大环穴醚双铜硫氰酸根配合物[Cu_2(SCN)_3(C_(16)H_(38)N_6)]_2(ClO_4)_2的合成和结构

THE SYNTHESIS AND CRYSTAL STRUCTURE OF THIOCYANATE-BRIDGED BI-COPPER(Ⅱ) MACROCYCLIC COMPLEX OF 1,4,7, 12,15,18-HEXAAZACYCLODOCOSANE [Cu_2 (SCN)_3 (C_(16)H_(38)N_6)]_2 (CIO_4)_2

合成了大环穴醚配体C_(16)H_(32)N_6。在SCN^-参与下,进一步合成了大环穴醚配合物[Cu_2(SCN)_3(C_(16)H_(38)N_6)]_2(ClO_4)_2,并用X射线单晶结构分析测定了其晶体结构。晶体属单斜空间群C_(2h)~4-P2/n,α=16.274(8),b=8.114(3),c=23.199(10)A,β=98.46(4)°,V=3030.1A^3,Z=2。晶体中的Cu(Ⅱ)的配位几何构型为畸变的四方锥。硫氰酸根有两种配位形式,一种是以N端的单配位,处于四方锥的底面;另一种是以S端和N端的桥连配位,处于四方锥的顶端,桥连的硫氰酸根把大环穴醚双铜络合物联成一维无限链状。

In the study on the model of the active site of superoxide dismutase, some hicopper (Ⅱ) maerocyclic complexes have been synthesized. This paper discribes the synthesis and crystal structure of a new μ-thiocyanato-complex. The crystal belongs to monoclinic space group P2/n with a=16.274(8), b=8.110 (3), c=23.199(10)A, β=98.46(4)°, V=3030A^3, Z=4, D_c=1.57g.cm^(-3). The crystal structure was solved by direct method and difference Fourier synthesis. The refinement with anisotropic temperature factors for non-hydrogen atoms gave the final discrepancy factor R=0.088 for 1945 reflections. The macrocycles are at the symmetric center of the cell. Both coppers are in a distorted square-pyramidal environment. The two copper ions in the same macrocycle are noninteracting (Cu-Cu=5.478A).The copper ions in the different macrocycles are bridged by thiocyanate to form a infinite chain in the crystal. The basal positions of the pyramid consist of three nitrogen atoms of the diethylenetriamine fragment of the macrocycle and one nitrogen atom from a non-bridged thiocyanate ligand and the vertex of the distorted square-pyramid is nitrogen or sulfur atom of the bridged thiocyanate. The distance of two copper ions bridged by thiocyanate is 6.695A. The interaction of copper with the vertical nitrogen atom (Cu-N=2.315A) is stronger than with vertical sulfur atom (Cu-S=2.824A).