Combining a Titanium-Organic Cage and a Hydrogen-Bonded Organic Cage for Highly Effective Third-Order Nonlinear Optics.

Many metal-organic cages (MOCs) and a few hydrogen-bonded organic cages (HOCs) have been investigated, but little is reported about cooperative self-assembly of MOCs and HOCs. Herein, we describe an unprecedented MOC&HOC co-crystal composed of tetrahedral Ti L (L=embonate) cages and in-situ-generated [(NH ) (TIPA) ] (TIPA=tris(4-(1H-1,2,4-triazol-1-yl)phenyl)amine) cages. Chiral transfer is observed from the enantiopure Ti L cage to enantiopure [(NH ) (TIPA) ] cage. Two homochiral supramolecular frameworks with opposite handedness (PTC-235(Δ) and PTC-235(Λ)) are formed. Such MOC&HOC co-crystal features high stability in water and other solvents, affording single-crystal-to-single-crystal transformation to trap CH CN molecules and identify disordered NH cations. A tablet pressing method is developed to test the third-order nonlinear optical property of KBr-based PTC-235 thin film. Such a thin film exhibits an excellent optical limiting effect.