Negative area compressibility of a hydrogen-bonded two-dimensional material

Area of Science:

• Materials Science
• Crystallography
• Supramolecular Chemistry

Background:

• Negative area compressibility (NAC) is a rare phenomenon where materials expand in two dimensions under applied pressure.
• Existing NAC materials are primarily 2D crystals linked by coordination bonds, limiting exploration of other 2D systems.
• NAC materials are highly sought after for applications in pressure sensors and actuators due to their unique mechanical response.

Purpose of the Study:

• To report the discovery and characterization of a novel hydrogen-bonded 2D supramolecular coordination complex with significant negative area compressibility (NAC).
• To elucidate the microscopic mechanism responsible for the observed NAC phenomenon in the new material.
• To explore the potential applications of this NAC material in pressure-sensing technologies.

Main Methods:

• Synthesis and characterization of a hydrogen-bonded 2D supramolecular coordination complex, Zn(CH3COO)2·2H2O.
• Investigation of the material's mechanical response under varying pressure conditions (0.15-4.44 GPa).
• Analysis of the interplay between intra-layer coordination, hydrogen bonding, and inter-layer van der Waals forces contributing to NAC.

Main Results:

• The synthesized Zn(CH3COO)2·2H2O complex exhibits large negative area compressibility (NAC) over an extended pressure range.
• The NAC phenomenon occurs without any phase transitions, indicating a robust and stable response.
• The mechanism involves a synergistic cooperation of intra-layer and inter-layer interactions.

Conclusions:

• Hydrogen-bonded 2D supramolecular coordination complexes can exhibit significant negative area compressibility (NAC).
• The discovered material, Zn(CH3COO)2·2H2O, presents a novel class of NAC materials.
• These NAC crystals hold promise for developing ultrasensitive pressure-converting materials for advanced sensor applications.