Tautomerism in chromic materials: a combined neutron diffration and Raman study.

As part of a facility project aimed at developing a new sample environment allowing simultaneous in-situ neutron diffraction and Raman measurements, we propose to study the proton migration in N-(3,5-Di-tert-butylsalicylidene)-4-iodobenzene, N-(3,5-Di-tert-butylsalicylidene)-2-iodobenzene and in N-(3,5-di-tert-butylsalicylidene)-3-nitroaniline. All these compounds are chromotropic and such behaviour is associated with tautomerism, i.e.the transfer of a hydrogen atom from the oxygen atom of a phenolic group to a nitrogen atom to produce an enamine. The possibility of collecting diffraction data and Raman response at the same time and on the same crystal will allow to probe the mechanisms of action in fine details whilst building fundamental knowledge to be used in further theoretical calculations on these systems.