Coordination polymers of CoII and 3,3′,5,5′-tetramethyl-4,4′-bipyrazolyl: a novel metal–organic three-dimensional network with four-coordinated planar vertices

Abstract

The bitopic exodentate ligand 3,3′,5,5′-tetramethyl-4,4′-bipyrazolyl (4,4′-bpz), designed as an angular bridging unit capable of formation of a set of coordination and hydrogen bonds, gave the coordination polymers [Co(4,4′-bpz)₂{C₆H₅CO₂}₂]·2C₆H₅Br 1 and [Co(4,4′-bpz){C₆H₅CO₂}{CH₃CO₂}]·2C₆H₅Br 2. Complex 1 exhibits a 3-D structure containing rectangular channels. The topology of the array has no precedents in crystal engineering of linear spacer ligands of the 4,4′-bipyridine type and may be a prototype for engineering of a novel family of functional solids. Complex 2 exists as a hybrid coordination/hydrogen-bonded porous network which incorporates two guest bromobenzene molecules per metal atom.