TETRACARBONYL(CARBENE-PHOSPHINE) AND TETRACARBONYL(IMIDATE-PHOSPHINE) COMPLEXES OF CHROMIUM(0)

Article abstract of DOI:10.1016/0022-328X(86)80392-8

Treatment of the carbene complexes <(CO)5Cr> (I) with LiBu followed by alkylation with gives the carbene-phosphine chelates (IV) and (V).The tungsten analogs cannot be prepared similarly.With the substituted hydrazine, MeNHNH2 at -80 deg C, NH addition to the carbene carbon atoms in the precursor complexes and concomitant ligand rearrangement produces the pentacarbonylphosphine compounds <(CO)5M> (VIII, IX; M=Cr, W).The heterometallocyclic carbene-phosphine compounds react by formal NH insertion into the metal-carbene bond to give the six-membered chelates (X) and (XI).The complex (VI), obtained by aminolysis of (V), has been the subject of a single crystal X-ray diffraction study.It crystallizes in the monoclinic space group P2₁/c with a 12.55(1), b 13.50(1), c12.83(1) Angstroem, β 90.2(1) deg, V 2174 Angstroem³ and D(calcd) 1.37 g cm^-3 for mol.wt. 447.37 and Z=4.The structure was refined to R=0.067 and R_w=0.050.The Cr-C(carbene) bond length is 2.067(5) Angstroem and the Cr-P distance 2.352(1) Angstroem.