Mark W. Kryman, Gregory A. Schamerhorn, K. Yung
Jul 17, 2013
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0
Influential Citations
32
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Journal
Organometallics
Abstract
Several 9-aryl-3,6-diaminotelluroxanthylium dyes with phenyl, 2-methylphenyl, and 2,4,6-trimethylphenyl substituents at the 9-position were prepared. The characterization of these compounds included determination of 125Te NMR spectra, fluorescence quantum yields (ΦF), and quantum yields for the generation of singlet oxygen [Φ(1O2)]. While these compounds were essentially nonfluorescent (ΦF < 0.005), they produce 1O2 with Φ(1O2) between 0.43 and 0.90. The tellurorosamines were oxidized with 1O2 via self-photosensitization to the corresponding telluroxides, which allowed their preparation free of excess oxidant. Telluroxides with a 9-(2-methylphenyl) or 9-(2,4,6-trimethylphenyl) substituent were fluorescent with quantum yields for fluorescence between 0.20 and 0.31. Steric bulk at the 9-position of the resulting telluroxides impacted rates of inter- and intramolecular attack of nucleophiles and stability of the telluroxide in aqueous media near physiological pH. The yield of reduction of the telluroxide wit...