Structure and Physical Properties of Two- and Three-Dimensional Divalent Metal Adipate Coordination Polymers with Bis(4-pyridylmethyl)piperazine Tethers

Abstract

Hydrothermal reaction of divalent metal salts, adipic acid and bis(4-pyridylmethyl)piperazine (bpmp), resulted in the generation of a series of coordination polymers whose two-dimensional and three-dimensional topologies depend on coordination environment, adipate conformation and carboxylate binding mode, and piperazinyl ring protonation. {[Cd(adipate)(H2bpmp)(H2O)]SO4·4H2O}n (1) manifests simple (4,4) grid cationic layers, while its oxoanion-free congener [Cd(adipate)(bpmp)]n (2) has a 5-fold interpenetrated diamondoid lattice. {[Cu(adipate)(Hbpmp)(H2O)]ClO4·3H2O}n (3) displays {Cu2O2} dimer-based (4,4) grid cationic layers. The isostructural complexes [M(adipate)(bpmp)(H2O)]n (M = Co, 4; M = Ni, 5) possess anti−syn bridged one-dimensional [M(OCO)]n chains and rare 3,5-connected binodal nets with (4.62)(4.6683) topology. The cadmium derivatives 1 and 2 undergo blue-violet light emission on excitation with ultraviolet. Antiferromagnetic coupling is observed in 3, while ferromagnetic superexchange occurs ...