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Dioxomolybdenum(VI) and ‐tungsten(VI) Complexes with Multidentate Aminobisphenol Ligands as Catalysts for Olefin Epoxidation
Author(s) -
Dupé Antoine,
Hossain Md. Kamal,
Schachner Jörg A.,
Belaj Ferdinand,
Lehtonen Ari,
Nordlander Ebbe,
MöschZanetti Nadia C.
Publication year - 2015
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201500055
Subject(s) - chemistry , cyclooctene , catalysis , substituent , molybdenum , medicinal chemistry , denticity , polymer chemistry , hexacoordinate , olefin fiber , tungsten , crystal structure , solvent , metal , inorganic chemistry , organic chemistry , silicon
Abstract The synthesis of four molybdenum and tungsten complexes bearing tetradentate tripodal amino bisphenolate ligands with either hydroxyethylene ( 1a ) or hydroxyglycolene ( 1b ) substituents is reported. The molybdenum dioxo complexes [MoO 2 L] (L = 2a , 2b ) and tungsten complexes [WO 2 L] ( 3a , 3b ) were synthesized using [MoO 2 (acac) 2 ] and [W(eg) 3 ] (eg = 1,2‐ethanediolato, ethylene glycolate), respectively, as precursors. All complexes were characterized by spectroscopic means as well as by single‐crystal X‐ray diffraction analyses. The latter reveal, in all cases, hexacoordinate complexes in which the hydrogen atom of the hydroxy group is involved in hydrogen bonding with one of the metal oxo groups. In the case of the glycol substituent, the ether oxygen atom is coordinated to the metal whereas the hydroxy group remains uncoordinated. The complexes were tested as catalysts in the epoxidation of cyclooctene under eco‐friendly conditions, using an aqueous solution of H 2 O 2 as the oxidant and dimethyl carbonate (DMC) as solvent or neat conditions, as substitutes for chlorinated solvents. Molybdenum complexes 2a and 2b showed good catalytic activity using H 2 O 2 without added solvent, and tungsten complexes 3a and 3b showed very high activity in the epoxidation of cyclooctene using H 2 O 2 and DMC as solvents.