Khriachtchev Leonid, Lignell Antti, Tanskanen Hanna, Lundell Jan, Kiljunen Harri, Räsänen Markku
Department of Chemistry, and VERIFIN, PO Box 55, FIN-00014 University of Helsinki, Finland.
J Phys Chem A. 2006 Oct 26;110(42):11876-85. doi: 10.1021/jp063731f.
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 the MP2 level of theory, including four molecules with argon. The first group of the computationally studied molecules 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 previously reported HKrCN and HXeCN. The HArCCCN molecule seems to have a weaker H-Ar bond than in the previously identified HArF molecule. The HNgCCNC molecules are less stable than the HNgCCCN isomers for all noble gas atoms. The second group of the computational insertion compounds, HCCNgCN and HCCNgNC, are of a different type, and they also are kinetically stable for Ng = Ar, Kr, and Xe. Our photolysis and annealing experiments with low-temperature cyanoacetylene/Ng (Ng = Ar, Kr, and Xe) matrixes evidence the formation of two noble gas hydrides for Ng = Kr and Xe, with the strongest IR absorption bands at 1492.1 and 1624.5 cm(-1), and two additional absorption modes for each species are found. The computational spectra of HKrCCCN and HXeCCCN fit most closely the experimental data, which is the basis for our assignment. The obtained species absorb at quite similar frequencies as the known HKrCN and HXeCN molecules, which is in agreement with the theoretical predictions. No strong candidates for an Ar compound are observed in the IR absorption spectra. As an important side product of this work, the data obtained in long-term decay of KrHKr+ cations suggest a tentative assignment for the CCCN radical.
本文介绍了一项关于稀有气体原子插入氰基乙炔（HCCCN）的计算和实验矩阵隔离研究。发现12种新型稀有气体插入化合物在MP2理论水平上动力学稳定，其中包括4种含氩分子。计算研究的第一组分子属于稀有气体氢化物（HNgCCCN和HNgCCNC），我们发现它们对于Ng = Ar、Kr和Xe是稳定的。含Kr和Xe的HNgCCCN化合物与先前报道的HKrCN和HXeCN具有相似的稳定性。HArCCCN分子中的H-Ar键似乎比先前鉴定的HArF分子中的键更弱。对于所有稀有气体原子，HNgCCNC分子比HNgCCCN异构体稳定性更低。计算插入化合物的第二组，HCCNgCN和HCCNgNC，属于不同类型，并且对于Ng = Ar、Kr和Xe它们在动力学上也是稳定的。我们对低温氰基乙炔/Ng（Ng = Ar、Kr和Xe）基质进行的光解和退火实验证明，对于Ng = Kr和Xe形成了两种稀有气体氢化物，最强红外吸收带出现在1492.1和1624.5 cm⁻¹处，并且每种物质还发现了另外两种吸收模式。HKrCCCN和HXeCCCN的计算光谱与实验数据拟合得最紧密，这是我们进行归属的基础。所得到的物质在与已知的HKrCN和HXeCN分子非常相似的频率处吸收，这与理论预测一致。在红外吸收光谱中未观察到强的氩化合物候选物。作为这项工作的一个重要副产品，在KrHKr⁺阳离子的长期衰变中获得的数据表明对CCCN自由基进行了初步归属。
