Silicon(II) Coordination Chemistry: N‐Heterocyclic Carbene Complexes of Si²⁺ and SiI⁺

Abstract

Der Austausch von N‐heterocyclischen Carbenliganden (NHC) an SiII‐Zentren öffnet einen Zugang zu einem dikationischen NHC‐Komplex von Silicium(II) sowie zu [SiI(IiPr2Me2)(IDipp)]+, einem NHC‐Addukt des Iodsilyliumyliden‐Kations SiI+ (siehe Bild). Im Zuge von Charakterisierungsstudien wurde eine beispiellose anagostische CH⋅⋅⋅Si‐Wechselwirkung in [SiI(IiPr2Me2)(IDipp)]+ entdeckt.

Durch ein N‐heterocyclisches Carben koordinierte neutrale und kationische schwere Cyclopropylidenanaloga

“…Angesichts der aktuellen Diskussion über den Gebrauch von Pfeilen für die Darstellung von Donor-Akzeptor-Bindungen [16] [17] oder an das Siliciumzentrum der Si=Ge-Bindung koordinieren kçnnte. [18] Rechnungen auf dem wB97XD/6- [12,13] was stattdessen auf die Bildung eines Dreiringes, ähnlich den NHC-koordinierten Cyclopropyildenen 4, schließen lässt.…”

S–H Bond Activation in Hydrogen Sulfide by NHC-Stabilized Silyliumylidene Ions

“…Key to these developments have been the usage of suitable synthetic methodologies in combination with thermodynamic and kinetic stabilization by appropriately chosen ligands. In particular, for the heavier carbon analogue silicon, a plethora of studies reported new low-valent compounds in recent years [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] and the chemistry of silylene base adducts has already been carefully developed [14,[26][27][28][29][30][31][32][33][34][35][36]. Before these findings, silyliumylidene ions, cationic Si(II) species were found to be promising as similar versatile Lewis amphiphiles [37,38].…”

“…As NHCs are strong σ donors, donors, their application in main group chemistry enabled the isolation of a large variety of low coordinate and low-valent main group compounds [41,42]. The first NHC-stabilized silyliumylidenes, III and IV were synthesized by Filippou and coworkers via a three-step protocol from SiI4 [28], and by Driess and coworkers through the reaction of Roesky's NHC-stabilized dichlorosilylene with their bridged bis-carbene ligand [23].…”

Synthesis and Characterization of N-Heterocyclic Carbene-Coordinated Silicon Compounds Bearing a Fused-Ring Bulky Eind Group

“…In this context, some arylbromosilylidene and arylsilylidyne complexes of nickel and platinum were reported [32][33][34]. In 2013, Filippou's group reported the unprecedented dicationic NHC complexes of silicon(II) and NHC adducts of iodesilyliumylidene cation SiI + [35]. Subsequently, we reported the reaction of 1,2-dibromodisilenes (1b, 1e, and 1f) having EMind, Bbt, and Tbb groups (Tbb = 2,6-{CH(SiMe3)2}2-4-t Bu-C6H2 (f)) with NHCs (Im-Me4 and Im-i Pr2Me2) (Im-i Pr2Me2 = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) leading to the formation of mono-NHC adducts of arylbromosilylenes, NHC→SiBr(Ar) (VIb′ and VIe), and the bromide salts of the bis-NHC adducts of formal arylsilyliumylidene cations, [(NHC)2 →Si(Ar)] + [Br − ] (VIIb, VIIb′, and VIIf) [22].…”

“…In this context, some arylbromosilylidene and arylsilylidyne complexes of nickel and platinum were reported [32][33][34]. In 2013, Filippou's group reported the unprecedented dicationic NHC complexes of silicon(II) and NHC adducts of iodesilyliumylidene cation SiI + [35]. Subsequently, we reported the reaction of 1,2-dibromodisilenes (1b, 1e, and 1f) having EMind, Bbt, and Tbb groups (Tbb = 2,6-{CH(SiMe 3 ) 2 } 2 -4-t Bu-C 6 H 2 (f)) with NHCs (Im-Me 4 [24].…”