A High Yield Synthesis of an Octastannacubane and a Bis(silyl) Stannylene via Reductive Elimination of a Silane

Abstract

Thermolysis of tris(silyl) tin hydride 2 at 70 °C for 3 hours results in elimination of tBu2MeSiH and generation of bis(silyl) stannylene 3 which dimerizes instantaneously yielding distannene 4. Compound 3 can be trapped by NHCMe yielding stannylene‐NHCMe complex 5. Upon heating (70 °C, 24 h) 4 yields stannyl radical 8 along with pentastannatricyclo[2.1.0.02, 5]pentane 10 (ca. 30 %) and traces (ca. 5 %) of the novel octastannacubane 9. Remarkably, octastannacubane 9 is produced in 70 % yield by mild heating (50 °C) of 1,1,2,2‐tetrasilyldistannane 11, along with tBu2MeSiH. Octastannacubane 9 was characterized by X‐ray crystallography, NMR and UV/Vis spectroscopy. Based on DFT quantum‐mechanical calculations the 11 → 9 transformation occurs via reductive elimination of two tBu2MeSiH molecules from 11 yielding a distannyne, (or its bis‐stannylene isomer), followed by its tetramerization.

Ambiphilic Nature of Dipyrrolylpyridine-Supported Divalent Germanium and Tin Compounds

“…Figure a shows a valence bond model of bonding for group 14 dimetallenes based on the mutual donor–acceptor interactions, attributed to their ambiphilic nature. Tetrylenes react with L-type donors such as phosphines and N-heterocyclic carbenes , to form base-stabilized adducts (L→EX 2 ; see Figure b, left). These species can act as ligands or nucleophiles toward electrophilic centers using their active lone electron pair. ,− By employing sterically constrained and dianionic pincer-type ligands, the electronic structures of the resulting base-stabilized tetrylenes can be tuned to achieve ambiphilic properties (see Figure b, right).…”

A High Yield Synthesis of an Octastannacubane and a Bis(silyl) Stannylene via Reductive Elimination of a Silane

“…Structural details are given in the Supporting Information. [17] Angewandte [28] and a structural isomer of pentastanna-[1.1.1]propellane previously reported by Sita and Bickerstaff. [10a] An alternative synthesis and X-ray crystallography characterization of 10 is presented in the SI.…”

“…Formation of stannylene 3 from 2 is unambiguously demonstrated by thermolysis of 2 in the presence of NHC Me , an effective stannylene trapping reagent, [16] yielding the stannylene-carbene complex 5 (Scheme 2, path c), which was isolated as yellow crystals and characterized by NMR spectroscopy and X-ray crystallography ( Figure 1). [17] Stannylene 3 was also trapped in the thermolysis of 2 by 2,3-dimethylbuta-1,3-diene, yielding the expected [18] [1+4] cycloadduct 6 (Scheme 2, path d), and by reaction of distannene 4 with PMe 3 which produced the stannylene-PMe 3 complex 7 (Scheme 2, path e). Both 6 and 7 were characterized by NMR spectroscopy and 6 also by Xray crystallography (see Supporting Information (SI) for details).…”

“…Structural details are given in the Supporting Information. [17] Scheme 3. a)-c) Suggested mechanism for the high-yield conversion of 11 into octastannacubane 9.…”

Rapid and Mild Synthesis of an NHC-Coordinated Bis(trimethylsilyl)silylene via Elimination of Halotrimethylsilane

“…and the synthesis of such a silylene under ambient conditions remains challenging . Herein, we report the rapid and mild synthesis of an NHC-stabilized bis­(trimethylsilyl)­silylene via the dehalosilylation reaction based on our recent discovery of the elimination of Me 3 SiI from an iodooligosilane by a Lewis base. , …”