The crystal and molecular structures of di(nitrato- o)(η-pentamethylcyclopentadienyl)triphenylphosphinerhodium(III) (A) and (nitrato- o)(nitrato- o, o')(η-pentamethylcyclopentadienyl)rhodium(III) (b); a structural comparison of mono- and bi-dentate nitrato-ligands

Abstract

The crystal and molecular structures of the title compounds have been determined by single crystal X-ray analyses. Compound A crystallizes in the monoclinic system with a 11.925(2), b 14.616(2), c 15.709(3) », β 92.45(2)°, space group P2 1/ n and Z = 4, and B in the orthorhombic system with a 13.012(2), b 14.866(2), c 14.27(2) », space group Pbca and Z = 8. The structure of A was refined to an R value of 0.032 using 5143 observed ( F o) ⩾ 3σ ( F o) intensities, and B to an R value of 0.043 using 2711 observed intensities measured on an automatic diffractometer. Both A and B have a “piano stool” arrangement of ligands and provide a unique opportunity for comparing the structural parameters of the mono- and bi-dentate nitrato-ligand. In addition the infrared criteria for distinguishing these alternative coordination modes in this type of organometallic complex are discussed.