Tailor-Made PdnL2n Metal-Organic Cages via Covalent Post-Synthetic Modification
Dong Luo, Zi-Jun Yuan, Lin-Jie Ping, Xiao-Wei Zhu, Ji Zheng, Chuang-Wei Zhou, Xian-Chao Zhou, Xiao-Ping Zhou, Dan Li
Post-synthetic modification (PSM) is an effective approach for tailored functionalization of metal-organic architectures, but its generalizability remains challenging. Herein we report a general covalent PSM strategy to functionalize the PdnL2n metal-organic cages (MOCs, n = 2, 12) via an efficient Diels−Alder cycloaddition between peripheral anthracene substituents and various functional motifs bearing a maleimide group. As expected, the solubility of functionalized Pd12L24 in common solvents could be greatly improved. Interestingly, concentration-depended circular dichroism and aggregation-induced emission could be achieved with chiral binaphthol (BINOL)- and tetraphenylethylene-modified Pd12L24, respectively. Furthermore, Pd12L24 could be introduced two different functional groups (e.g., chiral BINOL and achiral pyrene) through a step-by-step PSM route to obtain chirality-induced circularly polarized luminescence. Moreover, similar results were smoothly observed in a smaller Pd2L4 system.
PdnL2N, PSM, metal-organic cages