Auxiliary ligand-directed synthesis of a series of Cd(ii)/Co(ii) coordination polymers with methylenebis(3,5-dimethylpyrazole): syntheses, crystal structures, and properties

Abstract

Using a flexible methylenebis(3,5-dimethylpyrazole) ligand (H₂MDP) with different aromatic carboxylate ligands, six new complexes {[Cd(H₂MDP)(OPh)](H₂O)}_n (1), {[Cd(H₂MDP)(MPh)](H₂O)_1/10}_n (2), {[Cd(H₂MDP)(PPh)](H₂O)_3/2}_n (3), {[Co(H₂MDP)(OPh)](H₂O)₂}_n (4), {Co(H₂MDP)(MPh)}_n (5), {Co(H₂MDP)(HBTC)}_n (6) (H₂OPh = phthalic acid, H₂MPh = isophthalic acid, H₂PPh = terephthalic acid, H₃BTC = benzene-1,3,5-tricarboxylic acid) have been isolated under hydrothermal conditions. The crystal structure analyses reveal that complexes 1 and 4 feature two-dimensional undulated sheets with 4⁴·6² topology. Both complexes 2 and 3 contain M₂L₂-type metallocyclic motifs composed of two H₂MDP ligands and two metal atoms, while complex 2 features a two-dimensional 4⁴·6² network constructed from binuclear cadmium units as four connected nodes, and complex 3 shows a two-dimensional network with 6³-hcb topology. Complex 5 affords a one-dimensional chain structure, and complex 6 shows a two-dimensional (4,4) network further connected into a 3D supramolecular structure connected by intermolecular hydrogen bonds and by π–π interactions. In addition, the luminescent properties of complexes 2 and 3 as well as the magnetic properties of 4 and 5 were studied.