1,2,4-Triazole controlled CdII/MnIIcomplexes with discrete mononuclear, polymeric 1D Chain, and 2D layer motifs

Article abstract of DOI:10.1002/zaac.200900145

Three Htrz-based metal complexes, [Cd(trz)(CH₃OH)(nb)] _n (1), [Cd(Htrz)(H₂O)(nb)₂]_n (2), and {[Mn(Htrz)₂(H₂O)₄]-2nb} (3) (Htrz = 1,2,4-triazole, Hnb = 4-nitrobenzoic a

Full text of DOI:10.1002/zaac.200900145

ARTICLE
DOI: 10.1002/zaac.200900145
1,2,4ꢀTriazole Controlled CdII/MnII Complexes with Discrete Mononuclear,
Polymeric 1D Chain, and 2D Layer Motifs
QingꢀQing Liang,[a] ZhengꢀYu Liu,[a] EnꢀCui Yang,[a] and XiaoꢀJun Zhao*[a]
Keywords: Coordination modes; Zinc; Manganese; Polymers; 1,2,4ꢀTriazole; Aromatic acids
Abstract. Three Htrzꢀbased metal complexes, [Cd(trz)(CH3OH)(nb)]n pound 3 is a supramolecular assembly containing a mononuclear
(1), [Cd(Htrz)(H2O)(nb)2]n (2), and {[Mn(Htrz)2(H2O)4]·2nb} (3) [Mn(Htrz)2(H2O)4]2+ dication and two free nb anions for charge comꢀ
(Htrz = 1,2,4ꢀtriazole, Hnb = 4ꢀnitrobenzoic acid), have been syntheꢀ pensation. Thus, the structural diversity of the three complexes is sigꢀ
sized by diffusion or solvent evaporation method and structurally charꢀ nificantly governed by the coordination modes of the neutral/depronꢀ
acterized by single crystal Xꢀray crystallography, elemental analysis, tated Htrz ligand, rather than the terminal/lattice nb anion.
IR and fluorescence spectroscopy, and TGꢀDTA. Structural determinaꢀ Additionally, the thermal stability of the complexes is observed to be
tions revealed that complex 1 has a twoꢀdimensional (2D) layer strucꢀ dependent on the polymeric or discrete structure nature. At room temꢀ
ture constructed by tridentate µN1,N2,N4ꢀbridging trz anions and CdII perature, the three solid complexes show Htrzꢀbased intraligand fluoꢀ
ions. Complex 2 presents a 1D polymeric chain structure bridged by rescent emission.
bidentate µN1,N4ꢀbridging Htrz molecule and CdII ions, whereas comꢀ
preparation methods and the metal ions, we successfully isoꢀ
Introduction
lated and characterized three novel Htrzꢀbased complex,
The 1,2,4ꢀtriazole (Htrz)ꢀbased coordination complexes have
[Cd(trz)(CH3OH)(nb)]n (1), [Cd(Htrz)(H2O)(nb)2]n (2), and
recently gained more and more interest due to their intriguing
{[Mn(Htrz)2(H2O)4]·2nb} (3) (Htrz = 1,2,4ꢀtriazole, Hnb = 4ꢀ
framework topologies and potential applications in magnetism,
nitrobenzoic acid). Interestingly, the complexes exhibit a polyꢀ
luminescence, and gas storage [1–13]. As one of the fiveꢀmemꢀ
meric 2D layer for 1, 1D chain for 2 as well as a discrete
bered nitrogen containing heterocycles, the neutral Htrz moleꢀ
cule or its deprotonated anion has exhibited multiple coordinaꢀ
mononuclear structure for 3, which is significantly controlled
by the binding modes of the Htrz. Additionally, their thermal
tion modes by far. For example, the neutral Htrz can act as a
stability and solid fluorescent emission were investigated and
terminal ligand coordinating with the discrete metal atom in a
compared.
