Rational synthesis and characterization of two three-dimensional metal-organic frameworks incorporating silver chains and 1,2,3,4,5,6- cyclohexanehexacarboxylate

Article abstract of DOI:10.1002/ejic.200501146

Two new silver polycarboxylate coordination polymers, [Ag ₃(H₃L)(H₂O)₂]_n· 2nH₂O (1) and [Ag₆L(NH₃)(H₂O) ₃]_n·nH₂O (2), have been obtained from the reaction of [Ag(NH₃)₂](OH) (freshly synthesized from Ag₂O and aqueous ammonia) with cis,cis,cis,cis,cis-1,2,3,4,5,6- cyclohexanehexacarboxylic acid (H₆L) by control of the molar ratio of starting materials. The X-ray crystal structure analysis reveals that both of them crystallize in the triclinic space group P1 with a = 6.375(4), b = 9.505(6), c = 15.097(8) A, α = 93.249(14), β = 100.364(15), γ = 96.453(15)°, V = 891.4(9) A³, Z = 2 for 1, and a = 8.0380(7), b = 10.1220(9), c = 13.8458(12) A, α = 76.3450(10), β = 80.9370(10), γ = 68.7230(10)°, V = 1016.83(15) A³, Z = 2 for 2. Complex 1 features a three-dimensional (3D) metal-organic framework (MOF) with one-dimensional (1D) rectangular channels surrounded by carboxylato-supported Ag-Ag dimers, Ag-Ag chains, and half deprotonated [H₃L]^3- ligands. Each [H₃L] ^3- ligand connects eight Ag^I atoms. The weakly coordinated water ligands and lattice water molecules are located at the channels and form interesting 1D hydrogen-bonded T4(2)8(2) water tapes with cyclic R ₈⁶(16) (H₂O)₈ and R₄ ⁴(8) (H₂O)₄ units. Complex 2 is also a 3D MOF structure constructed by two types of Ag-Ag chains with Ag8 cluster units and linear Ag4 units, respectively, and fully deprotonated L^6- ligands. The silver(i) atoms in 2 exhibit linear, T-shaped, Y-shaped, and tetrahedral coordination geometries. Each L^6- ligand connects thirteen Ag ^I atoms. The intrachain robust argentophilic interactions play a vital role in the formation of the structure. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.

Full text of DOI:10.1002/ejic.200501146

FULL PAPER
DOI: 10.1002/ejic.200501146
Rational Synthesis and Characterization of Two Three-Dimensional Metal-
Organic Frameworks Incorporating Silver Chains and 1,2,3,4,5,6-
Cyclohexanehexacarboxylate
Jing Wang,[a] Sheng Hu,[a] and Ming-Liang Tong*[a]
Keywords: Silver / MOFs / Cyclohexanehexacarboxylate / Water tape / Ag···Ag interactions / Supramolecular chemistry
Two new silver polycarboxylate coordination polymers,
[Ag3(H3L)(H2O)2]n·2nH2O (1) and [Ag6L(NH3)(H2O)3]n·nH2O
(2), have been obtained from the reaction of [Ag(NH3)2](OH)
(freshly synthesized from Ag2O and aqueous ammonia) with
cis,cis,cis,cis,cis-1,2,3,4,5,6-cyclohexanehexacarboxylic acid
(H6L) by control of the molar ratio of starting materials. The
X-ray crystal structure analysis reveals that both of them
mers, Ag–Ag chains, and half deprotonated [H3L]3– ligands.
Each [H3L]3– ligand connects eight AgI atoms. The weakly
coordinated water ligands and lattice water molecules are
located at the channels and form interesting 1D hydrogen-
bonded T4(2)8(2) water tapes with cyclic R68(16) (H2O)8 and
R44(8) (H2O)4 units. Complex 2 is also a 3D MOF structure
constructed by two types of Ag–Ag chains with Ag8 cluster
units and linear Ag4 units, respectively, and fully deproton-
¯
crystallize in the triclinic space group P1 with a = 6.375(4), b
= 9.505(6), c = 15.097(8) Å, α = 93.249(14), β = 100.364(15), γ
= 96.453(15)°, V = 891.4(9) Å3, Z = 2 for 1, and a = 8.0380(7),
b = 10.1220(9), c = 13.8458(12) Å, α = 76.3450(10), β =
80.9370(10), γ = 68.7230(10)°, V = 1016.83(15) Å3, Z = 2 for 2.
Complex 1 features a three-dimensional (3D) metal-organic
framework (MOF) with one-dimensional (1D) rectangular
channels surrounded by carboxylato-supported Ag–Ag di-
ated L6– ligands. The silver(
I) atoms in 2 exhibit linear, T-
shaped, Y-shaped, and tetrahedral coordination geometries.
Each L6– ligand connects thirteen AgI atoms. The intrachain
robust argentophilic interactions play a vital role in the for-
mation of the structure.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2006)
sign and synthesize MOFs depending on the ligand geome-
try and coordination propensity of the metal ion, which has
been proved by the reports of a large number of silver
MOFs.[7]
Introduction
The design and synthesis of metal-organic frameworks
(MOFs) are of great interest because of their intriguing
structural topologies and novel properties for potential ap-
plications.[1–3] In the past few decades, the development of
supramolecular assembled chemistry has allowed the pos-
sibility to rationally design and prepare supramolecular
architectures through noncovalent interactions, in which it
is crucial to meet both geometric as well as energetic con-
siderations.[4] Recent advances in this field have led to many
periodic MOFs formed through the deliberate selection of
functionalized organic ligands and coordination geometries
of transition-metal ions.[5] A successful strategy in building
such networks is to employ appropriate bridging ligands
that can bind metal ions in different modes and provide
a possible way to achieve more robust MOF structures.[6]
Moreover, the recent development of self-assembled supra-
molecular chemistry has made it possible to rationally de-
Silver() ion principally exhibits linear, trigonal, and tet-
rahedral coordination and has high affinity for hard donor
atoms such as nitrogen or oxygen atoms and soft donor
atoms such as sulfur atoms, being a favorable and fashion-
able building block for MOFs.[8] Furthermore, silver ion is
apt to form short Ag···Ag contacts as well as ligand unsup-
ported interactions, which have been proved to be two of
the most important factors contributing to the formation
of such complexes and special properties.[9–11] Previous
works[12,13] have proved rigid benzene-multicarboxylic ac-
ids, such as 1,4-benzenedicarboxylic acid, 1,3,5-benzenetri-
carboxylic acid, and 1,2,4,5-benzenetetracarboxylic acid,
are a good choice for the construction of MOFs owing to
their versatile coordination modes. However, although
many benzene multicarboxylate-bridged MOFs have been
reported, those on a silver() ion are relatively rare, probably
because of their low solubility, which makes structural
analyses difficult.[14–16] Compared with benzene multicar-
boxylic acid, cyclohexane multicarboxylic acid not only has
advantages over the former such as having rich coordina-
tion modes, being the hydrogen-bond donors and acceptors
as well as possessing potential high symmetries, but also
[a] State Key Laboratory of Optoelectronic Materials and Technol-
ogies, Institute of Optoelectronic and Composite Materials &
School of Chemistry and Chemical Engineering, Sun Yat-Sen
University,
Guangzhou 510275, China
Fax: +86-20-8411-2245
E-mail: tongml@mail.sysu.edu.cn
Supporting information for this article is available on the
WWW under http://www.eurjic.org or from the author.
