title: Catalytic and mechanistic studies into the epoxidation of styrenes using manganese complexes of structurally similar polyamine ligands.
abstract: Two structurally similar polyamine ligands (7 and 8) have been prepared, which differ only by the presence of either a secondary or tertiary nitrogen donor within their N5 donor set. The ligands, in combination with iron and manganese salts, have been screened for their efficacy as catalysts for the epoxidation of styrene, using both hydrogen peroxide and peracetic acid as oxidants. Clear differences in activity between the two systems were observed, with 7 proving most effective in the presence of MnSO4 with H2O2, whereas ligand 8 proved to be effective with Mn(OTf)2, MnCl2 and Mn(ClO4)2 using peracetic acid as the oxidant. A Hammett analysis of the initial rate kinetics of the optimal systems, combined with analysis by UV-vis spectroscopy, indicates that the small structural differences in the ligands elicit profound changes in the nature of the active species formed.
authors.affiliation: The Joseph Priestley Building, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK. m.watkinson@qmul.ac.uk.
authors.forename: Gennadiy
authors.initials: G
authors.lastname: Ilyashenko
authors.forename: Giorgio
authors.initials: G
authors.lastname: De Faveri
authors.forename: Thomas
authors.initials: T
authors.lastname: Follier
authors.forename: Rawan
authors.initials: R
authors.lastname: Al-Safadi
authors.forename: Majid
authors.initials: M
authors.lastname: Motevalli
authors.forename: Michael
authors.initials: M
authors.lastname: Watkinson