HYBRID LIGANDS - A NEW ROUTE TO (CARBAMOYLMETHYL)PHOSPHINES - MOLECULAR-STRUCTURE OF [(O-C6H4CH2NME2)PD(PH2PC=C(O)N(PH)N=C(ME))]

The (carbamoylmethyl)phosphines Ph2PCH2C(O)NRR'(R = R' = Ph (4); R = Me, R' = Ph (5), R = R = Me (6)) were obtained in high yields by reaction of chlorodiphenylphosphine with the enolates obtained from the corresponding acetamides, Li[CH2C(O)NRR']. This methodology was extended to the synthesis of the sodium phosphinopyrazolonate [Ph2PC=C(O)N(Ph)N=C(Me)]Na (9). Treatment of 9 with sulfur yields the phosphine sulfide [Ph2P(S)C=C(O)N(Ph)N=C(Me)]Na (10). Compound 9 reacts with [(o-C6H4CH2NMe2)PdCl]2 and Pd(acac)2 to yield respectively the chelate complexes [(o-C6H4CH2NMe2)Pd{Ph2PC=C(O)N(Ph)N=C(Me)}] (11) and cis-[Pd{Ph2PC=C(O)N(Ph)N=C(Me)}2] (12). The molecular structure of complex 12 was determined crystallographically: space group P2/c, a = 10.863(4) angstrom, b = 12.575(4) angstrom, c = 14.562(6) angstrom, beta = 103.43(3)degrees, V = 1935(1) angstrom3, and Z = 2. The palladium atom, which lies on a C2 axis, is complexed by two anionic chelating cis-P,O ligands (Pd-P = 2.248(1) angstrom; Pd-O = 2.078(3) angstrom). The aromatic pyrazole system is planar; the dihedral angle between this plane and the metal plane is 1.4(8)degrees, and that with the N-bonded phenyl ring is 7.7(8)degrees. All compounds were characterized by elemental analysis and IR and H-1, P-31, and C-13 NMR spectroscopy.