engleski

Kinetics and Mechanism of the Rections of Aquapentacyanofe(II) Ions with the Biologically Active Bis-pyridinium aldoxime (TMB-4)

It is well known that mono- and bis-quaternary pyridinium aldoximes are potent reactivators of the acetylcholinesterase activity inhibited by organophosphates. One of the representative of the bis-pyridinium class is the 1, 1'-bis(pyridinium-4-aldoxime)trimethylene dibromide (TMB-4). TMB-4 reacts with aquapentacyanoferrate(II) ions forming a blue pentacyanoferrate(II) complex. The kinetics of the substitution reactions of the aquapentacyanoferrate(II) ions with TMB-4 were studied in aqueous media in the range pH 5-11, I=0.50 M and 25 C. The rates of the formation and dissociation of the TMB-4 substituted pentacyanoferrate(II) was found to be pH dependent, which is attributed to the reactions of various ionic forms of the ligand. The relationships between the formation rate constants and the magnitude and position of charges on the ligand and its various possible configurations and conformations are discussed in terms of an ion-pair dissociative mechanism.

1; 1’; -Bis(pyridinium-4-aldoxime)trimethylene dibromide; Aquapentacyanoferrate(II); Kinetics

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