Show simple item record Budimir, A Kalmár, J Fábián, I Lente, G Bányai, I Batinić-Haberle, I Birus, M
dc.coverage.spatial England 2011-06-21T17:27:14Z 2010-05-14
dc.identifier.citation Dalton Trans, 2010, 39 (18), pp. 4405 - 4410
dc.description.abstract The activation parameters and the rate constants of the water-exchange reactions of Mn(III)TE-2-PyP(5+) (meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin) as cationic, Mn(III)TnHex-2-PyP(5+) (meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin) as sterically shielded cationic, and Mn(III)TSPP(3-) (meso-tetrakis(4-sulfonatophenyl)porphyrin) as anionic manganese(iii) porphyrins were determined from the temperature dependence of (17)O NMR relaxation rates. The rate constants at 298 K were obtained as 4.12 x 10(6) s(-1), 5.73 x 10(6) s(-1), and 2.74 x 10(7) s(-1), respectively. On the basis of the determined entropies of activation, an interchange-dissociative mechanism (I(d)) was proposed for the cationic complexes (DeltaS(double dagger) = approximately 0 J mol(-1) K(-1)) whereas a limiting dissociative mechanism (D) was proposed for Mn(III)TSPP(3-) complex (DeltaS(double dagger) = +79 J mol(-1) K(-1)). The obtained water exchange rate of Mn(III)TSPP(3-) corresponded well to the previously assumed value used by Koenig et al. (S. H. Koenig, R. D. Brown and M. Spiller, Magn. Reson. Med., 1987, 4, 52-260) to simulate the (1)H NMRD curves, therefore the measured value supports the theory developed for explaining the anomalous relaxivity of Mn(III)TSPP(3-) complex. A magnitude of the obtained water-exchange rate constants further confirms the suggested inner sphere electron transfer mechanism for the reactions of the two positively charged Mn(iii) porphyrins with the various biologically important oxygen and nitrogen reactive species. Due to the high biological and clinical relevance of the reactions that occur at the metal site of the studied Mn(iii) porphyrins, the determination of water exchange rates advanced our insight into their efficacy and mechanism of action, and in turn should impact their further development for both diagnostic (imaging) and therapeutic purposes.
dc.format.extent 4405 - 4410
dc.language eng
dc.language.iso en_US en_US
dc.relation.ispartof Dalton Trans
dc.relation.isversionof 10.1039/b926522h
dc.subject Coordination Complexes
dc.subject Magnetic Resonance Spectroscopy
dc.subject Manganese
dc.subject Porphyrins
dc.subject Temperature
dc.subject Thermodynamics
dc.subject Water
dc.title Water exchange rates of water-soluble manganese(III) porphyrins of therapeutical potential.
dc.title.alternative en_US
dc.type Journal Article
dc.description.version Version of Record en_US 2010-00-00 en_US
duke.description.endpage 4410 en_US
duke.description.issue 18 en_US
duke.description.startpage 4405 en_US
duke.description.volume 39 en_US
dc.relation.journal Dalton Transactions en_US
pubs.issue 18
pubs.organisational-group /Duke
pubs.organisational-group /Duke/School of Medicine
pubs.organisational-group /Duke/School of Medicine/Clinical Science Departments
pubs.organisational-group /Duke/School of Medicine/Clinical Science Departments/Radiation Oncology
pubs.organisational-group /Duke/School of Medicine/Institutes and Centers
pubs.organisational-group /Duke/School of Medicine/Institutes and Centers/Duke Cancer Institute
pubs.publication-status Published
pubs.volume 39
dc.identifier.eissn 1477-9234

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