Synthesis and coordination chemistry of the new unsymmetrical ligand Ph₂PCH₂NHC₆H₄PPh₂

Condensation of Ph2PCH2OH with 2-(diohenylphosphanyl)-alinine in toluene gave the new unsymmetrical ligand Ph2PCH2NHC6H4PPh2 (1) in good yield. Oxidation of 1 with H2O2 or elemental sulfur led to the oxidised products Ph2P(O)CH2NHC6H4P(O)Ph-2 (2) and Ph2P(S)CH2NHC6H4-P(S)Ph-2 (3). The new ligand 1 demonstrates three distinct modes of coordination. Reaction of compound 1 with [MX2(cod)] (M = Pd, Pt: X = Cl, Br, Me) or [Mo(CO)(4)(pip)(2)] gave the chelate complexes [PdCl2(Ph2PCH2NHC6H4PPh2-P-X,P-A)] (4), [PdBr2(Ph2PCH2NHC6H4PPh2-P-X,P-A)] (5), [PtCl2(Ph2PCH2NHC6H4PPh2-P-X,P-A)] (7) and [Mo(CO)(4)(Ph2PCH2-NHC6H4PPh2-P-X,P-A)] (8). Coordination of 1 with [{RuCl(mu-Cl)(eta(3):eta(3)-C10H16)}(2)] or [{RhCl(mu-Cl)(eta(2)-C5Me5)Ph2PCH2NCH6H4PPh2-P-X}] (9) and [RhCl2(eta(5)-C5Me5)(Ph2PCH2-NCH6H4PPh2-P-X)] (10). Reaction of 1 with [{IrCl(mu-Cl)(eta(5)-C5Me5)}(2)] led to a mixture from which the monodentate complex [IrCl2(eta(5)-C5Me5)(Ph2PCH2NHC6H4PPh2-P-X)] (11) and the chelate cationic complex [IrCl(eta(5)-C5Me5)(Ph2PCH2NHC6H4PPh2-P-X,P-A)][Cl] (12) were separated. Abstraction of the chloride ligands from complexes 9 and 10 with AgClO4 gave the cationic chelate complexes [RuCl(eta(3):eta(3)-C10H16)(Ph2PCH2NHC6H4PPh2-P-X,P-A)][ClO4] (13) and [RhCl(eta(5)-C5Me5)(Ph2PCH2NHC6H4PPh2-P-X,P-A)][ClO4] (14). Compound 1 also functions as a bridging ligand when reacted with two molar equivalents of [AuCl(tht)] or one molar equivalent of [{RhCl(mu-Cl)(eta(5)-C5Me5)}(2)] to give the bimetallic complexes [Ph2P{AuCl}CH2NHC6H4PPh2{AuCl}] (15) and [{RhCl2(eta(5)-C5Me5)}(2)(Ph2PCH2NHC6H4PPh2)] (16). The dioxidised compounds 2 and 3 and several typical complexes 8, 9, 11 and 14 were structurally characterised by X-ray diffraction. (C) Wiley-VCH Verlag VmbH, 69451 Weinheim, Germany, 2002.