КООРДИНАЦИОННАЯ ХИМИЯ, 2015, том 41, № 5, с. 306-311
УДК 541.49
ANION-DEPENDENT COPPER(II) COORDINATION POLYMERS BASED ON 1,3-DI-(1,2,4-TRIAZOLE-4-YL)BENZENE: SYNTHESES AND CRYSTAL STRUCTURES
© 2015 S. B. Miao1, 2, B. M. Ji1 *, and L. Zhou2, *
1College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang, 471022 P.R. China 2College of Science, Northwest A&F University, Yangling, 712100 P.R. China *E-mail: lyhxxjbm@126.com; zhoulechem@yahoo.com.cn Received September 9, 2014
Three Cu(II) coordination polymers, namely {[Cu(Dtb)(H2O)](SO4)(H2O)}n (I), {[Cu(Dtb)(C2O4)(H2O)](H2O)2}n (II), and {[Cu(Dtb)(NO3)](NO3)(H2O)2}n (III) (Dtb = 1,3-di-(1,2,4-triazole-4-yl)benzene), have been synthesized under hydrothermal conditions and characterized by elemental analyses, IR spectra, and single-crystal X-ray diffraction (CIF file CCDC nos. 1001347 (I); 1001348 (II); 1001349 (III)). Complex I is a 1D double-chain structure, Dtb acts as ^д.-bridging ligand
and SO4 does not participate in coordination. In contrast, complex II shows a 1D single-chain, in which Dtb
2_ _ shows ц 2-bridges mode and C2O4 occupies two coordination positions. In complex III, NO3 shortens the
distance of two Cu(II) centers by bridging coordination interaction, so Dtb becomes ц r 2 2.-bridges linker to extend the Cu(II) centers to the resulting 2D layer. DOI: 10.7868/S0132344X15050059
INTRODUCTION
Coordination polymers (CPs) have attracted considerable research interest in the past two decades, not only because of their intriguing variety of structures but also owing to their potential applications as functional materials [1—4]. It is well known that the structures and properties of the CPs are mainly dependent on two facts, organic ligands and metal atoms, which are main constructing elements of CPs. The reaction conditions used such as the temperature, solvent, pH, also usually result in completely different framework structures in the assemble process of CPs [5—7]. Moreover, counter anions in the crystal can also significantly influence the final structure by coordination or intermolecular interactions [8—10]. 1,2,4-Triazole and its derivatives are of particular interest in coordination chemistry [11—15], since they are effective bridging ligands combing the coordination modes of imidazoles and pyrazoles. As a double 1,2,4-triazole ligand, 1,3-di-(1,2,4-triaz-ole-4-yl)benzene (Dtb) has been paid attention due to its multiple coordination modes [16—18]. In
2_ 2- — this work, we have chosen SO4 , C2O4 , and NO3 as
the anions to construct different coordination polymers with Dtb. As a result, three Cu(II) coordination polymers, {[Cu(Dtb)(H2O)](SO4)(H2O)}„ (I), {[Cu(Dtb)(C2O4)(H2O)](H2O)2}„ (II), and {[Cu(Dtb)(NO3)](NO3)(H2O)2}„ (III), have been synthesized and characterized.
EXPERIMENTAL
Materials and methods. Dtb was prepared according to the literature method [18]. The other reagents for syntheses and analyses were obtained from commercial sources and used without further purification. IR spectra were recorded on a Nicolet Avatar-360 spectrometer. 1H NMR spectrum was measured using a Bruker DPX-400 spectrometer. Elemental analyses were carried out on a Flash 1112 analyzer.
Synthesis of I. A mixture of CuSO4 ■ 5H2O (49.9 mg, 0.2 mmol), Dtb (21.2 mg, 0.1 mmol), and 10 mL water was sealed in a 25 mL Teflon-lined stainless steel vessel, which was heated at 120°C for 72 h and then cooled to room temperature at a rate of 5°C h-1. The blue block crystals of I were obtained with yield of 33%.
IR (KBr; v, cm-1): 3089, 2989, 1650, 1534, 1236, 1104, 968, 799, 681.
For C20H24N12O8SCu
anal. calcd., %: C, 36.61; H, 3.69; N, 25.62. Found, %: C, 36.43; H, 3.75; N, 25.38.
Synthesis of II was carried out by the same procedure as I, except adding Na2C2O4 (13.4 mg, 0.1 mmol) in the reaction mixture. The blue block crystals of II were obtained with yield of 21%.
