Unsubstituted and substituted copper malonate coordination polymers with isomeric dipyridylamide ligands: Chain, layer, diamondoid, and self-penetrated topologies

Six dual-ligand divalent copper malonate coordination polymers have been prepared via solvent diffusion methods, and structurally characterized by single-crystal X-ray diffraction. The resulting dimensionality and topology depend crucially on the steric bulk of the malonate ligand and the nitrogen donor disposition within the dipyridylamide coligand. {[Cu(mal)(3-pina)(H2O)]·2H2O}n (1, mal = malonate, 3-pina = 3-pyridylisonicotinamide) possesses a simple 1-D chain structure, while the isomeric 4-pyridylnicotinamide (4-pna) ligand afforded a two-fold interpenetrated (6,3) grid layer structure in {[Cu(mal)(4-pna)(H2O)]·3H2O}n (2). Employing copper dimethylmalonate (dmmal) in the synthetic regime permitted synthesis of the (4,4) grid layered phase {[Cu2(dmmal)2(4-pna)2(H2O)3]·7H2O}n (3) and {[Cu2(dmmal)2(3-pina)2]·9.5H2O}n (4), which exhibited a three-fold interpenetrated diamondoid net with large water-filled incipient channels, built from [Cu4(dmmal)4] tetranuclear clusters. {[Cu2(Hdmmal)2(dmmal)(4-pina)2]·0.5H2O}n (5, 4-pina = 4-pyridylisonicotinamide) manifested a unique 5-connected self-penetrated 3D network with 42678 topology. {[Cu(emal)(4-pna)(H2O)]·3H2O}n (6, emal = ethylmalonate) is another simple 1-D chain phase. Ferromagnetic coupling (J = 11(3) cm−1) was observed within the tetranuclear clusters in 4. Thermal properties of these materials are also presented.