Anion-directed assembly: Framework conversion in dimensionality and photoluminescence

Article abstract of DOI:10.1016/j.jssc.2007.01.036

Six novel Ni(II)-fluconazole complexes formulated as (C₁₃H₁₁N₆OF₂)₂Ni₂(NO₃)₂ (1), (C₁₃H₁₂N₆OF₂)₂Ni(NO₃)₂·H₂O (2), (C₁₃H₁₂N₆OF₂)Ni(SO₄)(DMF)₂(H₂O) (3), (C₁₃H₁₂N₆OF₂)₂Ni(H₂O)₂(SO₄)·4H₂O (4), (C₁₃H₁₂N₆OF₂)₂NiCl₂·2(CH₃OH) (5), (C₁₃H₁₂N₆OF₂)₄Ni₂ (MoO₄)₂·6H₂O (6) have been hydrothermally or solvothermally synthesized under similar conditions except different anions and solvents. They are structurally characterized by elemental analysis, IR, TG and single crystal X-ray diffraction. Complex 1 is a molecular binuclear nickel cluster. Complex 2 exhibits a one-dimensional (1D) chain linked by double-stranded fluconazole-bridge. Complex 3 shows a novel 1D chain linked by double-stranded fluconazole-bridge and double-stranded SO₄^2--bridge. Complex 4 shows a three-dimensional (3D) architecture and SO₄^2- anions occupy the cavity. Complex 5 exhibits a two-dimensional (2D) structure constructed by alternating left- and right-handed helices. Complex 6 exhibits a 3D architecture, in which the 2D layers are pillared by {MoO₄} tetrahedra. Complex 2 can be irreversibly converted to complex 1 in the presence of DMF (N,N′-dimethyllformamide). Complexes 1, 3 and 6 show antiferromagnetic interactions between the nickel (II) ions The photoluminescence properties of the six complexes indicated that the introduction of different anions can enhance or weaken the intra-ligand transitions of fluconazole.

Full text of DOI:10.1016/j.jssc.2007.01.036

ARTICLE IN PRESS
Journal of Solid State Chemistry 180 (2007) 1476–1488
www.elsevier.com/locate/jssc
Anion-directed assembly: Framework conversion in
dimensionality and photoluminescence
Ã
Yun Gonga,b, Tianfu Liua, Wang Tanga, Fengjing Wub, Wenliang Gaob, Changwen Hua,
aDepartment of Chemistry, Beijing Institute of Technology, Beijing 100081, PR China
bDepartment of Chemistry, College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, PR China
Received 17 September 2006; received in revised form 18 January 2007; accepted 24 January 2007
Available online 16 February 2007
Abstract
Six novel Ni(II)–fluconazole complexes formulated as (C13H11N6OF2)2Ni2(NO3)2 (1), (C13H12N6OF2)2Ni(NO3)2 ꢀ H2O (2),
(C13H12N6OF2)Ni(SO4)(DMF)2(H2O) (3), (C13H12N6OF2)2Ni(H2O)2(SO4) ꢀ 4H2O (4), (C13H12N6OF2)2NiCl2 ꢀ 2(CH3OH) (5),
(C13H12N6OF2)4Ni2 (MoO4)2 ꢀ 6H2O (6) have been hydrothermally or solvothermally synthesized under similar conditions except
different anions and solvents. They are structurally characterized by elemental analysis, IR, TG and single crystal X-ray diffraction.
Complex 1 is a molecular binuclear nickel cluster. Complex 2 exhibits a one-dimensional (1D) chain linked by double-stranded
fluconazole-bridge. Complex 3 shows a novel 1D chain linked by double-stranded fluconazole-bridge and double-stranded SO24ꢁ-bridge.
Complex 4 shows a three-dimensional (3D) architecture and SO24ꢁ anions occupy the cavity. Complex 5 exhibits a two-dimensional (2D)
structure constructed by alternating left- and right-handed helices. Complex 6 exhibits a 3D architecture, in which the 2D layers are
pillared by {MoO4} tetrahedra. Complex 2 can be irreversibly converted to complex 1 in the presence of DMF (N,N0-
dimethyllformamide). Complexes 1, 3 and 6 show antiferromagnetic interactions between the nickel (II) ions The photoluminescence
properties of the six complexes indicated that the introduction of different anions can enhance or weaken the intra-ligand transitions of
fluconazole.
r 2007 Elsevier Inc. All rights reserved.
Keywords: Fluconazole; Anion; Solvent; Self-assembly; Photoluminescence
1. Introduction
their relative high solvation free energies [5]. Based on
the principle of electroneutrality that all pure substances
fulfill, in the crystalline phase all positive charges must
be compensated by negative counter charges, either
the positive charge on the metal center is balanced by the
negative charge on the organic ligand or if this was not the
case, a third anionic component would be required. In an
attempt to rationalize the effect of the counteranion upon
the self-assembly, our strategy is to choose a neutral
organic ligand which has a tendency to form metal
complexes.
Fluconazole, a good antifungal agent in the treatment of
candidiasis [6] first seized our attention based on the
following considerations: (a) from the view of biological
importance, the interaction between metal ions with drugs
is a subject of great interest [7]. In some cases, the highest
activity of drug is associated with a metal atom [8]. (b) Two
1,2,4-triazole ligands of fluconazole (Scheme 1a) can
Anion binding and recognition have received much
attention, because of its importance in biological and
chemical processes [1–2]. Many enzyme reactions involve
the selective transformation of anions [1]. The selective
extraction of anionic pollutants also requires the develop-
ment of specific coordination sites [2a]. Anion-directed self-
assembly is an important field in anion coordination
chemistry [3]. However, rational design of anion-assisted
self-assembly processes is particularly challenging com-
pared with to the analogous studies involving cationic and
neutral species [4], which is attributed to some of the
intrinsic properties of anions such as their diffuse nature
(small charge to radius ratio), pH sensitivity, and
Ã
Corresponding author. Fax: +86 23 6282 8869.
E-mail address: cwhu@bit.edu.cn (C. Hu).
0022-4596/$ - see front matter r 2007 Elsevier Inc. All rights reserved.
doi:10.1016/j.jssc.2007.01.036

