Characterizing triplet azo biradical and corannulene- halogen complexes by laser flash photolysis

<p>In this work the laser flash photolysis technique has been used to study two photo-reaction systems: 1) the photolysis of aryl azides in solution and in solid-state 2) the photo-reaction of corannulene in halogenated solvents.</p><p>Singlet aryl nitrene was formed upon irradiation of aryl azides, and the singlet nitrene could decay by intersystem-crossing to form triplet nitrene or by direct ring expansion reaction to produce azepine. In solution the singlet aryl nitrene underwent ring expansion reaction at room temperature, while the intersystem-cross competed with the ring expansion reaction pathway as the temperature cooled down. In solid-state the crystal lattice of the aryl azides restrained the formation of benzazirne. Thus the singlet nitrene decayed to form triplet nitrene that dimerized to produce the azo dimer as the final product. The azo dimer that formed in solid-state was trans- azo dimer only.</p><p>Irradiation of corannulene in halogenated solvent with UV light produced mono-halogenated corannulene. The singlet corannulene transferred energy to the solvent, which generated the halogen radical and solvent radical. The halogen radical formed a complex with ground state corannulene. The solvent radical could abstract a hydrogen atom from the corannulene-hydrogen complex to produce the halogenated corannulene as the final product. The TD-DFT calculation and laser flash photolysis study were applied to propose the conformation of complex. The structure of halogenated corannulene was confirmed by comparing the NMR spectra to the standard compound.</p>

Name thesis:degree_name

PhD

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Arts and Sciences: Chemistry

Grantor dc:publisher

University of Cincinnati

Year dc:date

2012

Author dc:creator

• Li, Qian

Contributors dc:contributor

• Gudmundsdottir, Anna

• Chemistry
• laser flash photolysis
• aryl azides
• triplet nitrene
• corannulene-halogen complex
• TD-DFT calculation
• Photochemistry

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=ucin1352403404

OAI identifier oai:identifier

oai:etd.ohiolink.edu:ucin1352403404