Reactions of Large Water Cluster Anions with Hydrogen Chloride:  Formation of Atomic Hydrogen and Phase Separation in the Gas Phase

Abstract

The reactions of water cluster anions (H2O)n-, n = 30-70, with hydrogen chloride have been studied by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. The first HCl taken up by the clusters is presumably ionically dissolved. The solvated electron recombines with the proton, which is thereby reduced to atomic hydrogen and evaporates from the cluster. This process is accompanied by blackbody radiation and collision induced loss of water molecules. Subsequent collisions lead to uptake of HCl and loss of H2O, yielding mixed clusters Cl-(HCl)m(H2O)n until they are saturated with HCl. Those saturated clusters lose H2O and HCl in a characteristic sequence. The final stage of the reaction, involving clusters with m = 0-4 and n = 0-6, is studied in detail with density functional theory calculations. The Cl-(HCl)4(H2O)6 cluster represents an example for supramolecular self-organization in the gas phase: it consists of a tetrahedral Cl-(HCl)4, connected on one side of the tetrahedron to a compact water hexamer.

Reduction of Acetonitrile by Hydrated Magnesium Cations Mg+(H2O)n (n≈20–60) in the Gas Phase

“…As shown previously for HCl, O 2 , and CO 2 , [10,22,23,39] this reflects the reactivity of the hydrated electron (H 2 O) n À , which in collisions with acetonitrile reacts to form OH À (H 2 O) m . [25] In principle, uptake of CH 3 CN could also trigger the formation and elimination of a hydrogen atom, but the required selective evaporation of CH 3 CN to rationalize the exclusive formation of MgOH + (H 2 O) m is, in view of the high efficiency of reaction (2), highly improbable.…”

Communication: Charge transfer dominates over proton transfer in the reaction of nitric acid with gas-phase hydrated electrons

“…Second, the energetics of the reaction can be probed using the concept of nanocalorimetry, [7][8][9] i.e., by detecting the number of evaporating water molecules when the reaction takes place. The analogous reaction of (H 2 O) n with HCl was studied by Siu et al 10 As HCl is a very strong acid, proton transfer prevails. Upon uptake of HCl by the (H 2 O) n clusters (n = 30-70), HCl dissociates, and the electron recombines with the proton.…”

Mass spectrometry of aerosol particle analogues in molecular beam experiments

“…The reactions of HCl with hydrated electron was interpreted as acidic dissociation of HCl on the cluster and subsequent recombination of the proton with the electron, yielding the H‐atom which left the cluster and (H 2 O) n Cl − anion was observed . Hydrated cluster anions, such as (H 2 O) n O − , (H 2 O) n OH − , (H 2 O) n or (H 2 O) n C, also yielded (H 2 O) n Cl − cluster ions upon reactions with HCl which was again interpreted as proton transfer from the acid to the anion .…”

“…[99][100][101]127 The reactions of HCl with hydrated electron H 2 O ð Þ À n was interpreted as acidic dissociation of HCl on the cluster and subsequent recombination of the proton with the electron, yielding the H-atom which left the cluster and (H 2 O) n Cl − anion was observed. 265 Hydrated cluster anions, such as (H 2 O) n O − , (H 2 O) n OH − , (H 2 O) n O À 2 or (H 2 O) n CO À 2 , also yielded (H 2 O) n Cl − cluster ions upon reactions with HCl which was again interpreted as proton transfer from the acid to the anion. 217,266 The proton transfer was also observed in reactions of small (H 2 O) n OH − clusters with HBr to proceed at a collision rate, however, upon further hydration the rate constants slowly decreased.…”