Catalytic activity of manganese(III)-oxazoline complexes in urea hydrogen peroxide epoxidation of olefins: The effect of axial ligands

✍ Scribed by Mojtaba Bagherzadeh; Reza Latifi; Laleh Tahsini

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 392 KB
• Volume: 260
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/j.molcata.2006.07.023

✦ Synopsis

The catalytic activity of two manganese(III)-oxazoline complexes [Mn(phox) 2 (CH 3 OH) 2 ]ClO 4 and Mn(phox) 3 (Hphox = 2-(2 -hydroxylphenyl)oxazoline), was studied in the epoxidation of various olefins. All of epoxidation reactions were carried out in (1:1) mixture of methanol:dichloromethane at room temperature using urea hydrogen peroxide (UHP) as oxidant and imidazole as co-catalyst. The epoxide yields clearly demonstrate the influence of steric and electronic properties of olefins, the catalysts and nitrogenous bases as axial ligand.

[Mn(phox) 2 (CH 3 OH) 2 ]ClO 4 catalyst with low steric properties has higher catalytic activity than Mn(phox) 3 . The highest epoxide yield (95%) was achieved for indene at the presence of [Mn(phox) 2 (CH 3 OH) 2 ]ClO 4 within 5 min. The proximal and distal interactions of strong -donor axial ligands such as imidazole with the active intermediate are efficiently increased activity of the catalytic system.