EPR-SPECTRA OF (C5ME5)MOCL2(PME3)2 IN SOLUTION AND IN SINGLE-CRYSTALS OF (C5ME5)MOCL(PME3)2(N2)

EPR spectra of the d3 species Cp*MoCl2(PMe3)2 (Cp* = C5Me5) have been observed both in solution at 173 K and in orthorhombic single crystals of Cp*MoCl(PMe3)2(N2) at 77K. C16H33ClMoN2P2 is orthorhombic, of space group P2(1)2(1)2(1), with a = 14.7195 (11) angstrom, b = 16.4715 (16) angstrom, c = 8.9180 (6) angstrom, V = 2162.2 (3) angstrom-3, Z = 4, R = 0.052, and R(w) = 0.060 for 1833 reflections. The matrices of g and the Mo-95 hyperfine interaction indicate that the unpaired spin population resides primarily in the 4d(z)2 orbital of the molybdenum atom. However, considerable anisotropy was also apparent in the P-31 hyperfine interactions, whence it is concluded that some unpaired spin is to be found in the phosphorus 3p orbitals. These conclusions confirm recent Fenske-Hall type molecular orbital descriptions of the model compound CpMoCl2(PH3)2.