COUNTER ION EFFECT ON PHOTOCHEMICAL REACTION OF CRYSTAL VIOLET

Abstract

On the basis of the examination of the influence of counter ion on the photoreaction of Crystal Violet (CV) we can draw the following conclusions. (1) Counter ion did not affect any influence in degassed isopropyl alcohol, while its distinct effect was observed in degassed acetonitrile. The reactivities of counter ions were arranged in the following order; (COOH) (COO)^-_??_Cl^->CH₃C₆H₄SO₃^- This order agrees well with the order of the electron donating ability of these counter ions. (2) A lack of the effect of counter ion was caused by the high ability of ionization and the hydrogen donation of isopropyl alcohol. (3) The corresponding triphenylmethyl radical was formed on PVA independently of counter ions. The radical formation was dramatically accelerated by the addition of moisture. It is concluded that the photoreduction of CV on PVA proceeded by the electron transfer from OH^-, produced by dissociation of water, to the excited dye. (4) The photoreduction of CV on nylon was also accelerated by the addition of moisture. Consequently the reactivities
of the electron transfer on the photoreduction of CV can be arranged in the following order; OH^->(COOH) (COO)^-_??_Cl^->CH₃C₆H₄SO₃ This order agrees very well with the order of the electron donating ability of the anion.