Letter | Published:

Effect of Introducing a Sulphur Bridge on the Herbicidal Activity of Diquat

Naturevolume 214pages381382 (1967) | Download Citation



DIQUAT1, paraquat2 and related diquaternary salts from 2,2′-and 4,4′-bipyridyls3 have attracted much attention as herbicides4,5. Their mode of action is thought6–8 to be connected with their ability to be reduced to a stable radical cation at a potential (E0) of about − 0.35 to − 0.45 V, the stability of the free radical being due to the delocalization of the odd electron over both pyridine rings. The influence of the introduction between the pyridine rings of an atom or group which is capable of acting as an electron transfer bridge has not so far been investigated. This communication reports our results with diquaternary salts of 2,2′-dipyridyl sulphide.

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  1. University of Newcastle, New South Wales, Australia

    • L. A. SUMMERS


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