Template-assisted synthesis of isomeric copper(i) clusters with tunable structures showing photophysical and electrochemical properties

Abstract

A comparative study of structure–property relationships in isomeric and isostructural atomically precise clusters is an ideal approach to unravel their fundamental properties. Herein, seven high-nuclearity copper(I) alkynyl clusters utilizing template-assisted strategies were synthesized. Spherical Cu₃₆ and Cu₅₆ clusters are formed with a [M@(V/PO₄)₆] (M: Cu²⁺, Na⁺, K⁺) skeleton motif, while peanut-shaped Cu₅₆ clusters feature four separate PO₄ templates. Experiments and theoretical calculations suggested that the photophysical properties of these clusters are dependent on both the inner templates and outer phosphonate ligands. Phenyl and 1-naphthyl phosphate-protected clusters exhibited enhanced emission features attributed to numerous well-arranged intermolecular C–H⋯π interactions between the ligands. Moreover, the electrocatalytic CO₂ reduction properties suggested that internal PO₄ templates and external naphthyl groups could promote an increase in C₂ products (C₂H₄ and C₂H₅OH). Our research provides new insight into the design and synthesis of multifunctional copper(I) clusters, and highlights the significance of atomic-level comparative studies of structure–property relationships.