High-temperature Raman spectra of dipeptide a-L-aspartyl-L-alanine crystal

Crystals of dipeptide & alpha;-L-aspartyl-L-alanine (& alpha;-Asp-Ala), C7H12N2O5, were studied under high-temperature conditions through vibrational spectroscopy (IR and Raman) and thermal analysis (Differential Scanning Calorimetry - DSC). From the analysis of the results, it is possible to conclude that: (i) the studied material undergoes a reversible order-disorder phase transition at 373 K on heating, where several changes were observed in the vibrational spectra, especially with vibrational modes of the units that participate directly of the hydrogen bonds; (ii) the phase transition undergone by the & alpha;-Asp-Ala crystal (about 373 K) involves changes in hydrogen bonds, possibly the rupture of at least one of them, and change in the conformation of the molecules in the unit cell.

Automated summary

The properties of C7H12N2O5 crystal were studied under high-temperature conditions using vibrational spectroscopy and thermal analysis techniques. The results showed that the material undergoes a reversible order-disorder phase transition at 373 K, where changes in the vibrational spectra, especially in the vibrational modes of the hydrogen bonds, were observed. The phase transition of the α-Asp-Ala crystal (around 373 K) involves changes in hydrogen bonds, possibly the rupture of at least one of them, and a change in the molecular conformation in the unit cell.