Tarczay György, Förstel Marko, Góbi Sándor, Maksyutenko Pavlo, Kaiser Ralf I
Department of Chemistry and W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA.
Permanent Address: Laboratory of Molecular Spectroscopy, Institute of Chemistry, Eötvös University, PO Box 32, H-1518, Budapest 112, Hungary.
Chemphyschem. 2017 Apr 19;18(8):882-889. doi: 10.1002/cphc.201601422. Epub 2017 Mar 7.
Exploiting photoionization reflectron time-of-flight mass spectrometry (PI-ReTOF-MS) combined with electronic structure calculations, it is shown that the hitherto elusive silylketene molecule (H SiC(H)=C=O)-the isovalent counterpart of the well-known methylketene molecule-is forming via interaction of energetic electrons with low-temperature silane-carbon monoxide ices. In combination with the infrared spectroscopically detected triplet dicarbon monoxide reactant, electronic structure calculations suggest that dicarbon monoxide reacts with silane via a de facto insertion of the terminal carbon atom into a silicon-hydrogen single bond. This is followed by non-adiabatic reaction dynamics triggered by the heavy silicon atom intersystem crossing from the triplet to the singlet manifold, eventually leading to the formation of silylketene. The non-equilibrium nature of the elementary reactions within the exposed ices results in an exciting and novel chemistry which cannot be explored via traditional preparative chemistry. Since the replacement of hydrogen in silane can introduce side groups such as silyl or alkyl, the reaction of triplet dicarbon monoxide with silane represents the parent system for a previously disregarded reaction class revealing an elegant path to access the largely reactive group of silylketenes.
