The synthesis and structure of a novel alternating 1-D cobalt coordination polymer [Co(2,5-PDC)2(H2O)2Co(H2O)4]·4H2O

A novel cobalt complex [Co(2,5-PDC)2(H2O)2Co(H2O)4]·4H2O (2,5-PDCH2 = 2,5-pyridinedicarboxylic acid) was synthesized and its crystal structure has been determined by X-ray diffraction. The crystallographic data are: triclinic P−1, a = 7.112(2) A, b = 8.939(3) A, c = 9.719(3) A, α = 91.153(5)°, β = 101.136(5)°, γ = 108.001(4)°, V = 574.4(3) A3, Z = 1. The compound [Co(2,5-PDC)2(H2O)2Co(H2O)4]·4H2O exhibits a novel one-dimensional network constructed from the interconnection of Co(2,5-PDC)2(H2O)2 and Co(H2O)4, in which two kinds of six-coordinated Co(II) atoms have both octahedral coordination environments. Each 2,5-PDC anion connects two different coordinated cobalt ions alternately in an one-dimensional chain. The zigzag 1D alternating chains are linked by extensive hydrogen bonds to form a three-dimensional (3D) supramolecular structure, in which uncoordinated solvate molecules act as space filling particles.