Definition of viologen in English:



  • Any of a series of synthetic compounds related to the weedkiller paraquat, used as redox indicators. They contain heteroaromatic cations of the general formula (C₅H₄NR)₂²⁺.

    • ‘The shift from a more sigmoidal plot of the binding isotherm in the case of ethidium toward a more hyperbolic plot in the case of methyl viologen demonstrates stronger versus weaker binding, respectively.’
    • ‘The intermolecular interactions between the viologens and the macrocyclic molecule were investigated in a solution before photoirradiation.’
    • ‘Leaves from the transformed maize plants showed enhanced tolerance to the oxidative stress induced by incubation of leaf discs in the pro-oxidant herbicide, methyl viologen.’
    • ‘Methyl viologen also affects electron-transducing reactions in the endoplasmic reticulum and in mitochondria.’
    • ‘The transgenic plants were also more tolerant to the oxidative damage caused by methyl viologen showing less chlorosis and less electrolyte leakage than the controls.’


1930s: from violet (because of the purple colour when electrochemically reduced) + -gen.