Bis(Pyridyl)Cadmium(II) Iodide Complexes: Thermal, Inclusion, and Structural Behavior
Bailey, R. D.; Hook, L. L.; Powers, A. K.; Hanks, T. W.; Pennington, W. T. Bis(Pyridyl)Cadmium(II) Iodide Complexes: Thermal, Inclusion, and Structural Behavior. Cryst. Eng. 1998, 1, 51-66.
Bis(4-cyanopyridine)cadmium(II) iodide (1) crystallizes as infinite CdI2 chains, in which cadmium atoms are doubly bridged by pairs of iodine atoms; 4-cyanopyridine ligands occupy trans positions to complete an octahedral coordination about the cadmium. The chains are associated into layers through self-association of the cyano groups. The layer structure of 1 is essentially unchanged as mercury(II) iodide molecules are intercalated between the layers to form 2. Bis(4-vinylpyridine)cadmium(II) iodide (3) crystallizes in a nearly isomorphous fashion with 1; however, lacking a donor site capable of binding to HgI2, it does not form an intercalation compound similar to 2. Bis(2-vinylpyridine)cadmium(II) iodide (4) crystallizes as a molecular species with approximate tetrahedral coordination about the four-coordinate cadmium atom; steric interactions involving the vinyl groups prevent formation of extended chains. The 4-vinylpyridine complex undergoes a thermally-induced solid-state polymerization of the ligand that is not observed in 1, 2 or 4.