{N,N′-[2,2′-(Ethane-1,2-diyldisulfanediyl)di-o-phenylene]bis(quinoline-2-carboxamidato)}copper(II)

In the title compound, [Cu(C34H24N4O2S2)] or [Cu(bqdapte)], where H2bqdapte is 1,2-{bis[2-(quinoline-2-carboxamido)phenyl]sulfanyl}ethane, the CuII ion is coordinated to the dianionic hexadentate bqdapte2− ligand by two amide and two quinoline N atoms and two thioether S atoms. In the observed conformation of the hexadentate ligand, the quinoline rings attain positions related by a twofold axis. The Cu atom displays a Jahn–Teller-distorted octahedral CuN4S2 geometry axially compressed along the two trans-configured Cu—Namidate bonds.

In the title compound, [Cu(C 34 H 24 N 4 O 2 S 2 )] or [Cu(bqdapte)], where H 2 bqdapte is 1,2-{bis[2-(quinoline-2-carboxamido)phenyl]sulfanyl}ethane, the Cu II ion is coordinated to the dianionic hexadentate bqdapte 2À ligand by two amide and two quinoline N atoms and two thioether S atoms. In the observed conformation of the hexadentate ligand, the quinoline rings attain positions related by a twofold axis. The Cu atom displays a Jahn-Teller-distorted octahedral CuN 4 S 2 geometry axially compressed along the two trans-configured Cu-N amidate bonds.

Experimental
Crystal data [Cu(C 34 (Ronson et al., 2006;Tavacoli et al.., 2003;Xie et al.., 2005) and in bioinorganic chemistry (Kouroulis et al. 2009;Lee et al., 2007). Many of these efforts have been devoted to the design and synthesis of new caboxamide ligands (Kouroulis et al. 2009;Singh & Mukherjee 2005;Sunatsuki et al., 1998;Zhang et al., 2004). The bioinorganic relevance of copper and its crucial role in many biological and catalytic functions have stimulated efforts towards the design, synthesis, and characterization of copper complexes as models for providing better understanding of biological systems and for the development of efficient catalysts (Lee et al., 2007;Zhang et al., 2004). In continuation of our studies on carboxamido metal complexes, we herein report the synthesis and structure of the title compound, [Cu(C 34 H 24 N 4 O 2 S 2 )], (I), and make a brief comparison with reported structures.
The structure of complex (I), and the atomic numbering used, is shown in Fig. 1. The Cu(II) ion displays a Jahn-Teller distorted octahedral CuN 4 S 2 geometry arising from the hexadentate thiocarboxamido ligand. This complex has a 2-fold axis passing through Cu and the midpoint of C17 and its symmetry related atom. Two quinoline nitrogen, two deprotonated amide nitrogen, and two thioether sulfur bind copper(II) in cis, trans, and cis orientations. The geometric parameters are listed below in the supplementary materials. The angles at the metal center between cis-positioned donor pairs span the range 80.23 (7) -105.76 (8)° and are close to those reported for related complexes (Singh & Mukherjee, 2005;Zhang et al., 2004). The three trans angles, N1-Cu-N1 i 171.46 (10)°, N2-Cu-S 163.79 (5)°, and N2 i -Cu-Si 163.79 (5)°, deviate significantly from the ideal value of 180° for a regular octahedral structure. This is presumably due to the structural demands imparted by the hexadentate ligand. The dimethylene bridge of the five-membered CuS 2 C 2 ring has gauche conformation.
The equatorial plane is occupied by two N atoms from quinoline moieties at longer Cu-N distances [2.183 (2) Å] and two thioether sulfur atoms [2.523 (1) Å]. The axial positions are occupied by the two amido nitrogen atoms at shorter Cu-N1 distances [1.956 (2) Å]. This Cu-N1 bond distance lies in the range of normal values for copper(II) to deprotonated amido nitrogen bond distances (Sunatsuki et al., 1998). On the other hand, Cu-N2 bond distance is longer than normal value of 1.96-2.08 Å for the copper(II) to pyridyl nitrogen in related complexes. (Singh & Mukherjee, 2005;Sunatsuki et al., 1998;Zhang et al., 2004). In agreement with findings on a pair of analogous Cu and Ni complexes with pyridine replacing quinoline in the bqdapte ligand (Sunatsuki et al., 1998), the coordination of the copper(II) ion in the title compound can be described as a Jahn-Teller distorted axially compressed (N1 and N1 i ) and equatorially elongated octahedron (N2, S, N2 i , S i ).
supplementary materials sup-2 The title complex was prepared as follows. To a stirring solution of H 2 bqctb (58.6 mg, 0.1 mmol) in dichloromethane (20 ml) was added a solution of Cu(CH 3 COO) 2 .H 2 O (20 mg, 0.1 mmol) in methanol (20 ml), and the mixture was stirred for 4 h. The final reaction mixture was filtered and the filtrate was left undisturbed for 24 h. Bright green crystals suitable for X-ray crystallography were obtained by slow evaporation of the filtrate at room temperature. The crystals were filtered off and washed with cold diethyl ether-dichloromethane (9/1), and dried under vacuum. Yield: 71%.

Refinement
Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger. Fig. 1. The ORTEP drawing of (I), with atom labeling scheme. Displacement ellipsoids are drawn at 50% probability level. Crystal data [Cu(C 34 (5) C8-C9-C10 120.4 (2) N2 i -Cu-S 92.79 (5) C8-C9-H9 119.8 N1 i -Cu-S i 83.73 (5)