Encapsulation of an Au25 Nanocluster inside a Porphyrin Nanoring Enhances Singlet Oxygen Generation and Photo‐Electrocatalytic CO2 Reduction

Abstract The synthesis of molecular host–guest complexes with enhanced performance, relative to those of their components, is a central theme in supramolecular chemistry. Here we explore a host‐guest system consisting of an atomically precise gold nanocluster bound inside a zinc porphyrin nanoring. UV/Vis absorption and fluorescence titrations with different sized nanorings revealed strong binding between a pyridinethiol‐coated Au 25 nanocluster and a nanoring consisting of six zinc porphyrin units, and complexation is confirmed by mass spectrometry. Formation of this assembly enhances the stability of the gold nanocluster. The host‐guest complex also exhibits remarkable activity and selectivity for photochemical CO 2 to CO conversion and singlet oxygen generation.