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Silyl Chalconium Ions: Synthesis, Structure and Application in Hydrodefluorination Reactions
Author(s) -
Kordts Natalie,
Künzler Sandra,
Rathjen Saskia,
Sieling Thorben,
Großekappenberg Henning,
Schmidtmann Marc,
Müller Thomas
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201700995
Subject(s) - chemistry , silanes , chalcogen , silylation , alkyl , silane , medicinal chemistry , crystallography , organic chemistry , catalysis
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 Me 2 SiH 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.