摘要
Chiral metal-organic clusters(cMOCs)are characterized by diverse chiral origins,tunable luminescence,and multifunctionality.Among them,chiral aluminum oxo clusters(AlOCs)exhibit unique advantages in terms of resource sustainability and environmental friendliness compared to other cluster materials.Nevertheless,the simultaneous achievement of precise enantiomeric control and optical response within AlOCs remains a critical challenge to be addressed in the field.Herein,we achieve precise control over the transition from chirality to circularly polarized luminescence properties in AlOCs by leveraging their highly flexible and modifiable coordination surfaces through a stepwise ligand functionalization strategy.We employed the Al2cluster as a platform with programmable surface coordination sites and introduced classical chiral L/D-valine molecules.We successfully constructed four pairs of alcohol-coordinated pure chiral enantiomers(AlOC-189-L/D-MeOH,EtOH,PrOH,and PDO).Absolute helical structures can be identified in the supramolecular architectures of clusters,achieving unambiguous chirality transfer from chiral ligands to chiral clusters and further to absolute helical superstructures.Hierarchical ligand modification,endowed with a top-down design paradigm,offers a rational and feasible route to cluster functionalization.Based on the excellent replaceability of the Al_(2)cluster's surface coordination sites,we achieved chiral-luminescent bifunctional coupling by partially substituting the chiral ligands withπ-conjugated naphthyl-based luminophores(HNA/HNN),yielding two new classes of enantiomers(AlOC-190-L/D-HNA and AlOC-190-L/D-HNN)exhibiting bright yellow-green photoluminescence(PL).DFT calculations reveal that this is attributed to a ligand-to-ligand charge transfer(LLCT)luminescence mechanism.Notably,AlOC-190-L/D-HNN exhibited promising circularly polarized luminescence(CPL)activity via the synergy between chiral induction from L/D-valine ligands and intermolecular charge transfer of the HNN ligands.This work not only highlights the highly designable coordination chemistry of AlOC-enabling on-demand integration of specific functionalities through modular ligand substitution-but also establishes a novel"ligand editing"paradigm for developing multifunctional chiral optical materials.
基金
supported by the National Natural Science Foundation of China(22371278,92261108,92061104)
the Natural Science Foundation of Fujian Province(2021J06035)
the Fujian Provincial Department of Science and Technology(#2023T3081)
the Youth Innovation Promotion Association Chinese Academy of Sciences(Y2021081).
