Cd(Gly-L-Phe)₂ metal-peptide frameworks evolution under high pressure conditions

Metal-peptide frameworks (MPFs) have gained considerable attention due to their advantages and properties, particularly in the field of biomedicine. In the current study in situ synchrotron powder X-ray diffraction (XRD) and Raman spectroscopy measurements under high pressure-room temperature conditions were conducted on Cd(Gly-L-Phe)₂ MPFs. The compound crystallizes in a monoclinic structure from C2 space group. Computational calculations were performed to assign the vibrational modes, yielding good agreement with the experimental data. High-pressure XRD analysis showed no structural phase transition, but hinted at a possible conformational change. After compression in the Raman spectroscopy experiment, vibrational analysis suggests a conformational rearrangement of Cd(Gly-L-Phe)₂ in the 1-2 GPa pressure range, corroborating the changes observed in the high-pressure XRD analysis. Upon decompression, the changes in the Cd(Gly-L-Phe)₂ sample proved to be reversible. These investigations contribute to a better understanding of the behavior of MPFs under pressure, which is highly relevant for their potential applications in the biomedical field.