NOVEL CHEMISTRY OF CARBON BOUND TO COBALT IN ORGANOCOBALT COMPLEXES RELATED TO B12

摘要: A rare Co−N−C three-membered ring has been formed by a novel pathway involving facile interligand nucleophilic addition of an equatorial nitrogen donor to ligated axial carbon in some organocobalt complexes. The highly distorted structure typical resulting complex provides clear experimental evidence useful assessing hypotheses and computations concerning Co−C bond activation B12 chemistry. Treatment R = −CH2X (X halogen) derivatives imine/oxime models the type [LCo((DO)(DOH)pn)R]+ with base afforded major products striking NMR spectral features common, e.g., two one-proton olefinic doublets (J ≈ 3 Hz) singlets. X-ray for pyridine (py) derivative [pyCo(N-CH2-CHEL)]+ (1) reveals unexpected features:  metallocycle containing η2-aminomethylene group, enamine (N−CCH2) place one imine moiety (NC−CH3). C−Co−N angle is acute (43.7°) distortion coordination sphere concentrated i...