Eur. J. Inorg. Chem. 2006, 2069–2077
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2069

J. Wang, S. Hu, M.-L. Tong
Ag2O + 4NH3 + 2H2O = 2[Ag(NH3)2](OH) (1)
FULL PAPER
has more conformations and flexibility, which remain
largely unexplored for constructing 3D MOFs. Cyclohexa-
nedicarboxylates and cyclohexanetricarboxylates are there-
fore regarded as excellent candidates for the construction of
multidimensional MOFs.[17] Although one could anticipate
that 1,2,3,4,5,6-cyclohexanehexacarboxylic acid (H6L) will
be applied as a more flexible ligand than cyclohexanedicar-
boxylates and cyclohexanetricarboxylates in the construc-
tion of functional MOFs (Scheme 1), its coordination
chemistry has not been explored until now. Herein, we re-
port the creation of two interesting silver() complexes with
robust argentophilic interactions by the self-assembled reac-
tion of cis,cis,cis,cis,cis-1,2,3,4,5,6-cyclohexanehexacarbox-
ylic acid (H6L) with freshly synthesized [Ag(NH3)2](OH),
[Ag3(H3L)(H2O)2]n·2nH2O (1), and [Ag6L(NH3)(H2O)3]n·
nH2O (2). Complex 1 is a 3D MOF with 1D rectangular
channels surrounded by carboxylato-supported Ag–Ag di-
mers, Ag–Ag chains and half deprotonated µ8-[H3L]3– brid-
ges, and water molecules in the channels forming interesting
hydrogen-bonded water tapes of eight- and four-membered
rings; while 2 is a 3D MOF constructed with two types of
Ag–Ag chains with Ag8 cluster units and linear Ag4 units,
respectively, and fully deprotonated µ13-L6– bridges.
3n[Ag(NH3)2](OH) + nH6L + nH2O =
[Ag3(H3L)(H2O)2]n·2nH2O + 6nNH3 (2)
6n[Ag(NH3)2](OH) + nH6L =
[Ag6L(NH3)(H2O)3]n·nH2O + 2nH2O + 11nNH3 (3)
We first selected the molar ratio of [Ag(NH3)2](OH)/H6L
= 3:1, resulting in the formation of complex 1, which pos-
sesses a 3D microporous MOF structure filled with water
molecules. As anticipated, only half of the carboxylate
groups are deprotonated and the others form intra- or inter-
molecular hydrogen-bond interactions with the deproton-
ated ones, which may be attributed to the cis conformation
of the ligand. The carboxylate groups lie alternately on the
axial position and on the equatorial position, which is use-
ful for the formation of intramolecular hydrogen-bonded
interactions.
As the self-assembly of the frameworks is greatly influ-
enced by factors such as the solvent system,[3a,20a] the tem-
plate,[16] the pH value of the solution,[20b,20c] and the steric
requirement of the counterion,[21] some changes in the reac-
tion conditions may result in significantly different final re-
action products. The successful isolation of 1, in which not
all the carboxylate groups are deprotonated, prompted us
to extend our study to change the molar ratio of [Ag-
(NH3)2](OH)/H6L. As expected, when the molar ratio of
[Ag(NH3)2](OH)/H6L was increased to 6:1, all the carboxyl-
ate groups were deprotonated and then complex 2 was ob-
tained. Furthermore, we attempted to change the silver()
salts and solvents such as MeOH or EtOH, and raise the
pH values in order to prepare different silver MOFs. How-
ever, the same product as 2 was obtained, although the
yields were somewhat different or precipitates were ob-
tained when treated by other silver() salts at higher pH
values, suggesting that the proper pH value and molar ratio
of the reactants play a vital role in the formation of the
products. It should be noted that, in our recently synthe-
Scheme 1. Schematic presentation of the L ligand in cis,cis,cis,cis,cis
(a) and trans,trans,trans,trans,trans conformations (b).
Results and Discussion
Synthesis and Characterization
As is well known, the reactions of silver() ion with multi-
carboxylates in aqueous solution often result in the forma-
tion of insoluble ‘silver salts’, presumably because of the
fast coordination of the carboxylates to silver ion to form
polymer structures. Mak and co-workers pioneered the gen-
eration of polymeric structures in silver()-carboxylate-like
complexes by using various zwitterionic betaine ligands.[18]
Smith and co-workers[19] obtained a series of Ag–multicar-
boxylate complexes by using ammoniacal conditions to en-
hance the solubility of the silver carboxylates. Michaelides
and co-workers[14b] reported a novel succinatodisilver()
complex that was synthesized by gel permeation. Hence,
properly tuning the reaction conditions may result in the
formation of appropriate crystalline products for X-ray
structural analysis. Considering this, we tried reactions of
freshly synthesized [Ag(NH3)2](OH) and the H6L ligand in
various molar ratios [Equations (1), (2), and (3)].
sized 3D MOFs [M3(trans-L)(H2O)6]n (M = Co2+, Mn2+
and Fe2+ [trans-L]6–
trans,trans,trans,trans,trans-
,
;
=
1,2,3,4,5,6-cyclohexanehexacarboxylate),[22] the fully depro-
tonated L6– ligand changed its cis conformation to trans
conformation under hydrothermal conditions, while in 1
and 2, the half and fully deprotonated L ligands keep their
cis,cis,cis,cis,cis conformation, which may be ascribed to the
cooperative effect of the intraligand hydrogen-bonding in-
teraction and the metal coordination.
Crystal Structure
X-ray crystallography has established that 1 is a 3D
MOF structure with 1D rectangular channels along the a
2070
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© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 2069–2077

Three-Dimensional Metal-Organic Frameworks
FULL PAPER
axis. As illustrated in part (a) of Figure 1, each asymmetric ver),[24] which provides supporting evidence for the signifi-
unit in 1 contains three crystallographically unique silver() cance of argentophilicity.[25] Similar Ag···Ag distances were
atoms, one [H3L]3– ligand, two coordinated water mole- found in silver benzenesulfonate (2.915 Å)[23b] and in the
cules, and two lattice water molecules, all of which lie on
general positions. The selected bond lengths and angles are
Table 1. Selected bond lengths [Å] and angles [°] for 1 and 2.[a]
listed in Table 1. Noticeably, the three deprotonated carbox-
ylate groups of each [H3L]3– ligand are located at the equa-
Compound 1
torial positions and the rest at the axial positions, in agree-
ment with the IR spectrum, where the absorption peak is
at around 1720 cm–1 for the protonated carboxylic groups.
Ag1 is coordinated in a greatly irregular geometry, by three
oxygen atoms from three [H3L]3– ligands [Ag1–O =
2.256(4)–2.584(4) Å, O–Ag1–O = 82.5(2)–162.4(2)°], an
aqua ligand [Ag1–O1w = 2.457(5) Å, O–Ag1–O1w =
80.0(2)–116.1(2)°], as well as a Ag···Ag contact [2.916(1) Å].
