Syntheses and structural studies of tris(N-phenothiazinyl)borane and its radical cation.

A radical comparison: The neutral (1) and radical cation (1(.+)) forms of tris(N-phenothiazinyl)borane were prepared and their molecular structures and spectral properties investigated. The results established that 1(.+) possessed a localized radical cation on one of the phenothiazine (PTZ) rings. The crystal structure of 1(.+) showed elongation of the B=N bond bound to the PTZ(.+) ring (B=N1: 1.53 Å).