Organo-noble-gas hydride compounds HKrCCH, HXeCCH, HXeCC, and HXeCCXeH: formation mechanisms and effect of 13C isotope substitution on the vibrational properties

Hanna Tanskanen; Leonid Khriachtchev; Jan Lundell; Markku Räsänen

doi:10.1063/1.1799611

Organo-noble-gas hydride compounds HKrCCH, HXeCCH, HXeCC, and HXeCCXeH: formation mechanisms and effect of 13C isotope substitution on the vibrational properties

J Chem Phys. 2004 Nov 1;121(17):8291-8. doi: 10.1063/1.1799611.

Authors

Hanna Tanskanen¹, Leonid Khriachtchev, Jan Lundell, Markku Räsänen

Affiliation

¹ Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland. [email protected]

PMID: 15511149
DOI: 10.1063/1.1799611

Abstract

We investigate the formation mechanism of HXeCCXeH in a Xe matrix. Our experimental results show that the HXeCCXeH molecules are formed in the secondary reactions involving HXeCC radicals. The experimental data on the formation of HXeCCXeH is fully explained based on the model involving the HXeCC+Xe+H-->HXeCCXeH reaction. This reaction is the first case when a noble-gas hydride molecule is formed from another noble-gas molecule. In addition, we investigate the (12)C/(13)C isotope effect on the vibrational properties of organo-noble-gas hydrides (HKrCCH, HXeCCH, HXeCC, and HXeCCXeH) in noble-gas matrixes. The present experimental results and ab initio calculations on carbon isotope shifts of the vibrational modes support the previous assignments of these molecules. Upon (12)C to (13)C isotope substitution, we observed a pronounced effect on the H-Kr stretching mode of HKrCCH (downshift of 1.0-3.6 cm(-1), depending on the matrix site) and a small anomalous shift (+0.1 cm(-1)) of the H-Xe stretching mode of HXeCCH and HXeCCXeH.