On Silylated Oxonium and Sulfonium Ions and Their Interaction with Weakly Coordinating Borate Anions.

Autor:	Bläsing, Kevin, Labbow, Rene, Michalik, Dirk, Reiß, Fabian, Schulz, Axel, Villinger, Alexander, Walker, Svenja
Předmět:	OXONIUM ions ANIONS BORATES BOND formation mechanism IONS INVESTIGATIONS PYRAZOLYL compounds CARBON-hydrogen bonds
Zdroj:	Chemistry - A European Journal; 2/3/2020, Vol. 26 Issue 7, p1640-1652, 13p
Abstrakt:	Attempts have been made to prepare salts with the labile tris(trimethylsilyl)chalconium ions, [(Me3Si)3E]+ (E=O, S), by reacting [Me3Si‐H‐SiMe3][B(C6F5)4] and Me3Si[CB] (CB−=carborate=[CHB11H5Cl6]−, [CHB11Cl11]−) with Me3Si‐E‐SiMe3. In the reaction of Me3Si‐O‐SiMe3 with [Me3Si‐H‐SiMe3][B(C6F5)4], a ligand exchange was observed in the [Me3Si‐H‐SiMe3]+ cation leading to the surprising formation of the persilylated [(Me3Si)2(Me2(H)Si)O]+ oxonium ion in a formal [Me2(H)Si]+ instead of the desired [Me3Si]+ transfer reaction. In contrast, the expected homoleptic persilylated [(Me3Si)3S]+ ion was formed and isolated as [B(C6F5)4]− and [CB]− salt, when Me3Si‐S‐SiMe3 was treated with either [Me3Si‐H‐SiMe3][B(C6F5)4] or Me3Si[CB]. However, the addition of Me3Si[CB] to Me3Si‐O‐SiMe3 unexpectedly led to the release of Me4Si with simultaneous formation of a cyclic dioxonium dication of the type [Me3Si‐μO‐SiMe2]2[CB]2 in an anion‐mediated reaction. DFT studies on structure, bonding and thermodynamics of the [(Me3Si)3E]+ and [(Me3Si)2(Me2(H)Si)E]+ ion formation are presented as well as mechanistic investigations on the template‐driven transformation of the [(Me3Si)3E]+ ion into a cyclic dichalconium dication [Me3Si‐μE‐SiMe2]22+. [ABSTRACT FROM AUTHOR]
Databáze:	Complementary Index
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