Stable and Catalytically Highly Active ansa Compounds with Cycloalkyl Moieties as Bridging Units

The complexes Moeta(5)-C(5)H(4)[CH(CH(2))(3)](3)]-eta(1)-CH(CO)(3) (2a) and Weta(5)-C(5)H(4)[CH(CH(2))(3)]-eta-CHCO)(3) (2b) were synthesized by reacting spiro[4.2]bicyclo[4.1]deca-6,8-diene (1) with the tri(acetonitrile)tri(carbonyl)metal complexes M(CO)(3)(CH(3)CN)(3) (M=Mo, W). Thermogravimetric (TGA) measurements confirm that the complexes are stable up to 140 degrees C in air in the solid state. The complexes 2a and 2b are very active catalysts at room temperature for the epoxidation of cyclooctene with tert-butyl hydroperoxide (TBHP) as oxidant, reaching TOFs of up to 3650 h(-1). Complex 2a achieves a quantitative product yield without formation of any by-products within 1.5 h, outperforming previously published ansa compounds and performing on par with the cyclopentadienyltri-(carbonyl) (halo)- or (alkyl)molybdenum compelxes CPMo(CO)(3)R (R=Hal, Me, Et).     «

The complexes Moeta(5)-C(5)H(4)[CH(CH(2))(3)](3)]-eta(1)-CH(CO)(3) (2a) and Weta(5)-C(5)H(4)[CH(CH(2))(3)]-eta-CHCO)(3) (2b) were synthesized by reacting spiro[4.2]bicyclo[4.1]deca-6,8-diene (1) with the tri(acetonitrile)tri(carbonyl)metal complexes M(CO)(3)(CH(3)CN)(3) (M=Mo, W). Thermogravimetric (TGA) measurements confirm that the complexes are stable up to 140 degrees C in air in the solid state. The complexes 2a and 2b are very active catalysts at room temperature for the epoxidation of cyc...     »