Size Determination of Catena-&mgr;-2,5-dihydroxy-p-benzoquinonatonickel(II) Coordination Polymer Colloid and Its Photochemical Reaction
Electric birefringence and streaming dichroism measurements of catena-&mgr;-2,5-dihydroxy-p-benzoquinonatonickel(II) [dhqNi(II)] aqua sol suggested that the average length of the sol particles was ca. 380 nm and the axial ratio was 2.0-2.3 as the prolate spheroid. The average particle length in the scanning microscopic images was 370 &plusmn; 60 nm and the axial ratio 2.3 &plusmn; 0.6. This aqua colloid was decomposed by UV irradiation under an O2 gas atmosphere, but under a N2 gas atmosphere its decomposition was depressed. Furthermore, addition of sacrificial reagents such as l-ascorbic acid depressed the decomposition. These facts suggested that the photogenerated electron originating from the irradiated dhqNi(II) colloidal particle reduced O2, while the positive hole on the colloid oxidized dhqNi(II) itself. It was found that the reduction product from O2 reduced Cr6+ (in Cr2O72-) to Cr3+, and the oxidized dhqNi(II) oxidized I- to I2/2. Therefore, H2O2 formation was proposed as the photochemical reduction product. Copyright 1997Academic Press
Miyoshi
H
Faculty of Engineering, University of Tokushima, Minamijousanjima-cho, Tokushima, 770, Japan
Matsumoto
M
Kanda
S