Sridevi, Bashyam ; Jeyaprakash Narayanan, Seenichamy ; Srinivasan, Alagar ; Chandrashekar, Tavarekere K. ; Subramanian, Japyesan (1998) Spectral, magnetic and electrochemical properties of metal oxa- and oxathia-porphyrins Journal of Chemical Soceity, Dalton Transactions (12). pp. 1979-1984. 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/a801934g
Abstract
Metal derivatives (CuII, NiII) of monooxa-, dioxa- and oxathia-tetraphenylporphyrins and their one-electron oxidised and reduced species have been studied. Electronic spectra of the monooxa and oxathia derivatives exhibit split Soret bands and a complicated pattern of Q-bands revealing their lower symmetry. The spectra of one-electron reduced species show only marginal shifts while the one-electron oxidised product of copper monooxaporphyrins show broad, red-shifted bands. Cyclic voltammetric studies indicated one-electron metalcentered reduction at fairly low potentials forming copper(I) and nickel(I) porphyrins. The ring-oxidised product exhibits weak antiferromagnetic interaction between the unpaired electrons of copper and the porphyrin ring. The ESR spectra of the copper dioxa- and oxathia-porphyrins exhibit rhombic symmetry with unusually small metal hyperfine couplings. A comparison of ACu values and the E½ values for metal reduction suggests that distortion towards tetrahedral symmetry and the presence of a soft donor atom like sulfur in porphyrins are required to generate spectral and electrochemical properties like those observed for the type I copper center in proteins.
Item Type: | Article |
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Source: | Copyright of this article belongs to Royal Society of Chemistry. |
ID Code: | 5431 |
Deposited On: | 18 Oct 2010 09:39 |
Last Modified: | 16 May 2016 15:56 |
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