µN4ꢀmonodentate fashion, probably resulted from the protonaꢀ
tion behavior. And the anionic trz can potentially function as
Experimental Section
Reagents and Instruments
a bridge ligand to connect different metal ions in µN1,N2ꢀ,
µN1,N4ꢀ, and µN1,N2,N4ꢀmodes. Obviously, the diverse coordinaꢀ
tion modes of Htrz in complexes are highly dependent on the
synthetic conditions, the presence of coligands as well as on
the nature of the metal ions, which critically determine the
final coordination architectures of the target complexes. To the
best of our knowledge, tridentate bridging mode of the trz is
commonly observed in the reported complexes with mixed liꢀ
gands especially those prepared by hydrothermal methods.
Therefore, the selective tuning of the coordination fashion of
Htrz is of significance for the detailed investigations on the
binding behavior as well as the controllable construction of the
wellꢀdesigned complexes. Herein, by judicious selection of the
Reagents were purchased commercially (Htrz and Hnb were from
Acros and other analytical grade reagents were from Tianjin chemical
reagent factory) and used without further purification. Doubly deionꢀ
ized water was used for the conventional synthesis. Elemental analyses
of carbon, hydrogen and nitrogen were carried out with a CEꢀ440 (Leeꢀ
man–Labs) analyzer. Fourier transform (FT) IR spectra (KBr pellets)
were taken with an AVATAR–370 (Nicolet) spectrometer in the range
4000–400 cm–1. Thermogravimetric analysis (TGA) experiments were
carried out with Shimadzu simultaneous DTG–60A thermal analysis
instrument from room temperature to 800 °C under a nitrogen atmosꢀ
phere (flow rate 10 mL·min–1) at a heating rate of 5 °C·min–1. Fluoresꢀ
cence spectra of the polycrystalline powder samples were performed
with a Cary Eclipse fluorescence spectrophotometer (Varian) equipped
with a xenon lamp and quartz carrier at room temperature.
* Prof. Dr. X.ꢀJ. Zhao
Fax: +86ꢀ22ꢀ23766556
EꢀMail: xiaojun_zhao15@yahoo.com.cn
[a] Tianjin Key Laboratory of Structure and Performance for
Functional Molecule
Synthesis of Complexes
College of Chemistry and Life Science
Tianjin Normal University
[Cd(trz)(CH3OH)(nb)]n (1): Hnb (16.7 mg, 0.1 mmol) and Htrz
(6.9 mg, 0.1 mmol) were dissolved in CH3OH (5 mL) and the pH vaꢀ
Tianjin 300387, P. R. China
Z. Anorg. Allg. Chem. 2009, 635, 2653–2659
© 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim
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Q.ꢀQ. Liang, Z.ꢀY. Liu, E.ꢀC. Yang, X.ꢀJ. Zhao
ARTICLE
lue of the mixture was carefully adjusted to 7 by triethylamine. The
mixture was then carefully layered onto an aqueous solution of
Cd(OAc)2·2H2O (26.6 mg, 0.1 mmol) in a straight test tube. Colorless
blockꢀshaped crystals appeared at the tube wall within two weeks at
room temperature. Yield: 60 % based on CdII salts. C10H10CdN4O5:
calcd. C 31.72; H 2.66; N 14.80 %, found: C 31.76; H 2.54; N
Xꢀray Crystallography
Diffraction intensities for complexes 1–3 were collected with a Bruker
APEX–II CCD diffractometer equipped with graphite–monochromated
Mo–Kα radiation with radiation wavelength 0.71073 Å by using the
φ–ω scan technique at ambient temperature. There was no evidence of
crystal decay during data collection. Semiempirical absorption correcꢀ
tions were applied (SADABS) [14], and the program SAINT was used
for integration of the diffraction profiles [15]. The structures were
solved by direct methods and refined with the full–matrix least–squares
technique using the SHELXS–97 and SHELXL–97 programs [16]. The
organic hydrogen atoms were generated geometrically; the hydrogen
atoms of the water molecules were located from difference maps and
refined with isotropic temperature factors. The crystallographic data
and selected bond lengths and angles were listed in Table 1, Table 2,
Table 3, and Table 4. Hydrogen bond arrangements were summarized
in Table 5.
