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@article{493328,
author = {Zabadal, Miroslav and Klán, Petr and Heger, Dominik and Kříž, Zdeněk},
article_location = {Praha},
article_number = {4},
keywords = {photochemistry; energy transfer},
language = {eng},
issn = {0010-0765},
journal = {Collect. Czech. Chem. Commun.},
note = {in print},
title = {Intramolecular Triplet-Triplet Energy Transfer in Short Flexible Bichromophoric Amino Acids, Dipeptides and Carboxylic Acid Diester},
volume = {69},
year = {2004}
}
TY - JOUR
ID - 493328
AU - Zabadal, Miroslav - Klán, Petr - Heger, Dominik - Kříž, Zdeněk
PY - 2004
TI - Intramolecular Triplet-Triplet Energy Transfer in Short Flexible Bichromophoric Amino Acids, Dipeptides and Carboxylic Acid Diester
JF - Collect. Czech. Chem. Commun.
VL - 69
IS - 4
SP - 776
EP - 776
SN - 00100765
N1 - in print
KW - photochemistry
KW - energy transfer
N2 - Efficiencies of the intramolecular triplet-triplet energy transfer (ITET) in various bichromophoric amino acids (glycine, valine, phenylalanine, and sarcosine), dipeptides (glycylglycine, phenylalanylphenylalanine), and a simple diester, with the benzoyl and naphthyl terminal groups serving as donor and acceptor, respectively, have been determined by the steady-state photokinetic measurements. The magnitude of the transfer rate constants (>10 exp8 s-1) and the number of bonds separating the chromophores (8 or 11 atoms) suggest a through-space exothermic exchange mechanism in all cases. The influence of interchromophore distance, the character of the connecting chain as well as of side chains, was evaluated. While the most efficient energy transfer was found in a flexible diester and in valine- and sarcosine-based molecules due to the steric effect of the side hydrocarbon groups, the benzyl groups in the phenylalanine and phenylalanylphenylalanine-based bichromophores had a suppressing effect on ITET. Rigidity of the peptide bond in short bichromophoric compounds causes that a large number of favorable geometries preexist already before excitation; thus the intramolecular processes are controlled by ground-state conformational distribution. Replacing this bond by a less rigid ester moiety would allow that certain unfavorable conformations may coil to favorable ones within the excited-state lifetime (a rotation-controlled photochemical model). Some conclusions were supported by a conformational search of the potential energy surface and molecular dynamics simulations.
ER -
ZABADAL, Miroslav, Petr KLÁN, Dominik HEGER a Zdeněk KŘÍŽ. Intramolecular Triplet-Triplet Energy Transfer in Short Flexible Bichromophoric Amino Acids, Dipeptides and Carboxylic Acid Diester. \textit{Collect. Czech. Chem. Commun.}. Praha, 2004, roč.~69, č.~4, s.~776-796. ISSN~0010-0765.
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