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Title: Synthesis and characterisation of some molybdenum complexes and their use as epoxidation catalysts
Author: Fernandez, Anil Thomas Anthony
Awarding Body: University of London
Current Institution: Royal Holloway, University of London
Date of Award: 1986
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With the aim of inducing asymmetric epoxidation, the metal catalysed epoxidation of alkenes and substituted alkenes using tert-butyl hydroperoxide and various molybdenum catalysts have been studied. In Chapter I, the synthesis of various cis-dioxomolybdenum complexes from 2,4-pentanedione dioxomolybdenum(VI) by reaction with various racemic and chiral diol ligands and amino alcohols is described. Under more vigorous reaction conditions, cis dioxomolybdenum(VI) complexes were dimerised giving complexes with a core. The reactions of L-histidine with molybdenum hexacarbonyl and molybdenum(VI) oxide afforded the potassium salts of tricarbonyl-L-histinato and histidinatotri-oxomolybdate (VI) respectively. The complexes were characterised by 1H and 13C nmr spectroscopy. In Chapter II, kinetic data is presented for the metal catalysed epoxidation of 1-decene and 1-dodecene at 70° using various molybdenum catalysts and tert-butyl hydroperoxide. Reactions with equimolar concentrations and a ten-fold excess of olefin to tert-butyl hydroperoxide were carried out. A possible mechanism is proposed. Chapter III deals with the asymmetric epoxidation experiments carried out using the molybdenum catalysts synthesised from chiral ligands. Geraniol, 3-methyl-2-butene-l-ol and 1-methyl cyclohexene were epoxidised with varying degrees of success. The highest enantiomeric excess achieved was 85% for 3-methyl-2-butene-l-ol oxide using cis-Bis(phenyl ethane-1,2-diolato) dioxomolybdenum (VI). Epoxy alcohols were reacted with (-)-a-methoxy-a-trifluoromethyl phenyl acetyl chloride to give the corresponding esters, enabling enantiomeric excess to be calculated by nmr. Reactions carried out at different temperatures showed variations in enantiomeric excess - a higher enantiomeric excess being obtained at lower temperature.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Inorganic Chemistry