14.82 %. IR (KBr): ν = 3426 br, 3130 m, 1615 w, 1567 s, 1524 m,
˜
1508 m, 1412 s, 1353 s, 1319 m, 1286 m, 1209 w, 1162 m, 1066 m,
1013 s, 984 m, 877 m, 845 s, 797 m, 722 s, 669 s, 524 m cm–1.
[Cd(Htrz)(H2O)(nb)2]n (2): A mixture containing Hnb (16.7 mg,
0.1 mmol) and Htrz (6.9 mg, 0.1 mmol) in CH3OH (5 mL) was careꢀ
fully layered onto an aqueous solution of Cd(OAc)2·2H2O (26.6 mg,
0.1 mmol) in a straight test tube. Pale yellow blockꢀshaped crystals
suitable Xꢀray diffractions were obtained at the tube wall within two
weeks at room temperature. Yield: 60 % based on CdII salts.
C16H13CdN5O9: calcd. C 36.14; H 2.46; N 13.17 %; found: C 36.22;
H 2.44; N 13.21 %. IR (KBr): ν = 3440 br, 3127 w, 1619 m, 1567 s,
˜
1523 w, 1508 w, 1411 s, 1351 s, 1319 w, 1283 m, 1159 m, 1106 m,
1066 m, 1013 m, 985 w, 878 m, 840 m, 799 s, 668 m, 523 m cm–1.
Table 2. Selected bond lengths /Å and angles /° for 1.
{[Mn(Htrz)2(H2O)4]·2nb} (3): To an aqueous solution (5 mL) of
Mn(ClO4)2·6H2O (36.2 mg, 0.1 mmol) was slowly added a methanol
Cd(1)–N(1)#1
Cd(1)–N(3)
2.261(3)
2.315(3)
Cd(1)–O(5)
Cd(1)–O(2)
Cd(1)–O(1)
N(3)–Cd(1)–O(5) 167.58(9)
N(1)#1–Cd(1)–O(2) 160.25(9)
O(1)–Cd(1)–O(2) 54.04(8)
N(2)#2–Cd(1)–O(2) 88.97(8)
N(3)–Cd(1)–O(2) 89.93(9)
O(5)–Cd(1)–O(2) 80.38(8)
N(2)#2–Cd(1)–O(5) 82.82(9)
2.405(2)
2.515(2)
2.299(2)
solution (10 mL) containing Htrz (13.8 mg, 0.2 mmol) and Hnb Cd(1)–N(2)#2
2.303(3)
N(1)#1–Cd(1)–O(1)
108.80(9)
(16.7 mg, 0.1 mmol) with constant stirring. The pH value of the mixꢀ
ture was then adjusted to 7 by triethylamine, and the mixture was
filtered. Colorless blockꢀshaped crystals suitable for Xꢀray diffraction
were obtained by slow evaporation of the filtrate at room temperature
within two weeks. Yield: 78 % based on Htrz. C9H11Mn0.5N4O6: calcd.
C 36.19; H 3.71; N 18.76 %; found: C 36.22; H 3.74; N 18.79 %. IR
N(1)#1–Cd(1)–N(2)#2 106.51(9)
O(1)–Cd(1)–N(2)#2
O(1)#1–Cd(1)–N(3)
N(2)#2–Cd(1)–N(3)
N(1)#1–Cd(1)–O(5)
N(1)#1–Cd(1)–N(3)
O(1)–Cd(1)–O(5)
142.69(9)
94.68(9)
89.31(1)
89.30(9)
102.18(1)
85.93(9)
(KBr): ν = 3349 br, 3141 w, 2940 w, 2894 w, 2751 w, 2677 m, 2491
˜
w, 1614 w, 1582 s, 1347 s, 1319 w, 1288 w, 1150 w, 1088 m, 987 w,
Symmetry codes: #1 x, – y + 5/2, z – 1/2; #2 – x + 1, y – 1/2, – z + 1/2.
