Combining a Titanium–Organic Cage and a Hydrogen‐Bonded Organic Cage for Highly Effective Third‐Order Nonlinear Optics

• Published in: Angewandte Chemie International Edition Vol. 60; no. 6; pp. 2920 - 2923
• Main Authors: He, Yan‐Ping, Chen, Guang‐Hui, Li, De‐Jing, Li, Qiao‐Hong, Zhang, Lei, Zhang, Jian
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 08.02.2021
• Edition: International ed. in English
• Subjects: Ammonia; Cages; Cations; Crystals; Handedness; metal–organic cages; Nonlinear optics; Optical properties; Optics; self-assembly; Supramolecular frameworks; Thin films; Titanium; nonlinear optics; self-assembly; metal-organic cages; titanium
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202013977

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 Ti4L6 (L=embonate) cages and in‐situ‐generated [(NH3)4(TIPA)4] (TIPA=tris(4‐(1H‐1,2,4‐triazol‐1‐yl)phenyl)amine) cages. Chiral transfer is observed from the enantiopure Ti4L6 cage to enantiopure [(NH3)4(TIPA)4] 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 CH3CN molecules and identify disordered NH4+ 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. The supramolecular self‐assembly between metal–organic cages (MOCs) and hydrogen‐bonded organic cages (HOCs) is realized in an MOC&HOC co‐crystal composed of tetrahedral Ti4L6 cages and [(NH3)4(TIPA)4] cages generated in situ. The MOC&HOC co‐crystal thin film exhibits an excellent optical limiting effect.