Local structure in a Barluenga's Reagent analogue: a modulated, molecular salt

The perchlorate analogue of Barluenga’s Reagent provides a relatively rare example of modulation in a molecular salt, which persists over a much wider temperature range than its parent compound. Our understanding of how the modulation emerges on cooling below 280 K, and decays by 30 K, is tied to the interaction mechanism that spatially relates the anion and cation. This has been suggested to resemble a ‘ratchet-type’ mechanism and we now seek confirmation of this. We propose to measure total scattering data at low temperatures so we can observe the local signature of the mechanism that gives rise to modulation. We can extract nearest-neighbour correlations which will inform us of the mechanism relating the iodopyridinium and perchlorate moieties, as well as establishing whether perchlorate disorder, apparent in the average structure, is static or dynamic.