SELECTIVE AZIDE OXIDATION OF 1,2-BIS(DIPHENYLPHOSPHINO)BENZENE AND RELATED ETHYLENEBIS(PHOSPHINES) TO ASYMMETRIC MULTIFUNCTIONAL PHOSPHORUSLIGANDS AND FORMATION OF RHODIUM(I) COMPLEXES OF THESE LIGANDS - STRUCTURAL CHARACTERIZATION OF THE PROTOTYPICAL LIGAND )DIPHENYLPHOSPHORANO)-2-(DIPHENYLPHOSPHINO)BENZENE AND ITS RHODIUM(I) COMPLEX - 1-PH(2)P=N(SIME(3))C6H4-2-(PH(2)P)RH(CO)CL

Selective azide mono-oxidation of o-bis(phosphines) such as o-bis(diph enylphosphino)benzene and other bis(phosphines) with cis-substituents on a rigid backbone such as an ethylene structure occurs as the result of the steric control exerted during the azide oxidation (Staudinger) reaction process. The azides used were the trimethylsilyl, 4-cyanotet rafluorophenyl, benzyl, and diphenoxyphosphonyl azides. The prototypic al ligand 1-Ph(2)P=N(SiMe(3))-2-(Ph(2)P)C6H4, 2, has been structurally characterized. Crystal data for 2: crystal dimensions, 0.38 x 0.38 x 0.57 mm; space group, monoclinic, P2(1)/c, (No. 14); a = 11.093(5) Ang strom, b = 14.898(5) Angstrom, 18.811(2) Angstrom, beta = 102.76(2)deg rees, V = 3031 Angstrom(3), Z = 4. Final R, R(w) and GOF values were 0 .068, 0.074, and 1.92 respectively. The P=N-SiMe(3) angle was wide, 15 2.7(3)degrees, and the P=N bond length short (1.529(5) Angstrom) relat ive to arylated iminophosphoranes but in keeping with the trends for s ilylated analogs. The iminophosphorane center can be selectively trans formed with other agents in a Wittig type reaction converting the azid es to the monooxide, monosulfide, etc. The iminophosphoranophosphines are also good complexing agents and the Rh(I) complex derived from 2, 1-Ph(2)P=N(SiMe(3))-C6H4-2-(Ph(2)P)Rh(CO)Cl, 15 was structurally chara cterized. Crystal data for 15: crystal dimensions, 0.32 x 0.44 x 0.66 mm; space group, monoclinic, P2(1)/c (No. 14); a 13.793(3) Angstrom, b = 12.622(11) Angstrom, c = 20.436(6) Angstrom, beta = 105.93(2)degree s, V = 3421.2 Angstrom(3), Z = 4. Final R, R(w), and GOF values were 0 .064, 0.061, and 1.45 respectively. The complex shows typical square p lanar geometry about Rh, a cis phosphine-CO relationship, and no excep tional steric crowding of the coordination site.