A Cheap, Efficient, and Environmentally Benign Synthesis of the Versatile Catalyst Methyltrioxorhenium (MTO)

Rhenium Nanochemistry for Catalyst Preparation

“…It involved either direct alkylation of dirhenium heptoxide (Re 2 O 7 ) with the non-reducing alkyl-transfer reagent tetramethyltin, wasting half of the expensive metal in the form of inactive (CH 3 ) 3 SnOReO 3 species, or alkylation of Re 2 O 7 by the same reagent in the presence of trifluoroacetic anhydride ("anhydride route") with formation of extremely poisonous methyltin trifluoroacetates. An unexpectedly clean and efficient synthesis of MTO has recently been reported by Herrmann et al, exploiting interaction of trioxorhenium acetate, derived from rhenium oxide and acetic anhydride, with methyl zinc acetate (see Scheme 3) [36,37]. Scheme 3.…”

((2-Hydroxynapthalen-1-yl)methylene)aniline derived Schiff base adducts of MTO: Synthesis and catalytic application

“…However, several well-defined transition metal epoxidation catalysts already operate at room temperature and atmospheric pressure with impressively high turnover frequencies and good stability against ''green solvents" such as water. Most prominent among them is methyltrioxorhenium (MTO) being available since quite recently from non-toxic, low price starting materials [8,9] and several organometallic and inorganic molybdenum and tungsten catalysts, employing comparatively cheap metals and being able to provide chiral ligand environments for chiral epoxidation [10,11] catalysis. The major drawback of most of these systems is their inability to utilize oxygen as an oxidizing agent, and, in part, the difficulty in immobilizing them on proper carrier materials or matrices and to obtain high epoxide selectivities [12].…”

Re(v) and Re(iii) complexes with sal2phen and triphenylphosphine: rearrangement, oxidation and reduction

“…High oxidation state Re-oxo complexes (Re VII and Re V ) have found utility in catalysis 2,4–10. Rhenium(VII) methylrhenium trioxide complexes (MTO) have proven particularly useful in oxidation catalysis 8,11. Rhenium(V) oxo and imido phosphine complexes effect hydrogen release from organosilane and alcohol mixtures and enantioselective reduction of imines 9,10.…”