Structural studies and photochromism of mercury(II)-iodo complexes of (arylazo)imidazoles

Neat reaction between Hg[I.sub.2] and 1-methyl-2-(phenylazo)imidazole under microwave irradiation has synthesized [Hg[I.sub.2]][[RaaiR'].sub.2], where RaaiR' = 1-alkyl-2-(arylazo)imidazole, in which the layers of reactants are separately positioned in the crystal structure. The activation energy ([E.sub.a]) of cis-to-trans of free ligands are found to be much higher than that of halo-bridged Hg(II)-azomidazole complexes, whereas chloro-bridged Hg(II) complexes have shown lower [E.sub.a]'s than those of iodo-bridged complexes.