Donor properties of metallomacrocyclic tetrapyrrole pigments with sym-trinitrobenzene

Chandrashekar, TK and Krishnan, V (1981) Donor properties of metallomacrocyclic tetrapyrrole pigments with sym-trinitrobenzene. In: Inorganic Chemistry, 20 (9). pp. 2782-2786.

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Abstract

The interactions of metallo derivatives of macrocyclic tetrapyrrole pigments, pheophytin a (pheo), phthalocyanin (phth), and tetraphenylporphyrin (TPP) with sym-trinitrobenzene (TNB) have been studied with use of spectroscopic methods. These macrocyles form 1:l molecular complexw with the acceptor. The association constants (K) for the interactions follow the decreasing order of binding as pheo > phth > TPP. The divalent metal ions influence the values of K for the various metallo TPP derivatives, and the relative order of stabilities decrease as Co > Cu = VO > Ni > Zn. The stereochemistry of M(TPP) and the electronic configuration of the metal ions are shown to contribute to the magnitudes of K. The acceptor strongly quenches the fluorescence of the metallo macrocycles, and the quenching constant decreases as pheo > phth > TPP. The formation of exciplexes is postulated on the basis of the rate of bimolecular quenching constants and solvent effects.

Item Type:	Journal Article
Publication:	Inorganic Chemistry
Publisher:	American Chemical Society
Additional Information:	Copyright of this article belongs to American Chemical Society.
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	03 Jul 2009 10:25
Last Modified:	19 Sep 2010 05:34
URI:	http://eprints.iisc.ac.in/id/eprint/20745

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