Functionalized fluorescent terephthalate monomers and their attempted polyester formation.

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Terephthalate esters are versatile building blocks in organic synthesis.
• Macrocyclic compounds, such as crown ethers, are known for their host-guest chemistry.
• Fluorescent organic materials are crucial for various technological applications.

Purpose of the Study:

• To synthesize novel macrocyclic compounds and oligomers from functionalized terephthalate derivatives.
• To investigate the structural characteristics and properties of the synthesized molecules.
• To explore the potential of these compounds in fluorescence applications.

Main Methods:

• High-dilution cyclization reactions to form macrocycles.
• X-ray crystallography for structural determination of macrocycles.
• Transesterification and polymerization reactions to create oligomers.
• Spectroscopic analysis (absorption and fluorescence) to characterize optical properties.

Main Results:

• Two macrocyclic crown ether derivatives (1+1 and 2+2) were synthesized with isolated yields of 10% and 19%, respectively.
• X-ray structure of a 1+1 crown ether revealed its molecular architecture and weak ion-binding capabilities.
• Transesterification and subsequent polymerization yielded short oligomers (PolyM1-PolyM3) with solid-state fluorescence.
• Significant Stokes shift (15,627 cm-1) was observed for one monomer (M2) in solution, indicating unique photophysical behavior.

Conclusions:

• Novel macrocyclic crown ethers and fluorescent oligomers were successfully synthesized from terephthalate precursors.
• The synthesized macrocycles exhibit limited ion-binding capacity due to cavity size.
• The oligomers display promising solid-state fluorescence, with potential for tuning optical properties through structural modifications.