Thermochemical stabilities and structures of the cluster ions OCS+, S2+, H+(OCS), and C2H5+ with OCS molecules in the gas phase

K. Hiraoka, K. Fujita, M. Ishida, K. Hiizumi, F. Nakagawa, A. Wada, S. Yamabe, N. Tsuchida

doi:10.1016/j.jasms.2005.07.007

The gas-phase clustering reactions of OCS+, S2+, H+(OCS), and C2H5+ ions with carbonyl sulfide (OCS) molecules were studied using a pulsed electron-beam high-pressure mass spectrometer and applying density functional theory (DFT) calculations. In the cluster ions OCS+(OCS)(n) and H+(OCS)(OCS)(n), a moderately strong, here referred to as "semi-covalent", bond was formed with n = 1. However, the nature of bonding changed from semi-covalent to electrostatic with n = 1 --> 2. The bond energy of S2(+)(OCS) was determined experimentally to be 12.9 +/- 1 kcal/mol, which is significantly smaller than that of the isovalent S2(+)(CS2) complex (30.9 +/- 1.5 kcal/mol). DFT based calculations predicted the presence of several isomeric structures for H+(OCS)(OCS)(n) complexes. The bond energies in the C2H5+(OCS)(n) clusters showed an irregular decrease for n = 1 --> 2 and 7 --> 8. The nonclassical bridge structure for the free C2H5+ isomerized to form a semi-covalent bond with one OCS ligand, [H3CCH2...SCO]+, i.e., reverted to classical structure. However, the nonclassical bridge structure of C2H5+ was preserved in the cluster ions C2H5+(OCS)(n) below 140 K attributable to the lack of thermal energy for the isomerization. DFT calculations revealed that stability orders of the geometric isomers of H+(OCS)(OCS)(n) and C2H5+(OCS)(n) changed with increasing n values.

Thermochemical stabilities and structures of the cluster ions OCS<sup>+</sup>, S<sub>2</sub><sup>+</sup>, H<sup>+</sup>(OCS), and C<sub>2</sub>H<sub>5</sub><sup>+</sup> with OCS molecules in the gas phase

書誌事項

この論文をさがす

説明

収録刊行物

被引用文献 (1)*注記

キーワード

詳細情報詳細情報について

書き出し

問題の指摘