Fig. 22. (a) Chloride-triggered uptake of neutral guests by a coordination cage [Pd4518] following an allosteric mechanism; (b) both [3BF4@Pd4518] and [2Cl + 1@Pd4518] act as photosensitizers for singlet oxygen generation. Activated oxygen adds in a [2 + 4] cycloaddition to the substrate in the cavity and surrounding solution; (c) crystal structures of [2Cl + 1@Pd4518] and [2Cl+2@Pd4518].
