Effect of porphyrin ring distortion on the spectral and electrochemical properties of short-chain basket-handle porphyrins

Ravikanth, Mangalampalli ; Reddy, Damodar ; Misra, Ashutosh ; Chandrashekar, Tavarekere K. (1993) Effect of porphyrin ring distortion on the spectral and electrochemical properties of short-chain basket-handle porphyrins Journal of Chemical Soceity, Dalton Transactions . pp. 1137-1141. ISSN 0300-9246

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Official URL: http://www.rsc.org/publishing/journals/DT/article....

Related URL: http://dx.doi.org/10.1039/DT9930001137

Abstract

The effect of porphyrin ring distortion on the spectral and electrochemical properties of short-chain basket-handle porphyrins has been investigated. The covalent attachment of opposite phenyl rings of meso-5,10,15,20-tetraphenylporphyrin (H2tpp) by short bridging groups of varying nature and length induces distortion in the porphyrin ring. Optical absorption studies indicate large bathochromic shifts (502-1139 cm1) for both Q and Soret bands and the magnitude of these shifts are linearly correlated with the degree of distortion. The potential values for the porphyrin ring oxidation and reduction were shifted to less-positive (180260 mV) and to more-negative (280390 mV) values respectively relative to planar H2tpp. The magnitude of the shifts in the optical absorption bands and redox potentials are independent of the nature of the bridging chain. The origin of these shifts are traced to structural effects caused due to the introduction of a short bridging group rather than to the electronic effect of the bridging group. Introduction of Cu2+ into the porphyrin core does not affect the degree of distortion and ESR studies indicate no significant change in the electronic structure of the Cu2+ ion relative to [Cu(tpp)].

Item Type:Article
Source:Copyright of this article belongs to Royal Society of Chemistry.
ID Code:5258
Deposited On:18 Oct 2010 07:34
Last Modified:27 May 2011 11:51

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