title: A theoretical study of the photodetachment and intramolecular hydrogen-bonding energies of hydrogen maleate anions.
abstract: Three low-lying conformers of the hydrogen maleate anions (HMAs) regarding cis-HMA(HB) having the O-...HO intramolecular hydrogen bond (HB), cis-HMA(nHB) without the HB, and trans-HMA are studied by density functional theory (B3LYP) combined with natural bond orbital (NBO) and atoms-in-molecules (AIM) analyses. The photoelectron spectra of cis- and trans-HMA conformers recorded by Woo et al. (J. Phys. Chem. A 2005, 109, 10633) are reassigned on the basis of the present electron propagator theory calculations, indicating the significant energy differences between the Dyson orbitals and canonical molecular orbitals due to the electron-correlation and orbital relaxation effects considered in the electron propagator theory. The NBO associated with the natural resonance theory analyses and AIM electron topological study show that the strong O-...HO in cis-HMA(HB) has the remarkable characteristics of three-center four-electron hyperbond, and the bonding strength of ca. 30 kcal/mol is recommended with the reference calculations of the HO-...HOH complex. The further calculations for the microhydrated cis-HMA(HB) clusters indicate that the O-...HO bonding strength decreases in water solution.
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China. sxtian@ustc.edu.cn
authors.forename: Shan Xi
authors.initials: SX
authors.lastname: Tian
authors.forename: Hai-Bei
authors.initials: HB
authors.lastname: Li
mesh_terms: D000838:Anions; D006860:Hydrogen Bonding; D008298:Maleates / Q000737:chemistry*; D008962:Models, Theoretical; D010777:Photochemistry
chemical_list: D000838:Anions; D008298:Maleates; C030272:maleic acid