The Ag1–Ag1a distance is significantly shorter than the van
der Waals contact distance 3.40 Å,[23a] is comparable to the
Ag···Ag separation (2.89 Å) in metallic silver, and twice the
Ag(1)–O(2a)
Ag(1)–O(1)
Ag(1)–O(1w)
Ag(1)–O(3b)
Ag(2)–O(6c)
Ag(2)–O(5)
Ag(2)–O(2wd)
Ag(3)–O(10)
O(2a)–Ag(1)–O(1)
O(2a)–Ag(1)–O(1w) 116.1(2) O(10)–Ag(3)–O(9f)
O(1)–Ag(1)–O(1w)
O(2a)–Ag(1)–O(3b)
O(1)–Ag(1)–O(3b)
2.256(4) Ag(3)–O(9f)
2.267(4) Ag(3)–O(6g)
2.457(5) Ag(1)···Ag(1a)
2.584(4) Ag(2)···Ag(2c)
2.187(4) Ag(2)···Ag(3e)
2.191(4) Ag(3)···Ag(2h)
2.632(6) Ag(3)···Ag(3f)
2.235(4)
2.356(4)
2.542(5)
2.916(1)
2.916(1)
3.162(1)
3.162(1)
3.329(2)
162.4(2) O(5)–Ag(2)–O(2wd)
130.2(2)
142.3(2)
115.3(2)
85.0(2)
80.0(2)
82.5(2)
O(10)–Ag(3)–O(6g)
O(9f)–Ag(3)–O(6g)
106.5(2) Ag(2c)–O(6)···Ag(3i)
91.2(2)
O(1w)–Ag(1)–O(3b) 87.5(2)
Ag(2c)···Ag(2)···Ag(3e) 77.56(3)
covalent radius of silver (1.455 Å for four-coordinate sil- O(6c)–Ag(2)–O(5)
153.8(2) Ag(2h)···Ag(3)···Ag(3f) 62.89(2)
O(6c)–Ag(2)–O(2wd) 74.5(2)
Compound 2
Ag(1)–O(1a)
Ag(1)–O(1w)
Ag(1)–O(3)
Ag(1)–O(1)
Ag(2)–O(2c)
Ag(2)–O(2w)
Ag(2)–O(5)
Ag(3)–O(3e)
Ag(3)–O(3w)
Ag(3)–O(7)
Ag(3)–O(6)
Ag(4)–O(12e)
Ag(4)–O(7f)
Ag(4)–O(9)
Ag(5)–O(8)
2.213(3) Ag(5)–O(4g)
2.340(4) Ag(6)–N(1)
2.397(3) Ag(6)–O(11)
2.587(3) Ag(6)–O(10i)
2.196(3) Ag(1)···Ag(2b)
2.320(4) Ag(1)···Ag(1a)
2.335(3) Ag(2)···Ag(2d)
2.229(3) Ag(3)···Ag(5f)
2.344(4) Ag(3)···Ag(4)
2.354(3) Ag(4)···Ag(6e)
2.400(3) Ag(4)···Ag(5f)
2.166(3) Ag(4)···Ag(5e)
2.204(3) Ag(5)···Ag(5g)
2.502(3) Ag(5)···Ag(6)
2.176(3) Ag(6)···Ag(6j)
2.193(3)
2.125(4)
2.135(3)
2.528(3)
3.0938(6)
3.3396(8)
3.336(1)
2.9040(6)
3.1645(6)
2.9438(5)
3.1282(6)
3.3159(6)
3.1160(8)
3.1310(6)
3.2021(8)
125.9(1)
O(1a)–Ag(1)–O(1w) 132.8(1) Ag(4f)–O(7)–Ag(3)
O(1a)–Ag(1)–O(3)
O(1w)–Ag(1)–O(3)
O(1a)–Ag(1)–O(1)
O(1w)–Ag(1)–O(1)
O(3)–Ag(1)–O(1)
O(2c)–Ag(2)–O(2w)
O(2c)–Ag(2)–O(5)
O(2w)–Ag(2)–O(5)
O(3e)–Ag(3)–O(3w)
O(3e)–Ag(3)–O(7)
O(3w)–Ag(3)–O(7)
O(3e)–Ag(3)–O(6)
O(3w)–Ag(3)–O(6)
O(7)–Ag(3)–O(6)
134.0(1) Ag(2b)···Ag(1)···Ag(1a) 125.76(2)
93.2(1)
92.2(1)
Ag(1b)···Ag(2)···Ag(2d) 106.84(2)
Ag(5f)···Ag(3)···Ag(4) 61.88(1)
100.8(1) Ag(6e)···Ag(4)···Ag(5f) 116.21(2)
75.6(1) Ag(6e)···Ag(4)···Ag(3) 160.47(2)
135.3(1) Ag(5f)···Ag(4)···Ag(3) 54.96(1)
136.0(1) Ag(6e)···Ag(4)···Ag(5e) 59.67(1)
87.7(1) Ag(5f)···Ag(4)···Ag(5e) 57.75(2)
126.7(1) Ag(3)···Ag(4)···Ag(5e) 112.31(1)
139.1(1) Ag(3f)···Ag(5)···Ag(5g) 126.77(2)
93.9(1)
92.9(1)
Ag(3f)···Ag(5)···Ag(4f) 63.15(1)
Ag(5g)···Ag(5)···Ag(4f) 64.15(2)
104.6(1) Ag(3f)···Ag(5)···Ag(6)
79.0(1) Ag(5g)···Ag(5)···Ag(6) 111.25(2)
168.66(2)
97.7(1) Ag(3f)···Ag(5)···Ag(4h) 171.34(2)
121.92(2)
O(12e)–Ag(4)–O(7f) 161.7(1) Ag(4f)···Ag(5)···Ag(6)
O(12e)–Ag(4)–O(9)
O(7f)–Ag(4)–O(9)
O(8)–Ag(5)–O(4g)
N(1)–Ag(6)–O(11)
N(1)–Ag(6)–O(10i)
O(11)–Ag(6)–O(10i) 94.9(1)
Ag(1a)–O(1)–Ag(1)
Ag(3h)–O(3)–Ag(1)
100.6(1) Ag(5g)···Ag(5)···Ag(4h) 58.10(1)
166.5(1) Ag(4f)···Ag(5)···Ag(4h) 122.25(2)
170.1(2) Ag(6)···Ag(5)···Ag(4h) 54.25(1)
93.5(1)
Ag(4h)···Ag(6)···Ag(5) 66.08(1)
Ag(4h)···Ag(6)···Ag(6j) 89.51(2)
87.8(1)
114.0(1)
Ag(5)···Ag(6)···Ag(6j)
154.36(2)
[a] Symmetry codes for 1: a) –x + 1, –y + 2, –z; b) –x, –y + 2, –z;
c) –x, –y + 3, –z – 1; d) x, y + 1, z; e) –x, –y + 1, –z; f) –x – 1, –y
+ 1, –z – 1; g) x – 1, y – 1, z; h) x, y – 1, z; i) x + 1, y + 1, z. For
2: a) –x + 2, –y + 3, –z; b) –x + 3, –y + 2, –z; c) x + 1, y – 1, z;
d) –x + 4, –y + 2, –z; e) x + 1, y, z; f) –x + 4, –y + 3, –z – 1; g) –
x + 3, –y + 3, –z – 1; h) x – 1, y, z; i) –x + 3, –y + 4, –z – 1; j) –x
+ 2, –y + 4, –z – 1; k) x – 1, y + 1, z.
