Triplet Energy Transfer in Bichromophoric Amino Acids, Dipeptides and Carboxylic Acid Diesters

Triplet Energy Transfer in Bichromophoric Amino Acids, Dipeptides and Carboxylic Acid Diesters

Peer-reviewed article not indexed in WoS or Scopus

The Intramolecular Triplet-triplet Energy Transfer (ITET) in various bichromophoric amino acids (glycine, valine, phenylalanine, and sarcosine), dipeptides (diglycine, diphenylalanine), and a simple diester, with the benzoyl and naphthyl terminal groups serving as donor and acceptor, respectively (Fig. 1), were studied by the steady-state photokinetic measurements. The efficiency of a through-space exothermic ITET was affected by the interchromophore distance (8 or 11 atoms), the nature of the connecting chain as well as the side chains. Rigidity of the peptide bond in short bichromophoric compounds causes that the ITET processes are controlled by ground-state conformational distribution. Whereas a less rigid diester would allow that certain unfavorable conformations may coil to favorable ones within an excited-state lifetime (< 10-8 s). Flexibility of the bichromophore with ester moiety and the steric effect of the side hydrocarbon groups in valine- and sarcosine-based molecules lead into the most efficient energy transfer. While the benzyl groups in the phenylalanine and phenylalanylphenylalanine-based bichromophores had a suppressing effect on ITET.

The Intramolecular Triplet-triplet Energy Transfer (ITET) in various bichromophoric amino acids (glycine, valine, phenylalanine, and sarcosine), dipeptides (diglycine, diphenylalanine), and a simple diester, with the benzoyl and naphthyl terminal groups serving as donor and acceptor, respectively (Fig. 1), were studied by the steady-state photokinetic measurements. The efficiency of a through-space exothermic ITET was affected by the interchromophore distance (8 or 11 atoms), the nature of the connecting chain as well as the side chains. Rigidity of the peptide bond in short bichromophoric compounds causes that the ITET processes are controlled by ground-state conformational distribution. Whereas a less rigid diester would allow that certain unfavorable conformations may coil to favorable ones within an excited-state lifetime (< 10-8 s). Flexibility of the bichromophore with ester moiety and the steric effect of the side hydrocarbon groups in valine- and sarcosine-based molecules lead into the most efficient energy transfer. While the benzyl groups in the phenylalanine and phenylalanylphenylalanine-based bichromophores had a suppressing effect on ITET.

bichromophore; triplet-triplet energy transfer; imtramolecular energy transfer; amino acid; steady-state methods

bichromophore; triplet-triplet energy transfer; imtramolecular energy transfer; amino acid; steady-state methods

ZABADAL, Miroslav; HEGER, Dominik; KLÁN, Petr; KŘÍŽ, Zdeněk

20.09.2005

Česká chemická společnost

Chemické listy Novotného lávka 5 116 68 Praha 1

Chemické listy S

0009-2770

CHEMICKE LISTY

99

S

Czech Republic

513

514

2