Crystal Engineering of Ti₄(embonate)₆ Cage.

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Coordination Chemistry

Background:

• Discrete metal-organic cages (MOCs) are versatile supramolecular architectures with intrinsic porosity, offering advantages in processability and tunability over extended frameworks.
• Post-synthetic modification (PSM) of stable MOCs enables functionalization, expanding their application scope beyond direct synthesis limitations.
• Anionic coordination titanium tetrahedra (Ti4L6) cages, reported in 2017, possess unique structural features and active sites ideal for hierarchical assembly and PSM.

Purpose of the Study:

• To systematically summarize recent developments in the design, hierarchical assembly, and functional applications of titanium tetrahedra (Ti4L6) cages.
• To address the integration gap in the 'precursor design → hierarchical assembly → functional application' pipeline for Ti4L6 cages.
• To provide a conceptual framework for researchers in supramolecular chemistry and materials science.

Main Methods:

• Surface modification of Ti4L6 cages for catalysis and circularly polarized luminescence (CPL).
• Coordination-assembled cage-based frameworks derived from Ti4L6 for molecular recognition and separation.
• Supramolecular assembly (H-bonding/π-π stacking) of Ti4L6 cages for nonlinear optics (NLO).
• Template-directed synthesis of rare cage-supported MOFs using Ti4L6 for enhanced NLO properties.

Main Results:

• Demonstrated successful surface modification of Ti4L6 cages leading to applications in catalysis and CPL.
• Developed coordination-assembled frameworks and supramolecular assemblies from Ti4L6 cages for separation and NLO applications.
• Synthesized rare cage-supported MOFs utilizing Ti4L6 for enhanced NLO performance.

Conclusions:

• Ti4L6 cages serve as versatile precursors for hierarchical assembly and functionalization, bridging precursor design to application.
• The integration of precursor design, hierarchical assembly, and functional application is crucial for advancing Ti4L6 cage chemistry.
• Future research on Ti4L6 cages holds significant potential for innovation in supramolecular chemistry and materials science.