Synthesis of water soluble cobalt(II), copper(II) phthalocyanines and their usage as a catalyst in the photoxidation of benzyl alcohol in biphasic catalysis

Abstract

In this study, we synthesized and characterized cobalt(II), copper(II) phthalocyanines (2, 3) and their water soluble derivatives (2a, 3a) bearing dimethylamino groups. Then, benzaldehyde selective photoxidation of benzyl alcohol with four different oxygen sources and catalysts (2a, 3a) was carried out by biphasic catalysis. Optimal photocatalytic reaction conditions were determined as benzyl alcohol/ oxidant molar ratio 4.0/1 amount of the catalyst 2.0 mg (9.61 × 10−7 mmol), 25 ◦C and 30 min. 92 % conversion of benzyl alcohol with 1640 turnover number for 2a and 75 % benzaldehyde selectivity for 3a are achieved under the optimal conditions. Both catalysts can be used in three times and 2a can be catalytically active after 5 cycles with giving 72 % product conversion.