Nitrogen- and oxygen-bridged bidentate phosphaalkene ligands

Abstract An overview is given on synthesis and structures of new bidentate phosphaalkene ligands [(RMe 2 Si) 2 C P] 2 E (E = O, NR, N − ) and (RMe 2 Si) 2 C P N(R′) PR′′ 2 . Exceptional properties of these ligands, extending beyond predictable properties of phosphaalkenes are: (i) the N Si bond cleavage of [( i PrMe 2 Si) 2 C P] 2 NSiMe 3 with Au I and Rh I chloro complexes under mild conditions leading to binuclear complexes of the 6π-delocalised imidobisphosphaalkene anion [( i PrMe 2 Si) 2 C P] 2 N − , and (ii) the chlorotropic formation of molecular 1:2 Pd II and Pt II metallochloroylid complexes with novel ylid-type ligands [(RMe 2 Si) 2 C P(Cl) N(R) PR 2 ] − , and the transformation of a P -platina- P -chloroylid complex into a C -platina phosphaalkene by intramolecular chlorosilane elimination. Properties of the heavier congeners [(RMe 2 Si) 2 C P] 2 E (E = S, Se, Te, PR, P − , As − ) and (RMe 2 Si) 2 C P E PR′′ 2 (E = S, Se, Te) are also described.