HETEROFUNCTIONAL LIGANDS DERIVED FROM MONOOXIDIZED BIS(PHOSPHINO)AMINES - SYNTHESIS AND TRANSITION-METAL (RH(I), PD(II), PT(II)) COMPLEXES OF THE TRIPHOSPHORUS LIGANDS ((IMINOPHOSPHORANYL)AMINO)PHOSPHINE PHOSPHINIC OXIDES PH2PN(R)PH2P=NP(O)(OPH)2 (R = CH3, C2H5) - CRYSTAL AND MOLECULAR-STRUCTURES OF THE RHODIUM(I) AND PLATINUM(II) COMPLEXES (PHO)2(O)PN=PPH2N(C2H5)PH2PRH(CO)CL AND (PHO)2(O)PN=PPH2N(C2H5)PH2PPTCL2

Oxidation of bis(diphenylphosphino)alkylamines with a phosphinic azide gave ambifunctional triphosphorus ligands of the form Ph2PN(R)Ph2P=NP(O)(OPh)2 (R = CH3, C2H5). The P-31 NMR spectra show large values (ca. 100 Hz) for the couplings between the P(III) and the adjacent, central, P(V) and smaller (ca. 40 Hz) couplings between this central P(V) and the terminal P(V). The terminal P(III) did not show observable coupling to the terminal P(V). These ligands complexed readily with Rh(I), Pd(II), or Pt(II) centers. Crystal structures of the rhodium complex (PhO)2(O)-PN=PPh2N(C2H5) Ph2PRh(CO)Cl.CH3CN [at 23-degrees-C, orthorhombic, Pbca (No. 6 1), a = 20.277(2) angstrom, b = 21.860-(2) angstrom, c = 18.498(2) angstrom, V = 8200(1) angstrom3, Z = 8, R = 0.069, R(w) = 0.053] and the platinum complex (PhO)2(O)PN=PPh2N(C2H5)Ph2PPtCl2.2CH2Cl2 [at 23-degrees-C, triclinic, P1BAR (No. 2), a = 11.752(3) angstrom, b = 20.996(4) angstrom, c = 9.716(2) angstrom, alpha = 98.75(2)degrees, gamma = 105.04(2)degrees, gamma = 99.04(2)degrees, V = 2236(1) angstrom3, Z = 2, R = 0.049, R(w) = 0.043] showed that, in both cases, the ligand was coordinated to the metal through the P(III) and the imine nitrogen to form square planar complexes. The chelate framework structure of the Pt complex was almost planar throughout whereas the Rh complex showed significant puckering of the backbone atoms. For each complex, however, the backbone amine nitrogen is planar and the P(III)-N-P(V) angles are close to 120-degrees. The P(III)-N bond lengths lie in the single-bond range in both cases, but this bond is notably shorter in the Pt complex (1.70(1) angstrom) than in the Rh complex (1.777(12) angstrom). In the Pt complex this latter shortening is accompanied by a notable increase in the P(V)-amine nitrogen bond (1.67(1) angstrom versus 1.642(12) angstrom in the Rh complex) and the P(V)-imine nitrogen bond (1.67(1) angstrom versus 1.580(11) angstrom in the Rh complex), and both of the bonds between the bridging P(V) and the substituent nitrogen atoms are of identical length. In contrast the Rh complex shows dissimilar P(V)-N bond lengths toward the two different nitrogen atoms. The differences are in part due to the harder character of the Pt(II) center arising from the presence of two Cl substituents on Pt.