Ion pairing and host-guest complexation in low dielectric constant solvents.

摘要: We report an equilibrium treatment for complexation of ionic species in low dielectric constant media that explicitly includes ion pairing one the components. Experimental validation was achieved through study pseudorotaxane formation between dibenzylammonium salts and dibenzo-24-crown-8. In particular, we show concentration-dependent fluctuations apparent Ka,exp values as usually reported are attributable to pairing, with dissociation Kipd, Kap free cationic guest species, G+, by host crown ether is independent counterion. More generally, using a simple extension our model, ability diagnose relative extent complex, which may be readily applied other host−guest systems involving species.