Investigating Phase Transitions in 1-Adamantylamine and 1-Adamantanol

A recent study published in the Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy showcases the unique properties of phase transitions in 1-adamantylamine (1-NH₂-ADM) and 1-adamantanol (1-OH-ADM) (1). The research team demonstrated through their findings about how their behavior changes under different conditions.

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1-NH₂-ADM and 1-OH-ADM are important compounds that are important building blocks in pharmaceutical synthesis, enabling the development of biologically active compounds for various therapeutic purposes (1). These compounds can undergo phase transitions, which makes them valuable in materials science (1). 1-NH₂-ADM and 1-OH-ADM are used to design materials with tailored properties for applications in optoelectronics, sensors, and energy storage devices (1). These compounds can also work as corrosion inhibitors, which means that they can protect metal surfaces from degradation (1). As a result, these compounds are valuable in several key industries, including aerospace, petroleum, and automotive.

The research team sought to investigate the phase transitions of 1-NH₂-ADM and 1-OH-ADM in their study. To do this, the scientists employed various experimental techniques, including Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, differential scanning calorimetry (DSC), and broadband dielectric spectroscopy (1). The differential scanning calorimetry measurements revealed different thermal behaviors, with one endothermic peak observed for 1-OH-ADM and three for 1-NH₂-ADM (1).

By using spectroscopic analysis, the researchers learned more about thermal events in the compounds under study. In particular, their findings revealed that the thermal events in 1-NH2-ADM corresponded to transitions between different plastic crystal (PC) phases (I, II, III, IV), while the endothermic process in 1-OH-ADM indicated a phase transition between the PC and the ordinary crystal (OC) (1).

Notably, the dielectric studies conducted under both ambient and high-pressure conditions yielded interesting results. The researchers observed significant changes in the complex dielectric permittivity at temperatures corresponding to the detected endothermic events (1). Moreover, fluctuations in the dielectric properties were observed at pressures associated with the respective phase transitions (1).

The pressure coefficients of the phase transition temperatures were found to be approximately 0.2 K/MPa for both 1-NH₂-ADM and 1-OH-ADM, indicating their sensitivity to external pressure (1). Additionally, the volume variation (ΔV) at the PC (II)-PC (III) and PC (III)-PC (IV) transition temperatures in 1-NH₂-ADM differed significantly from the ΔV observed during the PC-OC transition in 1-OH-ADM (1).

These comprehensive experimental investigations enhanced our understanding of the phase behavior of 1-adamantylamine and 1-adamantanol. The results provide valuable insights into the structural changes and properties of these compounds during phase transitions, and their sensitivity to pressure variations (1). The research conducted offers a significant contribution to the scientific community's knowledge of these compounds. Further research and exploration in the field of phase transitions and their applications in diverse industries is needed to fully realize how valuable these compounds could be.

Reference

(1) Jesionek, P.; Hachula, B.; Heczko, D.; Lamrani, T.; Jurkiewicz, K.; Tarnacka, M.; Ksiazek, M.; Kaminski, K.; Kaminska, E. Studies on the nature and pressure evolution of phase transitions in 1-adamantylamine and 1-adamantanol. Spectrochimica Acta Part A: Mol. Biomol. Spectrosc. 2023, 299, 122794. DOI: 10.1016/j.saa.2023.122794