ARTICLE IN PRESS
Y. Gong et al. / Journal of Solid State Chemistry 180 (2007) 1476–1488
1477
spectrofluorometer equipped with a 450W xenon lamp as
the excitation source. All measurements were performed at
room temperature.
2.2. Synthesis
(C13H11N6OF2)2Ni2(NO3)2 (1): A mixture of Ni(NO3)2 ꢀ
6H2O (0.5 mmol, 0.146 g), fluconazole (0.5 mmol, 0.153 g)
and DMF (N,N0-dimethyllformamide) (10 mL) was sealed
in a Teflon-lined autoclave and heated at 110 1C for three
days, then followed by slow cooling to room temperature.
The resulting green crystals were filtered off and washed
with DMF (yield: ca. 95% based on fluconazole). Ele-
mental Anal. Found: C, 36.78; H, 2.66; N, 23.18%. Calcd.
for C26N14H22Ni2O8F4: C, 36.62; H, 2.58; N, 23.00%. IR
(cmꢁ1): 3419(m), 3111(m), 1619(m), 1497(s), 1386(s),
1288(s), 1151(s), 1058(m), 958(s), 870(m), 673(m), 656(m).
(C13H12N6OF2)2Ni(NO3)2 ꢀ H2O (2): The preparation of
complex 2 was similar to that of complex 1 except using
water instead of DMF. Yield: ca. 95% based on
fluconazole. Elemental Anal. Found: C, 38.49; H, 3.12;
N, 24.32%. Calcd. for C26N14H26NiO9F4: C, 38.38;
H, 3.20; N, 24.11%. IR(cmꢁ1): 3331(m), 3136(m),
1622(m), 1504(s), 1352(s), 1284(s), 1130(s), 1053(m),
962(s), 867(m), 678(m), 663(m).
(C13H12N6OF2)Ni(SO4)(DMF)2(H2O) (3): The prepara-
tion of complex 3 was similar to that of complex 1 except
using NiSO4 (0.5 mmol, 0.131 g) instead of Ni(NO3)2 ꢀ
6H2O. Yield: ca. 90% based on fluconazole. Elemental
Anal. Found: C, 36.59; H, 4.52; N, 17.78%. Calcd. for
C19N8H28NiO8F2S: C, 36.48; H, 4.48; N, 17.92%.
IR(cmꢁ1): 3128(s), 1660(s), 1530(s), 1504 (s), 1421(s),
1383(s), 1288(s), 1084(s), 967(m), 859(m), 680(m), 661(m).
(C13H12N6OF2)2Ni(H2O)2(SO4) ꢀ 4H2O (4): The prepara-
tion of complex 4 was similar to that of complex 3 except
using water instead of DMF. Yield: ca. 90% based on
fluconazole. Elemental Anal. Found: C, 35.59; H, 4.02; N,
19.01%. Calcd. for C26N12H36NiO12F4S: C, 35.66; H, 4.11;
N, 19.20%. IR(cmꢁ1): 3159(s), 1619(s), 1533(s), 1498(s),
1426(s), 1375(m), 1290(s), 1153(s), 1036(s), 967(m), 852(m),
671(s).
Scheme 1. The structure of fluconazole (a) and the geometrical config-
uration of anions (b).
combine metal ions in their neutral form and anion must be
incorporated into the metal complexes for the balance of
charge. (c) Three carbon atoms bridge the two triazole
ligands and the flexible C–C chain of fluconazole can be
rotated for suitable position and angle to fit the size and
geometrical configuration of anions in the self-assembly of
metal complexes. (d) The big substituent, 2,4-difluorophe-
nyl, can avoid the interpenetration due to steric hindrance
at metal center when fluconazole binds to metal ion.
In the present work, we choose four kinds of ordinary
anions with different sizes and geometrical configurations,
that is, spherical Clꢁ, trigonal planar NOꢁ3 , tetrahedral
SO24ꢁ and MoO24ꢁ (Scheme 1b). It is reported the syntheses,
characterization and conversion of a series of Ni(II)–
fluconazole complexes under similar reaction conditions
(including the same temperature, time and metal-to-ligand
ratio) except different counteranions. During the synthesis,
due to the pH sensitivity of anions, no acid or base was
added into the reaction mixtures. We change the species of
solvents for suitable single crystals. Their thermogravi-
metric analysis and photoluminescence properties have
been investigated. The magnetic characteristics of com-
plexes 1, 3 and 6 have been explored.
2. Experimental section
2.1. General considerations
All chemicals purchased were of reagent grade and used
without further purification. Fluconazole was supplied by
Chongqing care life pharmaceutical limited company. C,
H, N elemental analyses were performed on Perkin–Elmer
240c elemental analyzer. Infrared spectra were recorded as
KBr pellets on a Nicolet 170SXFT/IR spectrometer. TG
analyses were carried out in air between 20 and 1000 1C at a
heating rate of 10 1C minꢁ1 on a NETZSCH STA 449 1C
simultaneous thermal analyzer. The magnetic susceptibility
data were recorded over the 2–300 K temperature range
using a Quantum Design MPMS-5S SQUID suscept-
ometer. X-ray powder diffraction (XRD) of samples were
collected on a Japan Rigaku D/max gA X-ray diffract-
ometer equipped with graphite monochromatized CuKa
radiation (l ¼ 0.154060 nm). The 2y range used was from
51 to 401 in steps of 0.041 with a count time 1 s. Excitation
and emission spectra were obtained on an RF-5301PC
(C13H12N6OF2)2NiCl2 ꢀ 2(CH3OH) (5): The synthesis of
complex 5 was carried out as described above for complex 1,
but starting with NiCl2 ꢀ 6H2O (0.5 mmol, 0.119 g) and
methanol instead of Ni(NO3)2 ꢀ 6H2O and DMF. Yield:
ca. 90% based on fluconazole. Elemental Anal. Found: C,
41.79; H, 4.02; N, 20.61%. Calcd. for C28N12H32NiO4F4Cl2:
C, 41.58; H, 3.96; N, 20.79%. IR(cmꢁ1): 3257(s), 1620(s),
1522(s), 1499(s), 1418(s), 1279(s), 1128(s), 1086(m), 968(m),
675(s).
(C13H12N6OF2)4Ni2 (MoO4)2 ꢀ 6H2O (6): The synthesis of
complex 6 was carried out as described above for complex
1, but starting with the mixture of NiCl2 ꢀ 6H2O (0.5 mmol,
0.119 g), Na2MoO4 ꢀ 2H2O (1 mmol, 0.242 g), fluconazole
(0.5 mmol, 0.153 g) and water (10 mL). Yield: ca. 60%
based on fluconazole. Elemental Anal. Found: C, 35.51; H,
3.12; N, 18.66%. Calcd. for C52N24H60Ni2O18F8Mo2: C,

