Phase Transitions and Dynamics in Adamantane Derivatives

Adamantane derivatives display a rich variety of solid-state phase transitions that hinge on the interplay between rigid cage-like frameworks and functional substituents. The archetypal adamantane structure confers high symmetry and low molecular polarity, which in turn facilitates rotational freedom within the crystal lattice. Substituents such as hydroxyl, amino and halogen groups introduce hydrogen bonding, dipolar interactions and steric constraints, giving rise to sequential transitions between ordinary crystalline and so-called plastic crystalline phases, and occasionally to semiordered or intermediate regimes. These transitions often manifest as multiple endothermic events, each corresponding to distinct orientational ordering or disordering processes. The dynamic behaviour near transition points encompasses changes in dielectric permittivity, lattice phonon modes, boson peaks and rotational diffusion rates, as probed by calorimetry, dielectric spectroscopy, X-ray and neutron diffraction, and vibrational spectroscopies. Recent investigations have uncovered kinetic aspects of certain transitions, wherein isothermal annealing leads to the slow evolution of intramolecular dynamics and ionic conductivity. Computational studies and two-dimensional correlation spectroscopy have further delineated asynchronous molecular motions that underlie macroscopic thermodynamic signatures. Beyond fundamental interest, understanding these phase behaviours holds promise for designing stimuli-responsive materials, molecular rotors, solid electrolytes, drug polymorphs and advanced photonic devices where control of crystallinity and dynamics is paramount.

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Phase Transitions and Dynamics in Adamantane Derivatives publication trend

The graph below shows the total number of articles in phase transitions and dynamics in adamantane derivatives across all publications each year (not limited to Nature Index journals).

Technical terms

Phase transition: A change in the structural or dynamic state of a material, often marked by abrupt changes in enthalpy or symmetry.

Plastic crystal: A phase in which molecules retain lattice positions but exhibit significant rotational freedom.

Ordinary crystal: A fully ordered phase with fixed molecular orientations and minimal rotational mobility.

Dielectric permittivity: A measure of a material’s response to an applied electric field, reflecting dipolar and conductive processes.

Endothermic peak: An absorption of heat detected during a phase transition, as observed in calorimetric thermograms.

X-ray diffraction: A technique for determining atomic arrangements by measuring the scattering of X-rays from a crystal lattice.

References

1. Comparative studies on the nature and kinetics of phase transitions in plastic crystals: Hydrogen-bonded adamantane derivatives. Journal of Molecular Liquids (2024).
2. Studies on the nature and pressure evolution of phase transitions in 1-adamantylamine and 1-adamantanol. Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy (2023).
3. Unraveling the Complex Solid-State Phase Transition Behavior of 1‑Iodoadamantane, a Material for Which Ostensibly Identical Crystals Undergo Different Transformation Pathways. Crystal Growth & Design (2023).
4. Revisiting the Disorder–Order Transition in 1‑X-Adamantane Plastic Crystals: Rayleigh Wing, Boson Peak, and Lattice Phonons. The Journal of Physical Chemistry C (2021).