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

Unsymmetrical bidentate ligands R2P(E)-N(H)-P(E')R'(2) [R, R' = Ph, OPh, Pr -i; 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 phosph orus electrophile, R'P-2(E')CI [R' = Pr-i, Ph, OPh; E' = O, S, Se]. Deproto nated ligands (with (KOBu)-Bu-t) can be treated with Pd(OAC)(2) to give [Ph 2P(S)-N-P(OXOPh)(2)](2)Pd, [(Pr2P)-Pr-i(S)-N-P(O)(OPh)(2)](2)Pd and [Ph2P(S )-N-P(S)(OPh)(2)](2)Pd, which show either four-membered or six-membered che late rings. The new compounds were studied spectroscopically (NMR, IR and R aman) and by X-ray crystallography.