ARTICLE IN PRESS
Y. Gong et al. / Journal of Solid State Chemistry 180 (2007) 1476–1488
1478
35.25; H, 3.39; N, 18.98%. IR(cmꢁ1): 3384(s), 3104(s),
1618(s), 1524(s), 1499(s), 1426(s), 1285(s), 1139(s), 1112(m),
839(s), 659(m).
2.3. Crystallographic studies
XRD data of complexes 1–6 were collected on a Bruker-
AXS CCD area detector-equipped diffractometer with
˚
graphite-monochromatized MoKa (l ¼ 0.71073 A) radia-
tion at room temperature. A total of 19,676 (3892 unique,
1
Rint ¼ 0.0302) reflections of complex
(ꢁ9php17,
ꢁ18pkp16, ꢁ22plp21, 2:38oyo28:27), a total of
8183 (2917 unique, Rint ¼ 0.0455) reflections of 2 (ꢁ11p
hp12, ꢁ18pkp14, ꢁ24plp23, 1:95oyo25:01), a total
of 14081 (4787 unique, Rint ¼ 0.0607) reflections of 3
(ꢁ11php15, ꢁ12pkp16, ꢁ17plp16, 2:00oyo25:01),
a total of 19,039 (6482 unique, Rint ¼ 0.0301) reflections of
4 (ꢁ15php18, ꢁ21pkp21, ꢁ13plp15, 1:95oyo25:01),
a total of 9121 (3173 unique, Rint ¼ 0.0381) reflections of 5
(ꢁ25php27, ꢁ11pkp10, ꢁ23plp22, 2:11oyo25:01), a
total of 11208 (4209 unique, Rint ¼ 0.0284) reflections of 6
(ꢁ20php24, ꢁ21pkp21, ꢁ17plp17, 1:80oyo28:36)
were measured. An empirical absorption correction from c
scan was applied. All the structures were solved by direct
methods and expanded using Fourier techniques. The
nonhydrogen atoms were refined anisotropically. All of
the hydrogen atoms were placed in the calculated positions.
All calculations were performed using the SHELXTL-97
program. The CCDC reference numbers are the following:
297,388 for complex 1, 297,389 for complex 2, 297,392 for
complex 3, 297,393 for complex 4, 297,390 for complex 5,
297,391 for complex 6. Crystal data and structure refine-
ments for compounds 1–6 are listed in Table 1. Selected
bond lengths and angles for compounds 1–6 are listed in
Tables 2–7. Further details are provided in the Supporting
Information.
3. Results and discussion
3.1. Synthesis
Hydrothermal or solvothermal synthesis has recently
been proved a useful technique in preparation of crystalline
inorganic–organic hybrids. In our case, compounds 1–6
were prepared by such method. Under such conditions, the
different solubilities of the organic and inorganic starting
materials are alleviated. The hydrothermal or solvothermal
temperature (below 200 1C) avoids decomposition of
organic components and promotes ‘‘self-assembly’’ of
crystalline metastable phases from simple molecular pre-
cursors.
In the present work, the preparations of compounds 1–6
were not susceptible to the reaction temperature and
reaction time. In general, solutions of fluconazole and
metal salt were treated hydrothermally or solvothermally
for 2–3 days at temperatures of 110–180 1C to produce

