Polymeric Malachite Green

N,N-dimethyl-p-phenylenediamine by the method of Bernthsen33 to give poly( -vinyl Methylene Blue), This polymer acts as a hydrogen acceptor in the enzymatic dehydrogenation of ethanol. The carbinol form (XVIl) of polymeric Malachite Green may be prepared by the. nucleophilic attack of poly(p-lithium styrene) on Michler s ketone 3 acidification gives the colored dye (XVIIl). 

On the other hand, the photoconductivity of a poly(vinyl chloride) copolymer and of sucrose benzoate each containing the leucobase of malachite green was characteristic of the dyestuff and independent of the polymeric host (137). This is similar to the behavior of conventional impurity semiconductors. However, a distinction must be drawn between an impurity which acts solely as an impurity providing an easier path to the conduction band, one which acts only as a plasticizer and one which may act as both impurity and plasticizer. 

Much of the work in this area has focussed on polymeric dyes which can participate in redox reactions. Early work by Manecke and Kossmehl on vinyl Malachite Green (VMG) is specially significant as it established a simple method of entry into the polymerizable triphenylmethane class of dyes. Thus the carbinol base form (ill) of VMG was synthesized by a Grignard reaction between vinyl-phenyl magnesium chloride (l) and Michler s ketone (ll). 

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