An Alternate [2×2] Grid Constructed Around TiO₄ N₂ Units

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Titanium alkoxides and nitrogen-containing ligands are key building blocks in coordination chemistry.
• Self-assembly offers a powerful route to construct complex molecular architectures.
• Understanding ligand effects is crucial for controlling self-assembly outcomes.

Purpose of the Study:

• To report the formation and structural characterization of a novel tetranuclear titanium self-assembled species.
• To investigate the stability of different isomeric tetrameric assemblies using computational methods.
• To evaluate the influence of different nitrogen ligands on the self-assembly process.

Main Methods:

• Synthesis of a tetranuclear titanium complex using Ti(Oⁱ Pr)₄, 2,2'-bipyrimidine (bpym), and a bis-biphenol ligand (L² H₄).
• Solid-state structural characterization of the resulting [Ti₄ (L² )₄ (bpym)₄] architecture.
• Density Functional Theory (DFT) calculations for geometry optimization and stability analysis of various isomers.
• Theoretical evaluation of ligand competition using different diimine chelates (bipy, bipyraz).

Main Results:

• Formation of an unprecedented chiral alternate [2×2] grid architecture, [Ti₄ (L² )₄ (bpym)₄].
• DFT calculations confirm the superior stability of the alternate [2×2] grid over other isomers.
• CH⋅⋅⋅N interactions are identified as the driving force for the exclusive formation of the alternate [2×2] grid.

Conclusions:

• The study successfully synthesized and characterized a novel chiral tetranuclear titanium grid.
• Computational analysis highlights the stability of the alternate [2×2] grid and the role of non-covalent interactions.
• The findings provide a foundation for understanding and controlling self-assembly processes through ligand design.