863 m, 801 m, 720 m, 675 m, 632 m, 553 w, 512 m cm–1.
Table 1. Crystal data and structure refinement for compounds 1–3.
Compound
1
2
3
Empirical formula
C10H10CdN4O5
378.62
C16H13CdN5O9
C9H11Mn0.50N4O6
298.69
Fw /g·mol–1
531.71
Crystal system
Monoclinic
P21/c
Monoclinic
P21/n
Triclinic
¯
Space group
a /Å
b /Å
c /Å
P1
14.8034(9)
8.0917(5)
10.5824(7)
90
7.8857(3)
22.5795(1)
10.4642(4)
90
6.4609(6)
7.5898(7)
12.6870(1)
97.9550(1)
92.8300(1)
102.4460(1)
599.64(1)
α /°
β /°
93.3230(1)
90
96.5780(1)
90
γ /°
V /Å3
Z
1265.48(1)
4
1850.94(1)
4
2
ρ
calcd. /g·cm–3
1.987
1.752
1.908
1.245
1.654
µ /mm–1
0.632
Crystal size /mm
F(000)
θ range
h / k / l
0.34 × 0.32 × 0.29
744
0.32 × 0.29 × 0.28
1056
0.28 × 0.21 × 0.20
307
2.76–25.01
–17, 16 / –9, 9 / –10, 12
6499 / 2202
0.0117
2.16–25.01
–9, 7 / –26, 26 / –12, 12
9966 / 3266
0.0141
2.78–25.01
–7, 7 /–8, 9 /–14, 15
3266 / 2075
0.0124
Reflections collected / unique
R(int)
GOF
1.048
1.043
1.054
R1, wR2 [I > 2σ (I)]a)
R1, wR2 (all data)a)
Max. and min. transmission
∆ρmax, ∆ρmin /e·Å–3
0.0246 / 0.0478
0.0268 / 0.0484
0.602 / 0.557
0.398 / –0.492
2
0.0190 / 0.0491
0.0214 / 0.0504
0.706 / 0.678
0.218 / –0.341
0.0261 / 0.0705
0.0280 / 0.0712
0.881 / 0.853
0.191 / –0.241
a) R1 = Σ(||Fo| – |Fc||)/Σ|Fo|; wR2 = [Σw(|Fo|2 – |Fc|2)2/Σw(Fo )]1/2
.
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Z. Anorg. Allg. Chem. 2009, 2653–2659

1,2,4ꢀTriazole Controlled CdII/MnII Complexes
Table 3. Selected bond lengths /Å and angles /° for 2.
Results and Discussion
Syntheses and FTꢀIR Spectra
Cd(1)–O(2)
Cd(1)–O(6)
Cd(1)–N(3)
Cd(1)–O(9)
2.2974(2) Cd(1)–N(2)#1
2.3376(2) Cd(1)–O(5)
2.3537(2) Cd(1)–O(1)
2.4083(2)
2.4693(2)
2.4973(2)
Colorless crystals of 1 and pale yellow crystals of 2, were
obtained by the reaction of Htrz, Hnb with Cd(OAc)2·2H2O
in a molar ratio of 1:1:1 under diffusion conditions. The sole
difference for the preparation of the two complexes is the pH
of the medium containing the mixedꢀligand. Indeed, the
slightly pH change significantly led to the deprotonation of
Htrz ligand to some different extent. In contrast, colorless crysꢀ
tals of 3 with suitable crystal size were obtained by solvent
evaporation in a satisfactory yield. Attempts to prepare 3 by
diffusion method were tried but failed. Additionally, the ratio
of the reactant mixture has also significantly decided the
growth of the MnIIꢀbased complex. Complex 3 is prepared
from the molar ratio of 1:2:1 (MnII:Htrz:Hnb). In contrast, the
two CdIIꢀbased complexes are obtained in an equimolar reacꢀ
tant mixture. Therefore, it can be concluded that the preparaꢀ
tion method, the ratio of the reactants and the pH value of the
medium are all important factors for the growth of the three
target complexes.