Figure 1. Perspective views showing the coordination environments
of silver atoms (a) and the bridging mode of the [H3L]3– ligand (b)
in 1.
Eur. J. Inorg. Chem. 2006, 2069–2077
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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2071

J. Wang, S. Hu, M.-L. Tong
FULL PAPER
succinatodisilver complex (2.938 and 3.104 Å).[14b] Ag2 Ag···Ag interactions make the silver() atoms form a silver
adopts a slightly distorted Y-shaped geometry, coordinated chain running along the a axis direction supported by the
by two oxygen atoms from two [H3L]3– ligands [Ag2–O = µ2- and µ3-carboxylate bridges. These dimeric motifs and
2.187(4) and 2.191(4) Å, O–Ag2–O = 153.8(2)°] and a 1D Ag···Ag chains are connected by the [H3L]3– ligands
weakly coordinated aqua ligand [Ag2–O2w = 2.632(6) Å, into an open MOF having a rectangular channel along the
O–Ag2–O2w = 74.5(2) and 130.2(2)°] as well as two a axis direction (Figure 2, c). Water molecules are located
Ag···Ag contacts [2.916(1) and 3.162(1) Å]. Similarly, Ag3 at these channels and form 1D hydrogen-bonded water
also has a distorted Y-shaped geometry, surrounded by tapes[26] (Figure 3, a, b). There are cyclic R86(16) (H2O)8 and
three oxygen atoms from three [H3L]3– ligands [Ag3–O = R44(8) (H2O)4 units with two water molecules shared be-
2.235(4)–2.542(5) Å, O–Ag3–O = 85.0(2)–142.3(2)°] as well tween the adjacent circles, leading to a T4(2)8(2) water tape.
as by two Ag···Ag contacts [3.162(1) and 3.329(2) Å]. Each The water tapes further donate hydrogen bonds to the de-
[H3L]3– ligand connects eight AgI atoms through one pro- protonated carboxylate groups of the host [O···O 2.738(7)–
tonated carboxylic group and three deprotonated carboxyl- 3.161(8) Å] (Table 2). Each water molecule is tetrahedrally
ato groups with µ2:η1:η1, µ2:η1:η1, and µ3:η2:η1 coordina- surrounded by four hydrogen bonds or three hydrogen
tion modes, respectively (Figure 1, b). Two of the three pro- bonds and one Ag–H2O coordination bond (Figure 3, b).
tonated carboxylic groups of each [H3L]3– ligand donate Other interesting water chains and tapes have been observed
two strong intraligand hydrogen bonds to the deprotonated in MOF structures of [(H2O)2ʚ{Ni(Hsglu)(H2O)2}]·
carboxylato groups, further stabilizing their cis conforma- H2O [Hsglu = N-(2-hydroxybenzyl)-l-glutamic acid],[27a]
tion [O8···O9 = 2.564(6) Å, O8–H8O···O9 = 164(9)°; apdo·4H2O (apdo = trans-4,4Ј-azopyridine dioxine),[27b]
O12···O1 = 2.582(6) Å, O12–H12O···O1 = 160(9)°]. More- [Co(tartarate)(2,2Ј-bipy)·5H2O],[27c] [Cu(DPA)(CO3)]·3H2O
over, there are rich intermolecular hydrogen-bond interac- (DPA = 2,2Ј-dipyridylamine),[27d] [Fe(2,2Ј-bipy)2(CN)2]·
tions between the protonated or deprotonated carboxylate
groups with water molecules (Table 2). Two types of cluster
units of Ag···Ag interactions exist: the carboxylato-sup-
ported Ag1···Ag1 dimer and the 1D carboxylato-supported
Ag2···Ag3···Ag3···Ag2 chain unit (Figure 2, a and b). The
distances of Ag2···Ag2a, Ag2···Ag3a, and Ag3···Ag3d are
2.916(1), 3.162(1), and 3.329(2) Å, respectively. Such robust
Table 2. Geometrical parameters of hydrogen bonds for 1 and 2.[a]
D–H···A
d(D–H)
d(H···A)
d(D···A)
Є(DHA)
Compound 1
O(4)–H(4O)···O(4wb)
O(8)–H(8O)···O(9)
O(12)–H(12O)···O(1)
O(1w)–H(1wa)···O(2w)
O(1w)–H(1wb)···O(3w)
O(2w)–H(2wa)···O(11d)
0.85(1)
0.85(1)
0.85(1)
0.85(1)
0.85(1)
0.85(1)
1.89(3)
1.74(3)
1.77(3)
2.08(3)
1.99(4)
1.90(3)
2.34(3)
2.12
2.731(6)
2.564(6)
2.582(6)
2.905(9)
2.775(7)
2.738(7)
3.161(8)
2.923(6)
2.790(7)
2.817
168(13)
164(9)
160(9)
163(8)
154(9)
168(13)
162(8)
157.9
O(2w)–H(2wb)···O(4we) 0.85(1)
O(3w)–H(3wa)···O(2c)
O(3w)–H(3wb)···O(1wf)
O(4w)–H(4wa)···O(3w)
O(4w)–H(4wb)···O(2a)
Compound 2
0.85
0.85
0.85
0.85
2.02
2.01
2.17
151.7
159.1
170.7
3.008(6)
O(1w)–H(1wa)···O(4w)
O(1w)–H(1wb)···O(5)
O(2w)–H(2wa)···O(6c)
O(2w)–H(2wb)···O(4w)
O(3w)–H(3wa)···O(9d)
O(3w)–H(3wb)···O(10b)
O(4w)–H(4wa)···O(4a)
O(4w)–H(4wa)···O(5a)
O(4w)–H(4wb)···O(10g)
N(1)–H(1Na)···O(2f)
N(1)–H(1Nb)···O(3we)
N(1)–H(1Nc)···O(6e)
0.85(1)
0.85(1)
0.85(1)
0.85(1)
0.85(1)
0.85(1)
0.85(1)
0.85(1)
0.85(1)
0.89(1)
0.90(1)
0.89(1)
1.94(1)
1.90(2)
1.82(2)
1.98(2)
1.84(1)
1.93(2)
2.31(4)
2.33(4)
1.82(2)
2.24(2)
2.26(2)
2.36(3)
2.772(5)
2.734(5)
2.644(5)
2.811(6)
2.675(5)
2.727(5)
3.039(5)
2.970(6)
2.650(5)
3.048(5)
3.134(6)
3.109(6)
166(5)
168(7)
162(6)
165(8)
171(4)
157(5)
144(6)
133(5)
167(6)
151(4)
165(4)
142(4)
[a] Symmetry codes for 1: a) –x + 1, –y + 2, –z; b) –x, –y + 2, –z;
c) x, y – 1, z; d) x + 1, y, z; c) –x + 1, –y + 1, –z; f) –x, –y + 1, –
z. For 2: a) –x + 3, –y + 2, –z; b) x + 1, y – 1, z; c) –x + 4, –y +
2, –z; d) –x + 4, –y + 3, –z – 1; e) –x + 3, –y + 3, –z – 1; f) –x +
2, –y + 4, –z – 1; g) –x + 3, –y + 3, –z.