ARTICLE IN PRESS
Y. Gong et al. / Journal of Solid State Chemistry 180 (2007) 1476–1488
1479
Table 2
Selected bond lengths (A) and angles (deg) for complex 1
Table 5
Selected bond lengths (A) and angles (deg) for complex 4
˚
˚
Bond lengths
Bond lengths
Ni(1)–N(6)#1
Ni(1)–N(3)
Ni(1)–O(1)#1
Ni(1)–N(2)
Ni(1)–O(2)
2.0160(14) Ni(1)–O(1)
2.051(2) Ni(1)–N(5)#1
2.1261(16) Ni(1)–O(3)
2.0242(13)
2.0573(19)
2.1548(18)
2.007(2) Ni(1)–N(6)#2
2.025(2) Ni(1)–N(3)#3
2.389(2) Ni(1)–O(2)
2.018(2) Ni(2)–N(12)#5
2.022(2) Ni(2)–N(9)
2.396(2) Ni(2)–O(4)
2.007(2)
2.025(2)
2.389(2)
2.018(2)
2.022(2)
2.396(2)
Ni(1)–O(2)#3
Ni(2)–N(12)#4
Ni(2)–N(9)#6
Ni(2)–O(4)#6
Bond angles
O(1)#1–Ni(1)–O(1) 82.06(6)
O(1)–Ni(1)–N(5)#1 170.52(7)
O(1)#1–Ni(1)–N(2) 98.92(7)
O(1)#1–Ni(1)–O(2) 159.62(7)
N(2)–Ni(1)–N(5)#1
C(4)–N(2)–Ni(1)
N(2)–Ni(1)–O(3)
93.69(8)
136.57(17)
160.84(7)
O(2)–Ni(1)–O(3)
N(1)–N(2)–Ni(1)
C(6)–N(5)–Ni(1)#1 136.24(18)
60.45(7)
Bond angles
118.63(14)
N(6)#1–Ni(1)–N(6)#2
N(6)#2–Ni(1)–N(3)
N(12)#4–Ni(2)–N(12)#5 180.0
180.0
N(6)#1–Ni(1)–N(3)
88.67(9)
89.43(8)
91.33(9) N(9)#6–Ni(2)–O(4)
N(12)#4–Ni(2)–O(4)#6 89.59(9)
C(20)–N(12)–Ni(2)#8 128.2(2)
129.90(19)
Symmetry transformations used to generate equivalent atoms: #1
ꢁx þ 1; ꢁy þ 2; ꢁz þ 1.
C(7)–N(6)–Ni(1)#7
C(5)–N(3)–Ni(1)
129.2(2)
126.12(19) C(18)–N(9)–Ni(2)
Symmetry transformations used to generate equivalent atoms: #1
x; ꢁy þ 3=2; z ꢁ 1=2; #2 ꢁx þ 2; y ꢁ 1=2; ꢁz þ 3=2; #3 ꢁx þ 2; ꢁy þ 1;
ꢁz þ 1; #4 x; ꢁy þ 3=2; z þ 1=2; #5 ꢁx þ 1; y ꢁ 1=2; ꢁz þ 1=2 #6
ꢁx þ 1; ꢁy þ 1; ꢁz þ 1; #7 ꢁx þ 2; y þ 1=2; ꢁz þ 3=2; #8 ꢁx þ 1;
y þ 1=2; ꢁz þ 1=2.
Table 3
Selected bond lengths (A) and angles (deg) for complex 2
˚
Bond lengths
Ni(1)–N(6)#1
Ni(1)–N(3)
Ni(1)–O(2)
2.024(4)
2.026(4)
2.427(4)
Ni(1)–N(6)
Ni(1)–N(3)#1
Ni(1)–O(2) #1
2.024(4)
2.026(4)
2.427(4)
Table 6
Selected bond lengths (A) and angles (deg) for complex 5
˚
Bond angles
Bond lengths
N(6)#1–Ni(1)–N(6)
N(6)–Ni(1)–O(2)
N(3)–Ni(1)–O(2)
C(2)–N(3)–Ni(1)
N(7)–O(2)–Ni(1)
180.00(16)
87.65(17)
88.09(15)
126.6(3)
N(6)#1–Ni(1)–N(3)
N(3)#1–Ni(1)–O(2)
N(6)#1–Ni(1)–N(3)#1
C(1)–N(3)–Ni(1)
90.43(15)
91.91(15)
89.57(15)
131.1(3)
Ni(1)–N(6)#1
Ni(1)–N(3)#3
Ni(1)–Cl(1)
2.133(3)
2.145(3)
2.5246(10) Ni(1)–Cl(1)#3
Ni(1)–N(6)#2
Ni(1)–N(3)
2.133(3)
2.145(3)
2.5246(10)
Bond angles
N(6)#1–Ni(1)–N(6)#2 180.00(12)
N(6)#2–Ni(1)–N(3)#3 91.14(11)
148.8(3)
O(1)–C(4)–C(5)#2
109.2(3)
N(6)#1–Ni(1)–N(3)#3 88.86(11)
N(3)–Ni(1)–Cl(1)
N(6)#2–Ni(1)–Cl(1)
C(5)–N(3)–Ni(1)
C(6)–N(6)–Ni(1)#4
90.00(8)
89.46(8)
129.6(2)
132.1(2)
Symmetry transformations used to generate equivalent atoms: #1
ꢁx þ 1=2; ꢁy þ 3=2; ꢁz þ 1; #2 ꢁx þ 3=2; ꢁy þ 3=2; ꢁz þ 1.
N(6)#1–Ni(1)–Cl(1)
Cl(1)–Ni(1)–Cl(1)#3 180.00(4)
C(4)–N(3)–Ni(1) 127.2(3)
90.54(8)
Symmetry transformations used to generate equivalent atoms: #1
x; ꢁy þ 1; z ꢁ 1=2; #2 ꢁx þ 1=2; y þ 1=2; ꢁz þ 1=2; #3 ꢁx þ 1=2;
ꢁy þ 3=2; ꢁz; #4 ꢁx þ 1=2; y ꢁ 1=2; ꢁz þ 1=2.
Table 4
Selected bond lengths (A) and angles (deg) for complex 3
˚
Bond lengths
Ni(1)–O(2)
Ni(1)–O(6)
Ni(1)–O(7)
2.065(3)
2.087(4)
2.091(3)
Ni(1)–N(3)
Ni(1)–O(3)#1
Ni(1)–N(6)#2
2.081(4)
2.089(3)
2.094(4)
Table 7
Selected bond lengths (A) and angles (deg) for complex 6
˚
Bond angles
O(2)–Ni(1)–N(3)
O(7)–Ni(1)–N(6)#2
N(3)–Ni(1)–O(3)#1
C(4)–N(3)–Ni(1)
C(5)–N(3)–Ni(1)
88.80(15)
177.12(15)
175.88(15)
126.0(3)
O(2)–Ni(1)–O(6)
N(3)–Ni(1)–O(6)
N(3)–Ni(1)–O(7)
S(1)–O(2)–Ni(1)
S(1)–O(3)–Ni(1)#1
174.30(15)
85.50(16)
87.37(15)
138.0(2)
Bond lengths
Mo(1)–O(3)#1
Mo(1)–O(2)#1
Ni(1)–O(2)#2
Ni(1)–N(3)
1.736(3) Mo(1)–O(3)
1.757(2) Mo(1)–O(2)
2.005(2) Ni(1)–O(2)
2.112(3) Ni(1)–N(3)#2
2.126(3) Ni(1)–N(6)#4
1.736(3)
1.757(2)
2.005(2)
2.112(3)
2.126(3)
131.5(4)
134.7(2)
Ni(1)–N(6)#3
Symmetry transformations used to generate equivalent atoms: #1
ꢁx; ꢁy þ 1; ꢁz; #2 ꢁx; ꢁy þ 1; ꢁz þ 1.
Bond angles
O(3)#1–Mo(1)–O(3)
O(3)–Mo(1)–O(2)#1
O(2)#2–Ni(1)–O(2)
N(3)#2–Ni(1)–N(6)#4
C(6)–N(6)–Ni(1)#5
111.0(3) O(3)#1–Mo(1)–O(2)
108.41(14) O(3)#1–Mo(1)–O(2)#1 109.71(15)
108.41(14)
180.0(2)
87.61(10) N(6)#3–Ni(1)–N(6)#4
131.2(2) Mo(1)–O(2)–Ni(1)
O(2)#2–Ni(1)–N(3)
88.10(11)
180.0(2)
158.11(16)
crystalline products in good yields (90–95% for complexes
1–5 and 60% for complex 6).
The preparations of compounds 1–5 were not susceptible
to the molar ratios of reactants. Compounds 1–5 can be
obtained upon the 1:1 or 2:1 mol ratio of Ni(II)/flucona-
zole. As well known, the 1:1 mol ratio of Ni(II)/fluconazole
represents 1:1 mol ratio of SO24ꢁ/fluconazole and 2:1 mol
ratio of NOꢁ3 (or Clꢁ)/ fluconazole in starting materials.
According to the molecular formula of complexes 1–6, the
Symmetry transformations used to generate equivalent atoms: #1
ꢁx þ 1; y; ꢁz ꢁ 1=2; #2 ꢁx þ 1; ꢁy; ꢁz; #3 x ꢁ 1=2; ꢁy þ 1=2; z ꢁ 1=2;
#4 ꢁx þ 3=2; y ꢁ 1=2; ꢁz þ 1=2; #5 ꢁx þ 3=2; y þ 1=2; ꢁz þ 1=2.
stoichiometric ratio of Ni(II) (or anions)/ fluconazole in
complexes 1–6 is 1:1 or 1:2. The experimental data and
stoichiometric ratio show that both Ni(II) and anions in

