Abstract
Triphenyl-pararosaniline (TPPR) and n-propyl gallate (PG) are charge-control agents (CCA)of the positive and negative type, respectively. Suganami et al. reported that a 1:2 complex of TPPR and PG (colored deep blue) is a powerful CCA of the positive type due to the formation of a charge-transfer (CT) complex. The electronic structure of the complex has been studied in the present investigation in solution and in the solid state in order to clarify the charge-transfer mechanism. Quite contrary to our expectation, the blue color is found to arise from protonation of TPPR by means of PG, not due to a CT transition between TPPR and PG. The charge-control ability of the 1:2 complex is then attributed to the property of protonated TPPR.