Figure 2. (a) The silver chain along the a axis, (b) the binuclear
motif of silver atom, and (c) perspective view of the 1D channels
along the a axis direction in 1.
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Three-Dimensional Metal-Organic Frameworks
FULL PAPER
2.5H2O,[27e] and [Co2(ptc)(py)2(H2O)4]·4H2O (ptc
=
ato oxygen atoms from two L6– ligands [Ag1–O = 2.213(3)–
2.587(3) Å, O–Ag1–O = 75.6(1)–134.0(1)°; Ag3–O =
pyrazine-2,3,5,6-tetracarboxylate).[27f]
Complex 2 is also a 3D MOF structure with more com- 2.229(3)–2.400(3) Å, O–Ag3–O = 79.0(1)–139.1(1)°] and an
plicated Ag···Ag interactions. As illustrated in Figure 4 (a), aqua ligand [Ag1–O1w = 2.340(4) Å, O–Ag1–O1w =
each asymmetric unit in 2 contains one formula unit, and 93.2(1)–132.8(1)°; Ag3–O3w = 2.340(4) Å, O–Ag3–O3w =
therefore there are six crystallographically unique silver() 93.9(1)–126.7(1)°] as well as surrounded by two Ag···Ag
atoms, one L6– ligand, one ammonia ligand, three aqua li- contacts [3.0938(6) and 3.3396(8) Å for Ag1 and 2.9040(6)
gands, and one lattice water molecule, all of which lie in and 3.1645(6) Å for Ag3]. Ag2 is coordinated in a Y-shaped
general positions. Compared with 1, all the carboxylate coordination geometry by two carboxylato oxygen atoms
groups are deprotonated, which is in agreement with the IR from different L6– ligands [Ag2–O
spectrum with no absorption peak around 1720 cm–1. Ag1 2.335(3) Å; O–Ag2–O = 136.0(1)°] and an aqua molecule
and Ag3 have similar greatly distorted tetrahedral coordi- [Ag2–O2w 2.320(4), O–Ag2–O2w 87.7(1) and
nation geometries. They are coordinated by three carboxyl- 135.3(1)°] as well as two relatively weak Ag···Ag contacts
= 2.196(3) and
=
=
Figure 3. Perspective views showing 1D water tape (a) and the hydrogen-bonding modes of each water molecule (b) in 1.
Eur. J. Inorg. Chem. 2006, 2069–2077
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J. Wang, S. Hu, M.-L. Tong
FULL PAPER
[Ag2···Ag1b = 3.0938(6) Å, Ag2···Ag2d = 3.336(1) Å]. Ag4 2.9144 Å).[9b] Each L6– ligand connects 13 silver atoms
and Ag6 have similar slightly distorted T-shaped coordina- (Figure 4, b) to generate a complicated 3D MOF structure.
tion geometries. Ag4 is coordinated by three carboxylato
oxygen atoms from three L6– ligands [Ag4–O = 2.166(3),
2.204(3), and 2.502(3) Å, O–Ag4–O = 97.7(1), 100.6(1), and
161.7(1)°], while Ag6 is coordinated by two carboxylato
oxygen atoms from two L6– ligands and an ammonia ligand
[Ag6–O/N = 2.125(4), 2.135(3), and 2.528(3) Å, O/N–Ag6–
O = 93.5(1), 94.9(1), and 170.1(2)°]. Moreover, Ag4 and
Ag6 are further surrounded by four and three Ag···Ag con-
tacts, respectively [Ag···Ag = 2.9438(6)–3.3159(6) Å for Ag4
and 2.9438(6)–3.2021(8) Å for Ag6]. Ag5 adopts a nearly
linear geometry, coordinated by two oxygen atoms from dif-
ferent L6– ligands [Ag5–O = 2.176(3) and 2.193(3) Å, O–
Ag5–O = 166.5(1)°]. Interestingly, Ag5 is surrounded by
five strong or weak Ag···Ag contacts [Ag···Ag = 2.9040(6)–
3.3159(6) Å]. Most of these Ag···Ag interactions are
slightly longer than that found in ternary silver-hexa-
methylenetetramine-carboxylato
compounds
(2.8154–
Figure 5. (a) The 1D silver chain constructed from Ag1 and Ag2
atoms by Ag···Ag interactions, (b) the Ag8 cluster aggregated by
Ag···Ag interactions, (c) the 1D silver chain constructed by Ag8
clusters, (d) the 2D silver layer formed by the 1D silver chains and
carboxylates along the c axis, and (e) the 3D MOF along the b axis
direction in 2.
Figure 4. Perspective views showing the coordination environment
of silver atoms (a) and the bridging mode of the L6– ligand (b) in 2.
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Three-Dimensional Metal-Organic Frameworks
FULL PAPER
The Ag···Ag interactions in 2 are much more compli-
cated and interesting than in compound 1. As shown in
Figure 5, the six crystallographically independent silver()
atoms can be divided into two groups. Ag1 and Ag2 are
connected by Ag···Ag interactions to generate 1D µ3-car-
boxylato-supported ···Ag1···Ag1···Ag2···Ag2··· silver()
chains running along the b axis (Figure 5, a), while Ag3,
Ag4, Ag5, and Ag6 are aggregated by complicated µ2-car-
boxylato-supported Ag···Ag interactions into 1D Ag···Ag
tapes with a Ag8 cluster unit with six edge-sharing triangles
(Figure 5b, c, d). Two of the six triangles constructed by
Ag4, Ag4a, Ag5, and Ag5a are coplanar but others are
somewhat out of the plane. The dihedral angles between
this plane and the plane made of Ag3, Ag4, and Ag5a as
well as the plane of Ag5, Ag6, and Ag4a by edge-sharing
are 7.8 and 13.0°. Interestingly, the 1D Ag···Ag tapes are
further connected by carboxylates into 2D layers along the
bc plane (Figure 5, c), which are further extended by adja-
cent ···Ag1···Ag1···Ag2···Ag2··· silver() chains into a 3D
MOF structure (Figure 5e). The lattice water molecules are
located at the cavities of 2 and form rich hydrogen-bonding
interactions with the MOF host [O4w···O4a = 3.039(5) Å,
O4w–H4wa···O4a = 144(6)°; O4w···O5a = 2.970(6) Å,
O4w–H4wb···O5a = 133(5)°; O4w···O10g = 2.650(5) Å,
O4w–H4wb···O10g = 167(6)°; O1w···O4w = 2.772(5) Å,
O1w–H1wa···O4w = 166(5)°; O2w···O4w = 2.811(6) Å,
O2w–H2wb···O4w = 165(8)°].
Figure 6. Observed (black) and calculated (gray) powder X-ray dif-
fraction patterns for 1 and 2.
Figure 7. TG analyses for 1 (black) and 2 (gray).
