Crystal Structure of Some Charge-Control Agents: 3,5-di-tert-butyl-2-hydroxybenzoic Acid and its Zinc Complexes

摘要

The title compounds are charge-control agents used in electrophotography. In 3,5-Di-tert-butyl-2-hydroxyben7oic acid (TBS), there are two independent molecules A and B in the asymmetric unit. The molecules form centrosymmetric dimers A-A and B-B via pair of OH···O hydrogen bonds between the two carboxyl groups. On the other hand, the zinc complex of TBS (Zn(TBS)_2) is found to include solvent molecules when recrystallized from ethanol and acetonitrile: (Zn(TBS)_2) (ethanol)_2 and (Zn(TBS)_2) (acetnitrile)_2. The former complex has C_2 symmetry, and exhibits a deformed octahedral coordination. Two O atoms of the ethanol molecules are coordinated in a cis fashion to the Zn atom. On the other hand, the latter forms a trinuclear complex: one central six-coordinate Zn complex and two four-coordinate Zn ones. Each O-ligand of TBS is coordinated to a different Zn atom.