Externally and Internally Functionalized Copper(II) β-Diketonate Molecular Squares

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Bis(β-diketones) are versatile ligands in coordination chemistry.
• Copper(II) complexes can form intricate supramolecular structures.
• Functionalization of ligands influences complex properties and applications.

Purpose of the Study:

• To synthesize and characterize novel functionalized bis(β-diketones).
• To investigate the formation and properties of copper(II) molecular squares derived from these ligands.
• To explore the structural characteristics and guest-binding capabilities of the resulting molecular squares.

Main Methods:

• Organic synthesis of five new bis(β-diketones.
• Coordination of bis(β-diketones) with Cu(II) ions to form molecular squares.
• Single-crystal X-ray diffraction analysis of empty and guest-loaded molecular squares.

Main Results:

• Successful synthesis of five functionalized bis(β-diketones) with varying substituents (alkyl chains, alkoxy groups).
• Formation of four new Cu(II) molecular squares with distinct solubility profiles.
• Structural characterization revealing Cu···Cu distances ranging from 14.047 to 14.904 Å in empty squares and wider variations in guest adducts.

Conclusions:

• The nature and position of substituents on bis(β-diketones) significantly impact the solubility and structural properties of Cu(II) molecular squares.
• The synthesized molecular squares demonstrate potential for encapsulating various guest molecules (e.g., polypyridines, fullerenes).
• This work expands the library of functionalized molecular squares for potential applications in host-guest chemistry and materials science.