title: A three-dimensional cadmium(II) coordination polymer with unequal homochiral double-stranded concentric helical chains.
abstract: A homochiral helical three-dimensional coordination polymer, poly[[(μ2-acetato-κ(3)O,O':O)(hydroxido-κO)(μ4-5-nicotinamido-1H-1,2,3,4-tetrazol-1-ido-κ(5)N(1),O:N(2):N(4):N(5))(μ3-5-nicotinamido-1H-1,2,3,4-tetrazol-1-ido-κ(4)N(1),O:N(2):N(4):N(5))dicadmium(II)] 0.75-hydrate], {[Cd2(C7H5N6O)2(CH3COO)(OH)]·0.75H2O}n, was synthesized by the reaction of cadmium acetate, N-(1H-tetrazol-5-yl)isonicotinamide (H-NTIA), ethanol and H2O under hydrothermal conditions. The asymmetric unit contains two crystallographically independent Cd(II) cations, two deprotonated 5-nicotinamido-1H-1,2,3,4-tetrazol-1-ide (NTIA(-)) ligands, one acetate anion, one hydroxide anion and three independent partially occupied water sites. The two Cd(II) cations, with six-coordinated octahedral and seven-coordinated pentagonal bipyramidal geometries are located on general sites. The tetrazole group of one symmetry-independent NTIA(-) ligand links one of the independent Cd(II) cations into 61 helical chains, while the other NTIA(-) ligand links the other independent Cd(II) cations into similar but unequal 61 helical chains. These chains, with a pitch of 24.937 (5) Å, intertwine into a double-stranded helix. Each of the double-stranded 61 helices is further connected to six adjacent helical chains through an acetate μ2-O atom and the tetrazole group of the NTIA(-) ligand into a three-dimensional framework. The helical channel is occupied by the isonicotinamide groups of NTIA(-) ligands and two helices are connected to each other through the pyridine N and carbonyl O atoms of isonicotinamide groups. In addition, N-H···O and O-H···N hydrogen bonds exist in the complex.
authors.affiliation: College of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Shi
authors.affiliation: College of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, People's Republic of China.
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: Liu
authors.affiliation: College of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, People's Republic of China.
authors.forename: Xiang-Ping
authors.initials: XP
authors.lastname: Ou
authors.affiliation: College of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, People's Republic of China.
authors.forename: Chang-Cang
authors.initials: CC
authors.lastname: Huang
mesh_terms: D002104:Cadmium / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008024:Ligands; D015394:Molecular Structure; D009536:Niacinamide / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D008024:Ligands; D011108:Polymers; D002104:Cadmium; D009536:Niacinamide; C027681:isonicotinamide
keywords: N-(1H-tetrazol-5-yl)isonicotinamide; crystal structure; double helical coordination polymer; homochiral helices; hydrogen bonding; powder X-ray diffraction; three-dimensional cadmium(II) coordination polymer