ARTICLE IN PRESS
Y. Gong et al. / Journal of Solid State Chemistry 180 (2007) 1476–1488
1480
starting materials are in excess with respect to fluconazole
and it is ensured that fluconazole can be transformed as
possible as totally in the self-assembly of the six
compounds. Interestingly, in the synthesis of complex 6,
both the molar ratio of MoO24ꢁ/fluconazole and that of
Clꢁ/fluconazole are 2:1 in starting materials, but only
MoO24ꢁ has entered into the crystalline phase of complex 6.
dihedral angle of the two triazole planes in one fluconazole
is 57.91.
3.2.2. Crystal structure of (C13H12N6OF2)2Ni(NO3)2 ꢀ
H2O (2)
In the construction of metal–organic polymers, solvent
effect has received much attention [9]. If protic solvent such
as water was utilized instead of DMF in the preparation of
complex 1, a new complex (C13H12N6OF2)2 Ni(NO3)2 ꢀ
H2O (2) was obtained. Complex 2 crystallizes in C2/c space
group, its asymmetric unit is similar to that in complex 1
except containing an additional dissociated water. The
Ni(II) center is coordinated by four nitrogen atoms from
four fluconazole and two oxygen atoms from two NOꢁ3 to
furnish an octahedral geometry. Each fluconazole links two
Ni(II) centers via its two triazole ligands, leaving the
hydroxyl group uncoordinated. The Ni?Ni distance is
3.2. Description of crystal structures
3.2.1. Crystal structure of (C13H11N6OF2)2Ni2(NO3)2 (1)
DMF, as a polar aprotic solvent, possesses superior
solvent power. When Ni(NO3)2 and DMF were utilized, a
molecular binuclear nickel cluster (C13H11N6OF2)2Ni2
(NO3)2 (1) was obtained (Fig. 1). Complex 1 crystallizes
in Pbca space group, with one Ni(II), one fluconazole and
one bidentate-coordinated NOꢁ3 in the asymmetric unit.
The Ni(II) center exhibits a distorted octahedral geometry
and is six coordinated by two nitrogen atoms and four
oxygen atoms. The nitrogen atoms are from two triazole
ligands of two fluconazole. Two oxygen atoms are from
one NOꢁ3 and another two oxygen atoms are from two
hydroxyl groups of two fluconazole. Complex 1 consists of
two symmetrical fluconazole, each of which links two
Ni(II) centers via its deprotonated hydroxyl group and two
˚
10.356 A and the dihedral angle between the two triazole
planes in one fluconazole is 91.21. The Ni(II) centers are
bridged by double-stranded fluconazole and complex 2
exhibits a one-dimensional (1D) chain-like structure
(Fig. 2).
The NOꢁ3 in complex 2 exhibits monodentate coordina-
˚
tion mode (Fig. 2) and the Ni–O distance (2.427 A)
(Table 3) is much longer than that in complex 1 (Ni(1)–
˚
˚
O(2): 2.1261(16) A, Ni(1)–O(3) 2.1548(18) A) (Table 2),
which indicates that the binding strength of NOꢁ3 anion in
polar protic solvent (water) is weaker than that in polar
aprotic solvent (DMF). Interestingly, on heating complex 2
in DMF under reaction conditions (sealed in Teflon-lined
autoclaves and heated at 110 1C for 3 days), we can obtain
complex 1, as evidenced by the powder XRD pattern of the
product, which is in good accordance with the simulated
XRD powder pattern of complex 1 (see Fig. S1 in the
supporting information). However, heating complex 1 in
water can not give complex 2. The irreversible conversion
between complexes 1 and 2 indicated that complex 1 is
more thermodynamic stable than complex 2. Actually, the
edge-sharing binuclear nickel clusters are common in
biological system [10], maybe it is due to their thermo-
dynamic stability.
˚
triazole ligands. The Ni?Ni distance is 3.048 A and the
Fig. 1. Binuclear nickel cluster of complex 1 (H atoms omitted for clarity).
Fig. 2. 1D chain-like structure of complex 2 (H atoms and dissociated water omitted for clarity).

ARTICLE IN PRESS
Y. Gong et al. / Journal of Solid State Chemistry 180 (2007) 1476–1488
1481
3.2.3. Crystal structure of (C13H12N6OF2)Ni(SO4)(DMF)2
(H2O) (3)
zole-bridge and double stranded SO24ꢁ-bridge are observed
in complex 3 (Fig. 3). SO24ꢁ, as a good H-bond acceptor,
can be coordinated to metal center, however, such double-
stranded SO24ꢁ-bridge is rarely reported in previous work.
In order to investigate the effect of anionic size on the
structural motif, a bigger anion such as SO24ꢁ is chosen.
When NiSO4 was utilized as starting material instead of
Ni(NO3)2 in the preparation of complex 1, a novel complex
(C13H12N6OF2)Ni(SO4)(DMF)2(H2O) (3) was obtained.
Complex 3 crystallizes in P21/c space group, its asymmetric
unit contains one Ni(II), one fluconazole, one SO24ꢁ, one
coordinated water, one coordinated DMF and one
dissociated DMF.
3.2.4. Crystal structure of (C13H12N6OF2)2Ni(H2O)2(SO4)ꢀ
4H2O (4)
If water was utilized as solvent instead of DMF in the
preparation of complex 3, another novel complex
(C13H12N6OF2)2Ni(H2O)2(SO4) ꢀ 4H2O (4) was obtained.
Complex 4 crystallizes in P21/c space group, its asymmetric
unit contains two Ni(II), two fluconazole, two coordinated
water, one dissociated SO24ꢁ and four dissociated water.
Two crystallographically unique Ni(II) exhibit similar
octahedral coordination spheres, each of them is six
coordinated by two aqua ligands and four nitrogen atoms
from four fluconazole. Complex 4 exhibits a two-dimen-
sional (2D) parquet motif with a uniform (4, 4) net
topology (Fig. 4). The two crystallographically unique
metal centers, Ni(1) (position coordinates: 1.000, 0.500,
The Ni(II) center in complex 3 exhibits a distorted
octahedral geometry and is six coordinated by one aqua
ligand, one DMF, two nitrogen atoms from two flucona-
zole, and two oxygen atoms from two SO24ꢁ. Each
fluconazole links two Ni(II) centers (Ni?Ni distance:
˚
10.794 A) via its two triazole ligands (dihedral angle: 80.41),
leaving the hydroxyl group uncoordinated. One SO24ꢁ links
˚
two Ni(II) centers with the Ni?Ni distance of 4.937 A.
Thus, 1D chains constructed by double stranded flucona-
Fig. 3. 1D chain bridged by two stranded SO24ꢁ and fluconazole in complex 3 (H atoms and dissociated DMF omitted for clarity).
Fig. 4. 2D structure of complex 4 (H atoms, dissociated SO24ꢁ and water omitted for clarity).

