научная статья по теме SYNTHESIS AND CRYSTAL STRUCTURE OF TWO COMPLEXES [CU2(NIL)2CL4] AND [CD2(CUL)2CL4] Химия

KOOPMHH^HOHHÂS XHMH3, 2011, m0M 37, № 5, c. 360-364

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SYNTHESIS AND CRYSTAL STRUCTURE OF TWO COMPLEXES [Cu2(NiL)2Cl4] AND [Cd2(CuL)2Cl4]

X. X. Liu, Y. Q. Sun*, Y. Y. Xu, and D. Z. Gao-

Tianjin Key Laboratory of Structure and Performance for Functional Molecule, College of Chemistry, Tianjin Normal

University, Tianjin 300387, P.R. China *E-mail: hxxysyq@mail.tjnu.edu.cn Received June 24, 2010

Macrocyclic and supermolecular complexes [Cu2(NiL)2Cl4] (I) and [Cd2(CuL)2Cl4] (II) (H2L = 2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-diene) have been synthesized and structurally determined by X-ray diffraction and IR spectrum. Complex I crystallizes in the monoclinic system with P21/n group, a = 10.9019(15), b = 14.3589(19), c = 12.4748(17) Â, P = 108.645(2)°, Z= 4. Complex II crystallizes in the monoclinic system with P2j/n group, a = 10.9784(16), b = 14.580(2), c = 12.8904(18) Â, P = 109.339(2)°, Z = 4.

INTRODUCTION

Substantial interest has been devoted to the development of synthesis, design, and characterization of su-pramolecular complexes over the past decade [1—3]. Many self-assembly supramolecular networks exhibit novel structural topologies and interesting electrical, magnetic, optical, catalytic, or biological properties [46]. One class of bi- or polynuclear supramolecular complexes derived from oxamide with transition metals has became increasingly important [7—10]. For these complexes, a successful strategy of design and synthesis is used for mononuclear metal complexes as building blocks reacting with another metal ions and then leading to binuclear units, polymetallic systems, or extended networks [11]. On the other hand, the synthesis of homo-and heterometallic transition metal complexes supported by Cl- bridges has attracted a special attention in view of architectonical diversity and interesting properties of the complexes obtained [12-15]. Chloro-bridged complexes with the macrocyclic oxamide ligand have been made rarely.

Considering the auxiliary contributions of the chloride anion in inducing and controlling the supermolecular construction, we used the chloride ligand and two prepared macrocyclic oxamide complex ligands, CuL and NiL, to prepare two novel complexes [Cu2(NiL)2Cl4] (I) and [Cd2(CuL)2Cl4] (II). Here, we described the synthesis and crystal structure of two complexes I and II.

EXPERIMENTAL

All the starting reagents were of A.R. grade and used as purchased. Two complex ligands CuL and NiL were prepared as described elsewhere [16, 17]. Analyses of C, H, and N were determined on a PerkinElmer 240 elemental analyzer. The IR spectra were recorded as KBr discs on a Shimadzu IR-408 infrared spectrophotometer in the 4000-600 cm-1 range. Electronic spectra in DMF

were recorded on a Shimadzu UV-2101 PC scanning spectrophotometer.

Synthesis of I. Single crystals of the complex were grown in a MeOH solution by the slow diffusion method using an H-shaped tube. The precursor NiL (0.1 mmol) was added into one arm, CuCl2 • 2H2O (0.1 mmol) was added to another arm, and then MeOH was added to the tube. Brown red crystals suitable for X-ray determination were formed on the H-shaped tube wall (4.5% yield based on NiL) after several days.

For C19H16N4Cl2O2NiCu anal. calcd., %: C, 43.4; Found, %: C, 43.3;

H, 3.0; N, 10.7. H, 3.1; N, 10.6.

IR spectrum (v, cm-1): 1640 v(C=O), 1550 v(C=N), 1450-1400 v(C=C).

