Structures,vibrational frequencies,topologies, and energies of hydrogen bonds in cysteine‐formaldehyde complexes |
| |
Authors: | Lei Yu Yuhua Wang Zhengguo Huang Hongke Wang Yumei Dai |
| |
Institution: | 1. Tianjin Key Laboratory of Structure and Performance for Functional Molecules, College of Chemistry, Tianjin Normal University, Tianjin 300387, People's Republic of China;2. College of Materials Science and Engineering, Shijiazhuang Tiedao University, Hebei, Shijiazhuang 050043, People's Republic of China |
| |
Abstract: | The hydrogen bonding interactions between cysteine (Cys) and formaldehyde (FA) were studied with density functional theory regarding their geometries, energies, vibrational frequencies, and topological features of the electron density. The quantum theory of atoms in molecules and natural bond orbital analyses were employed to elucidate the interaction characteristics in the Cys‐FA complexes. The intramolecular hydrogen bonds (H‐bonds) formed between the hydroxyl and the N atom of cysteine moiety in some Cys‐FA complexes were strengthened because of the cooperativity. Most of intermolecular H‐bonds involve the O atom of cysteine/FA moiety as proton acceptors, while the strongest H‐bond involves the O atom of FA moiety as proton acceptor, which indicates that FA would rather accept proton than providing one. The H‐bonds formed between the CH group of FA and the S atom of cysteine in some complexes are so weak that no hydrogen bonding interactions exist among them. In most of complexes, the orbital interaction of H‐bond is predominant during the formation of complex. The electron density (ρb) and its Laplace (?2ρb) at the bond critical point significantly correlate with the H‐bond parameter δR, while a linearly relationship between the second‐perturbation energy E(2) and ρb has been found as well. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012 |
| |
Keywords: | hydrogen bond quantum theory of atoms in molecules (QTAIM) natural bond orbital (NBO) cysteine formaldehyde |
|
|