Structures of host OAH, OAMe, CBClip and their guest molecules. OA and OAMe are also known as OA and TEMOA, respectively. All host molecules are shown in two perspectives. Silver carbon, Blue nitrogen, Red oxygen, Yellow sulfur. Non-polar hydrogen atoms were omitted for clarity. OA-G1–OA-G6 are the common guest molecules for OAH and OAMe, and CBC-G1–CBC-G10 are guests for CBClip. Protonation states of all host and guest molecules shown in the figure were suggested by the organizers based on the expected pKas and the experimental pH values