ARTICLE IN PRESS
Y. Gong et al. / Journal of Solid State Chemistry 180 (2007) 1476–1488
1482
Fig. 5. 3D porous framework of complex 4 and guest SO24ꢁ anions and water molecules occupy the channel (H atoms omitted for clarity).
Fig. 6. 2D framework of complex 5, which is constructed by alternating left and right-handed helices: (a) side-view; (b) top-view; (c) space filling diagrams
of the isolated right-handed and left-handed helices (H, Clꢁ atoms, 2,4-difluorophenyl group of fluconazole and methanol molecules omitted for clarity).
0.500) and Ni(2) (position coordinates: 0.500, 0.500, 0.500)
are located in two neighboring layers. The neighboring
Ni(1)?Ni(1A) and Ni(2)?Ni(2A) distances are the same
(11.077 A). The dihedral angles between the two triazole
planes of the two crystallographically unique fluconazole
are 79.61 and 89.41, respectively. The 2,4-difluorophenyl
ligands of fluconazole orient above or below each layer and
there is not strong p–p stacking interactions between the
aromatic groups because the centroid–centroid distance is
˚
˚
no shorter than 4.3 A. However, weak interactions exist

ARTICLE IN PRESS
Y. Gong et al. / Journal of Solid State Chemistry 180 (2007) 1476–1488
1483
Fig. 7. 2D structure of complex 6 with the phenyl rings of fluconazole orderly array within the layer (H, Mo atoms, and dissociated water omitted for
clarity).
between the F atom of phenyl ligand and the O atom in the
neighboring layers, for example, the F4?O2A distance is
˚
3.350 A (atom with additional label A refers to the
symmetry operation: 1 ꢁ x, ꢁ0:5 þ y, 0:5 ꢁ z). Complex 4
exhibits a three-dimensional (3D) porous architecture and
the channels are occupied by the dissociated SO24ꢁ and
water molecules (Fig. 5). Calculated by PLATON soft-
3
˚
ware, the channel is ca. 472 A per unit cell. Weak
interactions also exist between the SO24ꢁ and the neighbor-
ing layers, for example, the O5?O2B, O5?O4, O6?O1C
˚
distances are 2.734, 2.775, 2.790 A, respectively (atom with
additional labels B and C refer to the symmetry operations:
B xꢁ1, y, z; C xꢁ1, 1.5ꢁy, ꢁ0.5+z). The shorter O?O
2ꢁ
˚
distances (less than 2.8 A) indicate that SO4 (guest) plays
an important role in stabilizing the porous framework of
complex 4. Thus it is presumed that the porosity is not
permanent and it is closely related with the guests.
The SO24ꢁ in complex 4 is uncoordinated, whereas in
complex 3, SO24ꢁ anion covalently bridges two Ni(II)
Fig. 8. 2D layers pillared by {MoO4} tetrahedra to construct a 3D
architecture in complex 6 (H atoms and dissociated water omitted for
clarity).
˚
˚
centers (Ni(1)–O(2): 2.065(3) A, Ni(1)–O(3)#1, 2.089(3) A)
(Table 4). It is indicated that the binding strength of SO42ꢁ
anion in water is much weaker than that in DMF [11]. It is
inferred that solvents will influence the properties of the
anions, thus change the network of the product. Different
from complexes 1 and 2, complexes 3 and 4 can not be
interconverted under similar reaction conditions if change
the species of solvent.
geometry and is six coordinated by two Clꢁ and four
nitrogen atoms from four fluconazole. Each fluconazole
links two Ni(II) centers (Ni?Ni distances: 11.096 and
˚
9.288 A) via its two triazole ligands (dihedral angle: 74.51),
leaving the hydroxyl group uncoordinated. A 2D frame-
work is observed in complex 5. However, the layer is
completely different from that in complex 4, it is composed
of alternating left- and right-handed helices with a pitch of
3.2.5. Crystal structure of (C13H12N6OF2)2NiCl2 ꢀ
2(CH3OH) (5)
˚
In an attempt to explore the effect of a smaller anion on
the self-assembly of Ni(II)–fluconazole complex, Clꢁ was
chosen in our experiment. When NiCl2 and methanol were
utilized as starting materials, a complex (C13H12N6OF2)2
NiCl2 ꢀ 2(CH3OH) (5) is obtained. Complex 5 crystallizes in
C2/c space group, its asymmetric unit contains one Ni (II),
one fluconazole, one Clꢁ and one dissociated methanol
molecule. The Ni(II) center exhibits a distorted octahedral
18.576 A (Fig. 6). Interestingly, the top-view (Fig. 6b) of
the layer exhibits a 1D chain, which is similar to that
observed in complex 2.
3.2.6. Crystal structure of (C13H12N6OF2)4Ni2(MoO4)2 ꢀ
6H2O (6)
In an attempt to construct a 3D network in which anion
can act as bridging ligand, an anion with suitable size

ARTICLE IN PRESS
Y. Gong et al. / Journal of Solid State Chemistry 180 (2007) 1476–1488
1484
should be considered. When the starting material is the
mixture of NiCl2 (0.5 mmol), Na2MoO4 ꢀ 2H2O (1 mmol),
fluconazole (0.5 mmol) and water (10 mL), a novel co-
ordination polymer (C13H12N6OF2)4Ni2 (MoO4)2 ꢀ 6H2O
(6) is obtained. Complex 6 crystallizes in C2/c space group.
The ratio of the crystallographically unique Ni(II),
fluconazole, MoOꢁ4 and dissociated water molecule is
1:1:0.5:2. One dissociated water has two positions owing
to the crystallographic disorder of O(5) and O(5A). Each of
them has 50% occupancy over the two positions. The
Ni(II) center exhibits a distorted octahedral geometry and
is six coordinated by two MoOꢁ4 and four nitrogen atoms
from four fluconazole. Each fluconazole links two Ni(II)
ligands (dihedral angle: 116.51), leaving the hydroxyl group
uncoordinated. The Ni(II) centers are linked by fluconazole
to form a 2D parquet motif with a uniform (4, 4) net
topology (Fig. 7). However, different from the layers in
complex 4, the 2,4-difluorophenyl ligands of fluconazole
aren’t above or below the layer, but orderly array within
the layer. There are not weak interactions between the F
atoms and O atoms in the neighboring layers. The
centroid–centroid distance of two neighboring phenyl rings
˚
is no shorter than 4.2 A, and no strong p–p stacking
interactions exist.
Each MoOꢁ4 anion links two Ni(II) centers via its two
oxygen atoms, leaving another two oxygen atoms uncoor-
dinated. Complex 6 exhibits a 3D architecture, in which the
˚
centers (Ni?Ni distance: 11.507 A) via its two triazole
Fig. 9. TG curves for compounds 1 (a), 2 (b), 3 (b), 4 (d), 5 (e) and 6 (f).

