Chiral manganese(III) Schiff base complexes anchored onto activated carbon as enantio selective heterogeneous catalysts for alkene epoxidation

• Type: Article in International Scientific Journal
• Date: 2005

Authors

Silva, AR (Author) REIT; Budarin, V (Author) Other; Clark, JH (Author) Other; de Castro, B (Author) FCUP; Freire, C (Author) FCUP

Journal

Title: Carbon

Vol. 43

Pages: 2096-2105

ISSN: 0008-6223

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 61 Citations

Scopus - 49 Citations

Scientific classification

FOS: Engineering and technology > Materials engineering

Other information

Authenticus ID: P-000-20H

DOI: 10.1016/j.carbon.2005.03.024

Abstract (EN): Two chiral manganese(III) salen catalysts, bearing different chiral diamine bridges, were anchored by direct axial coordination of the metal centre onto the phenolate groups of a modified commercial activated carbon. The modification of the activated carbon was achieved by reaction between sodium hydroxide and surface phenol groups giving rise to phenolate groups (CoxONa), which were characterised by XPS, TG and TG-IR. Characterisation of immobilised manganese(III) salen catalysts onto CoxONa material by XPS, ICP-AES and TG-IR clearly point to reaction between carbon surface phenolate groups and the manganese(III) complexes through axial coordination of the metal centre to these groups. These materials were active and enantioselective in the epoxidation of styrene and a-methylstyrene in dichloromethane at 0 degrees C using, respectively, m-CPBA/NMO and NaOCl. Only for alpha-methylstyrene comparable asymmetric inductions were found in the epoxide as the homogeneous phase reactions and catalyst reuse led to no significant loss of catalytic activity and enantioselectivity.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10