Synthesis and catalytic reactivity in Friedel–Crafts acylations of monobridged bis(cyclopentadienyl)molybdenum(I) carbonyl complexes

Abstract

When the monobridged biscyclopentadienes (C5H5)R(C5H5) [R = C(CH3)2 (1), Si(CH3)2 (2), C(CH2)5 (3)] reacted with Mo(CO)6 in refluxing xylene, the corresponding complexes [(η5-C5H4)2R][Mo(CO)3]2 [R = C(CH3)2 (4), Si(CH3)2 (5), C(CH2)5 (6)] were obtained. These complexes were separated by chromatography and characterized by elemental analysis, IR, and 1H NMR spectroscopy. The molecular structures of 4 and 5 were determined by X-ray diffraction analysis. Friedel–Crafts acylation reactions of anisole derivatives with aromatic or aliphatic acyl chlorides catalyzed by complexes 4–6 showed that all of these monobridged bis(cyclopentadienyl)molybdenum carbonyl complexes have catalytic activity.