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

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)]. 2C(6)H(5)Br 1 and [Co(4,4'-bpz){C6H5CO2}{CH3CO2}]. 2C(6)H(5)Br 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.