A Chain of Changes:  Influence of Noncovalent Interactions on the One-Dimensional Structures of Nickel(II) Dicarboxylate Coordination Polymers with Chelating Aromatic Amine Ligands

Five one-dimensional coordination polymers, Ni(BDC)(1,10-phen) (1), Ni(BDC)(2,2‘-bipy)·0.75H₂BDC (2), Ni(BDC)(1,10-phen)(H₂O) (3), Ni(BDC)(1,10-phen)(H₂O)·0.5H₂BDC (4) and Ni(BDC)(2,2‘-bipy)(H₂O) (5) [where BDC = 1,4-benzenedicarboxylate, 2,2-bipy = 2,2‘-bipyridine, and 1,10-phen = 1,10-phenanthroline] that have the same topology but markedly different geometry and packing of the chains have been synthesized by hydrothermal reactions. The results of variations of synthesis conditions and substitutions of 1,10-phenanthroline with 2,2‘-bipyridine indicate that incorporation of the coordinating water molecule, which affects the degree of bending of the chain, is primarily influenced by the amine ligand size, suggesting a substantial structural role of aromatic−aromatic interactions and amine ligand steric effects. The incorporation of the guest H₂BDC molecules was found to be favored by lower pH conditions. Crystal data:  1, monoclinic, space group P2₁/n, a = 9.5589(6) Å, b = 12.6776(8) Å, c = 13.5121(9) Å, β = 95.437(1)°, Z = 4; 2, monoclinic, space group P2₁/c, a = 20.532(3) Å, b = 21.505(3) Å, c = 18.872(3) Å, β = 93.86(1)°, Z = 16; 3, triclinic, space group P1̄, a = 8.618(3) Å, b = 10.058(4) Å, c = 11.353(4) Å, α = 115.31(1)°, β = 92.33(1)°, γ = 94.03(1)°, Z = 2; 4, triclinic, space group P1̄, a = 9.7682(12) Å, b = 10.6490(13) Å, c = 11.2468(14) Å, α = 76.685(2)°, β = 65.309(2)°, γ = 85.612(2)°, Z = 2; 5, monoclinic, space group P2₁/c, a = 13.9683(9) Å, b = 17.4489(11) Å, c = 13.7737(9) Å, β = 99.12(1)°, Z = 8.