A cross-shaped organic framework: a multi-functional template arranging chromophores

Area of Science:

• Organic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Investigating multi-functionalized chromophores is crucial for developing advanced optical materials.
• Designing versatile building blocks simplifies the synthesis of complex molecular architectures.

Purpose of the Study:

• To design and synthesize a universal cross-shaped organic framework as a template for multi-functionalized chromophores.
• To explore selective functionalization and characterization of the resulting compounds.
• To investigate intramolecular energy transfer in hybrid chromophore systems.

Main Methods:

• Synthesis of a cross-shaped building block with peripheral bromine and iodine atoms.
• Gram-scale synthesis via a five-step reaction including oxidative homo-coupling and macro-cyclization.
• Selective Suzuki cross-coupling reactions with various chromophore derivatives (methoxynaphthalene, naphthalimide, BODIPY).
• Chiral stationary phase High-Performance Liquid Chromatography (HPLC) for enantiomeric resolution.
• Electronic Circular Dichroism (ECD) spectroscopy and single-crystal X-ray diffraction for enantiomer assignment.

Main Results:

• Successful synthesis of a gram-scale, five-step universal cross-shaped building block.
• Selective functionalization yielded a library of bis- and tetra-substituted cross-shaped chromophore compounds.
• Enantiomeric resolution of racemic compounds and assignment of absolute configurations.
• Demonstration of intramolecular Förster Resonance Energy Transfer (FRET) in a hybrid naphthalimide/BODIPY system.

Conclusions:

• The developed cross-shaped building block is a versatile and easily functionalizable platform for chromophore research.
• This approach facilitates the study of diverse chromophore sets and their photophysical properties.
• The findings contribute to the design of novel functional organic materials with tailored optical characteristics.