Crystal and Electronic Structure of Stable Nitrenium Ions. A Comparison with Structurally Related Carbenes

The isolation of bis-amino-substituted carbenes of the Arduengo (3a) and Wanzlick type 4a has prompted us to look for stable nitrenium ions of the related structural type 3d+ and 4d+. Thus 5+I- (6+I-) and 18+ClO4- were isolated and structurally characterized by X-ray crystallography. Theoretical studies give insight into the different (electronic) structures and stabilities of 3a,d+, 4a,d+, and of related compounds.