Active catalytic centers in silica-supported Cu(II) and Mn(II) biomimetic complexes: Correlation between catalytic and EPR data
Φόρτωση...
Ημερομηνία
Συγγραφείς
Zois, D.
Vartzouma, C.
Deligiannakis, Y.
Hadjiliadis, N.
Casella, L.
Monzani, E.
Louloudi, M.
Τίτλος Εφημερίδας
Περιοδικό ISSN
Τίτλος τόμου
Εκδότης
Elsevier
Περίληψη
Τύπος
Είδος δημοσίευσης σε συνέδριο
Είδος περιοδικού
peer reviewed
Είδος εκπαιδευτικού υλικού
Όνομα συνεδρίου
Όνομα περιοδικού
Journal of Molecular Catalysis a-Chemical
Όνομα βιβλίου
Σειρά βιβλίου
Έκδοση βιβλίου
Συμπληρωματικός/δευτερεύων τίτλος
Περιγραφή
Two polydentate ligands represented as L-A and L-B have been synthesized and subsequently grafted on a silica surface via covalent bonds. The organic ligands LA and LB as well as the heterogenized ligands (LASiO2)-Si-. and L-B .SiO2 reacted with manganese(II) and copper(II) ions leading to the formation of the corresponding metal complexes. Catalytic epoxidations of simple olefins with hydrogen peroxide were studied using the above manganese complexes in the presence of a cocatalyst. The major products of the oxidations were the epoxides and the studied manganese complexes showed significant catalytic activities. The copper(II) complexes have been evaluated for the catalytic oxidation of 3,5-di-t-butylcatechol (DTBC) by dioxygen. Based on a combination of structural information, obtained form EPR spectroscopy, and the catalytic activity we suggest that the catalysis of DTBC oxidation by copper complexes is critically determined by two factors (a) for dinuclear complexes, it is enhanced when the (CuCu)-Cu-... distance approaches the (OCCO)-C-... distance in the catechol molecule (2.7 angstrom), and (b) immobilization on silica support results in enhancement of the catalytic activity in cases where even monomeric complexes are located at relative distances approaching the critical (OCCO)-C-... distance (2.7 angstrom). This provides a practical rule for design and synthesis of more efficient copper-catalysts for the catechol oxidation. (c) 2006 Elsevier B.V. All rights reserved.
Περιγραφή
Λέξεις-κλειδιά
supported complexes, copper and manganese complexes, biomimetic catalysis, epr and hyscore spectra, alkene epoxidation, catechol oxidation, dtbq, electron-spin-resonance, enantioselective epoxidation catalysts, catechol oxidase activity, dinuclear copper complex, manganese porphyrins, unpaired electrons, interspin distance, hydrogen-peroxide, oxidation, spectroscopy
Θεματική κατηγορία
Παραπομπή
Σύνδεσμος
<Go to ISI>://000243561000027
http://ac.els-cdn.com/S1381116906013811/1-s2.0-S1381116906013811-main.pdf?_tid=f7057cc4-362e-11e3-8e39-00000aacb360&acdnat=1381906289_428405f2aca9adeccbaecc4e500880f0
http://ac.els-cdn.com/S1381116906013811/1-s2.0-S1381116906013811-main.pdf?_tid=f7057cc4-362e-11e3-8e39-00000aacb360&acdnat=1381906289_428405f2aca9adeccbaecc4e500880f0
Γλώσσα
en
Εκδίδον τμήμα/τομέας
Όνομα επιβλέποντος
Εξεταστική επιτροπή
Γενική Περιγραφή / Σχόλια
Ίδρυμα και Σχολή/Τμήμα του υποβάλλοντος
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας