engleski

A New Class of Mo(VI) Catalyst for Olefin Epoxidation by Aqueous tert-Butyl Hydroperoxide

The synthesis of coordination compounds yielding greater selectivities in catalysis and adaptable to ″greener conditions″ represents a current scientific challenge. We have based our research on the synthesis of dioxomolybdenum(VI) polynuclear [MoO2L]n and mononuclear [MoO2L(CH3OH)] compounds with pyridoxal – thiosemicarbazone ligands and on the study of their catalytic properties in olefin epoxidation. These ligands are of great interest because of their antiviral, antitumor and antibacterial properties.For instance, the preparation of complexes with pyridoxal 4-phenylthiosemicarbazone ligand is detailed in the proposed scheme. In all prepared complexes, the ligand is coordinated to the central molybdenum atom as a deprotonated ONS – donor. In mononuclear complexes, the sixth coordination site around molybdenum is completed by a methanol molecule. All complexes were characterised by elemental analysis, IR, TGA and NMR. [MoO2L(CH3OH)] and [MoO2(L∙HCl)(CH3OH)] complexes were characterised by X-ray crystallography. The prepared complexes were tested as catalysts for epoxidation of cis- cyclooctene (0, 05% mol Mo vs. olefin) by aqueous tert-butylhydroperoxide (TBHP), without any other co-solvent.

molybdenum; pyridoxal; epoxidation of cyclooctene; TBHP

nije evidentirano