Oxatriquinane (oxoniaperhydrotriquinacene) is an alkyl

oxonium ion In chemistry, an oxonium ion is any cation containing an oxygen atom that has three bonds and 1+ formal charge. The simplest oxonium ion is the hydronium ion (). Alkyloxonium Hydronium is one of a series of oxonium ions with the formula R''n' ...

with formula (CH₂CH₂CH)₃O⁺. It has a

cyclononane Cyclononane is an alicyclic In organic chemistry, an alicyclic compound contains one or more all-carbon rings which may be either saturated or unsaturated, but do not have aromatic character. Alicyclic compounds may have one or more aliphat ...

backbone, with a trivalent

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

connected to

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...

1, 4, and 7, forming three fused pentagonal rings. In contrast to most trialkyloxonium ions, oxatriquinane hydrolyzes slowly.

History

Oxatriquinane was first described in 2008. It five-step synthesis starts from 1,4,7-cyclononatriene. Ita C–O bond lengths are 1.54 Å. The C−O−C angles are also acute.

Reactions

Oxonium ions normally are strong

alkylating agent Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effectin ...

s and are hydrolytically sensitive. Oxatriquinane does not react with boiling water or with alcohols, thiols, halide ions, or amines, although it does react with stronger nucleophiles such as hydroxide, cyanide, and azide. The ability of the oxygen to enter into a fourth covalent bond has been of some theoretical interest and was achieved using carborane acid. As illustrated by the structures of most

metal oxide An oxide () is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O2– (molecular) ion. with oxygen in the oxidation state of −2. Most of the E ...

s, oxygen compounds routinely have bonds to >3 elements in other classes of compounds.

Analogues

Related species include oxatriquinacene, the tri-unsaturated analogue, which is of interest as a possible precursor to oxaacepentalene, a neutral aromatic species. 1,4,7-tri-''tert''-butyloxatriquinane has also been synthesised; this compound contains significant amounts of intramolecular steric strain, resulting in further bond elongation to give C–O bond lengths of 1.622 Å, the longest recorded in any species. File:Oxatriquinacene.svg, Oxatriquinacene File:Oxaacepentalene.svg, Oxaacepentalene

References

{{reflist, 2 Oxonium compounds Oxygen heterocycles