The Crystal Structures of Disordered Crystals of Adducts of Diphenylmercury with Bidentate Ligands

The crystal structures of two adducts of diphenylmercury with neutral bidentate nitrogen donor atom ligands have been determined, showing very weak interactions between mercury and nitrogen atoms. The crystals are disordered in a manner giving rise to diffuse reflexions for which k is odd. The crystal of diphenylbis-(2,4,7,9-tetramethyl-l,10-phenanthroline)mercury(lI) studied has a=21.09, b= 14.54, c= 14.65 A, beta = 120°34', Z=4, and space group Cm. Crystals of diphenylbis(2,9-dimethyl-l,1O-phenanthroline)mercury(II) have a= 15.42, b= 14.28, c= 14.55 A, alpha~beta~gamma 90°, Z=4,and spacegroup PI with approximate Pm symmetry. Both adducts have their planar ligands in (040) with the C-Hg-C units of Ph2Hg moieties aligned in the [010] direction. Each diphenylmercury moiety has one ligand adjacent to it with Hg-N distances of 2.8-3.0 A, and one-half of the ligands in the crystals do not have a mercury atom adjacent to their nitrogen atoms. Within the unit cell of each adduct every second (040) plane has 0,5 occupancy for two Ph2Hg moieties with mercury atoms in those planes, and every other (040) plane has 0,8 and 0.2 occupancy for two Ph2Hg moieties in those planes, giving one Ph2Hg for every two ligands.