Dynamically Chiral Surfaces Using Photoresponsive Overcrowded Alkenes

Area of Science:

• Surface chemistry and supramolecular assembly
• Chirality and stereochemistry
• Molecular machines and photoresponsive materials

Background:

• Combining surface chirality with photoresponsiveness offers dynamic stereochemical properties.
• Tunable chiral recognition at interfaces is crucial for advanced material applications.
• Self-assembled molecular networks (SAMNs) provide a platform for confined molecular behavior.

Purpose of the Study:

• To develop dynamically chiral surfaces using molecular motors within SAMNs.
• To investigate the light-induced stereochemical transformations of molecular motors at interfaces.
• To demonstrate reversible control over surface chirality for tunable recognition.

Main Methods:

• Fabrication of SAMNs using overcrowded alkene-based molecular motors on highly oriented pyrolytic graphite.
• Utilized scanning tunneling microscopy (STM) with in situ irradiation to observe molecular behavior.
• Analyzed chiroptical properties and dynamic transformations under light stimuli.

Main Results:

• Molecular motors retained their chiroptical properties and dynamic behavior within the SAMN.
• Photoirradiation induced a reversible transition from homochiral (RP) to heterochiral (RP/RM) assembly.
• The heterochiral coassembly represents a light-triggered kinetic phase, reversible upon stimulus removal.

Conclusions:

• Molecular motion within SAMNs can be harnessed to create surfaces with switchable chirality.
• This strategy enables the design of interfaces with dynamically tunable chiral recognition capabilities.
• The reversible nature of the system highlights potential for responsive chiral materials.