Cations Controlling the Chiral Assembly of Luminescent Atomically Precise Copper(I) Clusters

Abstract Chiral assembly and asymmetric synthesis are critically important for the generation of chiral metal clusters with chiroptical activities. Here, a racemic mixture of [K(CH 3 OH) 2 (18‐crown‐6)] + [Cu 5 (S t Bu) 6 ] − ( 1⋅CH 3 OH ) in the chiral space group was prepared, in which the chiral red‐emissive anionic [Cu 5 (S t Bu) 6 ] − cluster was arranged along a twofold screw axis. Interestingly, the release of the coordinated CH 3 OH of the cationic units turned the chiral 1⋅CH 3 OH crystal into a mesomeric crystal [K(18‐crown‐6)] + [Cu 5 (S t Bu) 6 ] − ( 1 ), which has a centrosymmetric space group, by adding symmetry elements of glide and mirror planes through both disordered [Cu 5 (S t Bu) 6 ] − units. The switchable chiral/achiral rearrangement of [Cu 5 (S t Bu) 6 ] − clusters along with the capture/release of CH 3 OH were concomitant with an intense increase/decrease in luminescence. We also used cationic chiral amino alcohols to induce the chiral assembly of a pair of enantiomers, [ d / l ‐valinol(18‐crown‐6)] + [Cu 5 (S t Bu) 6 ] − ( d / l ‐Cu 5V ), which display impressive circularly polarized luminescence (CPL) in contrast to the CPL‐silent racemic mixture of 1⋅CH 3 OH and mesomeric 1 .