B. Y.; Ku, Y. T.; Wang, X. Inorg. Chim. Acta 1989, 161, 233.
(e) Breen, J. M.; Schmitt, W. Angew. Chem., Int. Ed. 2008, 47, 6904.
(6) (a) DeBurgomaster, P.; Liu, H. X.; O’Connor, C. J.; Zubieta, J.
Inorg. Chim. Acta 2010, 363, 3254. (b) Li, L.; Liu, B.; Xue, G.; Hu, H.;
Fu, F.; Wang, J. Cryst. Growth Des. 2009, 9, 5206. (c) Darling, K.;
Burkholder, E. M.; Pellizzeri, S.; Nanao, M.; Zubieta, J. Inorg. Chem.
Commun. 2011, 14, 1745. (d) Onat, C. I.; Zhang, L.; Clerac, R.; Jean-
Denis, J. B.; Feeney, M.; McCabe, T.; Schmitt, W. Inorg. Chem. 2011,
50, 604. (e) Soghomonian, V.; Slebodnick, C.; Spencer, E. C. Dalton
Trans. 2010, 39, 8652.
(24) Pramanik, S.; Zheng, C.; Zhang, X.; Emge, T. J.; Li, J. J. Am.
Chem. Soc. 2011, 133, 4153.
(25) (a) Kyle, K. R.; Ryu, C. K.; Ford, P. C.; DiBenedetto, J. A. J. Am.
Chem. Soc. 1991, 113, 2954. (b) Zhu, Q.; Sheng, T.; Tan, C.; Hu, S.;
Fu, R.; Wu, X. Inorg. Chem. 2011, 50, 7618. (c) Shan, X. C.; Jiang, F.
L.; Yuan, D. Q.; Wu, M. Y.; Zhang, S. Q.; Hong, M. C. Dalton Trans.
2012, 41, 9411. (d) Matsumoto, K.; Shindo, T.; Mukasa, N.; Tsukuda,
T.; Tsubomura, T. Inorg. Chem. 2010, 49, 805. (e) Kitagawa, H.;
Ozawa, Y.; Toriumi, K. Chem. Commun. 2010, 46, 6302. (f) Braga, D.;
Maini, L.; Mazzeo, P. P.; Ventura, B. Chem.Eur. J. 2010, 16, 1553.
(7) Izarova, N. V.; Dickman, M. H.; Biboum, R. N.; Keita, B.; Nadjo,
L.; Ramachandran, V.; Dalal, N. S.; Kortz, U. Inorg. Chem. 2009, 48,
7504.
(8) (a) Xie, Y. P.; Yang, J.; Ma, J. F.; Zhang, L. P.; Song, S. Y.; Su, Z.
M. Chem.Eur. J. 2008, 14, 4093. (b) Xie, Y. P.; Ma, J. F.; Yang, J.; Su,
Z. M. Dalton Trans. 2010, 39, 1568.
(9) Yi, F. Y.; Song, J. L.; Zhao, N.; Mao, J. G. J. Solid State Chem.
2008, 181, 1393.
(10) (a) Yi, F. Y.; Zhao, N.; Wu, W.; Mao, J. G. Inorg. Chem. 2009,
48, 628. (b) Yi, F. Y.; Xu, H. B.; Zhou, T. H.; Mao, J. G.
CrystEngComm 2011, 13, 1480. (c) Yi, F. Y.; Lin, Q. P.; Zhou, T. H.;
Mao, J. G. J. Mol. Struct. 2010, 984, 416. (d) Yi, F. Y.; Zhou, T. H.;
Mao, J. G. J. Mol. Struct. 2011, 987, 51.
(11) Zhou, T. H.; Zhang, J.; Zhang, H. X.; Feng, R.; Mao, J. G. Chem.
Commun. 2011, 47, 8862.
(12) Qian, X. Y.; Zhang, J. H.; Zhou, T. H.; Mao, J. G. Dalton Trans.
2012, 41, 1229.
1853
dx.doi.org/10.1021/ic301935g | Inorg. Chem. 2013, 52, 1843−1853