Electron spin resonance of dimeric species from the radical cations of vanadyl porphyrins

Lemtur, A.; Chakravorty, Basab K.; Dhar, Tripti K.; Subramanian, J.

doi:10.1021/j150667a029

Cited by 17 publications

(28 citation statements)

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“…Similar splittings though not so well-resolved as in the present case have been reported for (VO) 2+ and Zn 2+ protoporphyrin. 20 Maiya and Krishnan 23 report a study on dimeric crown ether porphyrins wherein the difference in the oxidation potential between the monomeric and dimeric systems is about 150-200 mV. That the aggregate is a dimer is borne out by EPR studies.…”

Section: Resultsmentioning

confidence: 99%

“…VO(MESO) was prepared from mesoporphyrin dimethyl ester as reported earlier. 20 Tetra-n-butylammonium perchlorate was prepared by treating tetra-n-butylammonium bromide (SISCO Research Chemicals, India) with sodium perchlorate. It was recrystallized from methanol.…”

Section: Methodsmentioning

confidence: 99%

“…20 This species dimerises at low temperature and hence the monomeric cation radical could not be studied at low temperatures. Two types of dimers have been identified by EPR spectroscopy: one with S ) 1 ground state and the other with S ) 3 / 2 ground state.…”

Section: Introductionmentioning

confidence: 99%

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Cyclic Voltammetric and EPR Studies on the Oxidation Products of Vanadyl Mesoporphyrin

et al. 1996

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The results of cyclic voltammetric studies on vanadyl mesoporphyrin dimethyl ester, VO(MESO), at various concentration ranges are reported. Redox peaks have been identified for the dimeric species in the cyclic voltammograms. The monomeric radical cation of VO(MESO) has been identified at low temperatures, and the triplet EPR spectrum of this species is reported. The zero-field splitting parameters have been obtained by computer simulation. A distance of 3.8 Å between the d electron in the vanadium orbital and the unpaired π electron in the porphyrin ring in the monomeric radical cation of VO(MESO) has been obtained. This result is interpreted as arising from a 1u ground state for the π electron in the porphyrin.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Cyclic Voltammetric and EPR Studies on the Oxidation Products of Vanadyl Mesoporphyrin

et al. 1996

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“…The reaction is utilized to synthesize 18 O-labeled oxo-vanadium(IV) porphyrin complex [191]. One electron oxidation of oxo-vanadium(IV) porphyrin gives stable oxo-vanadium(IV) porphyrin p-cation radical complex [192], which allows to facilitate systematic studies of the effect of solvent and porphyrin oxidation on m(V@O) vibration as models for compounds I and II. Raman studies shows that the frequency for m(V@O) decreased with increase in solvent acceptor number, consistent with solvent-induced polarization of the m(V@O) bond [193].…”

Section: Aoamomentioning

confidence: 99%

“…ESEEM spectra of oxo-vanadium porphyrins are also reported [196]. Oxo-vanadium(IV) porphyrin p-cation radical is biradical which exhibits a triplet EPR signal at low temperature [192]. Recent study of O@V(OEP )(H 2 O) showed that the radical complex forms a dimer both in solid and in solution at low temperature and exhibits intramolecular ferromagnetic coupling and intermolecular antiferromagnetic coupling [197].…”

Section: Aoamomentioning

confidence: 99%

Characterization of High-Valent Oxo-Metalloporphyrins

Watanabe

Fujii

2000

Structure and Bonding

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High-valent oxo metalloporphyrins have been known as reactive intermediates in the catalytic cycles of many heme enzymes and in the oxidation reactions mediated by synthetic metalloporphyrins. In this review, we survey studies of high-valent oxo metalloporphyrins in the past decade. In Sect. 2, electronic structures and magnetic properties of compound I and compound II species in various heme enzymes are discussed on the basis of recent studies of synthetic model complexes of the compound I and compound II. In Sect. 3, spectroscopic properties of oxo manganese porphyrin complexes and their application to biological systems are summarized. In the Sects. 4 and 5, synthesis and characterization of oxo chromium and oxo ruthenium porphyrin complexes are reviewed. In the last section, we have summarized the synthesis and characterization of Mo, Nb, Ti, and V oxo metalloporphyrins complexes.

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Availability of π–Cation Radical in the Oxidative Products of Oxidovanadium Porphyrin: Significance for DNA Binding and Antibacterial Activity

Muzaddadi,

Murugan,

Saha

et al. 2024

Applied Organom Chemis

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Oxidovanadium meso‐tetrakis(3,4,5‐trimethoxyphenyl) porphyrin [VO(T(OMe)3PP)] (Complex 1) was prepared. The oxidation product of Complex 1 has been characterized by cyclic voltammetry (CV), UV–visible spectrophotometer, electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) by the addition of SbCl5 to Complex 1. There is a one‐electron oxidation product in Complex 1 that creates π–cation radicals in CV data. This is supported by an IR spectrophotometer. Subsequent EPR spectra verified the initiation of the π–cation monoradical, which subsequently transforms into a triplet state where S = 1. DNA binding and antibacterial analysis with Complex 1 have also been analysed. In the DNA‐binding analysis, the CV data confirm the interaction between Complex 1 and DNA. Furthermore, the fact that Complex 1 is more effective at killing bacteria shows that the metal ion's chelation with the porphyrin ligand makes it more lipophilic.

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Electron spin resonance of dimeric species from the radical cations of vanadyl porphyrins

Cited by 17 publications

References 0 publications

Cyclic Voltammetric and EPR Studies on the Oxidation Products of Vanadyl Mesoporphyrin

Cyclic Voltammetric and EPR Studies on the Oxidation Products of Vanadyl Mesoporphyrin

Characterization of High-Valent Oxo-Metalloporphyrins

Availability of π–Cation Radical in the Oxidative Products of Oxidovanadium Porphyrin: Significance for DNA Binding and Antibacterial Activity

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