164. Allyl, alkyl, and olefin complexes of molybdenum

(Pentabenzylcyclopentadienyl)molybdenum Complexes: Synthesis, Structures and Redox Properties

“…[6,9] Treatment of Li[MoCpBz(CO) 3 3 ], which, upon dimerisation and a thermally induced Mo-CO bond cleavage, [10] finally gives [MoCpBz(CO) 2 )] may, however, be excluded, as it goes against the usual reactivity trend that affords π-allyl coordination by thermal or photochemical activation of σ-allyl precursors. [11,12] [10,13] should reflect extensive Mo-CO backbonding. [14,15] The hydrido resonances in 6 appear at δ = -4.85 ppm and in 7 at δ = -6.31 ppm.…”

Monomeric cyclopentadiene molybdenum oxides and their carbonyl precursors as epoxidation catalysts

“…1) [1], being one of the first monomeric high oxidation state organometallic oxides ever obtained. This complex was synthesized in very low yields and adventitiously as the only isolable product from air oxidation of CpMo(CO) 2 (p-C 3 H 5 ) in the presence of HCl.…”

“…When the first high oxidation state organometallics were described about 45 years ago, they seemed to be mere curiosities. Accordingly, the first molybdenum (VI) cyclopentadienyl dioxo complex, CpMoO 2 Cl, described by Cousins and Green [1] was not viewed as a potential catalyst. The quite difficult synthesis was only one of the obstacles on the way to possible applications.…”

CpMo(CO)3Cl as a precatalyst for the epoxidation of olefins

“…Dioxomolybdenum(VI) complexes of the type MoO 2 R 2 L 2 (R = Me, Et; L = Lewis base ligand) have also been shown to be active catalysts for olefin epoxidation using tert-butyl hydroperoxide (TBHP) as the oxidising agent [4][5][6][7]. Surprisingly, complexes of the type (g 5 -C 5 R 5 )MoO 2 X (X = Cl, Br) have been less well studied as oxidation catalysts, despite the fact that they are among the earliest examples of organometallic oxides [8][9][10]. Nevertheless it has been known for some time that the pentamethylcyclopentadienyl analogue Cp * MoO 2 Cl is able to catalyse the olefin epoxidation reaction with TBHP [11].…”