Table 1. Crystallographic data and structure refinement for complexes I—III
Parameter Value
I II III
Formula weight 656.11 417.83 435.82
Crystal system Monoclinic Triclinic Monoclinic
Space group C2/c PI P/c
a, A 12.5018(17) 7.5775(10) 11.023(3)
b, A 14.629(2) 9.9701(13) 7.039(2)
c, A 15.259(2) 10.8440(14) 20.662(6)
a, deg 90 88.4030(10) 90
P, deg 93.077(2) 78.7990(10) 101.707(4)
Y, deg 90 77.0810(10) 90
V, A3 2786.7(7) 783.20(18) 1569.8(8)
Z 4 2 4
P calcd mg/m3 1.564 1.772 1.844
p., mm-1 0.926 1.448 1.457
/(000) 1348 426 884
9 Range, deg 2.48-25.50 2.81-25.50 2.46-25.00
Reflections collected 9278 5880 5225
Independent reflections (Rint) 2572 (0.0343) 2901 (0.0152) 2700 (0.0468)
Goodness of fit on F2 1.055 1.061 1.068
R1, wR2 (I> 2ct(I)) 0.0403, 0.1015 0.0307, 0.0816 0.0768, 0.2258
R1, wR2 (all data) 0.0570, 0.1086 0.0363, 0.0858 0.1088, 0.2467
^max^mim eA— 0.417/-0.357 0.366/-0.330 1.742/—1.986
IR (KBr; v, cm-1): 3100, 2987, 1674, 1605, 1402, 1240, 1058, 788,686.
For C12H14N6O7Cu
anal. calcd., %: C, 34.50; H, 3.38; N, 20.11. Found, %: C, 34.33; H, 3.52; N, 19.93.
Synthesis of III was carried out by the same procedure as I, except using of Cu(NO3)2 • 3H2O (48.2 mg, 0.2 mmol) instead of CuSO4 • 5H2O. The blue block crystals of III were obtained with yield of 25%.
IR (KBr; v, cm-1): 3146, 3065, 1617, 1504, 1424, 1367, 1293, 1056, 887, 685.
For C10H12N8O8Cu
anal. calcd., %: C, 27.56; H, 2.78; N, 25.71. Found, %: C, 27.33; H, 2.85; N, 25.91.
X-ray diffraction analysis. Diffraction data for I—III were collected on a Bruker SMART APEX II CCD diffractometer equipped with a graphite-monochro-mated MoKa radiation (X = 0.71073 A). The structures were solved by direct methods with SHELXS-97 [19] and refined by the least-squared method with SHELXL-97
program [20]. Most hydrogen atoms were assigned with common isotropic displacement factors and included in the final refinement by use of geometrical restrains. The crystallographic data for compound I—III are listed in Table 1, and the selected bond lengths and bond angles are given in Table 2.
Supplementary material for structures I—III has been deposited with the Cambridge Crystallographic Data Centre (nos. 1001347 (I); 1001348 (II); 1001349 (III); deposit@ccdc.cam.ac.uk or http://www.ccdc. cam.ac.uk).
RESULTS AND DISCUSSION
Three Cu(II) coordination polymers based on 1,3-di-(1,2,4-triazole-4-yl)benzene (Dtb) with different counter anions have been synthesized through hydrothermal reactions of the similar precursors. Complexes I—III exhibit different 1D, 1D, and 2D structures, respectively. The structures depend on the
2_ 2- — nature of the anions (SO4 , C2O2 , and NO3), which
present during the synthesis. In complex III, the bridging NO- shorten the distance between Cu2+ ions, so Dtb can bridging four Cu2+ ions as ^ I. 2 2. mode to
Table 2. Selected bond distances (A) and angles (deg) for complexes I—III
I
Bond d, Â Bond d, Â
Cu(1)—N(2) 2.022(3) Cu(1)—O(1) 2.339(3)
Cu(1)—N(5£)#* 2.031(3)
Angle ro, deg Angle ro, deg
