Synthesis and characterisation of E,O-mixed donor (E = P, S or Se) ligand complexes of palladium(II) and platinum(II)

New palladium(II) and platinum(II) complexes with the hybrid ligands Ph2PNHP(O)Ph-2 [Ph2PNP(O)Ph-2](-) or [Ph2P(E)NP(O)Ph-2](-) (E = S or Se) have been prepared and characterised. Hence reaction of the cyclometallated dimers [{Pd(mu-Cl)(C similar to N}(2)] [C similar to N = C12H9N2 or C13H8N] With Ph2PNHP(O)Ph-2 Save the mononuclear compounds [PdCl(C similar to N) {Ph2PNHP(O)Ph-2-P}]. Chloride abstraction, or amine deprotonation, afforded [Pd(C similar to N) {Ph2PNHP(O)Ph-2-P,O}][BF4] or [Pd(C similar to N){Ph2PNP(O)Ph-2-P,O}] bearing a neutral or anionic P,O-chelating ligand, respectively. Reaction of [{Pd(mu-Cl)(C9H12N)}(2)] with Ph2PNHP(O)Ph-2 in CDCl3, solution gave the known, rather unstable compound, [PdCl(C9H12N){Ph2PNHP(O)Ph-2-P}]. Spectroscopic and analytical evidence presented here suggest that [PdCl(C9H12N) {Ph2PNHP(O)Ph-2-P}] undergoes amine deprotonation/Pd-C bond rupture to give an isomeric compound, tentatively assigned as [PdCl{Ph2PNP(O)Ph-2- P,O}(NMe2CH2Ph)]. Bridge cleavage of [(Pd(mu-Cl)(C12H9N2)}(2)] with the unsymmetrical anions [Ph2P(E)NP(O)Ph-2] (E = S or Se) gave the square-planar complexes [Pd(C12H9N2){Ph2P(E)NP(O)Ph-2-E, O}] exclusively as one isomer (E trans to N). In a similar manner the new metal(II) compounds [PtCl{Ph2P(E)NP(O)Ph-2-E, O}(PMe2Ph)] (E trans to Cl) and [Pd(C9H15O)-{Ph2P(E)NP(O)Ph-2-E O}] (E trans to olefin double bond) were synthesised. All compounds were characterised by a combination of multinuclear NMR [H-1, P-31{H-1}, Pt-195{H-1)], IR spectroscopy and elemental analyses. Furthermore, the X-ray structures of [Pd(C12H12N,{Ph2PNHP(O)Ph-2-P,O}][BF4] and [Pd(C12H12N){Ph2PNP(O)Ph-2-P,O}] are reported and reveal, upon amine deprotonation, pi-delocalisation within the P-N-P-O backbone of the anionic P,O-chelating ligand. (C) 2000 Elsevier Science S.A. All rights reserved.