Dynamics-structure-properties relations to design functional molecular crystals

Functional properties of molecular crystals are often governed not only by static structure but also by collective lattice dynamics, including low-frequency vibrations, cooperative molecular motions, and soft phonon modes. Establishing clear dynamics-structure-properties relationships is therefore essential to move beyond empirical crystal engineering toward predictive material design. Recent advances in vibrational spectroscopy, in situ structural characterization, and multiscale molecular design enable direct access to these dynamic degrees of freedom and their rational modulation.
By integrating molecular and supramolecular engineering with external stimuli, such as temperature, pressure, and electric or electromagnetic fields, polymorphic energy landscapes can be reshaped on demand, reversible phase transitions can be programmed, and adaptive functionalities such as flexibility, self-healing, and tunable thermal and optoelectronic properties can be achieved. Representative examples illustrate how lattice dynamics can be elevated from a descriptive parameter to an active design variable, enabling the development of dynamic functional molecular crystals.