Iminium

An iminium cation in organic chemistry is a functional group with the general structure +. They are common in synthetic chemistry and biology. An iminium cation in organic chemistry is a functional group with the general structure +. They are common in synthetic chemistry and biology. Imininium cations adopt alkene-like geometries. The central CN unit is nearly coplanar with all four substituents. The C=N distances, which are near 129 picometers in length, are shorter than C-N single bonds. Iminium cations are obtained by protonation and alkylation of imines: They also are generated by the condensation of secondary amines with ketones or aldehydes: More exotic routes to iminium cations are known, e.g. from ring-opening reactions of pyridine. Iminium derivatives are common in biology. Pyridoxal phosphate reacts with amino acids to give iminium derivatives. Many iminium salts are encountered in organic chemistry. Iminium salts hydrolyse to give the corresponding ketone or aldehyde: Iminium cations are readily reduced to the amines, e.g. by sodium cyanoborohydride. They are intermediates in the reductive amination of ketones and aldehydes. Iminylium ions have the general structure R2C=N+. They form a subclass of nitrenium ions.