Synthetic efforts towards new stable free radicals

Date

2008-04-10T06:03:45Z

Authors

McKinnon, Stephen David James

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Abstract

A series of new 1,5-dimethyl-6-0x0-verdazyl radicals were prepared bearing either a hydroquinone or the 3,5-di-tertiary-butyl phenol substituent in the 3 position of the verdazyl ring as precursors to verdazyl 1 semiquinone diradical anions or verdazyl 1 phenoxyl diradicals. All radical precursor tetrazanes were characterized by 'H / 13c NMR and FTIR spectroscopies, MS, and elemental analysis. Oxidation of the tetrazane precursors with NaI04 or A ~ + gave verdazyl radicals as microcrystalline solids. All verdazyl radicals were characterized by EPR, UV-visible, and FTIR spectroscopies, and high-resolution MS or elemental analysis. All attempts to oxidize the hydroquinone or phenol moieties were unsuccessful as was coordination chemistry with those verdazyls bearing a chelating ortho-hydroquinone. Several molecules were synthesized as building blocks towards tris(2,6- disubstituted-4-pyridy1)methyl radicals where the substituents were ether chloro- or methoxy- groups. All of these building blocks (aldehydes, ester, alcohol, and ketone) were characterized by 'H / 13c NMR and FTIR spectroscopies, MS, and elemental analysis. All attempts to insert a third ring onto bis(2,6-dichloro-4-pyridy1)ketone to give the radical precursor triarylmethanol have been unsuccessful. Supervisor: Dr. R. G. Hicks (Department of Chemistry)

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