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 (gin) 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 P-31, H-1 and of pure and treated compounds were recorded at room temperature and interpreted. A lift of degeneracies of the v(4) 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 C-13 MAS NMR. These observations indicate that the host-additives interactions were achieved. (c) 2013 Elsevier B.V. All rights reserved.