ARTICLE IN PRESS
Y. Gong et al. / Journal of Solid State Chemistry 180 (2007) 1476–1488
1485
2D layers are pillared by {MoO4} tetrahedra (Fig. 8).
Dissociated water molecules occupied the cavities. Calcu-
3
lated by PLATON software, the cavity is ca. 83 A per unit
˚
cell. The porosity of complex 6 is more stable than that of
complex 4 because the interlayer interactions are covalent
bonds. It is rarely reported that MoOꢁ4 anion acts as
covalently bridging ligand [12], the present work shows it is
possible when MoOꢁ4 meets the size of pillar.
3.3. TG analysis
The TG analyses of the six compounds are performed in
the temperature range of 20–1000 1C. From 100 to 1000 1C,
compound 1 gradually loses its weight and the total weight
loss is 70.72% (calculated value: 71.60%), corresponding
to the oxidization and decomposition of fluconazole
(Fig. 9a).
From about 120 to 310 1C, compound 2 loses its crystal
water, the weight loss is 2.30%, in good accordance with
the calculated value (2.21%). From 310 to 1000 1C, the
weight loss is 75.20% (calculated value: 75.28%), corre-
sponding to the oxidization and decomposition of fluco-
nazole (Fig. 9b).
In the range of 50–300 1C, compound 3 loses its crystal
and coordinated solvent molecules (DMF and water), the
weight loss of this step is 26.05%, in good accordance with
the calculated value (26.24%). From 300 to 1000 1C, the
TG curve of 3 exhibits steady weight losses, which
corresponds to the oxidization and decomposition of
fluconazole (Fig. 9c). The total weight loss of 3 is
75.40%, in good accordance with the calculated value
(75.20%).
From room temperature to 320 1C, compound 4 loses its
crystal water, the weight loss is 8.45%, in good accordance
with the calculated value (8.23%). From 320 to 1000 1C,
the weight loss is 74.27% (calculated value: 74.05%),
corresponding to the loss of the coordinated water and the
oxidization and decomposition of fluconazole (Fig. 9d).
From room temperature to 310 1C, compound 5 loses its
crystal methanol molecules, the weight loss of this step is
8.05%, in good accordance with the calculated value
(7.94%). From 310 to 10001C, the TG curve of 5 exhibits
steady weight losses, which corresponds to the loss of
chlorine and the oxidization and decomposition of flucona-
zole (Fig. 9e). The total weight loss of 5 is 90.10%, in good
accordance with the calculated value (90.69%).
Compound 6 loses its crystal water in the range of
100–300 1C, the weight loss of this step is 5.95%, in good
accordance with the calculated value (6.10%). From 300 to
1000 1C, the weight loss of 6 is 69.80% (calculated value:
69.15%), which corresponds to the oxidization and
decomposition of fluconazole (Fig. 9f).
Fig. 10. The magnetic susceptibility of compounds 1 (a), 3(b) and 6 (c).
3.4. Magnetic property
range 2–300 K under 1 kOe. As for complex 1, the wꢁ1
versus T is nearly a straight line above 30 K (Fig. 10a),
which it obeys the Curie–Weiss law. The Curie and Weiss
The variable temperature magnetic susceptibility data of
compounds 1, 3 and 6 were measured in the temperature

ARTICLE IN PRESS
Y. Gong et al. / Journal of Solid State Chemistry 180 (2007) 1476–1488
1486
Fig. 11. Solid-state emission spectra at room temperature of fluconazole (a), complex 1 (b), complex 2 (c), complex 3 (d), complex 4 (e), complex 5 (f),
complex 6 (g).

ARTICLE IN PRESS
Y. Gong et al. / Journal of Solid State Chemistry 180 (2007) 1476–1488
1487
emission at 361 nm of complex 1, which is different from
that of discrete fluconazole, might be the ligand-to-metal
charge transfer (LMCT) [14]. It is indicated that the
hydroxyl group and triazole ligand of fluconazole coordi-
nated to Ni(II) center plays an important role in the
photoluminescence property of complex 1.
However, the emission spectra of complexes 2–6 are
somewhat similar to that of the discrete fuconazole, that is
to say, the four emission peaks of discrete fuconazole still
appear although some peaks shift a little, which may be due
to the uncoordinated hydroxyl group in complexes 2–6
compared with the coordinated ligands in complex 1
[13,14b]. Interestingly, it is found that the relative
intensities of the four peaks in the emission spectra of
complexes 2–6 are different (Fig. 11c–g), which indicates
that the intra-ligand transitions of fuconazole have been
enhanced or weaken to different extent due to the
introduction of different anions and the different structures
of complexes. The detailed mechanism is under investiga-
tion. Such phenomenon is rarely reported in previous work
[15] and the difference of photoluminescence between the
organic ligand and the metal–organic complex is usually
caused by the metal ion-involved charge transfer, such as
LMCT [13,14], but not by the intra-ligand transition.
Scheme 2. Anion-directed self-assembly.
constants, C and y are 1.18 cm3 K molꢁ1 and ꢁ4.24 K,
respectively, based on the equation wꢁ1 ¼ C=ðT2yÞ. The
negative Weiss constant indicates an overall intramolecular
weakly antiferromagnetic interaction between the nickel(II)
ions. At low temperature, the wMT increasing maybe
caused by zero splitting and magnetic anisotropy.
The variable temperature magnetic susceptibility data for
complex 3 is similar to complex 1 (Fig. 10b). However, C
and y are 1.26cm3 K molꢁ1 and ꢁ8.77K, respectively,
indicating an overall intramolecular antiferromagnetic
interaction between the nickel(II) ions. The magnetic
coupling between nickel(II) through the ligand and inter-
4. Conclusion
In conclusion, using fluconazole and Ni (II) salts, six
anion-directed self-assemblies have been synthesized with
their structures spanning zero, one, two and three
dimensions (Scheme 2). Complex 2 can be irreversibly
converted to complex 1 in the presence of DMF. The
photoluminescence properties of complexes 1–6 indicate
that the introduction of different anions can lead to
different structures of Ni(II)-complexes, and thus enhance
or weaken the intra-ligand transitions of fluconazole.
As well known, the interaction of metal ions with drugs
would influence the activities of drugs. The metal oxidation
state, the type and number of donor atoms, as well as their
relative disposition within the ligand are major factors
determining structural and activity relationship [7,8].
However, so far the effect of anion on the property of
drug is still unexplored. The field is firstly investigated in
the present work and it is indicated that the anions can
influence the photoluminescence property of drug.
˚
chain can be ignored for the long distance (410.794A).
Complex 6 shows an antiferromagnetic interaction
between the nickel (II) ions. Magnetic data for the
compound is plotted in Fig. 10c. The wMT value of
complex 6 smoothly decreases as the temperature is
lowered, attains about 70 K and quickly decreases in the
lower temperature region. According to the structural data,
nickel (II) ions are separated by fluconazole and the
magnetic coupling is very weak, the magnetic properties
are similar to single ions behavior.
3.5. Photoluminescence property
The powder X-ray diffraction patterns of complexes 1–6
are shown in Fig. S2 in the supporting information. All the
peaks of the six complexes can be indexed to their
respective simulated XRD powder pattern, which indicates
each of the six complexes is pure phase. The emission
spectra of fluconazole and complexes 1–6 in the solid state
(lex ¼ 310 nm) at room temperature are depicted in Fig. 11.
As shown in Fig. 11a, fluconazole displays one intense
emission peak at 371 nm and three weak shoulder peaks at
397, 453, 470 nm, they are attributable to different intra-
ligand transitions of fuconazole, such as p-p*, p*-n,
n-n*, p-n transitions [13]. In the emission spectra of
complex 1, the weak shoulder peaks at 397 and 453 nm of
discrete fuconazole disappear, whereas the peak of 470 nm
appears as the maximum emission peak (Fig. 11b). The
Owning to the variety of anions, further research can
focus on the introduction of various kinds of anions with
different functions into the metal–fluconazole complexes,
such as Nꢁ3 , polyanions. It is under investigation now.
Acknowledgments
This work was supported by the National Natural
Science Foundation of China (No. 20331010), and the
Natural Science Foundation Project of Chongqing
(No. CSTC/ 2006BB4178).

