Evidence For a Water-Stabilised Ion Radical Complex: Photoelectron Spectroscopy and Ab Initio Calculations

Abstract

A photoelectron spectrum corresponding to an unknown 174m/z anion complex has been recorded. Initially believed to be I−…CH3CH2OH (173m/z), the spectrum has been assigned as belonging to that of an I−…H2O…CH3CH2 radical anion complex. The major peaks in the photoelectron spectrum occur at 3.54eV and 4.48eV as the 2P3/2 and 2P1/2 spin-orbit states of iodine respectively. Ab initio calculations were performed in order to rationalise the existence of the complex, with all structures converging to a ‘ring-like’ geometry, with the iodide anion bound to both the water molecule as well as a hydrogen of the ethyl radical, with the other hydrogen of water bound to the unpaired electron site of the ethyl. Simulated vertical detachment energies of 3.59eV and 4.53eV were found to be in agreement with the experimental results.

Spectroscopic Investigation of Chalcogen Bonding: Halide–Carbon Disulfide Complexes

“…[30][31][32] Details associated with the experimental and computational methods have been provided in the Supporting Information. The relative agreement between calculated electron binding energies and their experimental counterparts has been established in previous publications, [26,[32][33][34][35] and will be reiterated in the current work.…”

Noncovalent chalcogen and tetrel bonding interactions: Spectroscopic study of halide–carbonyl sulfide complexes

“…In addition, the experimental data are rationalized by high-level theoretical structures of the dimer and trimer halide-carbonyl sulfide complexes, with CCSD(T) energetics extrapolated to the complete basis set limit. The relative agreement observed between experimental photoelectron peaks and the corresponding peaks determined utilizing ab initio calculations has been demonstrated in previous publications; 43,[61][62][63][64][65] this agreement allows inference of the structural motif responsible for the experimental spectra.…”

Photoelectron Spectroscopy and High-Level Ab Initio Calculations of the Iodide–Methylperoxy Radical Complex

“…45 The E stab value also serves as a good proxy to infer the strength of the electrostatic interaction as these interactions dominate the binding of anion van der Waals complexes. By this metric, the iodide−methylperoxy complex (E stab = 0.40 eV) is similarly bound compared to other iodide−molecule complexes, with values of 0.40, 0.41, 0.48, and 0.44/0.43 eV for 48 and 41,4941,49 respectively. also corresponds in mass to CH 3 IO 2 − ; however, experiments where they have been observed required addition of these solvent molecules to the gas mixture in similar quantities as the halide precursor.…”