Synthesis of II. Single crystals of the complex were grown in a MeOH solution by the slow diffusion method using an H-shaped tube. The precursor CuL (0.1 mmol) was added into one arm, CdCl2 • 2.5H2O (0.1 mmol) was added to another arm, and then MeOH was added to the tube. Brown green crystals suitable for X-ray determination were formed on the H-shaped tube wall (4.5% yield based on CuL) after several days.

For C19H16N4Cl2O2CdCu

anal. calcd., %: Found, %:

C, 39.3; C, 39.4;

H, 2.7; H, 2.6;

N, 9.7. N, 9.7.

IR spectrum (v, cm-1): 1640 v(C=O), 1550 v(C=N), 1450-1400 v(C=C).

X-ray cructure determination. The data were collected on a Bruker Smart-1000-CCD area detector all using graphite-monchromated MoKa radiation (X = 0.71073 Â). The structures were solved by the direct method and sub-

Table 1. Crystallographic data and experimental details for complexes I and II

Parameter Value

I II

M 525.51 579.20

System Monoclinic Monoclinic

Space group P 2x/n P 2j/n

a, Â 10.9019(15) 10.9784(16)

b, Â 14.3589(19) 14.580(2)

c, Â 12.4748(17) 12.8904(18)

ß, deg 108.645(2) 109.339(2)

V, Â3 1850.3(4) 1946.8(5)

Z 4 4

Pcalcd g/cm3 1.886 1.976

^(MoÄ"a), mm-1 2.481 2.484

/(000) 1060 1140

Crystal size, mm 0.20 x 0.20 x 0.10 0.38 x 0.32 x 0.20

Data collection 9 range, deg 2.16-27.59 2.12-25.03

Index ranges -14 < h < 13 -12 < h < 13

-18 < k < 12 -17 < k < 10

-15 < l < 15 -15 < l < 14

Measured reflections 10533 9760

Independent reflections 4171 (Rint = 0.0310) 3435 (Rint = 0.0286)

GOOF for F 2 1.037 1.066

Final R index (I> 2o(I)) Rx = 0.0378, wR2 = 0.0993 Rx = 0.0286, wR2 = 0.0738

R index (all data) Ri = 0.0496, wR2 = 0.1080 Rj = 0.0323, wR2 = 0.0769

Residual electron density (max/min), e Â-3 1.062/—0.618 1.460/-0.812

sequent Fourier difference techniques and refined using a full-matrix least-squares procedure on F2 with aniso-tropic thermal parameters for all non-hydrogen atoms (SHELXS-97 and SHELXL-97). Hydrogen atoms were added geometrically and refined with riding model position parameters and fixed isotropic thermal parameters. Crystal data collection and refinement parameters are given in Table 1. Supplementary material for structure I and II has been deposited with the Cambridge Crystallographic Data Centre (№ 779855 and 779856, respectively; www.ccdc.cam.ac.uk/data_request/cif).

RESULTS AND DISCUSSION

Complex I consists of a neutral tetraunclear [Cu2(NiL)2Cl4] unit. A perspective view of the structure is depicted in Fig. 1. Selected bond lengths and angles are listed in Table 2. The crystal structure is a centrosymmer-tric tetranuclear complex in which Ni2+ and Cu2+ ions are bridged by macrocyclic oxamide groups and two adjacent copper ions are bridged by chloride atoms. In the symmetrical [Cu2(NiL)2Cl4] unit, the chloride atoms adopt distinct bridging (for Cl(2)) and terminal (for

Cl(1)) coordination modes. The Cu2+ ion has distorted trigonal-bipyramidal geometry with two oxygen atoms from one oxamido bridge and three chlorine atoms. The т value is 0.703 calculated from т = (в — a)/60 [18], the Cu-C(l) distances are 2.2792(10), 2.2449(12) and 2.5193(11) A, and Cu-O distances vary from 1.991(2) to 2.076(2) A. The external Ni2+ ions are coordinated by four nitrogen atoms from the macrocyclic organic ligand with the [NiN4] chromophore exhibiting distorted pla-narity. The Ni(1) ion is displaced from the least-square plane by -0.0204 A, the deviations of the four donor atoms (N(1), N(2), N(3), and N(4)) from their mean plane are -0.2156, 0.2205, -0.2069, and 0.2224 A, respectively. The four metal ions form a Z-type arrangement through the oxamido bridges with a Cu—Ni separation of 5.2563(8) A and through the chloride bridges with a Cu—Cu separation of3.4888(7) A (Fig. 1). As depicted in Fig. 2, the aromatic я—я stackings are found between two phenyl rings with centroid-to-centroid and centroid-to-plane separations of 3.814 and 3.638 A, which link the [Cu2(NiL)2Cl4] units into a 2D array.

