Amino acid-functionalized cyclopentadienyl molybdenum tricarbonyl complex and its use in catalytic olefin epoxidation

Oxidation of [CpMo(CO)3R] olefin epoxidation precatalysts with tert-butylhydroperoxide

“…[38]). Formation of a precipitate during catalytic epoxidation of alkenes with similar Mo-based complexes has also been reported, but the nature of the precipitate has remained elusive [10,28,[44][45][46][47].…”

N-heterocyclic carbene complexes of Group 6 metals

“…It is a rare example of a third-row metal radical with an NHC ligand [132]. Its crystal structure shows a three legged piano stool configuration with W- -44(a,b) give similarly high activity for olefin epoxidation as CpMo(CO) 3 X (X = Cl, Br, CH 3 ) [138][139][140][141][142][143][144][145]. Such strong activity is attributed to the high stability of the Mo-C carbene bond in these ionic complexes under oxidative conditions.…”

Synthesis and characterization of novel cyclopentadienyl molybdenum imidazo[1,5-a]pyridine-3-ylidene complexes and their application in olefin epoxidation catalysis

“…In neat reaction mixtures, the continuous formation of tert-butanol results in a polar reaction medium. This is analogous to solvent coordination to the metal center as described above [14].…”

“…Due to their coordinating character, epoxidation in polar solvents such as methanol, THF, and acetonitrile results in lower catalytic activities compared to chlorinated and non-polar solvents. A coordinating solvent can compete with the oxidant TBHP for coordination to molybdenum, thus lowering catalytic activity [14]. Benzotrifluoride (BTF) is in some cases a useful alternative for chlorinated solvents (e.g.…”

“…To date, a number of g 5 -cyclopentadienyl tricarbonyl molybdenum complexes with different ligand spheres have been investigated as pre-catalysts in olefin epoxidation [2,[9][10][11][12][13][14][15]. Of these, the ansa-bridged cyclopentadienyl Mo complex [{g 5 -C 5 H 4 [CH(CH 2 ) 3 ]-g 1 -CH}Mo(CO) 3 ] [16] shows the highest TOF in ciscyclooctene epoxidation, namely 11,800 h À1 in organic solvents [17] and TOFs up to 44,000 h À1 in room temperature ionic liquids (RTILs) [18].…”