Thermogravimetric Analysis
In order to examine the thermal stabilities of the porous
networks, we carried out thermogravimetric (TG) analyses
and measurement of the XPRD patterns to confirm the pu-
rity of the two complexes (Figure 6). Samples of the com-
plexes were heated to 600 °C with exposure to air. The TGA
curve (Figure 7) of 1 shows that the first weight loss of
5.1% between 20 and 68 °C corresponds to a loss of the
included water molecules (calculated: 4.9%), while the sec-
ond weight loss of 2.4% between 68 and 93 °C is in accord-
ance with the loss of one coordinated water molecule per
unit cell (calculated: 2.5%), and the succeeding weight loss
of 2.8% corresponds to another coordinated water mole-
cule between 93 and 175 °C (calculated: 2.5%). Complex 1
began to decompose at 190 °C to yield the residue Ag2O at
about 450 °C (found: 43.4%; calculated: 46.9%). The TGA
curve of 2 shows that the first weight loss of 4.5% between
50 and 110 °C corresponds to the gradual loss of one in-
cluded molecule, one coordinated water, and one coordi-
nated ammonia molecule or two coordinated water mole-
cules per unit cell (calculated: 4.8%), while the remaining
water molecules were completely removed at 225 °C. Com-
plex 2 began to decompose at 230 °C to yield the residue
Ag2O at about 455 °C (found: 61.3%; calculated: 64.5%).
Powder XRD patterns (Figure S2 in the Supporting Infor-
mation) of the dehydrated samples of 1 and 2 indicate that
removal of the guest molecules causes a significant struc-
tural change of crystalline to amorphous to the framework
of 1 and 2.
Conclusion
Two new silver() compounds incorporating cis,cis,cis,cis,-
cis,cis-1,2,3,4,5,6-cyclohexanehexacarboxylic acid (H6L)
have been successfully obtained, by controlling the molar
ratio of the self-assembled reactions, and crystallographi-
cally characterized. Rich Ag···Ag interactions and versatile
coordination modes of the half or fully deprotonated li-
gands ([H3L]3– or L6–) lead to two interesting microporous
MOFs. Our work is the first to reveal that the H6L ligand
is characteristic of multifunctional coordination sites and
pH-dependent coordination fashions and has a much more
important effect on the structures of MOFs.
Experimental Section
General Remarks: The reagents and solvents employed were com-
mercially available and used as received without further purifica-
tion. The C, H, and N microanalyses were carried out with an
Elementar Vario-EL CHNS elemental analyzer. The IR spectra
were recorded from KBr pellets in the range 4000–400 cm–1 with a
Bio-Rad FTS-7 spectrometer. Powder X-ray diffraction (PXRD)
intensities for 1 and 2 were measured at 293 K on a Rigaku D/max-
IIIA diffractometer (Cu-Kα, λ = 1.54056 Å). The crushed single-
crystalline powder samples were prepared by crushing the crystals
and scanned from 5 to 60° with a step of 0.1°/s.
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J. Wang, S. Hu, M.-L. Tong
FULL PAPER
Table 3. Crystal and structure refinement for compounds 1 and 2.[a]
Compound
1
2
Empirical formula
Formula weight
Temperature [K]
Wavelength [Å]
Crystal system
C12Ag3H17O16
740.87
293(2)
C12H17Ag6NO16
1078.49
293(2)
0.71073
0.71073
triclinic (no. 2)
triclinic (no. 2)
¯
P1
¯
P1
Space group
a [Å]
b [Å]
6.375(4)
9.505(6)
8.038(1)
10.122(1)
c [Å]
α [°]
15.097(8)
96.453(15)
13.846(1)
80.937(1)
β [°]
93.249(14)
100.364(15)
891.4(9)
76.345(1)
68.723(1)
1016.8(2)
γ [°]
V [Å3]
Z
2
2
Calculated density [g/cm3]
Absorption coefficient [mm–1]
F(000)
2.768
3.363
716
3.522
5.753
1012
Crystal size [mm]
θ range for data collection [°]
Limiting indices
Reflections collected/unique
Completeness
Absorption correction
Max. and min. transmission
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
R indexes [I Ͼ 2σ(I)]
R indices (all data)
Largest diff. peak and hole [e/Å3]
0.17×0.17×0.14
2.2–27.0
–8 Յ h Յ 7, –11 Յ k Յ 12, –19 Յ l Յ 16
6378/3635
0.18×0.12×0.05
2.2–26.0
–9 Յ h Յ 9, –12 Յ k Յ 12, –16 Յ l Յ 17
7866/3894
93.9% (θmax = 27.0°)
multiscan (SADABS; Bruker, 2002)
0.6521/0.5922
97.4% (θmax = 26.0°)
multiscan (SADABS; Bruker, 2002)
0.7619/0.4241
full-matrix least-square on F2
3635/16/321
full-matrix least-square on F2
3894/18/359
1.026
1.064
R1 = 0.0454, wR2 = 0.1132
R1 = 0.0494, wR2 = 0.1165
2.803/–1.661
R1 = 0.0270, wR2 = 0.0599
R1 = 0.0315, wR2 = 0.0618
0.820/–0.751
[a] R1 = ∑||Fo| – |Fc||/∑|Fo|, wR2 = [∑w(Fo – Fc ) /∑w(Fo2)2]1/2
.
2
2 2
Synthesis of 1: Excess aqueous NH3 solution was dropped slowly
into a suspension of Ag2O (0.087 g, 0.375 mmol) in MeCN/H2O
(30 mL, v/v = 2:1) with magnetic stirring for 15 min. Then the pow-
der of the ligand cis,cis,cis,cis,cis-1,2,3,4,5,6-cyclohexanehexacar-
boxylic acid (0.092 g, 0.25 mmol) was slowly added to the former
solution and stirred for 30 min after being dissolved. The resultant
solution was allowed to slowly diffuse in darkness at room tem-
perature for several weeks to give colorless needle-like crystals. The
crystals were isolated by deionized water and dried in air (yield
tion effects. Absorption corrections were applied by using the
multiscan program SADABS.[28] The structures were solved by di-
rect methods, and all non-hydrogen atoms were refined anisotropi-
cally by least-squares on F2 using the SHELXTL program.[29] Hy-
drogen atoms on organic ligands were generated by the riding mode
(C–H bond length: 0.98 Å); the water, hydroxy, and ammonia hy-
drogen atoms were located from difference maps, and refined with
nominal geometric restraints [O–H 0.85(1), N–H 0.90 Å]. Selected
bond lengths and bond angles are listed in Table 1. A summary of
0.112 g, about 60% based on Ag). C12H17Ag3O16 (740.87): calcd. the crystal data is given in Table 3.
C 19.45, H 2.31; found C 19.69, H 2.34. IR (KBr) (400–4000 cm–1):
CCDC-291579 (for 1) and -291580 (for 2) contain the supplemen-
ν = 3430 m, 2903 w, 2563 w, 1916 vw, 1717 vs, 1557 vs, 1460 vs,
˜
tary crystallographic data for this paper. These data can be ob-
tained free of charge from The Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif.
1385 vs, 1316 s, 1240 s, 1206 s, 1160 m, 1028 m, 994 m, 894 m,
803 m, 760 m 687 m, 618 w, 495 w cm–1.
Synthesis of 2: Complex 2 was prepared as described for 1 by only
changing the molar ratio of Ag2O to H6L ligand from 1.5:1 to 3:1.
