Redox-Responsive Host–Guest Association between γ-Cyclodextrin and Mixed-Metal Keggin-Type Polyoxometalates

The complexation of Keggin-type polyoxometalates (POMs) with γ-cyclodextrin (γ-CD) leads to supramolecular inclusion assemblies in aqueous solution driven by a chaotropic effect. strength the interaction between γ-CD and oxidized or one-electron reduced POMs series molybdenum vanadium monosubstituted phospho- silico-tungstates, [XW11MO40]n- anions where X = P Si M MoV/VI VIV/V, has been evaluated isothermal titration calorimetry (ITC), NMR spectroscopy, cyclic voltammetry. Such study reveals that host-guest binding constant K1:1 increases strongly decrease global ionic charge POM unit. There is an almost one magnitude order variation per unit, falls down from about 105 M-1 values close zero as varies 3- 6-. addenda offer possibility tuning association simple addition/removal electron POMs, opening new avenue for design smart materials through redox stimuli.