טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentToledo Hila
SubjectNovel Nitroxides and their Applications
DepartmentDepartment of Chemistry
Supervisors Professor Yoav Eichen
Professor Alex.m Szpilman
Full Thesis textFull thesis text - English Version


Abstract

Nitroxides hold a unique place in science due to their stable radical nature. They have multitude of applications in chemistry, biology and radical polymerization.

One of the most efficient and widely used nitroxides is TEMPO. However, it has limited reactivity due to its highly hindered structure. Theoretically, the steric congestion could be reduced by replacing an α-alkyl substituent with a hydrogen. However, most α-hydrogen nitroxides undergo disproportionation in the absence of special stabilizing structural features.

This work allowed the design and preparation of novel cyclic nitroxides having one and two α-hydrogens. Specifically we describe two new families of nitroxides; isoindoline nitroxide and 2,3-dihydro-isoazaphenalene nitroxide. The basis of their stability is the interaction between the R1 substituent on the planar aromatic backbone and the R2 substituent of the nitroxide containing alicyclic ring. In this thesis we describe the synthesis of both types of nitroxides, and the minimum structural requirements necessary to achieve kinetic stability of these compounds. We examine their stabilities by ESR and computational studies. Additionally, we study their activity as catalysts in anaerobic and aerobic oxidations of alcohols.