Date of Award

Summer 8-17-2015

Degree Type

Dissertation

Degree Name

PhD. Chemistry

Department

Chemistry and Biochemistry

Advisor

Sergiu M. Gorun, Ph.D

Committee Member

David Sabatino, Ph.D

Committee Member

Stephen P. Kelty, Ph.D

Committee Member

Wyatt R. Murphy, Ph.D

Committee Member

Nicholas H. Snow, Ph.D

Keywords

fluorinated phthalocyanines, singlet oxygen (1O2), mercaptan oxidation (MEROX), photodynamic therapy (PDT), photooxidation, citronellol, zinc and cobalt phthalocyanines

Abstract

The rational design of robust oxidation catalysts based on organic molecules is hindered by the presence of labile C-H bonds. We have shown recently that replacing all C-H bonds by a combination of fluoro- and perfluoro-groups in a bioinspired Cytochrome P450 model based on a phthalocyanine, Pc, scaffold results in a stable yet reactive oxidation catalyst. The Pc cobalt complex catalyzes, for example, the aerobic oxidation of thiols to disulfides, a reaction of both biological significance and industrial importance.

The presence of robust C-F bonds, however, renders the catalyst unsuitable for attachment to solid-state supports, except via van der Waals bonds or via the metal center. The first option is based only on weak interactions, while the second may result in the undesired blocking of the catalyst metal active site. Covalent links that do not interfere with the catalyst reactivity while maintaining its robustness are, therefore, desired.

We report the grafting of mono functional groups, both basic, namely -NRR’ (R, R’ = H/CH3), and acidic, namely -COOH on the fluoro phthalocyanine scaffold, generating the 3rd generation fluorinated phthalocyanines. Fluorophthalocyanines exhibiting a ratio, ρ, of aliphatic/aromatic fluoro groups, ρ, ρ does not equal to 1.0 constitute the 2nd generation fluorinated phthalocyanines.

The amino functionalized complexes retain their oxidation catalytic activity both in solution, as well as when supported on various solid-state supports, such as silica gels. The latter materials, when incorporating cobalt, are efficient heterogeneous catalysts for the "green", aerobic oxidation of thiols to disulfides. The functional fluoro F48H7PcZn-COOH retains the parent complex ability to produce 1O2 while being able to conjugate with bio-molecules, leading to promising candidates for the targeted photodynamic therapy of cancer.

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