title: Silyl Chalconium Ions: Synthesis, Structure and Application in Hydrodefluorination Reactions.
abstract: The synthesis of two series of silylated chalconium borates, 9 and 10, which are based on the peri-naphthyl and peri-acenaphthyl framework, is reported (chalcogen (Ch): O, S, Se, Te). NMR investigations of the selenium- and tellurium-containing precursor silanes 3 d-f and 8 d, f revealed a significant through-space J-coupling between the chalcogen nuclei and the Me2SiH group. Experimental and computational results typify the synthesized cations 9 and 10 as chalconium ions. The imposed ring strain weakens the Si-Ch linkage compared to acyclic chalconium ions. This attenuation of the Si-Ch bond strength is more pronounced in the acenaphthene series. Surprisingly, the Si-O bonds in oxonium ions 9 a and 10 a are the weakest Si-Ch linkage in both series. The synthesized silyl chalconium borates are active in hydrodefluorination reactions of alkyl fluorides with silanes. A cooperative activation of the silane by the Lewis acidic (silicon) and by the Lewis basic side (chalcogen) is suggested.
authors.affiliation: Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky Str. 9-11, 26211, Oldenburg, Germany.
authors.forename: Natalie
authors.initials: N
authors.lastname: Kordts
authors.affiliation: Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky Str. 9-11, 26211, Oldenburg, Germany.
authors.forename: Sandra
authors.identifier: http://orcid.org/0000-0001-5855-1276
authors.initials: S
authors.lastname: Künzler
authors.affiliation: Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky Str. 9-11, 26211, Oldenburg, Germany.
authors.forename: Saskia
authors.identifier: http://orcid.org/0000-0001-5057-2929
authors.initials: S
authors.lastname: Rathjen
authors.affiliation: Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky Str. 9-11, 26211, Oldenburg, Germany.
authors.forename: Thorben
authors.initials: T
authors.lastname: Sieling
authors.affiliation: Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky Str. 9-11, 26211, Oldenburg, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Großekappenberg
authors.affiliation: Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky Str. 9-11, 26211, Oldenburg, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Schmidtmann
authors.affiliation: Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky Str. 9-11, 26211, Oldenburg, Germany.
authors.forename: Thomas
authors.identifier: http://orcid.org/0000-0002-4247-3776
authors.initials: T
authors.lastname: Müller
keywords: NMR spectroscopy; X-ray diffraction; bond activation; cations; chalconium ions; silicon