Steric control in the formation of Co2(CO)6-alkyne complexes from Group 14 tetraalkynes and their reactions with acid

Oxidative coupling of tetraalkynyltin with aldehydes leading to alkynyl ketones

A small library of acetylenic ketones was synthesized by the reaction of tetraalkynyltin reagents with aldehydes.

Fourfold Diels-Alder reaction of tetraethynylsilane

A series of ethynylated silanes, including tetraethynylsilane, was treated with tetraphenylcyclopentadienone at 300 °C under microwave irradiation to give the aromatized Diels-Alder adducts as sterically encumbered mini-dendrimers with up to 20 benzene rings. The sterically most congested adducts display red-shifted emission through intramolecular π-π interactions in the excited state.

Synthesis and structure of tetraethynylsilane and its silylated derivatives

The known tetrakis((trimethylsilyl)ethynyl)silane was prepared and deprotected. By using trifluoromethanesulfonic acid, the smooth stepwise desilylation of the starting material was achieved, and all of the partially protected and the fully deprotected species were isolated by sublimation. Crystal structures of all of the partially and the fully deprotected species were obtained. None of the compounds is thermally sensitive. Attempts to explosively decompose these species upon heating failed.

En route to dinitroacetylene: nitro(trimethylsilyl)acetylene and nitroacetylene harnessed by dicobalt hexacarbonyl

Dinitroacetylene and other nitroacetylenes are attractive stoichiometric precursors to high energy-density materials, but suffer from high reactivity and thermal instability. Herein, we report that nitroacetylenes can be dramatically stabilized in the form of their dicobalt hexacarbonyl complexes. In particular, we describe the syntheses and characterization of the first two transition-metal complexes of nitroalkynes, [μ-1-nitro-2-(trimethylsilyl)ethyne-1,2-diyl]bis(tricarbonylcobalt)(Co-Co) and [μ-1-nitroethyne-1,2-diyl]bis(tricarbonylcobalt)(Co-Co). The chemistry of these compounds reveals their potential as reaction partners in [2+2+2] cyclotrimerizations, furnishing nitroindane, nitrotetralin, and trinitrobenzene products. The X-ray crystal structure of 1,3,5-trinitro-2,4,6-tris(trimethylsilyl)benzene presents a distorted, yet planar, aromatic ring.