Coordination Driven Self-Assembly in Co(II) Coordination Polymers Displaying Unprecedented Topology, Water Cluster, Chirality, and Spin-Canted Magnetic Behavior

The present work reports facile synthesis, full characterization, and architectural diversity of seven Co(II) coordination polymers, namely, [{CO(H2MBP)(2)(12-CDA)}center dot CH3OH](infinity) (1), [{(H2MBP) (12-CDA) (H2O)}](infinity) (2), [{Co-0.5(H2MBP)(14-CDA)(0.5)}center dot(H2O)(2.5)](infinity) (3), [{Co(H2MBP)(14-CDA)-(H2O)(2)}](infinity) (4), [{Co(H2MBP)(13-ADA)(0.5)}](infinity) (5), [{Co(H2MBP)(2)(135-CTA)-(H2O)}(H2O)(3.5)](infinity) (6), and [{Co-2(mu O-2)(H2MBP)(3)(1245-CHA)}(H2O)(12)](infinity) (7), derived from a 4,4'-methylene bispyrazole (H2MBP) ligand and various flexible dicarboxylate coligands. The type of alicyclic flexible carboxylate coligand used in the synthesis and its coordination to the metal center play a key role in controlling the dimensionality and topology of the frameworks. Topological analysis of the simplified nets reveals that 1 and 3 possess a 4-connected sql topology, 2 features a 3-connected uninodal hcb topology, 5 contains a 3D cds topology, and 7 possesses an unprecedented new 3D topology. Interestingly, a well-resolved 1D water chain is found within 3 and the presence of a heptanuclear water cluster assisted via a free carboxylate group is observed in 6. Chirality associated with 5 has been supported by solid-state CD spectra, and variable-temperature magnetic studies indicate that 7 exhibits canted magnetic coupling between the carboxylate bridged Co(II) ions.