Crystal structure of a novel one-dimensional zigzag chain-like cobalt(II) coordination polymer constructed from 4,4′-bipyridine and 2-hydroxy-benzoate ligands

A novel one-dimensional zigzag chain-like Co-II coordination polymer constructed from 4,4'-bipyridine (4,4'-bpy) and 2-hydroxybenzoate (2-OHbenz) ligands, namely, catena-poly[[(4,4'-bipyridine-kappa N)(mu-2-hydroxybenzoato kappa O-2:O0O')(2-hydroxybenzoato-2 O, O0)cobalt(II)]-mu-4,40-bipyridine-kappa N-2:NO-[aquahemi(-4,40-bipyridine-kappa N-2:N0)( 2-hydroxybenzoato-O(2- hydroxybenzoato mu 2 O:O0)cobalt( II)], [Co-2(C7H5O3)(4)(C10H8N2)2.5((H)2O)]n, has been synthesized by reacting cobalt(II) nitrate trihydrate, 4,40-bpy and 2-hydroxybenzoic acid in a mixture of water and methanol at room temperature. There are two independent Co-II centers, Co1 and Co2, in the asymmetric unit, revealing a distorted octahedral geometry with chromophore types of [CoN2O4] and [CoN2O3O '], respectively. The Co1 ions are doubly bridged by 2-OHbenz ligands with syn-anti coordination mode, generating a dinuclear unit. The bridging 4,40-bpy ligands connect these dinuclear units and the mononuclear Co2 chromophores, providing a one-dimensional alternating zigzag chain-like structure. In the crystal, intermolecular hydrogen bonds, C-H center dot center dot center dot pi and pi-pi stacking interactions are observed and these help to consolidate the packing. In addition, the physical properties of the title compound are reported.