title: Incorporation of ROH (R = CH3, C2H5, 2-C3H7) into (H2O)6(-): substituent effect on the growth process of the hydrogen-bond network.
abstract: The condensation reaction of water cluster anions, (H2O)n(-) + H2O → (H2O)n+1(-), offers a prime opportunity to explore the growth process of the hydrogen-bond network involving molecular uptake and network rearrangement. Here, by exploiting an Ar-mediated approach, we investigate the association reaction of water hexamer anions, (H2O)6(-), with ROH (R = CH3, C2H5, 2-C3H7) by mass spectrometry combined with photoelectron spectroscopy. Quantitative analysis of the product mass spectra reveals that incorporation of ROH (R = CH3, C2H5) into (H2O)6(-) occurs with a cross section of the same size as in the (H2O)6(-) + D2O condensation, but with a slightly smaller cross section for R = 2-C3H7. Coexistence of two types of isomers, high electron-binding (type I) and low electron-binding (type II) forms, is observed in all the product ROH·(H2O)6(-) species by photoelectron spectroscopic measurement. These findings, in conjunction with ab initio study of MeOH·(H2O)6(-) structures, lead us to propose a molecular uptake mechanism at play in the incorporation of ROH into the (H2O)6(-) network. This also provides complementary information on the homogeneous condensation process of pure water cluster anions.
authors.affiliation: Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo , Komaba, Meguro-ku, Tokyo 153-8902, Japan.
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Nakanishi
authors.forename: Takashi
authors.initials: T
authors.lastname: Nagata