Synthesis and structural characterization of the helical coordination polymers [Co(phen)(oba)(H2O)2] and [Cd3(phen)3(oba)2(Hoba)2(H2O)2] (phen=1,10-phenanthroline; oba=4,4′-oxybis(benzoate)

Two coordination polymers, [Co(phen)(oba)(H2O)(2)] (1) and [Cd-3(phen)(3)(oba)(2)(Hoba)(2)(H2O)(2)] (2) (oba = 4,4'-oxybis(benzoate), phen = 1,10-phenanthroline) have been synthesized under hydrothermal conditions. Complex 1 crystallizes in monoclinic, P2(1)/n, a = 7.543(6), b = 33.05(2), c = 9.902(5)Angstrom, beta = 103.69(2)degrees, V = 2398(3) Angstrom(3), Z = 4; 2 in monoclinic, P2/n, a = 15.11(1), b = 10.069(8), c = 28.02(2)Angstrom, beta = 101.83(1)degrees, V = 4174(5) Angstrom(3), Z = 2. X-ray single-crystal diffraction investigations shows that the complexes 1 and 2 consist of helical chains, which are further assembled into layers and networks via supramolecular interactions such as pi-pi stacking interactions and hydrogen bonds, respectively. The results indicate that the coordination environment is one of the most important factors for assembly of single-stranded helical chains into double-stranded helical chains via supramolecular interactions.