Phosphine-Stabilized Germasilenylidene: Source for a Silicon-Atom Transfer

Abstract

A phosphine-stabilized germasilenylidene is synthesized following the pathway of SiCl 4 oxidative addition at a germylene−phosphine Lewis pair. Low-temperature reduction using {( Mes Nacnac)Mg} 2 resulted in a chlorosilylene intermediate and finally a molecule exhibiting a GeSi: motif. Inside the chelating phosphine−germylene, a low-valent silicon atom is stabilized and was transferred to diazabutadiene to give N-heterocyclic silylenes. Because of the high reactivity of the phosphine-stabilized germasilenylidene, a reaction of two GeSi: units was found to yield a Si 2 Ge 2 -ring molecule exhibiting a germasilene substituted with a silylene.

A donor-supported silavinylidene and silylium ylides: boroles as a flexible platform for versatile Si(ii) chemistry

“…The value is reproduced by computational predictions (GIAO:PBE0/def2-TZVP δ( 29 Si)calc = 228 ppm). This value deviates drastically from other silavinylidene derivatives such as Filippou's reported value for (NHC):Si=CNR (δ( 29 Si) = -142 ppm) 99 or Wesemann's germasila vinylidene (δ( 29 Si) = -48 ppm) 96 Please do not adjust margins Please do not adjust margins…”

“…-30°C led to an intensely blood red colourisation and we were able to isolate the unprecedented silavinylidene 5B-Me featuring an authentic C=Si: double bond. A number of donor-stabilised heavier homologs of vinylidenes have been reported in the last decade (R2Ge=Ge*, 92,93 R2Si=Ge*, 94,95 R2Ge=Si*, 96 R2Si=Si*; 97,98 denote further donor-stabilisation of the atom). To the best of our knowledge, silavinylidene 5B-Me is the first example for the lightest heavier congener of (donor-stabilised) vinylidenes.…”

Definition of the tetrel bond

“…As will be shown in this paper, a covalently bonded carbon without and with π bonds in molecular entities can act as a nucleophile and is capable of acting as an acceptor of, inter alia, hydrogen bonds, halogen bonds, chalcogen bonds and pnictogen bonds. The heavier members of the tetrel family in molecular entities can also act as nucleophiles, depending on their chemical environment; an example is double-bonded Si in molecular entities such as a phosphine-stabilized germasilenylidene, featuring a GeS: unit 8 and an NHC-stabilized bromo(silyl)silylene, (R) (Br) 2 SiSi(Br)(R′). 9 Methyl groups, when bonded to atoms that are less electronegative than carbon, can act as a Lewis base for the formation of non-covalent interactions; 10,11 however, when bonded to an electron-withdrawing entity such as F, CN, Cl, or NO 2 , the carbon atom behaves as an electrophile (as in CF 4 ).…”

“…As will be shown in this paper, a covalently bonded carbon without and with π bonds in molecular entities can act as a nucleophile and is capable of acting as an acceptor of, inter alia , hydrogen bonds, halogen bonds, chalcogen bonds and pnictogen bonds. The heavier members of the tetrel family in molecular entities can also act as nucleophiles, depending on their chemical environment; an example is double-bonded Si in molecular entities such as a phosphine-stabilized germasilenylidene, featuring a GeS: unit 8 and an NHC-stabilized bromo(silyl)silylene, (R)(Br) 2 SiSi(Br)(R′). 9…”

Precise Transfer of an Aluminium Atom: An Avenue to Aluminium Heterocycles

“…[14] Scheschkewitz et al showed atomically precise expansion of unsaturated silicon clusters through SiCp*2 (E) [15] and (NHC)GeCl2 (NHC = 2,3,4,5-tetramethylimidazolylidene) [16] , while the group of Wesemann disclosed a base-stabilized germasilenylidene F that delivers a Si atom. [17] Nevertheless, the development of analogous reactions with group 13 elements remains extremely challenging due to the lack of suitable precursors. Transfer of a single Al atom to unsaturated hydrocarbons is hitherto unknown.…”