Photogalvanic behaviour of [Cr2O2S2(1-Pipdtc)2(H2O)2] in aqueous DMF

The photogalvanic behaviour of [Cr2O2S2(1-Pipdtc)(2)(H2O)(2)] was performed in a Honda Cell using 100% DMF and different percentages of water-DMF systems. The maximum potential of 200 mV with 18 mu A of current was generated in DMF. The experiments were performed at different pH conditions and added dyes. The system was found to generate a maximum potential of 86, 67 and 36 mV at pH similar to 4, 7 and 8, respectively, at 65 degrees C. Malachite green and methylene blue (10(-4) M) produced maximum potential of 100 and 82 mV, respectively. The system was reversible when the irradiated solution was aerated immediately. When the solution was kept in dark for a long time (12 h) and then aerated, the solution was found to be irreversible. The Cr(V) is photoreduced to Cr(IV) with the light irradiation and the unstable Cr(IV) reverts to Cr(V) by aerial oxidation. (C) 2008 Elsevier B.V. All rights reserved.