In their infrared spectra, the strong and broad absorption
bands centered at 3426 cm–1 for 1, 3440 cm–1 for 2, and
3349 cm–1for 3 are ascribed to ν(O–H) of methanol for 1 and
water for both 2 and 3, respectively [17]. Compared with the
free Hnb, the absence of strong absorption band at 1694 cm–1
in the three complexes indicates the full deprontonation of carꢀ
boxylic group. Correspondingly, the asymmetric stretching freꢀ
quencies (vas) for carboxylate group occur at 1567 and
1508 cm–1 for 1 and 2, and the symmetric carboxylate stretchꢀ
ing frequencies (vs) appeared at 1412 and 1353 cm–1 for 1,
1411 and 1351 cm–1 for 2, respectively. Their small difference
∆v (∆v = vas – vs < 200 cm–1) indicates the chelating bidentate
coordination modes of carboxylate group, which is also conꢀ
firmed by single crystal structure analysis. The stretching viꢀ
bration bands of the carboxylate group in 3 (1614, 1582, 1347,
and 1319 cm–1) are comparable to the corresponding values in
sodium 4ꢀnitrobenzoate (1617, 1585, 1351, and 1319 cm–1),
suggesting that the nb anion in 3 is isolated. Additionally, the
bands in the range of 800–1400 cm–1 are associated with trz
ligand vibrations [11b].
2.3719(2) O(5)–Cd(1)–O(1) 130.17(5)
O(2)–Cd(1)–O(6) 130.29(5) O(2)–Cd(1)–O(5) 76.56(6)
O(2)–Cd(1)–N(3) 93.37(6)
O(6)–Cd(1)–N(3) 92.09(6)
O(2)–Cd(1)–O(9) 136.48(5) O(9)–Cd(1)–O(5) 146.91(5)
O(6)–Cd(1)–O(5) 53.82(5)
N(3)–Cd(1)–O(5) 99.51(7)
O(6)–Cd(1)–O(9) 93.10(5)
N(3)–Cd(1)–O(9) 79.98(6)
O(2)–Cd(1)–N(2)#1 96.97(6)
O(6)–Cd(1)–N(2)#1 93.58(6)
N(2)#1–Cd(1)–O(5) 98.73(6)
O(2)–Cd(1)–O(1) 54.24(5)
O(6)–Cd(1)–O(1) 173.99(5)
N(3)–Cd(1)–O(1) 91.49(5)
N(3)–Cd(1)–N(2)#1 160.69(7) O(9)–Cd(1)–O(1) 82.77(5)
O(9)–Cd(1)–N(2)#1 81.29(6)
N(2)#1–Cd(1)–O(1) 81.51(5)
Symmetry code: #1 x – 1/2, – y + 1/2, z + 1/2.
Table 4. Selected bond lengths /Å and angles /° for 3.
Mn(1)–O(6)
Mn(1)–N(3)
2.1476(1) Mn(1)–O(5)
2.2169(1)
2.2345(1) N(3)#1–Mn(1)–N(3) 180.00
O(6)–Mn(1)–O(6)#1 180.00
O(5)–Mn(1)–N(3)#1 89.08(5)
O(6)–Mn(1)–O(5)
93.49(5) O(6)–Mn(1)–N(3)
89.19(5)
90.92(5)
O(5)–Mn(1)–O(5)#1 180.00
O(5)–Mn(1)–N(3)
Symmetry code: #1 – x, – y, – z + 1.
Table 5. Hydrogenꢀbonding parameters /Å,° for compounds 1–3.
