Benefiting from the strong inherent π-conjugation properties, the integration of Ti4L6 (L = embonate) cages and various N,N-chelated transition-metal cations into tightly packed structures accurately leads to high-performance materials with adjustable nonlinear optical (NLO) effects. These cage-based ionic pairs possess different supramolecular packing structures, including a π⋯π stacked porous framework where the Ti4L6 cages are tactically located at the channels. Interestingly, by introducing the large π-conjugated 1,10-phenanthroline type ligands and adjusting the aromatic ring electron cloud density, we have effectively regulated their third-order NLO properties, realizing nonlinear absorption responses from reverse saturated absorption (RSA) to saturated absorption (SA). This work not only presents an extraordinary coordination cage-based assembly, but also provides new insights into the function of cage materials.

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Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences