Oxidative coupling of 2-aminophenol to 2-amino-phenoxazine-3-one catalyzed by organotin (IV)–copper (I) cyanide coordination polymers as heterogeneous catalysts

• Published in: Arabian journal of chemistry 2017-05, Vol.10 (S2), p.S2829-S2835
• Main Authors: El-Khalafy, Sahar H., Hassanein, Mahmoud T., Etaiw, Safaa El-din H., Badr El-Din, Ahmed S.
• Format: Article
• Language: English
• Subjects: 2-Aminophenol; 2-Aminophenoxazine-3-one; Auto-oxidation; Coordination polymers; Copper cyanide; Organotin
• ISSN: 1878-5352; 1878-5379
• DOI: 10.1016/j.arabjc.2013.11.005

The activity of organotin (IV)–copper (I) cyanide coordination polymers [Ph3SnCu (CN)2·L] where L=1,2-bis(4-pyridyl)ethane (bpe) 1, 4,4′-bipyridine (bpy) 2, methylpyrazine (mepyz) 3 or trans-1,2-bis(4-pyridyl)ethene (tbpe) 4 has been investigated as heterogeneous catalysts for the biomimetic oxidative coupling of 2-aminophenol (OAP) to 2-aminophenoxazine-3-one (APX). The rate of OAP consumption was determined by measuring the amount of dioxygen consumed using a gas burette. All the coordination polymeric catalysts showed high activity for auto-oxidation of OAP. The coordination polymer 4 has been found to be the most reactive catalyst. The rate of auto-oxidation reaction of OAP catalyzed by the coordination polymer 4 has been found to increase with increasing the pH from 7 to 9 then decreased at higher pH. The rate of auto-oxidation reaction showed linear dependence on catalyst concentration and pressure of dioxygen. The rate of reaction has been found to fit a Michaelis–Menten kinetic model for saturation of catalyst sites with increasing OAP concentration. The catalyst 4 showed no deactivation after six runs.