Confined Self-Assembly of Anionic [Cu₈I₁₄]^6–-Type Supramolecular Cluster and Performance Enhancement of Photo-Oxidation and Photo-Click Reaction

Abstract

The self-assembly of cuprous iodide supramolecular clusters with novel molecular structures and excellent photocatalytic performance through weak noncovalent interactions remains a major challenge. In this work, we fabricate a dimeric anionic cuprous iodide supramolecular cluster [(Cu 8 I 14 ) 6− (L 1 3+ ) 2 ] (HUBU-1) using a multicomponent confined self-assembly strategy via host−guest encapsulation associated with multicharge electrostatic interaction. Furthermore, cluster HUBU-1 exhibits exceptional visible light absorption capability and a surmountable energy bandgap (E g = 2.73 eV), which is crucial for the generation of reactive oxygen species and other reactive radicals in the photocatalysis process. Excellent photoelectric performance endows cluster HUBU-1 with highly photocatalytic activity toward both oxidative coupling reaction of benzylamine and cycloaddition reaction of azide−alkynes (CuAAC) in acetonitrile. Specifically, the photocatalytic yields of imine products reach 60−76% for nine amine substrates under illumination. Likewise, the photoinduced catalytic efficiency of the CuAAC reactions involving nine alkyne derivatives ranges from 56 to 90%. Consequently, by utilizing density functional theory calculations and electron paramagnetic resonance experiments, we propose a photocatalytic mechanism for superoxide radical-triggered photo-oxidation and phenylacetylene radical-initiated cycloaddition.