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

Aminocarboxygermatanes were synthesized by the reaction of germatranol hydrate [HOGeN(CH2CH2O)3]H2O with simple amino acids (glycine, α-alanine, β-alanine and L-valine) and characterized by the IR and 1H, 13C 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 H2NCHR-COO− (RH, 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.