Kinetics and mechanism of formation of nickel(II)porphyrin and its interaction with DNA in aqueous medium.
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ABSTRACT: Kinetics between 5,10,15,20-tetrakis(N-methylpyridium-4-yl)porphyrin and Ni2+ species were investigated in aqueous solution at 25 ±1 °C in I = 0.10 M (NaNO3). Speciation of Ni2+ was done in I = 0.10 M (NaNO3) for knowing distribution of Ni2+ species with solution pH. Experimental data were compared with speciation diagram constructed from the values of hydrolysis constants of Ni2+ ion. Speciation data showed that hexaaquanickel(II) ions took place in hydrolysis reactions through formation of [Ni(OH2)6-n(OH)n]2-n species with solution pH. According to speciation of Ni2+ and pH dependent rate constants, rate expression can be written as: d[Ni(TMPyP)4+]/dt = (k 1[Ni2+ (aq)] + k 2[Ni(OH)+ (aq)] + k 3[Ni(OH)2 o (aq)] + k 4[Ni(OH)3 - (aq)])[H2TMPyP4+], where k 1, k 2, k 3 and k 4 were found to be k 1 = (0.62 ± 0.22) × 10-2; k 2 = (3.60 ± 0.40) × 10-2; k 3 = (2.09 ± 0.52) × 10-2, k 4 = (0.53 ± 0.04) × 10-2 M-1s-1 at 25 ±1 °C, respectively. Formation of hydrogen bonding between [Ni(H2O)5(OH)]+ and [H2TMPyP]4+ causes enhanced reactivity. Rate of formation of [Ni(II)TMPyP]4+ complex was to be 3.99 × 10-2 M-1s-1 in I = 0.10 M, NaNO3 (25 ± 1 °C). UV-Vis and fluorescence data suggested that [Ni(II)TMPyP]4+ and [H2(TMPyP)]4+ interact with DNA via outside binding with self-stacking and intercalation, respectively. SYNOPSIS.Supplementary information
The online version contains supplementary material available at 10.1007/s12039-021-01945-y.
SUBMITTER: Habib A
PROVIDER: S-EPMC8329907 | biostudies-literature |
REPOSITORIES: biostudies-literature
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