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

Halide substituted Schiff-bases: Different activities in methyltrioxorhenium(VII) catalyzed epoxidation via different substitution patterns

“…The obtained Schiff-bases were characterized by NMR and elemental analysis. All analytical data is in accordance with literature [21,26,30,32,33,43].…”

“…All Schiff-bases were obtained by reacting different hydroxybenzaldehydes with aniline derivates in ethanol according to published procedures [21,26,30,32,33,43]. Based on former research results, indicating that electron donating groups decrease the catalyst activity and reduce the lifetime of the catalyst, electron withdrawing groups, especially halides were chosen for this study.…”

“…Based on earlier experiments, MTO and the Schiff-base-ligands have been used in a ratio of 1:1 for this study [21,32,33]. The catalyst:substrate:oxidant ratio was chosen to be 1:100:200 and the substrate concentration in the reaction solution was 1 M. Hydrogen peroxide (aqueous solution 27%) was used as oxidant.…”

Synthesis of di‐nitrogen Schiff base complexes of methyltrioxorhenium(VII) and their application in epoxidation with aqueous hydrogen peroxide as oxidant

“…The differences of 20-27 and 60-80 cm −1 between ν sym (Re O) and ν asym (Re O) correspond to the octahedral and trigonal-bipyramidal coordination geometry, respectively. [25,30,32] For the free MTO, the difference is 33 cm −1 , which corresponds to a tetrahedral coordination geometry. [39] Therefore, it can be deduced that the structures of the title complexes are closer to an octahedral geometry, in which the Schiff bases act as bidentate ligands to coordinate to MTO through the two nitrogen atoms.…”

Methyltrioxorhenium catalysed epoxidations: A comparative study of different N-donor ligands

“…Furthermore, all systems are well soluble in a variety of solvents. Previous papers already described the coordination of N-donors to MTO [4][5][6]11,13,[19][20][21][22]. Herein, we report for the first time on a direct comparison between a monodentate, a bidentate and a Schiff-base ligand under identical conditions.…”