Reversible Transformation between 0D Cluster and 1D Chain with Luminescence and Dielectric Dual Switching in Two New Decanuclear Copper(I) Iodide Halides

Low-dimensional emissive Cu(I) halides have garnered extensive attention owing to their structural diversity and unique, structure-dependent photophysical properties. Nevertheless, achieving structural transitions with switchable physical properties remains a formidable challenge for high-nuclearity Cu(I) halides, and reported zero-dimensional (0D) to one-dimensional (1D) structural dimensionality transformations are extremely scarce. Herein, two decanuclear Cu(I) iodide halides, namely [Pr 2 -DABCO] 5 [Me 2 NH 2 ]Cu 10 I 20 I·(MeCN) 2 ( 1 ) and [Pr 2 -DABCO] 3 [Me 2 NH 2 ]Cu 10 I 17 ( 2 ) ([Pr 2 -DABCO] 2+ = N, N ′-dipropyl-1,4-diazabicyclo-[2.2.2]octan-1-ium cation; [Me 2 NH 2 ] + = dimethylamine cation; MeCN = acetonitrile) are synthesized. Compound 1 features isolated [Cu 10 I 20 ] 10– clusters, while 2 exhibits infinite 1D [Cu 10 I 17 ] n 7n– chains, and both represent rare structural prototypes among the reported Cu(I) iodide clusters. Remarkably, a reversible structural transformation between 1 and 2 is achieved, accompanied by a high-contrast emission color change from a weakly orange-emissive 0D phase to a bright green-emissive 1D structure. Compound 2 exhibits a 3-fold enhancement in the photoluminescence quantum yield (PLQY), reaching a maximum value of 74.59%. Impressively, 2 also enables high-contrast, stable, and reversible dielectric “silent → active” switching owing to the order–disorder transition of organic [Me 2 NH 2 ] + cations. This work reports two decanuclear Cu(I) halides, capable of reversible 0D/1D structural interconversion, which enables dual optical and dielectric bistable switching, providing a new platform for the design and fabrication of multifunctional responsive materials.