Cadmium coordination polymers based on flexible bis(imidazole) ligands: A rare example for doublet of doublet cadmium polyhedron arrangements

摘要

Two one-dimensional (1D) coordination polymers, [{LCd(O_2NO)_2(DMF)_2}_2{(LCd(O_2NO)_2(DMF))(DMF)}_2]n (1) and [L′Cd(O_2NO)(ONO_2)(DMF)_2]_n (2), having an aryl chromophoric unit and a flexible bis(imidazole) tail, 9,10-bis{(benzimidazol)methyl}anthracene (L) and 1,4-bis{(imidazol)methyl}benzene (L′), with various coordination modes have been obtained. Molecule 1 represents the first structurally characterized one dimensional coordination polymer consisting of both hepta- and octa-coordinated cadmium centers. In 1, two distorted pentagonal bipyramidal Cd(II) centers and two distorted triangular dodecahedral Cd(II) centers are alternately arranged via bridging bidentate N,N-chelating ligand, L.Whereas, a distorted pentagonal bipyramidal Cd(II) center is formed in 2 where the sterically less crowded L0 serves as a bridging bidentate N,N-chelating ligand. Furthermore, 1 and 2 have been characterized by elemental analysis, FT-IR, ~1H NMR, UV–vis and fluorescent techniques.