RESUMEN
Gas-phase solvation of halides by 1,3-butadiene has been studied via a combination of photoelectron spectroscopy and density functional theory. Photoelectron spectra for X- â¯(C4 H6 )n (X=Cl, Br, I where n=1-3, 1-3 and 1-7 respectively) are presented. For all complexes, the calculated structures indicate that butadiene is bound in a bidentate fashion through hydrogen-bonding, with the chloride complex showing the greatest degree of stabilisation of the internal C-C rotation of cis-butadiene. In both Cl- and Br- complexes, the first solvation shell is shown to be at least n = 4 ${n = 4}$ from the vertical detachment energies (VDEs), however for I- , increases in the VDE may suggest a metastable, partially filled, first solvation shell for n = 4 ${n = 4}$ and a complete shell at n = 6 ${n = 6}$ . These results have implications for gas-phase clustering in atmospheric and extraterrestrial environments.
RESUMEN
Halide-formic acid complexes have been studied utilising a combined experimental and theoretical approach. Formic acid exists as two conformers, distinguished by the relative rotation about the C-OH bond. Computational investigation of the formic acid isomerisation reaction between the two conformers has revealed the ability of halide anions to catalyse the formation of, and preferentially stabilise, the higher energy conformer. Anion photoelectron spectroscopy has been used to study the halide-formic acid complexes, with the experimental vertical detachment energies compared with simulated photodetachment energies with respect to halide complexes with both formic acid conformers. The existence of experimental spectral features associated with halide complexes of the higher energy formic acid confomer confirms in situ generation, likely as a result of the halide mediated catalytic formation.