Interaction of simple amino acids (glycine, α-alanine, β-alanine and L-valine) with germatranol hydrate

• Germatranyl glycinate, alaninates, and valinate are studied by IR and NMR. • Structures of molecular conformations are optimized by DFT methods. • Two most stable conformations differ in the orientation of the NH 2 group to Ge. Aminocarboxygermatanes were synthesized by the reaction of germatranol hydrate [HOGeN(CH 2 CH 2 O) 3 ]H 2 O with simple amino acids (glycine, α-alanine, β-alanine and L-valine) and characterized by the IR and 1 H, 13 C NMR spectroscopy. Equilibrium structures of corresponding molecules were obtained by the ωB97X-D DFT and B3LYP/ 6–31+ G (d) methods. For molecules with amino residues H 2 N CHR-COO − (R H, Me, i -Pr), i.e. germatranyl glycinate ( I ), α-alaninate ( II ), and L- valinate ( IV ) two low-lying isomers were located at their potential energy surfaces (PES). In β -alaninate ( III) only one isomer was located. The IR spectra of I and II evidence the presence of two isomers in the species discussed, however the amount of the second isomer significantly decrease on going from I to II .