3.3.1. Typical Procedure for 1H NMR Titrations

All of the reagents were weighted separately on an analytical balance (readability to 0.01 mg) in screw-capped vials sealed with Teflon-covered septa. A DMSO-d₆ + 0.5% H₂O (w/w) mixture was prepared and used as the solvent. All the solvents/solutions manipulations were performed using gas-tight Hamilton glass syringes. Titrant was prepared by dissolving TBACl in a solution of the receptor to avoid dilution of the receptor during the titration. To a solution of host (600 μL, 0.01 M) in a screw-capped NMR tube sealed with Teflon-covered septum seal, appropriate aliquots of titrant (up to 10 equiv., 0.3 M, dissolved in a host solution to avoid dilution) were added with a 25 μL gas-tight microsyringe. An ¹H NMR spectrum was recorded after each addition of the salt, and the temperature inside the NMR probe was held constant at 25 °C. Association constants were calculated based on the changes in the chemical shifts of the most affected protons in the ligands, as indicated in each case below.