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Proceedings Paper

Extra-ligation and screening effects upon interaction of photoinduced excited states of multiporphyrin arrays with molecular oxygen in solutions
Author(s): Eduard I. Zenkevich; E. I. Sagun; Valentin N. Knyukshto; Alexander M. Shulga; Christian von Borczyskowski
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Paper Abstract

In this work we present the results showing how the extra-ligation, spacer properties and porphyrin macrocycle screening may influence on the conformational dynamics and photophysical properties of multiporphyrin arrays as well as on their interaction with molecular oxygen in solutions at 293 K. Steady-state and time-resolved studies indicate that for a sequence of porphyrin or chlorin chemical dimers Zn- cyclodimer yields (ZnOEP)2Ph yields (ZnOEP)2 yields (ZnOEChl)2 with relative lowering of excited S1- and T1-states, the extra-ligation by pyridine does not influence essentially on fluorescence parameters but leads to an increase of T1-states non-radiative decay. At 293 K the T1-state quenching by O2 for Zn-dimer- pyridine complexes depends on the nature and flexibility of the spacer between macrocycles and donor-acceptor interactions with pyridine. In triads and pentads the dimeric subunit plays the role of screen weakening O2 interaction with the second subunit. As a result, the T1-state quenching by O2 in triads and pentads is decreased by 50 divided by 70 percent with respect to that for the corresponding individual monomers.

Paper Details

Date Published: 30 May 2002
PDF: 10 pages
Proc. SPIE 4749, ICONO 2001: Novel Trends in Nonlinear Laser Spectroscopy and Optical Diagnostics and Lasers in Chemistry, Biophysics, and Biomedicine, (30 May 2002); doi: 10.1117/12.468916
Show Author Affiliations
Eduard I. Zenkevich, Institute of Molecular and Atomic Physics (Belarus)
E. I. Sagun, Institute of Molecular and Atomic Physics (Belarus)
Valentin N. Knyukshto, Institute of Molecular and Atomic Physics (Belarus)
Alexander M. Shulga, Institute of Molecular and Atomic Physics (Belarus)
Christian von Borczyskowski, Technische Univ. Chemnitz-Zwickau (Germany)


Published in SPIE Proceedings Vol. 4749:
ICONO 2001: Novel Trends in Nonlinear Laser Spectroscopy and Optical Diagnostics and Lasers in Chemistry, Biophysics, and Biomedicine

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