†In association with Jawaharlal Nehru Center for Advanced Scientific Research, Indian Institute of Sci ence, Bangalore, India.
INTER AND INTRAMOLECULAR INTERACTIONS OF PORPHYRINS WITH 5,5′-DITHIOBIS(2-NITROBENZOIC ACID)
Article first published online: 2 JAN 2008
Photochemistry and Photobiology
Volume 56, Issue 2, pages 145–156, August 1992
How to Cite
D'Souza, F. and Krishnan, V. (1992), INTER AND INTRAMOLECULAR INTERACTIONS OF PORPHYRINS WITH 5,5′-DITHIOBIS(2-NITROBENZOIC ACID). Photochemistry and Photobiology, 56: 145–156. doi: 10.1111/j.1751-1097.1992.tb02141.x
- Issue published online: 2 JAN 2008
- Article first published online: 2 JAN 2008
- Received 2 July 1991; accepted 2 January 1992
meso-Tetraphenylporphyrin and its metal [zinc(II) and copper(II)] derivatives form both inter and intramolecular complexes with 5,5′-dithiobis(2-nitrobenzoic acid) (DTNB). The nature of interaction is predominantly charge transfer (CT) in origin, with the porphyrin functioning as a II-donor and DTNB as an acceptor. Among the covalently linked intramolecular systems, the magnitude of CT interaction varies with the position (of one of the aryl groups of the porphyrin) to which DTNB is attached as ortho meta > para. Steady-state and time-resolved fluorescence studies revealed electron transfer to be the dominant pathway for the fluorescence quenching in these systems. Steady-state photolysis experiments probed using EPR and optical absorption studies have shown that electron transfer (from the excited singlet state of the porphyrin) to DTNB results in the formation of thiyl radical and production of free thiolate anion. It is found that the products of electrochemical reduction of covalently linked porphyrin-DTNB systems are different from those observed for the photochemical studies.