Steric control in the synthesis and stereochemistry of the asymmetric "head-to-head" isomer of rhodium binuclear [Rh2(.mu.-HTP5)2(.mu.-dppm)2](PF6)2 (HTP5 = 1,5-diisocyano-1,1,5-triphenylpentane; dppm = bis(diphenylphosphino)methane)

Abstract

The reaction of the asymmetrical diisocyanide ligand 1,5-diisocyano-1,1,5-triphenylpentane (HTP5) with (Rh(dppm)(CO)Cl] 2 (dppm=bis(diphenylphosphino)methane) results in the exclusive formation of the «head-to-head» RR and SS isomers of the face-to-face binuclear complex [Rh 2 (μ-HTP5) 2 (μ-dppm) 2 ] (PF 6 ) 2 . Herein we report the synthesis and characterization of this complex by 31 P NMR, homonuclear 2D δ/J resolved 31 P NMR, infrared, and electronic spectra, cyclic voltammetry, and X-ray crystallography