Crystal Engineering with Mercuric Chloride

Abstract

Two new network solids containing mercury ions are reported. The structure of HgCl 4 ·H 2 tpt·H 2 O (tpt = 1,3,5-tri(4-pyridyl)-2,4,6-triazine) contains H 2 tpt 2+ cations connected into 1D zigzag chains via hydrogen bonding between protonated and unprotonated pyridyl groups of adjacent cations. The third pyridyl group of each H 2 tpt 2+ cation is also protonated and hydrogen-bonds to tetrahedral HgCl 4 2- anions that lie as appendages to the main hydrogen-bonded chain. (HgCl 2 ) 2 (hmt) (hmt = hexamethylenetetramine) contains HgCl 2 and hmt molecules. The mercury is pseudo-octahedral, coordinating to two trans chloride ligands (Hg−Cl = 2.351(1) Å) and making four much longer equatorial interactions with hmt molecules (Hg−N = 2.735(4) Å) and adjoining HgCl 2 molecules (Hg−Cl = 3.105(1) Å). The long Hg−N interactions link the two species into 2D (4,4) sheets, while long Hg−Cl interactions connect these sheets into an overall 3D network through chains of rhombohedral Hg−Cl···Hg−Cl··· motifs.