Syntheses, structures, and catalytic activity in Friedel–Crafts acylations of substituted tetramethylcyclopentadienyl molybdenum carbonyl complexes

Abstract

Reactions of the substituted tetramethylcyclopentadienes [C5HMe4R] [R = t Bu, Ph, CH2CH2C(CH3)3] with Mo(CO)3(CH3CN)3 in refluxing xylene gave a series of dinuclear molybdenum carbonyl complexes [(η5-C5Me4R)Mo(CO)3]2 [R = t Bu (1), Ph (2), CH2CH2C(CH3)3 (3)], [(η5-C5Me t Bu)Mo(μ-CO)2]2 (4)], and [(η5-C5Me4) t Bu]2Mo2O4(μ-O) (5)], respectively. Complexes 1–5 were characterized by elemental analysis, IR, 1H NMR, and 13C NMR spectroscopy. In addition, their crystal structures were determined by X-ray crystal diffraction analysis. The catalytic activities of complexes 1–3 in Friedel–Crafts acylation in the presence of o-chloranil has also been investigated; the reactions were achieved under mild conditions to give the corresponding products in moderate yields.