Growth and spectroscopy studies of ADP single crystals with l-glutamine and l-cysteine amino acids

Ammonium dihydrogen orthophosphate (ADP) crystals were grown with l-glutamine C₅H₁₀N₂O₃ (gln) and l-cysteine C₃H₇NO₂S (cys) amino acids, with polar side-chains, as additives at 4% molar concentrations. X-ray diffractograms, vibrational FT-IR, and Raman and NMR MAS of ³¹P, ¹H and of pure and treated compounds were recorded at room temperature and interpreted. A lift of degeneracies of the ν₄ asymmetric bending modes of both PO₄ and NH₄ tetrahedron species, as well as a shift of the wavenumbers of some of their internal modes was observed. At the same time, some characteristic vibrational modes of the organic molecules appeared. However, NMR results show a little shift of the resonance of the phosphorus and hydrogen nucleus, associated with some shoulders for this latter. The presence of the organic molecules was also revealed by ¹³C MAS NMR. These observations indicate that the host-additives interactions were achieved.