Abstract
3,5-Di-tert-butyl-2-hydroxybenzoic acid (TBS) and 3,5-di-tert-butylsalicylate zinc complex (SZC) are charge-control agents of the negative type used in electrophotography. Structure analysis of TBS and SZC has been carried out on single crystals recrystallized from solution in ethanol, acetonitrile, dimethylsulfoxide (DMSO) and dimethylacetamide (DMA). In 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 O-H…O hydrogen bonds between the two carboxyl groups. On the other hand, a variety of solvated SZC have been isolated: SZC/(ethanol)2, acetonitrile-solvated Zn-complex of TBS, SZC/(DMSO)2, SZC/(H2O)3(DMA)3 and SZC/(H2O)2(DMA)3. In these complexes, TBS molecules are coordinated to the central Zn as mono or bidentate ligands, depending on the recrystallization solvent as well as recrystallization conditions. These results suggest that the structural changes can also occur in the toner preparation process, resulting in scattered characteristics of the charge-control ability.
