Metal-Dependent Topologies and Water Aggregations in Copper and Nickel Carboxycinnamate Coordination Polymers with a Long-Spanning Dipyridylamide Ligand

Hydrothermal reaction of the requisite metal nitrate, carboxycinnamic acid (H(2)cca), and the long-spanning dipyridylamide bis(4-pyridylformyl)piperazine (4-bpfp) generate crystalline coordination polymers whose topology depends critically on the metal coordination geometric preference. These two new phases were structurally characterized by single-crystal X-ray diffraction. {[Cu(cca)(4-bpfp)]2.5H(2)O}(n) (1) manifests a non-interpenetrated 6-connected pcu net based on chain motifs featuring carboxylate-bridged {Cu-2(OCO)(2)} dinuclear units, with embedded D(5) water molecule chains. {[Ni(cca)(4-bpfp)(H2O)(2)]3H(2)O}(n) (2) displays an acentric twofold interpenetrated 4-connected 6(6) dia network topology with entrapped R(4)A(1) water molecule rings. Variable temperature magnetic studies performed on 1 revealed very weak antiferromagnetic coupling within its dinuclear units. Thermal properties of these two new materials are also discussed.