Reactions of a Silicon-Based Cyclic Silylone with Chalcogens

Abstract

Tetrasilasilylone N is composed of a silicon(0) atom, two NHC-coordinated silylenes, and a silaimine (SiN) group. It reacts rapidly and selectively with the chalcogens selenium and tellurium to afford corresponding dichalcogenides 1 and 2 in high yields of 69–79%. In these compounds, one chalcogen atom is connected to the silicon(0) atom with a short bond in the range of SiE double bonds. The second chalcogen atom adopts the bridging position between the Si(0) atom and the SiN group. Using only 1 equiv of tellurium affords the selective formation of monotelluride 3 in 84% yield. In this monotelluride, the tellurium atom adopts a bridging position between the silylone functionality and the SiN group.

(NHC)Si═C═N–R: A Two-Coordinated Si0-Isocyanide Compound as Si(NHC) Transfer Reagent

“…It is an unprecedented reaction in monatomic silicon(0) chemistry, illustrating the synthetic potential of 1 as a Si 0 (NHC) transfer reagent. In fact, several reactions of siladicarbenes (“silylones”) and related monatomic Si 0 compounds have been reported, but in none of them was a ligand elimination observed due to the rigid, chelating ligand scaffold of the silylones . In this context, it is noteworthy that the reaction of 1 with Ge­(Ar Mes )Cl is reminiscent of those of the transition metal complexes [ML 4 (N 2 ) 2 ] (M = Mo, W; L = phosphane) with the organohalotetrylenes E­(R)­X (E = Ge – Pb, X = Cl–I, R = bulky alkyl or aryl group), affording the tetrylidyne complexes trans -[XL 4 MER], which also involve a halide migration with concomitant elimination of a neutral 2e-donor ligand (N 2 ) to form a multiple bond …”

Base-stabilized formally zero-valent mono and diatomic molecular main-group compounds

“…Further, the reactivity of 88 with chalcogens was investigated. 116 When silylone 88 reacts with two equivalents of chalcogens (S, Se, and Te), formation of silicondichalcogenides was observed (89a-c, Scheme 23). In these reactions, both of the chalcogen atoms add to the dicoordinated silicon atom, which justifies the silylone character of 88.…”

“…In these reactions, both of the chalcogen atoms add to the dicoordinated silicon atom, which justifies the silylone character of 88. 116 At −78 °C, reaction of 88 with one equivalent of tellurium affords the selective formation of a monotelluride 89d.…”

Entering new chemical space with isolable complexes of single, zero-valent silicon and germanium atoms

“…Very recently, starting from the silicon(0) complex K, Lips obtained another series of SiX 2 complexes K-1 (Chart 3) with one of the chalcogen atoms interacting with the silicon atom of the SiN(Dipp) moiety of the ligand as well. 79 It is noted that dimeric SiX 2 (X = S, 80 Se, 81 Te 82 ) stabilised by NHC or cAAC have also been structurally characterised. A donor and acceptor supported SiO 2 complex has also been described recently.…”