Functionalised (phosphino)amines: synthesis, coordination and reactivity studies

Reaction of Ph2PCl with R(NH2)n (n = 1, 2 or 4) in the presence of NEt3 affords a series of mono-, di-, tetra- and octadentate (phosphino)amines, {Ph2PN(H)}nR or {(Ph2P)2N}nR (n =1, 2 or 4; R = functionalised aromatic group bearing methyl, keto, ester, ether, vinyl or thiazole substituents). Oxidation of these new (phosphino)amines with sulfur, selenium or hydrogen peroxide yields the corresponding phosphorus(V) compounds. Mixed phosphorus(III)/phosphorus(V) compounds containing P(III) and E donor centres are also described. The coordination chemistry of these new ligands towards various transition-metal centres (e.g. ruthenium, rhodium, palladium, platinum and gold) have been extensively studied. Thermal C–H activation of [PtMe2{PPh2N(H)R}2] or [RhCl2(η5-C5Me5){Ph2PN(H)R}] affords first examples of orthometallated (phosphino)amine complexes containing a five-membered ring M–P–N–C–C metalloring. Characterisation of a number of these novel compounds was achieved using single crystal X-ray analysis, revealing, in many cases, the presence of an intramolecular N–H···O hydrogen bond. [Continues.]