Synthesis and crystal structure of poly[[bis-(aqua-κ O )tetra-kis-(μ-4,4'-bi-pyridine-κ 2 N : N ')hexa-kis-(3-chloro-benzoato)-κ 5 O ;κ 2 O : O '-tricobalt(II)] methanol disolvate].

A novel ladder-chain cobalt(II) coordination polymer, {[Co 3 (C 7 H 4 ClO 2 ) 6 (C 10 H 8 N 2 ) 4 (H 2 O) 2 ]·2CH 3 OH} n , was synthesized and characterized. The structure contains two Co II centres with different octa-hedral environments, [Co(1)N 3 O 3 ] and [Co(2)N 2 O 4 ]. The O -donating 3-chloro-benzoate anions (3-Clbenz) act as the terminal ligands, while the N -donating 4,4'-bipy mol-ecules play the role of linkers. The Co(1) ions are linked by 4,4'-bipy mol-ecules into linear chains. Two such chains are joined by [Co(2)(3-Clbenz) 2 (H 2 O) 2 ] units via two 4,4'-bipy bridging ligands, thus forming the ladder-chain structure. The crystal packing of the title compound is stabilized by supra-molecular inter-actions, such as hydrogen bonding, π-π and halogen⋯π contacts, giving a three-dimensional framework. The spectroscopic and thermal properties of the title compound have also been investigated.