Singlet quenching of tetraphenylporphyrin and its metal derivatives by iron(III) coordination compounds

D'souza, Francis and Krishnan, V (1990) Singlet quenching of tetraphenylporphyrin and its metal derivatives by iron(III) coordination compounds. In: Proceedings of the Indian Academy of Sciences - Chemical Sciences, 102 (2). pp. 131-146.

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Abstract

The quenching of fluorescence of the free-base tetraphenylporphyrin, H2TPP, and its metal derivatives, MgTPP and ZnTPP by diverse iron(III) complexes, [Fe(CN)6]3−, Fe(acac)3, [Fe(mnt)2]−, Fe(Salen)Cl, [Fe4S4(SPh)4]2−·, FeTPPCl and [Fe(Cp)2]+ has been studied both in homogeneous medium (CH3CN) and micellar media, SDS., CTAB and Triton X-100. The quenching efficiencies are analysed in terms of diffusional encounters and it has been possible to separate static quenching components. The quenching constants are dependent on the nature of the ligating atoms around iron(III) and also on the extent of π-conjugation of the ligands. The quenching mechanism has been investigated using steady-state irradiation experiments. Evidence for oxidative quenching by iron(III) complexes was obtained, though the spin multiplicities of the excited electronic states of iron(III) complexes permit both energy and electron transfer mechanisms for quenching of the singlet excited state of the porphyrins.

Item Type:	Journal Article
Publication:	Proceedings of the Indian Academy of Sciences - Chemical Sciences
Publisher:	Indian Academy of Sciences
Additional Information:	Copyright of this article belongs to Indian Academy of Sciences.
Keywords:	Fluorescence quenching - porphyrins - iron(III) coordination compounds
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	12 Jan 2011 11:47
Last Modified:	12 Jan 2011 11:47
URI:	http://eprints.iisc.ac.in/id/eprint/34953

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