New mixed-donor unsymmetrical P–N–P ligands and their palladium(II) complexes

Abstract

Unsymmetrical bidentate ligands R2P(E)–N(H)–P(E′)R2′ [R, R′ = Ph, OPh, iPr; E, E′ = O, S, Se] have been synthesised using the condensation reaction of an amino compound, R2P(E)NH2 [R = PhO, Ph; E = O, S, Se], with a phosphorus electrophile, R2′P(E′)Cl [R′ = iPr, Ph, OPh; E′ = O, S, Se]. Deprotonated ligands (with KOtBu) can be treated with Pd(OAc)2 to give [Ph2P(S)–N–P(O)(OPh)2]2Pd, [iPr2P(S)–N–P(O)(OPh)2]2Pd and [Ph2P(S)–N–P(S)(OPh)2]2Pd, which show either four-membered or six-membered chelate rings. The new compounds were studied spectroscopically (NMR, IR and Raman) and by X-ray crystallography.