Donor–H···Acceptor
D–H
H···A D···A
D–H···A
1
O5–H5'···O2#1
C1–H1···O5#2
C2–H2···O4#3
2
0.85
0.93
0.93
1.89
2.48
2.56
2.684(7)
156
172
147
3.406(4)
3.377(9)
N1–H1A···O9#4
O9–H9B···O7#5
N1–H1A···O5#6
O9–H9A···O2#6
O9–H9B···O5#6
3
0.86
0.85
0.86
0.85
0.85
2.62
2.44
2.02
1.89
2.58
3.094(4)
3.222(0)
2.823(8)
2.700(8)
3.040(6)
116
153
156
160
115
O6–H6A···N2#7
O6–H6B···O1#8
O5–H5B···O2
O5–H5A···O1#9
N1–H1'···O1#10
0.85
0.85
0.85
0.85
0.86
2.02
1.92
1.82
2.06
1.96
2.852(2)
2.763(7)
2.660(5)
2.911(4)
2.794(8)
168
173
168
174
162
Structure Descriptions of Complexes 1–3
[Cd(trz)(CH3OH)(nb)]n (1)
Symmetry codes: #1 x, 1/2 –y, 1/2 + z; #2 x, 1/2 –y, –1/2 + z; #3 –
x, 1/2 + y, 1/2 –z; #4 1/2 + x, 1/2 –y, –1/2 + z; #5 3/2 –x, –1/2 + y,
1/2 –z; #6 1/2 + x, 1/2 –y, 1/2 + z; #7 – x, 1 –y, 1 –z; #8 – x, – y,
1 –z; #9–1 + x, y, z; #10 1 –x, 1 –y, 1 –z.
Single crystal Xꢀray analysis reveals that 1 presents an infiꢀ
nite twoꢀdimensional (2D) network built from dinuclear
[Cd2(trz)2]2+ subunits. As shown in Figure 1a, the asymmetric
unit of 1 contains one crystallographically independent CdII
atom, one deprotonated trz molecule, one nb anion and one
coordinated methanol molecule. The hexacoordinated Cd1
atom is bound to three nitrogen atoms from three separate trz
(N1B, N2A, and N3) anions, three oxygen atoms from one nb
anion (O1, O2) and one methanol (O5) molecule, leading to a
distorted octahedral arrangement. The bond lengths of Cd–N
and Cd–O vary slightly from 2.261(3) to 2.515(2) Å (Table 2),
and are similar to those previously reported values [8–11].
CCDCꢀ709593, CCDCꢀ709594, and CCDCꢀ709595 for complexes 1–
3 contain the supplementary crystallographic data for this paper. These
data can be obtained free of charge via www.ccdc.cam.ac.uk/conts/
retrieving.html (or from the Cambridge Crystallographic Centre, 12
Union Road, Cambridge CB21EZ, UK; Fax: (+44) 1223ꢀ336033; or
deposit@ccdc.cam.ac.uk).
Z. Anorg. Allg. Chem. 2009, 2653–2659
© 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim
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2655

Q.ꢀQ. Liang, Z.ꢀY. Liu, E.ꢀC. Yang, X.ꢀJ. Zhao
ARTICLE
rocycles composed by four CdII sites and four trz ligands.
Moreover, two hydrogenꢀbond interactions (O5–H5'···O2 and
C1–H1···O5, see Table 5) were observed within the 2D layer.
And the adjacent 2D layers were interlinked by weak C2–
H2···O4 (see Table 5) hydrogenꢀbonds interactions into a 3D
supramolecular network (Figure 1c).
[Cd(Htrz)(H2O)(nb)2]n (2)
Complex 2 crystallizes in the monoclinic P21/n space group,
exhibiting a 1D chain motif bridged by the neutral Htrz ligand.
