Addition eines Wasserstoffatoms an Acetonitril durch hydratisierte Elektronen in Nanotröpfchen

Abstract

Nanotröpfchen, die hydratisierte Elektronen enthalten, liefern ergänzende Informationen zum Standardverfahren der Pulsradiolyse. 25 Jahre nach der ersten Beobachtung der Reaktion des hydratisierten Elektrons mit Acetonitril in Lösung wird das Produkt in einem Gasphasenexperiment als das Wasserstoffaddukt identifiziert. Das Bild zeigt ein solvensstabilisiertes Radikalanion, das als reaktive Zwischenstufe vorgeschlagen wird.

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

“…[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. In addition, the zero-point-corrected binding energy of a hydrogen atom to CH 3 CN was calculated as 80 kJ mol À1 at the G3 level of theory, [40] 103 kJ mol À1 at the B3LYP/6-311 + +G(d,p) level of theory, [41] [42] and a preferential coordination of Mg 2 + with H 2 O in mixtures of water with deuterated acetonitrile, studied for mole fractions of up to 20 % H 2 O in CD 3 CN.…”

“…Like O 2 and CO 2 , acetonitrile exhibits a specific reactivity toward the hydrated electron. Collisions of (H 2 O) n À with CH 3 CN result in the formation of OH À (H 2 O) m , [25] which are detected by mass spectrometry. Thermochemical arguments require that 3 CNHC is formed as the neutral product.…”

Proton Transfer in Ionic Water Clusters

“…[25][26][27] ) were produced by laser vaporization [28,29] of a solid zinc target with the 5-ns pulse of a frequencydoubled Nd:YAG laser (Continuum Surelite II, 10 Hz, pulse energy 5 mJ), followed by supersonic expansion of the hot plasma entrained in a 50-ms helium pulse which was seeded with traces of water, and, in the case of O 2 (H 2 O) n À , O 2 . The cluster ions formed were transferred by a series of electrostatic lenses through four stages of differential pumping, decelerated, and stored in the ICR cell.…”

Reactions of Hydrated Electrons (H2O)n− with Carbon Dioxide and Molecular Oxygen: Hydration of the CO2− and O2− Ions

“…[2] We have recently pointed out that reactivity studies of solvated electrons in finite clusters, rather than in bulk solutions, could provide very useful complementary information. [3] This approach has the advantages that the elemental compositions of clusters can be unambiguously established based on their exact masses, and that side reactions that limit the lifetime of the hydrated electrons are absent.…”

“…In these cases, however, the water (H 2 O) n species are strongly distorted compared with the free clusters. Unlike in the free (H 2 O) 3 or (H 2 O) 4 , all of the "dangling" OH bonds are facing in the same direction, out of the plane defined by the water oxygen atoms, so that they can form hydrogen bonds to the negatively charged oxygen atoms of the CO 2 À anion. The n = 5 anion is again a cyclic water pentamer, but in this case, due to steric reasons, only four water molecules of the water pentamer are directly bound to the CO 2 À anion.…”