Two new polymeric cadmium(II) complexes containing end-to-end bridging azido or thiocyanato ligands with different topologies

Two new polymeric cadmium(II) complexes; [Cd(3,5-DMP)2(N3)2] (1) and [Cd(4-Brpy)2(NCS)2] (2), where 3,5-DMP=3,5-dimethylpyridine and 4-Brpy=4-bromopyridine, have been synthesized and characterized. IR spectral data suggest end-to-end bridging azido and thiocyanato ligands. X-ray crystal structure determination has shown the 1-D complex 1 to contain each cadmium octahedrally coordinated by two double μ(1,3)-bridging azides and the other two sites are occupied by two pyridine ligands in a cis-arrangement. The CdCd distances in the Cd2(N3)2 eight membered rings are 5.142(2) and 5.152(2) A, the azide ligands are almost symmetrical and linear [NN distances: 1.167(5)–1.182(5) A; ∠NNN=176.7(4)° and 177.6(4)°]. In complex 2 each octahedrally cadmium atom is coordinated by two trans pyridine ligands and two trans nitrogen or sulfur atoms from four μ(N,S) bridging thiocyanato groups. The other end atoms of these four thiocyanato ligands bind four different cadmium atoms giving a 2-D layer structure.