Diradicaloid or Zwitterionic Character: The Non‐Tetrahedral Unsaturated Compound [Si₄{N(SiMe₃)Dipp}₄] with a Butterfly‐type Si₄ Substructure

Abstract

The reduction of the tribromoamidosilane {N(SiMe )Dipp}SiBr (Dipp=2,6-iPr C H ) with potassium graphite or magnesium resulted in the formation of [Si {N(SiMe )Dipp} ] (1), a bicyclo[1.1.0]tetrasilatetraamide. The Si motif in 1 does not adopt a tetrahedral substructure and exhibits two three-coordinate and two four-coordinate silicon atoms. The electronic situation on the three-coordinate silicon atoms is rationalized with positive and negative polarization based on EPR analysis, magnetization measurements, and DFT calculations as well as Si CP MAS NMR and multinuclear NMR spectroscopy in solution. Reactivity studies with 1 and radical scavengers confirmed the partial charge separation. Compound 1 reacts with sulfur to give a novel type of silicon sulfur cage compound substituted with an amido ligand, [Si S {N(SiMe )Dipp} ] (2).

Facile Access to an NHC‐Coordinated Silicon Ring Compound with a Si=N Group and a Two‐Coordinate Silicon Atom

“…We recently reported on a bicyclic silicon ring compound Si 4 {N(SiMe 3 )Dipp} 4 1 with two three‐coordinate Si atoms and zwitterionic character . Herein, we describe the reaction of 1 with 1,3,4,5‐tetramethylimidazol‐2‐ylidene (NHC Me4 ).…”

Synthesis and Reactivity Studies of Amido‐Substituted Germanium(I)/Tin(I) Dimers and Clusters

“…That is, this method locates a bond critical point and corresponding bond path running between the bridgehead Ge(1) and Ge(3) atoms (and two ring critical points), which is consistent with the low, yet significant, WBI computed for such a weak interaction. These findings, together with the inspection of the molecular orbitals (MOs) of 9 (see HOMO−1 in Figure below), suggest that a 1,3‐bonding interaction between Ge(1) and Ge(3) can be assumed, a situation which is analogous to that found in its silicon counterpart [Si{N(SiMe 3 )(Dip)}] 4 …”

“…The compound can alternatively be prepared on a larger scale, and in good isolated yield, by treating the alkoxy/amido‐germylene DBu LGeO t Bu with HBpin in a σ‐bond metathesis reaction. It is worth noting that similar attempts to hydrogenate the closely related silicon(I) cluster, [Si{N(SiMe 3 )(Dip)}] 4 , were not successful, as the reaction did not proceed, even when it was carried out at 60 °C under 9 bar of H 2 …”

Amido Silicon Chalcogenide Compounds with Unprecedented Cluster Cores and Low Oxidation State Silicon Atoms

“…Sulfur was recrystallized from toluene (PhMe). [Si 4 {N(SiMe 3 )Dipp} 4 ] · 1.5PhMe, red selenium, and ( n Bu) 3 PTe were prepared according to literature procedures.…”

“…We recently synthesized the bicyclic silicon(I) ring compound [Si 4 {N(SiMe 3 )Dipp} 4 ] 1 and found that it reacts with sulfur (S 8 ) in refluxing toluene in an unprecedented manner to yield [Si 4 S 3 {N(SiMe 3 )Dipp} 4 ] 2 even if an excess of sulfur was used (see Scheme ) . Thus, we investigated the reactivity of 1 with selenium, tellurium, oxygen and the group 16 element compounds Me 3 NO and TeP( n Bu) 3 .…”