Conformation dependent network structures in the coordination polymers derived from pyridylisonicotinamides, carboxylates and Co(ii): Entrapment of (H2O)14 water cluster of an unprecedented topology

Abstract

Four coordination polymers, namely [{(H₂O)₄Co(μ-L1)₂}·fumarate·2H₂O]_n1, [{(H₂O)₃(μ-fumarate)Co(μ-L1)₂}·fumarate·2H₂O]_n2, [{(H₂O)₄Co(μ-L2)₂}·terephthalate·3H₂O]_n3 and [{(H₂O)₄Co(μ-L2)₂}·terephthalate·10H₂O]_n4 (L1 = N-(3-pyridyl)nicotinamide, L2 = N-(4-pyridyl)isonicotinamide) have been synthesized and structurally characterized mainly by single crystal X-ray diffraction techniques in order to explore the effect of hydrogen bond functionalized backbone and ligating topologies on the resultant supramolecular architectures in mixed ligand systems containing dicarboxylates as counter bridging anions. Interestingly, the counter bridging anions fumarate and terephthalate failed to coordinate to the metal centers in 1 and 3–4, respectively; fumarate, however, terminally connects to the metal centers in 2 resulting in the ladder topology. A (H₂O)₁₄ water cluster, having unprecedented topology, has been found entrapped in the lattice of 4.