Single-crystal X-ray analyses revealed that complexes I and II are isostructural with a small discrepancy. Com-

КООРДИНАЦИОННАЯ ХИМИЯ том 37 № 5 2011

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Fig. 1. Perspective view of tetranuclear complex I.

pared with complex I, complex II is a neutral centrosym-mertric tetraunclear [Cd2(CuL)2Cl4] unit. Selected bond lengths and angles are listed in Table 3. In the [Cd2(CuL)2Cl4] unit, the Cd2+ ion coordinates with two oxygen donors of the macrocyclic oxamide ligand, and three chlorine atoms. The coordination spheres of the cadmium centers are distorted trigonal-biyramidal geometry with a t value of0.512, the Cd—Cl distances being 2.4185(9), 2.5436(9), and 2.5900(8) A, and Cd-O distances vary from 2.269(2) to 2.280(2) A. The coordination geometry of Cu2+ ion is a slightly distorted square plane, the Cu(1) ion is displaced from the least-square plane by -0.0560 A, and the deviations of the four donor

atoms (N(1), N(2), N(3), and N(4)) from their mean plane are 0.2818, -0.2616, 0.2790, and -0.2432 A, respectively. The four metal ions are bridged by oxamide group and chlorine atoms, which form the [Cd2Cu2] unit, and the neighboring Cd—Cu and Cd—Cd separations are 5.5642(8) and 3.6964(7) A, respectively. The n—n interactions organize the tetranuclear molecules into a 2D supramolecular network.

The IR spectra of the two complexes are similar. The IR spectra of I and II show three strong bands around 1640, 1610, and 1448 cm-1 attributed to the v(N-C-O) stretching bands, which are characteristic of the bridging

Table 2. Selected bond distances (A) and angles (deg) for I*

Bond d, A Bond d, A

Cu(1)-Cl(1) 2.2449(12) Cu(1)-Cl(2) 2.5193(11)

Cu(1)-O(1) 1.991(2) Cu(1)-O(2) 2.076(2)

Cu(1)-Cl(2)#1 2.2792(10) Ni(1)-N(1) 1.900(2)

Ni(1)-N(2) 1.916(2) Ni(1)-N(3) 1.880(2)

Ni(1)-N(4) 1.880(2)

Angle ro, deg Angle ro, deg

Cl(1)Cu(1)Cl(2) 127.80(4) Cl(1)Cu(1)O(1) 91.85(7)

Cl(1)Cu(1)O(2) 127.61(7) Cl(1)Cu(1)Cl(2)#! 98.15(4)

Cl(2)Cu(1)O(1) 88.60(7) Cl(2)Cu(1)O(2) 103.86(7)

Cl(2)Cu(1)Cl(2)#1 86.86(3) O(1)Cu(1)O(2) 80.09(8)

O(1)Cu(1)Cl(2)#1 169.80(7) O(2)Cu(1)Cl(2)#1 92.14(6)

N(1)NiN(2) 86.85(10) N(1)NiN(3) 168.39(10)

N(1)NiN(4) 91.89(10) N(2)NiN(3) 94.10(10)

N(2)NiN(4) 165.12(10) N(3)NiN(4) 90.11(10)

* Symmetry codes: #1 -x + 1, -y, -z + 2.

Fig. 2. View of the self-assembly 2D superamolecular architecture through n—n interactions for I and II.

oxamide group. The band ranging from 1400 to 1450 cm-1 is attributed to the v(C=C).

The electrionic absorption spectra of complexes I and II were measured in a DMF solution. In complexes I, the broad absorption ba

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