The Intriguing Diversity of Neutral and Cationic Selenium-Nitrogen Heterocycles

Abstract

Abstract Salts containing ternary Se,N,Cl cations, [(SeCl)2N]+X− (X− = SbCl6 −, 1; FeCl4 −, 2) and [(SeCl2)2N]+Y− (Y− = AsF6 −, 3), were prepared by reaction of N(SiMe3)3 with [SeCl3]+X− or [SeCl3]+Y−, respectively. In addition, 1 was formed from the reaction of Se2NCl3 with SbCl5. The structures of 1–3 were determined by X-ray crystallography. Reaction of 1 with F3C-C[tbnd]C-CF3 led to the formation of the novel five-membered heterocyclic cation . Compound 4 turned out to be a useful building block to generate new selenium containing heterocycles such as the neutral rings (7π radical) (5), (6) and (7). The heterocycle 6 was shown by electron diffraction studies to have a close to planar four-ring structure. The solid state structure of compound 7 was determined by X-ray crystallography. The existence of the neutral radical 5 was established by means of neutralization-reionization mass spectrometry. The structures of 6 and of the cation in 4 were computed ab initio using model compounds in which the CF3 g...