ARTICLE IN PRESS
Y. Gong et al. / Journal of Solid State Chemistry 180 (2007) 1476–1488
1488
Appendix A. Supporting information
[6] A.E. Heald, G.M. Cox, W.A. Schell, J.A. Barlett, J.A. Perfect, AIDS
10 (1996) 263.
[7] (a) R.J. Sunberg, R.B. Martin, Chem. Rev. 74 (1974) 471;
(b) M.A. Ali, A.H. Mirza, M. Nazimuddin, P.K. Dhar, R.J. Butcher,
Trans. Met. Chem. 27 (2002) 27.
Supplementary data associated with this article can be
found in the online version at doi:10.1016/j.jssc.2007.01.036.
[8] (a) N.M. Agh-Atabay, B. Dulger, F. Gucin, Eur. J. Med. Chem. 38
(2003) 875;
(b) Y. Inoue, M. Hoshino, H. Takahashi, T. Noguchi, T. Murata, Y.
Kanzaki, H. Hamashima, M. Sasatru, J. Inorg. Biochem. 92
(2002) 37;
References
[1] (a) P. Molenveld, S. Kapsabelis, J.F.J. Engbersen, D.N. Reinhoudt,
Chem. Rev. 119 (1997) 2948;
(c) S.E. Castilo-Blum, N. Barba-Behrens, Coord. Chem. Rev. 196
(2000) 3;
(b) F.P. Schmidtchen, M. Berger, Chem. Rev. 97 (1997) 1609.
[2] (a) P.D. Beer, Chem. Commun. (1996) 689;
(b) W. Xu, J.J. Vittal, R.J. Puddephatt, Chem. Commun. 117 (1995)
8362;
(d) R.N. Patel, S. Kumar, K.B. Pandeya, J. Inorg. Biochem. 9 (2002)
61;
¨
(e) A. Tavman, B. Ulkuseven, N.M. Agh-Atabay, Trans. Met.
¨
Chem. 25 (2000) 324.
(c) A. Bianchi, E. Garcı
´
a- Espana, K. Bowman-James, Supramole-
[9] (a) T. Wu, D. Li, S.W. Ng, Cryst. Eng. Commun. 7 (2005) 514;
(b) M.A. Withersby, A.J. Blake, N.R. Champness, P.A. Cooke,
P. Hubberstey, W.S. Li, M. Schroder, Inorg. Chem. 38 (1999)
2259.
cular Chemistry of Anions, Wiley-VCH, Weinheim, 1997,
pp. 1–30.
[3] (a) H.J. Kim, W.C. Zin, M. Lee, J. Am. Chem. Soc. 126 (2004) 7009;
(b) S.J. Coles, J.G. Frey, P.A. Gale, M.B. Hursthouse, M.E. Light,
K. Navakhun, G.L. Thomas, Chem. Commun. (2003) 1462;
(c) P.A. Gale, Coord. Chem. Rev. 240 (2003) 191;
(d) R. Vilar, Angew. Chem. Int. Ed. 42 (2003) 1460;
(e) J.L. Atwood, A. Szumna, Chem. Commun. (2003) 940;
(f) M. Schweiger, S.R. Seidel, A.M. Arif, P.J. Stang, Inorg. Chem.
41 (2002) 2556;
[10] (a) P. Amara, A. Volbeda, J.C. Fontecilla-Camps, M.J. Field, J. Am.
Chem. Soc. 127 (2005) 2776;
(b) T.C. Harrop, M.M. Olmstead, P.K. Mascharak, J. Am. Chem.
Soc. 126 (2004) 14714;
(c) S.J. George, J. Seravalli, S.W. Ragsdale, J. Am. Chem. Soc. 127
(2005) 13500.
[11] A.A. Fedorov, D. Joseph-McCarthy, E. Fedorov, D. Sirakova,
I. Graf, S.C. Almo, Biochemistry 35 (1996) 15962.
[12] B. Moulton, M.J. Zaworotko, Chem. Rev. 101 (2001) 1629.
[13] (a) W. Chen, J.Y. Wang, C. Chen, Q. Yue, H.M. Yuan, J.X. Chen,
S.N. Wang, Inorg. Chem. 42 (2003) 944;
(g) P.A. Gale, Coord. Chem. Rev. 213 (2001) 79;
(h) S.T. Cheng, E. Doxiadi, R. Vilar, A.J.P. White, D.J. Williams,
Dalton Trans. (2001) 2239;
(i) P.D. Beer, P.A. Gale, Angew. Chem. Int. Ed. 40 (2001) 486
(and references therein);
(b) M.S. Wang, G.C. Guo, M.L. Fu, L. Xu, L.Z. Cai, J.S. Huang,
Dalton Trans. (2005) 2899;
(j) P.A. Gale, Coord. Chem. Rev. 199 (2000) 181;
(k) R. Vilar, D.M.P. Mingos, A.J.P. White, D.J. Williams, Angew.
Chem. Int. Ed. 37 (1998) 1258;
(c) X.D. Chen, M. Du, T.C.W. Mak, Chem. Commun. (2005) 4417.
[14] (a) L.Y. Zhang, G.F. Liu, S.L. Zheng, B.H. Ye, X.M. Zhang,
X.M. Chen, Eur. J. Inorg. Chem. (2003) 2965;
(l) P.D. Beer, Acc. Chem. Res. 31 (1998) 71.
[4] F. Diederich, P.J. Stang, Templated Organic Synthesis, Wiley-VCH,
Weinheim, 2000, pp. 50–85.
(b) Z.Y. Fu, X.T. Wu, J.C. Dai, S.M. Hu, W.X. Du, H.H. Zhang,
R.Q. Sun, Eur. J. Inorg. Chem. (2002) 2730.
[5] B.A. Moyer, P.V. Bonnesen, Supramolecular Chemistry of Anions,
Wiley-VCH, Weinheim, 1997.
[15] Y. Gong, W. Tang, W.B. Hou, Z.Y. Zha, C.W. Hu, Inorg. Chem. 45
(2006) 4987.