Study of a novel reaction between N,N'-diphenylthiourea and p-chloranil through a charge-transfer intermediate

The well-known electron acceptor, p-chloranil (A) and donor, N,N'-diphenylt hiourea (B) have been observed to form a labile charge-transfer (CT) comple x (AB), which decays slowly into two products viz. 2,3,5-trichloro-6-(N,N'- diphenylthioureido)benzo-1,4-quinone (P) and 5,6-dichloro-2,3-(N,N'-dipheny lthioureylene)benzo-1,4-quinone (Q). The final products have been isolated in pure form and one of them, P, has been shown to exhibit sensitive solvat ochromism. A detailed kinetic study of the decay process of the CT complex has been carried out and based on kinetic data, the following steps have be en suggested for the decay process.