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Gas Phase Formation of the Interstellar Molecule Methyltriacetylene
Author(s) -
He Chao,
Thomas Aaron M.,
Galimova Galiya R.,
Mebel Alexander M.,
Kaiser Ralf I.
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201900305
Subject(s) - diacetylene , chemistry , radical , photochemistry , molecule , hydrocarbon , methyl radical , methyl group , organic chemistry , group (periodic table) , polymerization , polymer
Methyltriacetylene – the largest methylated polyacetylene detected in deep space – has been synthesized in the gas phase via the bimolecular reaction of the 1‐propynyl radical with diacetylene under single‐collision conditions. The barrier‐less route to methyltriacetylene represents a prototype of a polyyne chain extension through a radical substitution mechanism and provides a novel low temperature route, in which the propynyl radical piggybacks a methyl group to be incorporated into methylated polyynes. This mechanism overcomes a key obstacle in previously postulated reactions of methyl radicals with unsaturated hydrocarbon, which fail the inclusion of methyl groups into hydrocarbons due to insurmountable entrance barriers thus providing a fundamental understanding on the electronic structure, chemical bonding, and formation of methyl‐capped polyacetylenes. These species are key reactive intermediates leading to carbonaceous nanostructures in molecular clouds like TMC‐1.