Assembling Smallest Prussian Blue Analogs Using Chiral Hydrogen Bond-Donating Unit toward Complete Phase Transition

Area of Science:

• Molecular assembly
• Supramolecular chemistry
• Materials science

Background:

• Developing functional materials requires precise control over molecular assembly.
• Existing methods often lack abrupt and complete phase transitions responsive to external stimuli.
• Hydrogen bonding is a key interaction in supramolecular chemistry.

Purpose of the Study:

• To develop novel switchable molecular assemblies with abrupt, complete phase transitions.
• To investigate the role of hydrogen bonding and chirality in controlling phase transitions.
• To explore new strategies for observing electron-transfer-coupled spin transitions.

Main Methods:

• Preparation of molecular assemblies by aggregating discrete, stimulus-unresponsive molecules.
• Utilizing chiral carboxylic acids to promote hydrogen bonding and phase transitions.
• Comparing the behavior of enantiopure and racemic hydrogen-bond donor (HBD) molecules.

Main Results:

• Novel switchable molecular assemblies exhibiting abrupt, complete phase transitions were developed.
• Enantiopure HBD molecules induced cooperative and abrupt phase transitions.
• Racemic HBD mixtures resulted in broad, incomplete transitions with observed structural disordering.
• A novel strategy for observing metal-to-metal electron-transfer-coupled spin transitions via hydrogen bonding was presented.

Conclusions:

• Chiral hydrogen bonding provides a powerful strategy for designing switchable molecular materials with tunable phase transition properties.
• The developed assemblies offer a new platform for stimuli-responsive materials and observing complex electronic phenomena.
• This work advances the understanding of structure-property relationships in supramolecular systems.