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.
- Research Organization:
- Univ. of Texas, Austin, TX (US)
- Sponsoring Organization:
- National Institutes of Health (NIH); USDOE
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 20013122
- Journal Information:
- Journal of the American Chemical Society, Vol. 121, Issue 10; Other Information: PBD: 17 Mar 1999; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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