The asymmetric unit of 2 consists of one CdII atom, one neutral
Htrz molecule, two nb anions, and one coordinated water molꢀ
ecule. Different from 1, the sole CdII atom in 2 is heptacoordiꢀ
nated by two nitrogen atoms (N3, N2A) from a pair of symmeꢀ
tryꢀrelated Htrz ligands and five oxygen atoms from two nb
Figure 1. (a) Local coordination environments of CdII in 1 with atomic
labels in the asymmetric unit. (Hydrogen atoms were omitted for clarꢀ
ity). (b) 2D layer of 1 formed by trz molecules and CdII atoms. (c) 3D
hydrogen bonded network by weak interlayer C–H···O hydrogen bond
interactions.
Two symmetryꢀrelated CdII sites are doubly bridged by two
trz anions in a µN1,N2ꢀbridging mode to generate a dinuclear
[Cd2(trz)2]2+ subunit. The Cd···Cd separation within the dinuꢀ
clear subunit is 4.1006(2) Å and the two trz rings are strictly
coplanar. The dinuclear [Cd2(trz)2]2+ unit is connected with its
four adjacent subunits through the coordination of CdII atoms
with the remaining N4 position of the trz, generating an infinite
2D layer in the bc plane (Figure 1b). Thus, each trz ligand in
1 affords its three nitrogen atoms to link three CdII sites in a
Figure 2. (a) Local coordination environments of CdII atom in 2 with
atomic labels in the asymmetric unit (hydrogen atoms were omitted
for clarity). (b) 1D chain and 2D layer of 2 constructed from interchain
O–H···O hydrogen bond interactions. (c) 3D supramolecular structure
µ
N1,N2,N4ꢀtridentate bridging mode. Viewed along the crystalloꢀ
graphic a direction, the 2D layer contains 16ꢀmembered macꢀ of 2 by hydrogen bond interactions.
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Z. Anorg. Allg. Chem. 2009, 2653–2659

1,2,4ꢀTriazole Controlled CdII/MnII Complexes
anions (O1, O2, O5, and O6) and one coordinated water moleꢀ
cule (O9). The arrangement around each CdII atom can be deꢀ
scribed as a distorted pentagonal–bipyramidal polyhedron, in
which the CdII atom deviates from the least–squares plane genꢀ
erated by O1–O2–O5–O6–O9 only about 0.0177 Å. The Cd–
O and Cd–N bond lengths are in the range of 2.2974 Å to
2.4973(2) Å, and the bond angles around each CdII atom range
from 53.82(5)° to 173.99(5)° (Table 3). Acting as a terminal
ligand, the nb anion in complex 2 also affords its carboxylate
group to connect to the CdII atom in a bidentate chelating fashꢀ
ion. The neutral Htrz ligand in 2 adopts a µN1,N4ꢀbridging mode
to connect the adjacent CdII atoms into a 1D linear chain along
the c axis with a Cd···Cd separation of 6.9204(3) Å (Figꢀ
ure 2b). Such the linear chains are further stabilized by intraꢀ
chain N1–H1A···O9 hydrogen bond interactions between Htrz
and coordinated water molecules (see Table 5)
Furthermore, these neighboring 1D chains were interlinked
in an antiꢀparallel manner by O9–H9B···O7 hydrogenꢀbonds
between coordinated water and the nitro group of nb, forming
an interdigitated 2D supramolecular layer (Figure 2b). As
shown in Figure 2c, these layers are further stacked together
in a parallel manner though classic O9–H9A···O2 and N1–
H1A···O5 hydrogen bonds to generate a supramolecular archiꢀ
tecture (see Table 5).