Colorless prism-like crystals were isolated by deionized water and
dried in air (yield 0.135 g, about 80% based on Ag).
C12H17Ag6NO16 (1078.49): calcd. C 13.36, H 1.59, N 1.30; found
Supporting Information (for details see the footnote on the first
page of this article): The supporting information contains the IR
spectra for compounds 1 and 2, and the powder XRD of the dehy-
drated samples of 1 and 2.
C 13.47, H 1.58, N 1.22. IR (KBr) (400–4000 cm–1): ν = 3354 m,
˜
3320 m, 3259 m, 3181 m, 1545 vs, 1386 vs, 1319 s, 1203 m, 1166 m,
Acknowledgments
1032 w, 994 w, 916 w, 844 m, 767 m, 692 m, 591 m, 523 w cm–1.
This work was supported by the NSFC (20525102 and 20471069),
the FANEDD of China (200122), the Scientific and Technological
Project of Guangdong Province (04205405), and Sun Yat-Sen Uni-
versity.
X-ray Crystallographic Study: Single crystals of complexes 1 and 2
with approximate dimensions 0.21×0.20×0.14 mm3 (1) and
0.20×0.30×0.26 mm3 (2) were used for X-ray diffraction analyses.
The crystals were mounted on the end of a thin glass fiber using
an inert epoxy gel. Data collection of 1 and 2 was performed with
Mo-Kα radiation (λ = 0.71073 Å) with a Bruker Apex CCD dif-
fractometer at 123(2) K. The raw data frames were integrated with
SAINT+, which also applied corrections for Lorentz and polariza-
[1] a) J. M. Lehn, Angew. Chem. Int. Ed. Engl. 1990, 29, 1304–
1319; b) O. M. Yaghi, G. Li, H. Li, Nature 1995, 378, 703–706;
c) M. J. Zaworotko, Nature 1997, 386, 220–221.
2076
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Three-Dimensional Metal-Organic Frameworks
FULL PAPER
[2]
[15] a) R. L. Griffith, J. Chem. Phys. 1943, 11, 499; b) D. S. Sagatys,
G. Smith, R. C. Bott, D. E. Lynch, C. H. L. Kennard, Polyhe-
dron 1993, 12, 709–713; c) R. C. Bott, G. Smith, D. S. Sagatys,
T. C. W. Mak, D. E. Lynch, C. H. Kennard, Aust. J. Chem.
1993, 46, 1055–1065; d) P. R. Wei, D. D. Wu, T. C. W. Mak,
Inorg. Chim. Acta 1996, 249, 169–174.
[16] a) F. Jaber, F. Charbonnier, R. Faure, J. Chem. Crystallogr.
1997, 27, 397; b) F. Jaber, F. Charbonnier, R. Faure, Polyhedron
1996, 15, 2909–2913; c) X.-M. Chen, T. C. W. Mak, Aust. J.
Chem. 1991, 44, 1783–1787.
[17] a) M. Sanselme, J. M. Grenèche, M. Riou-Cavellec, G. Férey,
Chem. Commun. 2002, 2172–2173; b) R. Cao, D. F. Sun, Y. C.
Liang, M. C. Hong, K. Tatsumi, Q. Shi, Inorg. Chem. 2002, 41,
2087–2094; c) N. Snejko, E. Gutierrez-Puebla, J. L. Martinez,
M. A. Monge, C. Ruiz-Valero, Chem. Mater. 2002, 14, 1879–
1883; d) Y. Li, N. Hao, Y. Lu, E. Wang, Z. Kang, C. Hu, Inorg.
Chem. 2003, 42, 3119–3124; e) H. Kumagai, M. Akita-Tanaka,
K. Inoue, M. Kurmoo, J. Mater. Chem. 2001, 11, 2146–2151.
[18] a) X. L. Zhao, Q. M. Wang, T. C. W. Mak, Chem. Eur. J. 2005,
11, 2094–2102; b) X. Zhang, G. C. Guo, F. K. Zheng, G. W.
Zhou, J. G. Mao, Z. C. Dong, J. S. Huang, T. C. W. Mak, J.
Chem. Soc., Dalton Trans. 2002, 1344–1349; c) D. D. Wu,
T. C. W. Mak, J. Chem. Soc., Dalton Trans. 1995, 2671–2678;
d) X. M. Chen, T. C. W. Mak, J. Chem. Soc., Dalton Trans.
1991, 3253–3258; e) X. M. Chen, T. C. W. Mak, J. Chem. Soc.,
Dalton Trans. 1991, 1219–1222.
a) M. M. Conn, J. Rebek Jr, Chem. Rev. 1997, 97, 1647–1668;
b) L. J. Prins, J. Huskens, F. Jong, P. Timmerman, D. N. Rein-
houdt, Nature 1999, 398, 498–502; c) G. R. Desiraju, Nature
2001, 412, 397–400.
a) R. Robson, B. F. Abrahamas, S. R. Batten, R. W. Gable,
B. F. Hoskins, J. Liu, Supramolecular Architecture, American
Chemical Society, Washington, DC, 1992, p. 256; b) J.-M.
Lehn, Supramolecular Chemistry: Concepts and Perspectives,
VCH, Weinheim, Germany, 1995, ch. 9; c) A. J. Cheethan, Sci-
ence 1994, 264, 794, and refs therein; d) J. M. Thomas, R. Raja,
Chem. Commun. 2001, 675–687.
a) V. R. Pedireddi, W. Jones, A. P. Chorlton, R. Docherty,
Chem. Commun. 1996, 997–1002; b) Y. B. Dong, M. D. Smith,
R. C. Layland, H.-C. zur Loye, J. Chem. Soc., Dalton Trans.
2000, 775–780.
a) X. Xue, X. S. Wang, L. Z. Wang, R. G. Xiong, B. F. Abra-
hams, X. Z. You, Z. L. Xue, C. M. Che, Inorg. Chem. 2002, 41,
6544–6546; b) S. Leininger, B. Olenyuk, P. J. Stang, Chem. Rev.
2000, 100, 853–908; c) Y. Cui, H. L. Ngo, W. Lin, Inorg. Chem.
2002, 41, 1033–1035; d) L. Carlucci, G. Ciani, D. M. Proserpio,
S. Rizzato, Chem. Eur. J. 2002, 8, 1520–1526.
a) I. M. Müller, R. Robson, Angew. Chem. Int. Ed. 2000, 39,
4357–4359; b) B. F. Abrahams, P. A. Jackson, R. Robson, An-
gew. Chem. Int. Ed. 1998, 37, 2656–2659; c) B. F. Abrahams, J.
Coleiro, B. F. Hoskins, R. Robson, Chem. Commun. 1996, 603–
604.
a) L. Carlucci, G. Ciani, D. M. Proserpio, A. Sironi, Angew.
Chem. Int. Ed. Engl. 1995, 34, 1895–1898; b) X. H. Bu, K. Bi-
radha, T. Yamaguchi, M. Nishimura, T. Ito, K. Tanaka, M.
Shionoya, Chem. Commun. 2000, 1953–1954; c) K. Biradha,
M. Fujita, Chem. Commun. 2001, 15–16; d) M.-L. Tong, X.-
M. Chen, B.-H. Ye, L.-N. Ji, Angew. Chem. Int. Ed. 1999, 38,
2237–2240.
