Structural investigation in solution of a series of five-coordinate bisphosphanylaryl ruthenium(II) complexes

The structure of the ruthenium(II) complexes [RuCl{C6H2(CH2PPh2)(2)-2,6-R-4 )(PPh3)] [R = H (1), Ph (2) or Br (3)] was investigated in solution using t wo-dimensional NMR techniques (H-1-H-1-, C-13-H-1- and P-31-H-1-correlation NMR spectroscopy and H-1 NOESY). The H-1 and C-13 NMR spectra of the compl exes 1-3 were similar and could be completely assigned. The results of the NOESY study indicated that these complexes have a distorted square-pyramida l geometry in solution as was established for the parent complex R = H in t he solid state by an X-ray crystal structure determination. The strategies used for the interpretation of the H-1, C-13 and P-31 NMR spectra of these compounds and the resulting assignments form the basis for future in situ s tudies involving these complexes in catalytic processes.