Synthesis, structure and reactivity of molybdenum imido and oxo complexes. X-ray structure of MoCl3(NAr)L-2 (Ar = 2,6-diisopropyl phenyl; L = N-2 ',6 '-diisopropyl phenyl-2,5-dimethyl benzamide)

摘要

The reaction of MoCl4(O) with ArNCO (Ar = 2,6-(Pr2Ph)-Pr-i) afforded a series of paramagnetic oxo and imido Mo(V) complexes depending on the nature of the solvent used in each case. An X-ray study of one of this complexes, MoCl3,(NAr)L-2, (L = N-2',6'-diisopropyl phenyl-2,5-dimethyl benzamide) (3) (orthorhombic, P2(1)2(1)2(1), a = 10.8194(8), b = 23.528(2), c = 23.914(2) Angstrom, V = 6087.4(9) Angstrom(3), Z = 4) supports a pseudo-octahedral structure with the imido group occupying one of the axial positions. Reduction of Mo(VI) and Mo(V) oxo and imido complexes in the presence of three equivalents of P(OMe)(3) yields complexes MoCl2(E)[P(OMe)(3)](3) (E = O (5), NAr (6)). Spectroscopic data of 5 and 6 show a pseudo-octahedral structure with the oxo or imido ligand occupying one of the axial positions and the three phosphite ligands placed in the equatorial plane. Complexes 5 and 6 react with 3,3-diphenylcyclopropene leading to olefin complexes which are thermally unstable and decompose at room temperature affording 1,1,6,6 tetraphenyl hexatriene, presumably via intermediate molybdenum vinyl alkylidenes. (C) 1998 Elsevier Science S.A. Ltd. All rights reserved. [References: 31]