Contrasting photoelectrochemical behaviour of two isomeric supramolecular dyes based on meso-tetra(pyridyl)porphyrin incorporating four (μ3-oxo)- triruthenium(III) clusters

André Luiz Barboza Formiga; Ana Flavia Nogueira; Koiti Araki; Henrique Eisi Toma

doi:10.1039/B709888J

Contrasting photoelectrochemical behaviour of two isomeric supramolecular dyes based on meso-tetra(pyridyl)porphyrin incorporating four (μ₃-oxo)- triruthenium(iii) clusters

André Luiz Barboza Formiga,^a Ana Flavia Nogueira,^b Koiti Araki^c and Henrique Eisi Toma*^c

Author affiliations

* Corresponding authors

^a Instituto de Química, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil

^b Instituto de Química, Universidade Estadual de Campinas, Campinas, SP, Brazil

^c Instituto de Química, Universidade de São Paulo, P.O. Box 26077, São Paulo, SP, Brazil
E-mail: henetoma@iq.usp.br
Tel: +55 (11) 3091 3887

Abstract

A saddle shaped tetracluster porphyrin species containing four [Ru₃O(OAc)₆(py)₂]⁺ clusters coordinated to the N-pyridyl atoms of 5,10,15,20-tetra(3-pyridyl)porphyrin, H₂(3-TCPyP), has been investigated in comparison with the planar tetra(4-pyridyl)porphyrin analogue H₂(4-TCPyP). The steric effects from the bulky peripheral complexes play a critical role in the H₂(3-TCPyP) species, determining a non-planar configuration around the porphyrin centre and precluding any significant π-electronic coupling, in contrast with the less hindered H₂(4-TCPyP) species. Both systems exhibit a photoelectrochemical response in the presence of nanocrystalline TiO₂ films, involving the porphyrin excitation around 450 nm. However, only in the H₂(4-TCPyP) case do the cluster moieties also contribute to the photoinduced electron injection process at 670 nm, reflecting the relevance of the electronic coupling between the porphyrin centre and the peripheral complexes.

Article information

https://doi.org/10.1039/B709888J

Article type

Paper

Submitted

29 Jun 2007

Accepted

31 Jan 2008

First published

17 Mar 2008

Download Citation

New J. Chem., 2008,32, 1167-1174

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Contrasting photoelectrochemical behaviour of two isomeric supramolecular dyes based on meso-tetra(pyridyl)porphyrin incorporating four (μ₃-oxo)- triruthenium(III) clusters

A. L. B. Formiga, A. F. Nogueira, K. Araki and H. E. Toma, New J. Chem., 2008, 32, 1167 DOI: 10.1039/B709888J

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