Journal
CHEMCATCHEM
Volume 5, Issue 2, Pages 601-611Publisher
WILEY-V C H VERLAG GMBH
DOI: 10.1002/cctc.201200068
Keywords
density functional calculations; epoxidation; homogeneous catalysis; molybdenum; Schiff bases
Categories
Funding
- Centre National de la Recherche Scientifique (CNRS)
- Institut Universitaire de France (IUF)
- European Union
- Grand Equipement National de Calcul Intensif (GENCI) [2010-086343]
Ask authors/readers for more resources
The mononuclear molybdenum complexes [MoO2(acac)2] (1, acac=acetylacetonate), [MoO2(SAP)(MeOH)] (2), and dinuclear oxomolybdic complexes [MoO2L]2 [L=salicylideneaminophenolato (SAP, 5), salicylideneaminoethanolato (SAE, 6), salicylideneaminomethylpropanolato (SAMP, 7)] have been investigated as (pre)catalysts for the epoxidation of olefins under solvent-free conditions, using tert-butylhydroperoxide (TBHP, 70% in water) as an oxidant. Complexes 6 and 7, although active, are limited by ligand hydrolysis during the catalytic process, whereas complexes 2 and 5 are not altered under catalytic conditions and yield essentially the same selectivity and activity, which is not suppressed by excess MeOH. Although these catalysts are less active than 1, their selectivity is higher (9798%). DFT calculations are consistent with the active form of the catalyst being the 5-coordinate [MoO2(SAP)]. The oxidant is activated by forming a weak adduct stabilized by a very loose MoO interaction and a hydrogen bond, predisposing it to the oxygen transfer to external olefin by a mechanism closely related to Bartlett's epoxidation with peroxyacids.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available