Crystal-to-crystal transformation from a weak hydrogen-bonded two-dimensional network structure to a two-dimensional coordination polymer on heating

Single crystal to single crystal transformation of a new mercury(II) coordination polymer with ligand 1,4-bis(2-pyridyl)-2,3-diaza-1,3-butadiene (bpdb), [Hg-2(mu-bpdb)I-4] (1 alpha) to [Hg-2(mu-bpdb)(mu-I)(2)I-2](n) (1 beta), has been reported and structures of 1 alpha and 1 beta were determined by X-ray crystallography. The thermal stability of compounds 1 alpha and 1 beta were studied by thermal gravimetric (TG) and differential thermal analyses (DTA). Powder X-ray diffraction experiments showed that the phase transitions described for single crystals also occur in macroscopic powder samples and lead to monophasic products and the crystal-to-crystal transformation described is not reversible.