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Photoexcited triplet ESR studies on thiaporphyrins and their protonated derivatives

✍ Scribed by R.P. Pandian; T.K. Chandrashekar; Hans van Willigen

Book ID: 103030985
Publisher: Elsevier Science
Year: 1993
Tongue: English
Weight: 458 KB
Volume: 202
Category: Article
ISSN: 0009-2614
DOI: 10.1016/0009-2614(93)85361-q

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✦ Synopsis

The photoexcited triplet states of mono-and di-thi'aporphyrins and their protonated derivatives are investigated by ESR spectroscopy. A comparison of the magnitude of the zero-field splitting parameters (D and E) of neutral thiaporphyrins with H,TPP indicates no significant alterations in the triplet spin density. However, the protonated derivatives show large decreases in D (30%-40%) and E (40%-50%) values. The electron spin polarization pattern (ESP) indicates dominance of an in-plane spin sub-level with respect to the population and decay process for neutral species, while a redirection of spin sub-level activity is observed for protonated species. The structural change accompanying the protonation process accounts for most of these observations.

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