Stable Systems with a Triple Bond to Silicon or Its Homologues: Another Challenge

Abstract

By using tailor‐made substituents, it was possible in the past few decades to prepare stable compounds bearing a double bond to silicon or its homologues (for example, R4El2 and [LnMElR2]). The new challenge is now the triple‐bond systems. Whilst compounds of the type R2El2 (El=Si) are quasi “in the air”, the preparation of stable complexes of the type [LnM≡ElR] (El=Ge) containing a triple bond to germanium has already been achieved.

The Pentamethylcyclopentadienylsilicon(II) Cation: Synthesis, Characterization, and Reactivity

“…Bearing in mind the quite different substituent (R) dependent structures of species with the composition RSiSiR,42, 109 and with the aim to better understand the easy disproportionation of the compound (Me 5 C 5 )Si‐Si(C 5 Me 5 ) ( 20 ) into 2 and elemental silicon, a theoretical calculation of the structure of 20 was performed 110. Very interestingly, the calculated structure comprises a quite novel coordination mode of a π‐bonded cyclopentadienyl group, as presented in Figure 15: Three neighboring carbon atoms of the Cp* unit are involved in π‐bonding to two silicon atoms from a σ‐Cp*SiSi unit.…”

Theoretical Study of an Isolable Compound with a Short Silicon-Silicon Triple Bond, (tBu3Si)2MeSiSi≡SiSiMe(SitBu3)2

“…[6,7] It is the focus of much current interest whether disilynes are synthetically accessible and isolable as stable compounds. [3,4,8,9] The major difficulty in synthesizing and isolating disilynes is due to their high reactivities, especially toward isomerization and dimerization. [10Ϫ14] To suppress these reactivities, substituent effects have been extensively investigated.…”

Polyanionic Hexagons: X6n– (X = Si, Ge)

“…The silicon and germanium -electron systems, however, differ remarkably in structure and stability from a carbon -electron system [3][4][5][6][7][8], although the electronic structures are analogues and formally the same hybridization occurs. The rings of hexasilabenzene (SiH) 6 and OPEN ACCESS hexagermabenzene (GeH) 6 are puckered as in a chair-like cyclohexane (Scheme Ia) and are different from planar D 6h -symmetric benzene (Scheme Ib) [7,8].…”

“…Nearly-planar hexagons consisting of Si and Ge were found in solid-state Zintl anions: Si 6 10-in Ba 4 Li 2 Si 6 and Ge 6 10-in Ba 4 Li 2 Ge 6 [10]. These species are geometrically similar to benzene, but are Hückel arenes with 10  electrons.…”