Preparation and catalytic studies of bis(halogeno)dioxomolybdenum(VI)-diimine complexes

Dichloro- and dibromo MoO2X2L complexes containing the ethylenediimine ligands Ph2CNCH2CH2NCPh2 (PBED) and PhCHNCH2CH2NCHPh (BED) have been prepared and tested as catalysts for the epoxidation of cyclooctene with tert-butyl hydroperoxide at 55 °C. The dichloro complexes were much more active than the dibromo complexes, with the highest initial activity being observed for MoO2Cl2(BED) (63 mol molMo−1 h−1).