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2 January 1995 Photophysics of water-soluble Cu(II)-porphyrin: groove-bounding to polynucleotide as compared to dissolving in neat buffer solution
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Proceedings Volume 2370, 5th International Conference on Laser Applications in Life Sciences; (1995) https://doi.org/10.1117/12.197449
Event: Laser Applications in Life Sciences: 5th International Conference, 1994, Minsk, Belarus
Abstract
Excited-state dynamics of water-soluble Cu-5,10,15,20-tetrakis[4-(N- methylpyridyl)]porphyrin(Cu(TMpy-P4)) groove-bounded to poly(dA-dT) or dissolved in neat water phosphate buffer were investigated. In the first case, double-exponential decay kinetics were found with time constants of 35 +/- 7 ps and 3.2 +/- 0.5 ns. Spectral features of the transient absorption, a comparison with photophysical properties of CuP in oxygen-containing solvents as well as earlier RR investigations of an exciplex formation between Cu(TMpy-P4) and some polynucleotides enable us to attribute the two observed transient species to the triplet 2,4T1 state of four-coordinate Cu(TMpy-P4) and to the (d,d) state of five-coordinate Cu(TMpy-P4) axial liganded by CO group of thymine residue, respectively. In the case of Cu(TMpy-P4) in neat phosphate buffer, double-exponential kinetics of a transient species depopulation was observed with time constants of 21 +/- 3 ps and > 2 ns. Spectral feature of the transient absorption enables us to attribute the first transient species to the triplet 2,4T1 state. We believe, the reason of such short 2,4T1 state lifetime is liganding of the excited Cu(TMpy-P4) by molecules of H2O resulting in deactivation via downshifted CT state and/or (d,d) state. The second transient species corresponds, most likely, to the (d,d) state.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Vladimir A. Galievsky, Vladimir S. Chirvony, Laurent Chinsky, and Pierre-Yves Turpin "Photophysics of water-soluble Cu(II)-porphyrin: groove-bounding to polynucleotide as compared to dissolving in neat buffer solution", Proc. SPIE 2370, 5th International Conference on Laser Applications in Life Sciences, (2 January 1995); https://doi.org/10.1117/12.197449
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