Carbeniophosphanes and their carbon → phosphorus → metal ternary complexes

The discovery, recent developments and prospects of the carbeniophosphines, and in particular of imidazoliophosphines, are related. The P-conjugated positive charge brought by the stabilized carbenium center gives stable (1m(+))R2P -> metal dative bonds, while the ligands themselves contain a relatively stable C -> P+R2 dative bond, making imidazoliophosphines, more accurately described as NHC-phosphenium adducts. The preparation methods, structural features, electronic and coordination properties, reactivity, and catalytic properties of carbeniophosphines are reviewed.