Abstract:
Zinc, cadmium and mercury dihalides were reacted with benzopyridine- and benzopyrazinetype
N-donor molecules acridine (acr), phenazine (phe), quinoline (quin) and quinoxaline
(quinox) as ligands or cations. The solid-state structures of 16 novel, zero-dimensional
reaction products were studied by X-ray diffraction. Seven of the compounds were prepared
in the presence of an inorganic acid, HX, which resulted in the formation of anionic
tetrahalometallates, [MX4]2−, with either Cd2+ or Hg2+ as the cationic metal center and
quinolinium (quin-H), quinoxalinium (quinox-H), acridinium (acr-H) or phenazinium (phe-
H) as the counter cation. The other nine compounds contain Zn2+ as the tetrahedral cationic
node. Five of the nine Zn2+ compounds are neutral, and four are ionic. Three of the four ionic
Zn2+ compounds contain an anionic tetrahalometallate inorganic moiety, [ZnX4]2−, while the
inorganic component of the fourth ionic Zn2+ compound is coordinated by three halido
ligands and one aqua ligand, [ZnX3(H2O)]−. Structural trends, hydrogen bonding interactions
and aromatic interactions are identified. In addition, it is observed that in the case of the
neutral phenazine or acridine compounds, the size of the organic molecule prevents
coordination of the molecule to the metal ion.
