Synthesis, Spectroscopic Characterization and X-Ray Crystal Structures of Oxo-Bridged Oxo(haloaryl) Imido Hydrotris(3,5-Dimethylpyrazolyl)borate Molybdenum(v) Complexes

Abstract

Reaction of the oxomolybdenum(V) precursor [MoTp*(O)Cl2] (Tp* = hydrotris(3,5-dimethyl-1-pyrazolyl)borate) with m-fluoroaniline, H2NC6H4F, in toluene afforded the pair of geometric isomers of [MoTp*(O)Cl](μ-O)[MoTp*(Cl)(≡NC 6H4F)] (1a, cis; 1b, trans). Similarly the reaction with m-iodoaniline yielded the compound [MoTp*(O)Cl](μ-O)[MoTp*(Cl) (≡NC6H4I)] (2). This is a new synthetic method for preparing Mo-O-Mo bridged oxo(imido) molybdenum(V) species by double deprotonation of the anilines. The complexes were characterized by IR and 1H-NMR. spectroscopy, FAB mass spectrometry, elemental analysis and X-ray crystallography which revealed that the two chloro ligands are trans to each other in 1b and 2, whereas they are cis to each other in 1a. All compounds have Mo-O-Mo linkages and near linear arylimido moieties.