SYNTHESIS OF AND CRYSTAL STRUCTURE OF ITS MONOCLINIC FORM

Article abstract of DOI:10.1016/S0022-328X(00)99440-3

The reaction of 2 and LiPPh2 in 3:4 molar ratio in tetrahydrofuran afforded the dark brown cluster , which has been characterized by X-ray analysis.The crystals are monoclinic, space group P2₁/n with a = 11.985(2), b = 20.577(3), c = 22.345(2) Angstroem, β - 96.67(1) deg, Z = 4.The structure, refined to R_F = 0.046 for 7816 observed Mo-K_α data, is based on a nearly regular tetrahedral Rh4 skeleton , four of its six edges being spanned by diphenylphosphide ligands , and the remaining two by doubly-bridging carbonyl groups .The cluster geometry closely resembles that observed in a recently reported triclinic form of significantly higher density, and differs from it in some Rh-Rh and Rh-P bond distances and the orientations of several peripheral phenyl rings.