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Carboryne
Smokefoot: spin-off pretty specialized topic
In [[organoboron chemistry]], a '''carboryne''' is an unstable derivative of ortho-carborane with the formula B<sub>10</sub>C<sub>2</sub>H<sub>10</sub>.<ref>Liquid error: wrong number of arguments (1 for 2)</ref> They are also called 1,2-dehydro-o-carboranes. The hydrogen atoms on the C2 unit in the parent ''o''-carborane are missing. The compound resembles and is [[Isolobal principle|isolobal]] with [[benzyne]].<ref></ref><ref></ref><ref></ref> A carboryne compound was first generated in 1990 starting from o-carborane. The hydrogen atoms connected to carbon are removed by [[N-Butyllithium|''n''-butyllithium]] in [[tetrahydrofuran]] and the resulting lithium [[dianion]] is reacted with [[bromine]] at 0 °C to form the bromo monoanion.
:[[Image:Carboryne synthesis.png|600px|Carboryne synthesis, main chemical bonds involving carbon in red]]
Heating the reaction mixture to 35 °C releases carboryne, which can subsequently be trapped with suitable [[diene]]s:
:[[Image:Carboryne reactions.png|600px|carboryne reactions]]
such as [[anthracene]] (to afford a [[triptycene]]-like molecule) and [[furan]] in 10 to 25% [[chemical yield]].
Carborynes react with [[alkyne]]s to '''benzocarboranes''' <ref></ref><ref></ref> in an adaptation of the above described procedure. O-carborane is deprotonated with [[N-Butyllithium|''n''-butyllithium]] as before and then reacted with dichloro-di(triphenylphosphino) nickel to a nickel coordinated carboryne. This compound reacts with 3-hexyne in an [[alkyne trimerization]] to the benzocarborane.
:[[Image:BenzocarboraneSynthesis.png|600px|benzocarborane synthesis]]
Single crystal [[X-ray diffraction]] analysis of this compound shows considerable [[bond length]] alternation in the benzene ring (164.8 [[picometre|pm]] to 133.8 pm) ruling out [[aromaticity]].
== See also ==
* [[Heteroborane]]
* [[Organoboron chemistry]]
== References ==
[[Category:Organoboron compounds]]
[[Category:Cluster chemistry]]
:[[Image:Carboryne synthesis.png|600px|Carboryne synthesis, main chemical bonds involving carbon in red]]
Heating the reaction mixture to 35 °C releases carboryne, which can subsequently be trapped with suitable [[diene]]s:
:[[Image:Carboryne reactions.png|600px|carboryne reactions]]
such as [[anthracene]] (to afford a [[triptycene]]-like molecule) and [[furan]] in 10 to 25% [[chemical yield]].
Carborynes react with [[alkyne]]s to '''benzocarboranes''' <ref></ref><ref></ref> in an adaptation of the above described procedure. O-carborane is deprotonated with [[N-Butyllithium|''n''-butyllithium]] as before and then reacted with dichloro-di(triphenylphosphino) nickel to a nickel coordinated carboryne. This compound reacts with 3-hexyne in an [[alkyne trimerization]] to the benzocarborane.
:[[Image:BenzocarboraneSynthesis.png|600px|benzocarborane synthesis]]
Single crystal [[X-ray diffraction]] analysis of this compound shows considerable [[bond length]] alternation in the benzene ring (164.8 [[picometre|pm]] to 133.8 pm) ruling out [[aromaticity]].
== See also ==
* [[Heteroborane]]
* [[Organoboron chemistry]]
== References ==
[[Category:Organoboron compounds]]
[[Category:Cluster chemistry]]
August 26, 2018 at 12:27AM
