Photocyclisation of 1,2-diarylpyridinium cations and the photobis-cyclisation of 1,2,6-triarylpyridinium cations. X-Ray crystal structure of 9-phenyl-2,10b-diazadibenzo[fg,op]naphthacenium perchlorate

Photobis-cyclisation of 1,2,6-triarylpyridinium cations gives 10b-azadibenzo[fg,op]naphthacenium cations (3a–e) and their 2-aza-analogues (3f–c); the structures are supported by X-ray crystallographic analysis of 9-phenyl compound (3f).