AIE Triggers the Circularly Polarized Luminescence of Atomically Precise Enantiomeric Copper(I) Alkynyl Clusters

Abstract

Atomically precise enantiomeric metal clusters are scarce, and copper(I) alkynyl clusters with intense circularly polarized luminescence (CPL) responses have not been reported. A pair of chiral alkynyl ligands, (R/S)‐2‐diphenyl‐2‐hydroxylmethylpyrrolidine‐1‐propyne (abbreviated as R/S‐DPM) we successfully prepared and single crystals were characterized of optically pure enantiomeric pair of atomically‐precise copper(I) clusters, [Cu14(R/S‐DPM)8](PF6)6 (denoted as R/S‐Cu14), which feature bright red luminescence and CPL with a high luminescence anisotropy factor (glum). A dilute solution containing R/S‐Cu14 was nonluminescent and CPL inactive at room temperature. Crystallization‐ and aggregation‐induced emission (CIE and AIE, respectively) contribute to the triggering of the CPL of R/S‐Cu14 in the crystalline and aggregated states. Their AIE behavior and good biocompatibility indicated applications of these copper(I) clusters in cell imaging in HeLa and NG108‐15 cells.

Copper nanoclusters: designed synthesis, structural diversity, and multiplatform applications

“…In this regard, Shuang-Quan Zang and co-workers reported the synthesis of atomically precise [Cu14(R/S-DPM)8](PF6)6 cluster with strong CD and CPL properties. 173 In CD spectra the mirrorimage signals in the range of 300-460 nm contain additional Please do not adjust margins Please do not adjust margins signals different from pure ligand, indicating the chirality transfer from the ligand to the core. In addition, this is the first report on CPL-active atomically precise CuNCs.…”

Beyond Chiral Organic (p-Block) Chromophores for Circularly Polarized Luminescence: The Success of d-Block and f-Block Chiral Complexes

“…Regarding this last point, a favorable situation for an emissive 3d metal excited level requires (i) a minimum perturbation by the ligand field in order to retain the almost pure d–d character of the transition and (ii) an important energy gap with upper excited levels in order to prevent deleterious back inter system crossing (BISC). Because of those sophisticated conditions, the use of first-row metals is mainly restricted to closed shell ions with d 10 configuration, such as Zn II complexes showing ligand-based emission (Isla et al, 2016 ; Kögel et al, 2016 ; Aoki et al, 2017 ; Reiné et al, 2018b ; Maeda et al, 2019 ), or in Cu I complexes displaying MLCT emission (Zhang M.-M. et al, 2019 ; Deng et al, 2020 ). In the first case, the Zn II ions are responsible, upon their coordination to an organic ligand, for conformational changes affecting the optical and chiroptical properties, particularly in the CPL emission.…”

Spontaneous Resolution of Chiral Multi-Thiolate-Protected Ag30 Nanoclusters

“…As shown in Figure 5 c and Figure S16 , the obvious symmetric CPL response of the enantiomeric conglomerates appears in the same wavelength region with a dissymmetry factor of | g lum | = 7.0 × 10 –4 , which is comparable to those of the reported metal nanoclusters. 44 , 45 …”