Stimuli-induced reversible transformation between isomers of copper(I) clusters sharing an identical core.

Wang, Yao; Xiao, Fang-Xue; Chen, Ziyong; Wong, Eric Ka-Ho; Yi, Jun; Yan, Liang-Liang; Yam, Vivian Wing-Wah · Proc Natl Acad Sci U S A · 2026

basic_science · Level V

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Abstract

The construction of reversible structural isomerization in atomically precise metal clusters remains a daunting challenge. Herein, we report the application of a bifunctionalized phosphine-alkyne ligand, (2-ethynylphenyl)diphenylphosphine (HL), to synthesize an octanuclear copper(I) cluster <b>Cu<sub>8</sub>-1</b> [(Cu<sub>8</sub>(L)<sub>6</sub>(PF<sub>6</sub>)<sub>2</sub>], which can undergo a clean and reversible transformation to a <b>Cu<sub>8</sub>-2</b> isomer responsive to solvent or temperature stimuli. The structural isomerization process has been readily monitored by NMR in solution. Single-crystal X-ray diffraction studies further suggested the possible occurrence of a dynamic ligand rearrangement with reversible Cu-P coordination bond dissociation/reformation with the Cu<sub>8</sub> kernel remained intact. This reversible structural switching is accompanied by a luminescence color change between green (520 nm, <b>Cu<sub>8</sub>-1</b>) and red (625 nm, <b>Cu<sub>8</sub>-2</b>). This work not only provides a simple approach to achieve stimuli-induced isomerization between <b>Cu<sub>8</sub>-1</b> and <b>Cu<sub>8</sub>-2</b> but also offers an ideal platform for investigating their structure-property relationships.