{[Mn(Htrz)2(H2O)4]·2nb} (3)
Xꢀray crystal structural analysis points out that complex 3 is
a supramolecular assembly containing a discrete mononuclear
[Mn0.5(Htrz)(H2O)2]+ cation, and a free nb anion for charge
compensation (Figure 3a). The MnII atom is surrounded in a
distorted octahedral arrangement by two nitrogen atoms (N3,
N3A) from a pair of symmetryꢀrelated Htrz molecules and four
oxygen atoms (O5, O6, O5A, and O6A) from two pairs of
water molecules. Interestingly, rather than adopting the
µN1,N2,N4ꢀ and µN1,N4ꢀbridging coordination modes, the neutral
Htrz molecule in 3 only coordinates in a monodentate fashion
Figure 3. (a) Molecule structure of 3. (b) 1D supramolecular chain of
through its N3 atom to the MnII atom. Acting as a typical 3 by hydrogen bond interactions. (c) 3D supramolecular network of 3
by hydrogen bond and π–π stacking interactions.
hydrogenꢀbond donor, the four coordinated water molecules
produce abundant hydrogenꢀbonds interactions with the neutral
Htrz and anionic nb ligands (see Table 4 and Table 5), which
connects the discrete mononuclear [Mn0.5(Htrz)(H2O)2]+ catiꢀ
between 98 °C and 146 °C (obsd.: 8.7 %, calcd.: 8.5 %). And
ons into a 1D infinite chain with the free nb anions attached
on the both sides (Figure 3b). These adjacent chains are further
extended into a 2D supramolecular layer by O5–H5A···O1 and
N1–H1'···O1 hydrogenꢀbond interactions. π–πꢀstacking interacꢀ
tions between the aromatic ring of the attached nb anions asꢀ
semble these layers into a 3D supramolecular architecture. The
centroid–centroid separations and dihedral angle of the benꢀ
zene rings are 3.655 Å and 0.000(78)° respectively.
the framework is stable up to 317 °C. Upon further heating,
the organic mixedꢀligands of 1 are observed to be decomposed
progressively up to 446 °C, leaving CdO as the final product
(obsd.: 34.7 %, calcd.: 33.9 %). Much different from 1, comꢀ
plex 2 shows that the coordinated H2O and Htrz molecules are
released from 119 °C to 253 °C (obsd.: 17.1 %, calcd.:
16.4 %). The aromatic nb anions of 2 are removed from
340 °C to 504 °C. An amorphous powder, which is calculated
to be CdO, is left as final product above 504 °C (obsd.:
23.8 %, calcd.: 24.1 %).
Thermal Stability of 1–3
In contrast, complex 3 displays the thermal instability. When
To investigate the correlation between the complex structure the temperature is above 70 °C, the slow weightꢀloss process
and their thermal stability, thermogravimetric experiments of of 3 occurs and ends at 528 °C, corresponding to the continuꢀ
1–3 were carried out (Figure 4). The TGA curve of complex ous release of the coordinated water molecules, lattice nb aniꢀ
1 indicates that the coordinated CH3OH molecule is released ons and neutral Htrz ligand. The final product is calculated
Z. Anorg. Allg. Chem. 2009, 2653–2659
© 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wileyꢀvch.de
2657

Q.ꢀQ. Liang, Z.ꢀY. Liu, E.ꢀC. Yang, X.ꢀJ. Zhao
ARTICLE
Conclusions
In summary, three solid complexes with mixed Htrz and Hnb
ligands were prepared by diffusion or solvent evaporation,
which exhibit the structural diversity ranged from discrete
mononuclear, polymeric 1D chain to infinite 2D layer signifiꢀ
cantly dominated by the coordination modes of Htrz ligand. A
similar fluorescent emission based on intraligand charge transꢀ
fer and different structureꢀdependent thermal stability, were
also observed for the three complexes.
Acknowledgement
This present work was supported by the National Natural Science
Foundation of China (20871092), Natural Science Foundation of Tian
jin (07QTPTJC29800), Tianjin Educational Committee (2006ZD07).
Figure 4. TG curves for 1–3.
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2658 www.zaac.wileyꢀvch.de
© 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2009, 2653–2659

1,2,4ꢀTriazole Controlled CdII/MnII Complexes
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Received: March 4, 2009
Published Online: July 30, 2009
Z. Anorg. Allg. Chem. 2009, 2653–2659
© 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wileyꢀvch.de
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