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Identifier

000426169

Title

α)CD-C3N4 ως φωτοευαισθητοποιητής σε αντιδράσεις ενίου και μεταφοράς ηλεκτρονίου β)Ενθυλάκωση αναγωγικού ενζύμου σε νανοσωματίδια βιοπολυμερών : μελέτη καταλυτικής δράσης του νέου νανοαντιδραστήρα

Alternative Title

a)CD-g-C3N4 as photosensitizer for ene reaction and electron transfer reaction, b)Encapsulation of reducing enzyme in biopolymer nanoparticles: study of catalytic activity of the new nano-reactor

Author

Χατζούδης, Απόστολος Θ.

Thesis advisor

Σμόνου, Ιουλία

Reviewer

Βελώνια, Καλλιόπη
Στρατάκης, Εμμανουήλ

Abstract

The first chapter presents a new photocatalytic reactivity of carbon-nanodot-doped graphitic carbon nitride (CD-C₃N₄) with alkenes and dienes. It is shown that CD-C₃N₄ photosensitizes the oxidation of unsaturated substrates in a variety of solvents according to two competing mechanisms: the energy transfer via singlet oxygen (¹Ο₂) and/or the electron transfer via superoxide (O_2•‾). The singlet oxygen, derived by the CD-C₃N₄ photosensitized process, reacts with alkenes to form allylic hydroperoxides (ene products) whereas with dienes, endoperoxides. When the electron transfer mechanism operates, cleavage products are formed, derived from the corresponding dioxetanes. Which of the two mechanisms will prevail depends on solvent polarity and the particular substrate. The photocatalyst remains stable under the photooxidation conditions, unlike the most conventional photosensitizers, while the heterogeneous nature of CD-C₃N₄ overcomes usual solubility problems. The second chapter presents the encapsulation of the reducing enzyme Kred112 into protein-polysyrene nanoparticles which are synthesized via a controlled atom transfer radical polymerization. The catalytic activity of the nanoreactor, which contains the reducing enzyme, is studied in aqueous solution in the reduction of an α,α-unsaturated keto ester. The products of the catalyzed by the encapsulated enzyme reduction are compared to those from the bioreduction by the free, native enzyme, using chromatographic methods. Αn unexpected reduction of the substrate‟s double bond is observed. These preliminary results showed different catalytic behavior of the nanoreactor in the particular reduction system.

Language

Greek

Subject

Amphiphilic biopolymer

Biocatalysis

Encapsulation

Ene products

Graphitic carbon nitride

Ketoreductase Kred112

Nanoreactor

Photocatalyst

Photooxidation mechanism