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Proceedings Paper

Novel cycloketo tetraphenylporphyrins: spectroscopic study of structure-properties relationships
Author(s): Eugeny A. Ermilov; Stefan Jasinski; Norbert Jux; Beate Röder
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Paper Abstract

The developments in porphyrin chemistry over the last decades give great advantages for the practical use of porphyrin-based compounds. The properties of these compounds can be systematically tuned by rational utilization of substituents on meso- and/or β-positions as well as by using different metal atoms in the center of the tetrapyrrole macrocycle. Recently we prepared novel mono- and bis-functionalized cycloketo-porphyrins (CKPors). In this work the results of detailed spectroscopic investigations of these compounds are presented. It was found that a seven-membered ketone exocycle remarkably influences the photophysical properties of the CKPor systems. For mono-functionalized CKPors it results in strongly enhanced probability of intersystem crossing S1T1 with an ISC quantum yield up to 90%. Moreover, the absorption of all CKPors undergoes a bathochromic shift and the Q-bands extinction is above two times higher compared to that of H2TPP, what makes these compounds promising candidates for use as photosensitizers in photodynamic therapy of tumors. For the first time two NH-tautomers of nonsymmetrical CKPors were experimentally resolved at room temperature using optical spectroscopic methods. It was found that the concentration of tautomer A with a lower frequency of the S0,0 → S1,0 transition is higher than that one of tautomer B at room temperature, and becomes dominant with cooling down. In contrast - and as it is expected - only one optical active species was observed for non-symmetrical CKPor with a central Zn(II) atom as well as for symmetrical bis-CKPor.

Paper Details

Date Published: 2 September 2008
PDF: 11 pages
Proc. SPIE 7049, Linear and Nonlinear Optics of Organic Materials VIII, 704905 (2 September 2008); doi: 10.1117/12.793356
Show Author Affiliations
Eugeny A. Ermilov, Humboldt-Univ. zu Berlin (Germany)
Stefan Jasinski, Univ. Erlangen-Nürnberg (Germany)
Norbert Jux, Univ. Erlangen-Nürnberg (Germany)
Beate Röder, Humboldt-Univ. zu Berlin (Germany)

Published in SPIE Proceedings Vol. 7049:
Linear and Nonlinear Optics of Organic Materials VIII
Rachel Jakubiak, Editor(s)

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