Substantial solubility and fluorescence property changes upon inclusion of rutaecarpine in cucurbit[7]uril: Kinetics and thermodynamics of binding

•Rutaecarpin (Rut) water-solubility is enhanced 550-fold upon inclusion complex formation with cucurbit[7]uril (CB7).•The encapsulation of protonated rutaecarpin (RutH+) in cucurbit[7]uril is a highly exothermic process in water.•The stabilization of RutH+ by the host macrocycle leads to ∼3.2 unit pKa increase.•The intense fluorescence of RutH+-CB7 complex can be used for the visualization of pH differences in the 4.5–6.5 range.•The deprotonation of RutH+-CB7 complex results in a rapid Rut release from the host macrocycle.