A theoretical investigation of the electron-transfer reactions of the SiF2+3 dication with the rare gases, neon, argon, krypton and xenon

The SiF32+ Dication: Chemistry Counts!

“…Here, we investigate the chemical reactivity of the SiF 3 2 + dication, which had been already addressed theoretically [5] as well as experimentally [6] in the late 1990s because of its possible relevance in etching processes of silicon surfaces with fluorocarbons.…”

“…[16] The dication SiF 3 2 + has a doublet ground state and the unpaired electron is localized at the two equivalent fluorine atoms; [5] this situation is conserved also after complexation with N 2 .…”

Silicon Compounds of Neon and Argon

“…Therefore, we conclude that NeSiF 2 2+ is most probably formed from an excited state of the SiF 3 2+ precursor dication; such states are known to be formed upon electron ionization of SiF 4 . [17] We will address the reactivity of ground and excited states of SiF 3 2+ in future studies using reactive monitoring with synchrotron radiation.…”

“…[11,12] A more efficient dicationic reagent for the attack of noble gases must not only be a potent superelectrophile, but it also needs to meet the following requirements: 1) It should possess a potential leaving group that can be replaced by a noble gas atom without a significant kinetic barrier being involved, such as a homolytic bond cleavage; 2) the preferred oxidation states of noble gases [13] mean that increased stabilities can be expected for even-electron compounds; for homolytic cleavage, the dicationic reagent should be a radical; 3) to prevent electron transfer processes during homolysis of the bond to the leaving group, which would afford an open-shell noble gas compound, the leaving group should have a high ionization energy (IE); and 4) the superelectrophilic dication should be accessible in quantities that suffice for reactivity studies in the gas phase. [14,15] The SiF 3 2+ dication is a promising candidate that may fulfill these requirements: it can be readily generated by dissociative double ionization of SiF 4 as a stable, neutral precursor, [16] it has a very high recombination energy RE-(SiF 3 2+ ) of about 22.4 eV, [17] which allows it to be classified as a superelectrophile, it has one surprisingly weak Si À F bond, with D(F 2 Si 2+ ÀF) = 1.97 eV, and the IE of fluorine as the potential leaving group is exceptionally large (17.4 eV).…”

Siliciumverbindungen von Neon und Argon

“…[14,15] Das Siliciumtrifluorid-Dikation SiF 3 2+ bietet sich in diesem Zusammenhang als vielversprechender Kandidat an: Es ist einfach durch dissoziative Doppelionisation der stabilen neutralen Vorstufe SiF 4 zugänglich, [16] hat eine hohe Rekombinationsenergie RE(SiF 3 2+ ) von ca. 22.4 eV, [17] die es als Superelektrophil klassifiziert, verfügt über eine überraschend schwache Si-F-Bindung mit D(F 2 Si 2+ -F) = 1.97 eV, und die IE von Fluor als potenzieller Abgangsgruppe ist außergewöhnlich hoch (17.4 eV).…”