Integrated Anionic Zirconium-Organic Cage and Cationic Boron-Imidazolate Cage for Synergetic Optical Limiting

Making oppositely charged metal-organic cages (MOCs) into a tightly ordered structure may bring interesting functions. Herein, we report a novel structure composed of anionic (Zr4L6)8- (L=embonate) tetrahedral cages and in situ-formed cationic [Zn4(Bim)4]4+ (Bim=[BH(im)3]-; im=imidazole) cubic cages. Chiral transfer is observed from enantiopure (Zr4L6)8- cage to enantiopure [Zn4(Bim)4]4+ cage. A pair of enantiomers (PTC-373(Delta) and PTC-373(Lambda)) are formed. PTC-373 exhibits high chemical and thermal stabilities, affording an interesting single-crystal-to-single-crystal transformation. More importantly, the combination of ionic pair cages significantly enhances its third-order nonlinear optical property, and its thin-film exhibits an excellent optical limiting effect. Making anionic zirconium-organic cage and cationic boron-imidazolate cage into a tightly ordered structure achieves an efficient optical limiting response. image