title: H-bond network in amino acid cocrystals with H2O or H2O2. The DFT study of serine-H2O and serine-H2O2.
abstract: The structure, IR spectrum, and H-bond network in the serine-H(2)O and serine-H(2)O(2) crystals were studied using DFT computations with periodic boundary conditions. Two different basis sets were used: the all-electron Gaussian-type orbital basis set and the plane wave basis set. Computed frequencies of the IR-active vibrations of the titled crystals are quite different in the range of 10-100 cm(-1). Harmonic approximation fails to reproduce IR active bands in the 2500-2800 frequency region of serine-H(2)O and serine-H(2)O(2). The bands around 2500 and 2700 cm(-1) do exist in the anharmonic IR spectra and are caused by the first overtone of the OH bending vibrations of H(2)O and a combination vibration of the symmetric and asymmetric bendings of H(2)O(2). The quantum-topological analysis of the crystalline electron density enables us to describe quantitatively the H-bond network. It is much more complex in the title crystals than in a serine crystal. Appearance of water leads to an increase of the energy of the amino acid-amino acid interactions, up to ~50 kJ/mol. The energy of the amino acid-water H-bonds is ~30 kJ/mol. The H(2)O/H(2)O(2) substitution does not change the H-bond network; however, the energy of the amino acid-H(2)O(2) contacts increases up to 60 kJ/mol. This is caused by the fact that H(2)O(2) is a much better proton donor than H(2)O in the title crystals.
authors: Department of Quantum Chemistry, Mendeleev University of Chemical Technology, Moscow, Russia. mikhail.vener@gmail.com
authors: Mikhail V
authors: MV
authors: Vener
authors: Alexander G
authors: AG
authors: Medvedev
authors: Andrei V
authors: AV
authors: Churakov
authors: Petr V
authors: PV
authors: Prikhodchenko
authors: Tatiana A
authors: TA
authors: Tripol'skaya
authors: Ovadia
authors: O
authors: Lev
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D003460:Crystallization; D006860:Hydrogen Bonding; D006861:Hydrogen Peroxide / Q000737:chemistry*; D011789:Quantum Theory; D012694:Serine / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D014867:Water; D012694:Serine; D006861:Hydrogen Peroxide