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Electrochemical Reduction of Metribuzin
Author(s) -
Ludvík Jirˇí,
Riedl František,
Liška František,
Zuman Petr
Publication year - 1998
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/(sici)1521-4109(199810)10:13<869::aid-elan869>3.0.co;2-y
Subject(s) - metribuzin , chemistry , protonation , acetonitrile , aqueous solution , hydrolysis , electrochemistry , conjugated system , hydrogen bond , conjugate acid , conjugate , medicinal chemistry , combinatorial chemistry , inorganic chemistry , organic chemistry , molecule , ion , polymer , electrode , mathematical analysis , mathematics , weed control , agronomy , biology
Metribuzin [4‐amino‐6‐ tert ‐butyl‐3‐methylthio‐1,2,4‐triazin‐5(4 H )‐one] is a widely used weed controlling agent. In aqueous solutions and in 30 % v/v acetonitrile/water solutions it is reduced in two two‐electron steps. In both steps protonated forms of azomethine bonds are reduced, in the more positive the 1,6‐bond, in the more negative (by about 0.4 V) the 2,3‐bond. At pH > 7 the conjugated base is reduced at considerably more negative potentials in a one‐electron step. Reduction of both azomethine bonds is accompanied by acid‐base and hydration‐dehydration equilibria. The 1,6‐dihydrometribuzin, formed in the first reduction step, undergoes acid catalyzed hydrolysis. In many aspects the behavior of metribuzin resembles that of metamitron [4‐amino‐3‐methyl‐6‐phenyl‐1,2,4‐triazin‐5(4 H )‐one] investigated earlier. For analytical purposes waves between pH 2 and 4 are best suited.