[3]
[4]
[5]
[6]
[7]
[19] G. Smith, A. N. Reddy, K. A. Byriel, C. H. L. Kennard, J.
Chem. Soc., Dalton Trans. 1995, 3565–3570.
[20] a) C. B. Aakeröy, K. R. Seddon, Chem. Soc., Rev. 1993, 397–
407; b) T. L. Hennigar, D. C. MacQuarrie, P. Losier, R. D. Rog-
ers, M. J. Zaworotko, Angew. Chem. 1997, 109, 1044–1046; An-
gew. Chem. Int. Ed. Engl. 1997, 36, 972–973; c) H. Gudbjart-
son, K. Biradha, K. M. Poirier, M. J. Zaworotko, J. Am. Chem.
Soc. 1999, 121, 2599–2600.
[8] a) P. L. Caradoc-Davies, L. R. Hanton, Chem. Commun. 2001, [21] a) L. Carlucci, G. Ciani, D. M. Proserpio, A. Sironi, Angew.
1098–1099; b) I. Ino, L. P. Wu, M. Munakata, M. Maekawa,
Y. Suenaga, T. Kuroda-Sowa, Y. Kitamori, Inorg. Chem. 2000,
39, 2146–2151; c) K. A. Hirsch, S. R. Wilson, J. S. Moore, In-
org. Chem. 1997, 36, 2960–2968.
Chem. 1995, 107, 2037–2040; Angew. Chem. Int. Ed. Engl. 1995,
34, 1895–1898; b) M.-L. Tong, B.-H. Ye, X.-M. Chen, S. W.
Ng, Inorg. Chem. 1998, 37, 2645–2650.
[22] J. Wang, L.-L. Zheng, C.-J. Li, Y.-Z. Zheng, M.-L. Tong, Cryst.
Growth Des. 2006, 6, 357–359.
[23] a) M. Jansen, Angew. Chem. Int. Ed. Engl. 1987, 26, 1098–
1110; b) G. K. H. Shimizu, G. D. Enright, C. I. Ratcliffe, K. F.
Preston, J. L. Reid, J. A. Ripmeester, Chem. Commun. 1999,
1485–1486.
[24] a) A. Bayler, A. Schier, G. A. Bowmaker, H. Schmidbaur, J.
Am. Chem. Soc. 1996, 118, 7006–7007; b) U. M. Tripathi, A.
Bauer, H. Schmidbaur, J. Chem. Soc., Dalton Trans. 1997,
2865–2868.
[25] a) P. Pyykkö, Chem. Rev. 1997, 97, 597–636; b) Q.-M. Wang,
T. C. W. Mak, Chem. Commun. 2001, 807–808; c) D. Rais, J.
Yau, D. M. P. Mingos, R. Vilar, A. J. P. White, D. J. Williams,
Angew. Chem. Int. Ed. 2001, 40, 3464–3467.
[9] a) M. Maekawa, H. Konaka, Y. Suenaga, T. Kuroda-Sowa, M.
Munakata, J. Chem. Soc., Dalton Trans. 2000, 4160–4166; b)
M.-L. Tong, S.-L. Zheng, X.-M. Chen, Chem. Eur. J. 2000, 6,
3729–3738; c) R. Alberto, D. Angst, U. Abram, K. Ortner,
T. A. Kaden, A. P. Schubiger, Chem. Commun. 1999, 1513–
1514.
[10] a) K. S. Singh, J. R. Long, P. Stavropoulos, J. Am. Chem. Soc.
1997, 119, 2942–2943; b) L. Pan, E. B. Woodlock, X. T. Wang,
K. C. Lam, A. L. Rheingold, Chem. Commun. 2001, 1762–
1763; c) O. Kristiansson, Inorg. Chem. 2001, 40, 5058–5059.
[11] a) M. A. Omary, T. R. Webb, Z. Assefa, G. E. Shankle, H. H.
Patterson, Inorg. Chem. 1998, 37, 1380–1386; b) M.-L. Tong,
X.-M. Chen, B.-H. Ye, S. W. Ng, Inorg. Chem. 1998, 37, 5278–
5281; c) A. Erxleben, Inorg. Chem. 2001, 40, 2928–2931.
[12] a) D. F. Sun, R. Cao, Y. C. Liang, W. P. Su, M. C. Hong, J.
Chem. Soc., Dalton Trans. 2001, 2335–2340; b) R. Cao, D. F.
Sun, Y. C. Liang, M. C. Hong, K. Tatsumi, Q. Shi, Inorg.
Chem. 2002, 41, 2087–2094; c) D. F. Sun, R. Cao, Y. C. Liang,
Q. Shi, M. C. Hong, J. Chem. Soc., Dalton Trans. 2002, 1847–
1851.
[26] a) L. Infantes, S. Motherwell, CrystEngComm 2002, 4, 454–
461; b) L. Infantes, J. Chisholm, S. Motherwell, Crys-
tEngComm 2003, 5, 480–486.
[27] a) B. Sreenivasulu, J. J. Vittal, Angew. Chem. Int. Ed. 2004, 43,
5769–5772; b) B.-Q. Ma, H.-L. Sun, S. Gao, Chem. Commun.
2004, 2220–2221; c) J. Lu, J.-H. Yu, X.-Y. Chen, P. Cheng, X.
Zhang, J.-Q. Xu, Inorg. Chem. 2005, 44, 5978–5980; d) J. P.
Naskar, M. G. B. Drew, A. Hulme, D. A. Tocher, D. Datta,
CrystEngComm 2005, 7, 67–70; e) B.-Q. Ma, H.-L. Sun, S.
Gao, Eur. J. Inorg. Chem. 2005, 3902–3906; f) S. K. Ghosh,
P. K. Bharadwaj, Eur. J. Inorg. Chem. 2005, 4880–4885.
[13] a) H. J. Choi, M. P. Suh, Inorg. Chem. 1999, 38, 6309–6312; b)
S. M. Lo, S. S. Chui, L. Y. Shek, Z. Y. Lin, X. X. Zhang, G. H.
Wen, I. D. William, J. Am. Chem. Soc. 2000, 122, 6293–6294;
c) M. Eddaoudi, H. L. Li, O. M. Yaghi, J. Am. Chem. Soc.
2000, 122, 1391–1397; d) S. O. Gutschke, D. J. Price, A. K. [28] G. M. Sheldrick, SADABS 2.05, University of Göttingen,
Powell, P. T. Wood, Eur. J. Inorg. Chem. 2001, 2739–2741.
[14] a) G. Smith, A. N. Reddy, K. A. Byriel, C. H. L. Kennard, J.
Chem. Soc., Dalton Trans. 1995, 3565–3570; b) A. Michaelides,
V. Kiritsis, S. Skoulika, A. Aubry, Angew. Chem. Int. Ed. Engl.
1993, 32, 1495–1497.
Göttingen, Germany.
[29] SHELXTL 6.10, Bruker Analytical Instrumentation, Madison,
Wisconsin, USA, 2000.
Received: December 24, 2005
Published Online: March 29, 2006
Eur. J. Inorg. Chem. 2006, 2069–2077
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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