Syntheses, Structures of Four New Complexes Constructed by Flexible Pyridine Ligand and the Relationship Between Conformations and Structures

Four new complexes [Co(pcaede)(2)Cl-2 2CH(3) CN H2O](n) (1), [Co pcaede)(2)Cl-2 center dot H2O](n) (2), [Hg(pcaede)I-2](n) (3) and [Hg(pcaede)Br-2](n) (4) were prepared with a flexible ligand 3-pyridinecarboxylic acid 1,2-ethanediyl ester(pcaede) and Co/Hg salts. They were characterized by elemental analysis, 1R and X-ray single-crystal diffraction. Complexes 1 and 2 both have an one-dimensional (1D) chain sturcture with channels. Complex 3 processes a 1D meso-helix sturcture, and complex 4 exhibits a 1D infinite zig-zag chain structrue. The results demonstrated that the solvent molecules filled in channels and counteranions have a significant impact on the assembly of the complexes. Moreover, theoretical calculations were carried about the conformation of the ligand in four complexes.