Optically active Ag(i): o-OPE helicates using a single homochiral sulfoxide as chiral inducer

Area of Science:

• Supramolecular chemistry
• Organic chemistry
• Chiroptical spectroscopy

Background:

• Oligo ortho-phenylene ethynylenes (o-OPEs) are known for their unique structural and electronic properties.
• Controlling the folding and helical sense of foldamers is crucial for developing advanced functional materials.
• Chiral auxiliaries can direct the self-assembly of molecular architectures.

Purpose of the Study:

• To investigate the ability of an enantiopure sulfoxide group to induce helical folding in o-OPEs.
• To synthesize and characterize a series of o-OPE foldamers.
• To study the structural and chiroptical changes upon silver(I) coordination.

Main Methods:

• Synthesis and full characterization of o-OPE foldamers.
• Nuclear Magnetic Resonance (NMR) spectroscopy.
• UV-Vis absorption, Vibrational Circular Dichroism (VCD), and Electronic Circular Dichroism (ECD) measurements.
• Quantum mechanical Density Functional Theory (DFT) calculations.

Main Results:

• A simple enantiopure sulfoxide group successfully promoted folding of o-OPEs with a single helical sense.
• A family of foldamers with up to seven triple bonds was synthesized and characterized.
• Ag(I) coordination led to significant changes in the structure and chiroptical properties, consistent with experimental data and DFT calculations.

Conclusions:

• Enantiopure sulfoxide groups are effective directing units for achieving one-handed helical folding in o-OPE foldamers.
• Silver(I) coordination provides a means to modulate the conformational and chiroptical behavior of these foldamers.
• The combination of experimental techniques and computational modeling validates the observed structure-property relationships.