skip to main content

Title: Picosecond dynamics of energy transfer in porphyrin-sapphyrin noncovalent assemblies

The picosecond dynamics of noncovalent ensembles for energy transfer based on anion chelation are reported. The photoactive noncovalent complexes are assembled via salt-bridge formation between carboxyl-containing porphyrin photodonors and a monoprotonated pentapyrrolic sapphyrin acceptor. These complexes are formed with a K{sub a} of ca. 10{sup 3} M{sup {minus}1} upon mixing the receptor and substrate in their respective free-acid and free-base forms in CD{sub 2}Cl{sub 2} (as judged by {sup 1}H NMR spectroscopic means). Upon irradiation at 417 nm, singlet-singlet energy transfer from the porphyrin to the sapphyrin subunit takes place readily with energy transfer dynamics that are consistent with a Foerster-type mechanism. The title systems thus appear to be prototypic of a new kind of noncovalent energy transfer modeling that is predicated on the use of anion chelation.
Authors:
; ; ; ; ;
Publication Date:
OSTI Identifier:
20013122
DOE Contract Number:
W-31109-ENG-38
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of the American Chemical Society; Journal Volume: 121; Journal Issue: 10; Other Information: PBD: 17 Mar 1999
Research Org:
Univ. of Texas, Austin, TX (US)
Sponsoring Org:
National Institutes of Health; US Department of Energy
Country of Publication:
United States
Language:
English
Subject:
55 BIOLOGY AND MEDICINE, BASIC STUDIES; 14 SOLAR ENERGY; PORPHYRINS; ENERGY TRANSFER; PHOTOSYNTHESIS; CHEMICAL REACTION KINETICS; PHOTOSYNTHETIC REACTION CENTERS