Insertion of Noble Gas Atoms into Cyanoacetylene: An ab Initio and Matrix Isolation Study

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• 作者：Leonid Khriachtchev ; Antti Lignell ; Hanna Tanskanen ; Jan Lundell ; Harri Kiljunen ; Markku Rä ; sä ; nen
• 刊名：Journal of Physical Chemistry A
• 出版年：2006
• 出版时间：October 26, 2006
• 年：2006
• 卷：110
• 期：42
• 页码：11876 - 11885
• 全文大小：153K
• 年卷期：v.110,no.42(October 26, 2006)
• ISSN：1520-5215

文摘

A computational and experimental matrix isolation study of insertion of noble gas atoms into cyanoacetylene(HCCCN) is presented. Twelve novel noble gas insertion compounds are found to be kinetically stable at theMP2 level of theory, including four molecules with argon. The first group of the computationally studiedmolecules belongs to noble gas hydrides (HNgCCCN and HNgCCNC), and we found their stability for Ng= Ar, Kr, and Xe. The HNgCCCN compounds with Kr and Xe have similar stability to that of previouslyreported HKrCN and HXeCN. The HArCCCN molecule seems to have a weaker H-Ar bond than in thepreviously identified HArF molecule. The HNgCCNC molecules are less stable than the HNgCCCN isomersfor all noble gas atoms. The second group of the computational insertion compounds, HCCNgCN andHCCNgNC, are of a different type, and they also are kinetically stable for Ng = Ar, Kr, and Xe. Our photolysisand annealing experiments with low-temperature cyanoacetylene/Ng (Ng = Ar, Kr, and Xe) matrixes evidencethe formation of two noble gas hydrides for Ng = Kr and Xe, with the strongest IR absorption bands at1492.1 and 1624.5 cm^-1, and two additional absorption modes for each species are found. The computationalspectra of HKrCCCN and HXeCCCN fit most closely the experimental data, which is the basis for ourassignment. The obtained species absorb at quite similar frequencies as the known HKrCN and HXeCNmolecules, which is in agreement with the theoretical predictions. No strong candidates for an Ar compoundare observed in the IR absorption spectra. As an important side product of this work, the data obtained inlong-term decay of KrHKr⁺ cations suggest a tentative assignment for the CCCN radical.