N(2)Cu(1)N(5B)#* 89.30(14) N(5B)#xCu(1)O(1) 90.69(15)
N(2)Cu(1)O(1) 87.91(13)
II
Bond d, Â Bond d, Â
Cu(1)—O(3) 1.9297(18) Cu(1)—N(6^)#2 2.000(2)
Cu(1)—O(1) 1.9690(18) Cu(1)—O(5) 2.311(2)
Cu(1)—N(2) 1.9752(19)
Angle ro, deg Angle ro, deg
O(3)Cu(1)O(1) 83.33(8) N(2)Cu(1)N(6^)#2 96.87(8)
O(3)Cu(1)N(2) 168.75(10) O(3)Cu(1)O(5) 100.45(10)
O(1)Cu(1)N(2) 91.15(8) O(1)Cu(1)O(5) 95.96(9)
O(3)Cu(1)N(6^)#2 87.24(8) N(2)Cu(1)O(5) 89.84(9)
O(1)Cu(1)N(6^)#2 168.16(8) N(6^)#2Cu(1)O(5) 92.78(9)
III
Bond d, Â Bond d, Â
Cu(1)—N(6C)#3 1.986(7) Cu(1)—N(3^)#4 2.015(7)
Cu(1)—N(5B)#4 1.997(7) Cu(1)—O(1')#4 2.39(3)
Cu(1)—N(2) 2.007(7) Cu(1)—O(1) 2.299(16)
Angle ro, deg Angle ro, deg
N(6C)#3Cu(1)N(5B)#4 176.8(3) N(5B)#4Cu(1)O(1') 99.8(8)
N(6C)#3Cu(1)N(2) 88.5(3) N(2)Cu(1)O(1') 86.7(8)
N(5B)#4Cu(1)N(2) 90.2(3) N(3^)#5Cu(1)O(1') 97.6(8)
N(6C)#3Cu(1)N(3^)#5 91.0(3) O(1)Cu(1)O(1') 11.6(9)
N(5B)#4Cu(1)N(3^)#5 90.0(3) N(6C)#3Cu(1)O(1')#5 93.5(8)
N(2)Cu(1)N(3^)#5 175.6(3) N(5B)#4Cu(1)O(1')#5 83.5(9)
N(6C)#3Cu(1)O(1) 91.7(4) N(2)Cu(1)O(1')#5 89.2(7)
N(5B)#4Cu(1)O(1) 90.9(4) N(3^)#5Cu(1)O(1')#5 86.5(7)
N(2)Cu(1)O(1) 79.3(4) O(1)Cu(1)O(1')#5 167.2(8)
N(3^)#5Cu(1)O(1) 105.1(4) O(1')Cu(1)O(1')#5 174.7(11)
N(6C)#3Cu(1)O(1') 83.0(8)
* Symmetry codes: #1 x — 1/2, — y + 1/2, z + 1/2; #2 x + 1, y — 1, z; #3 x + 1, y, z; #4 — x + 1, y — 1/2, — z + 1/2; #5 —x + 2, y — 1/2, — z + 1/2.
generate the final 2D layer. As far as complexes I and
II, uncoordinated SO4 or terminal ligand C2O2 can not help Dtb to generate higher dimensional structures. Moreover, the geometry of Dtb in I, II, and III are greatly different, which can be seen from the dihedral angles between triazole ring and benzene ring.
The asymmetric unit of I contains one Cu2+ ion, two Dtb ligands, two coordinated water molecules, two
lattice water molecules, and one
SO4 anion (Fig. 1). The Cu(1) center is six-coordinated and has an alongated tetragonal bipyramid (4 + 2) coordination environment. The equatorial plane is completed by four nitro-
KOOP,3HHAUHOHHAH XHMH3 tom 41 № 5 2015
(a)
N(5Q N(3)
C(8)
C(6) C(5)
O(1)
Cu(1)
V
N(24)
C(4) C(10)
N(55)
N(6)
N(5)
(b)
Fig. 1. Coordination environment of Cu(II) atom (a) and the view of 1D double chain (b) in crystal of I.
(a)
N(5)
(b)
Fig. 2. Coordination environment of Cu(II) atom (a) and the view of 1D single chain (b) in crystal of II.
gen atoms (N(2), N(24), N(55), and N(5Q) from water molecules. All Cu-N bond distances of Cu(1) four Dtb ligands, while the axial positions are occu- (Table 2) are similar to those reported values for the pied by two oxygen atoms (O(1) and O(14)) from two Cu(II)/triazole complexes [21, 22]. In complex I, Dtb
(a)
N(34)
N(5)
C(5)
(b)
Fig. 3. Coordination environment of Cu(II) atom (a) and the view of 2D layer (b) in crystal of III.
acts as ^ 1. -bridging ligand, and the dihedral angles between triazole ring and benzene ring are 19.98(8)° and 42.17(5)°, respectively. Each Cu(II) center connects with four Dtb li
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