Abstract
The phenolṡN2 complex cation has been studied with a combination of two-color resonant zero kinetic energy (ZEKE) and mass analyzed threshold ionization (MATI) spectroscopies to probe the interaction of a polar cation with a quadrupolar solvent molecule. Extended vibrational progressions are observed in three modes which are assigned as the in-plane bend (35 cm-1), the stretch (117 cm-1), and in-plane wag (130 cm-1) intermolecular vibrations, and are consistent with a structure where the N2 forms a directional bond to the phenol OH group in the plane of the aromatic ring. Ab initio calculations at the UMP2/6-31G*, UHF/cc-pVDZ, and UMP2/cc-pVDZ levels of theory support this assignment. The spectra also provide a value for the adiabatic ionization energy (67423cm-1±4.5cm-1) and an estimate of the dissociation energy of the cluster (1650±20cm-1) which illustrate that the quadrupolar nitrogen molecule binds considerably more strongly to the phenol cation than a rare gas atom. These results constitute the first report of an aromaticṡN2 complex where the interaction can be described in terms of weak hydrogen bonding, rather than in terms of a van der Waals bond to the π-system of the benzene ring.
Original language | English |
---|---|
Pages (from-to) | 9244-9251 |
Number of pages | 8 |
Journal | Journal of Chemical Physics |
Volume | 109 |
Issue number | 21 |
DOIs | |
Publication status | Published - 1 Dec 1998 |