The HRuCCH, RuCCH sub(2), and Ru- eta super(2)-C sub(2)H sub(2) Molecules: Infrared Spectra and Density Functional Calculations

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Vol. 115; no. 44; pp. 12194 - 12200-12194-12200
• Main Authors: Wang, Qiang, Wang, Xuefeng, Andrews, Lester
• Format: Journal Article
• Language: English
• Published: 01.01.2011
• Subjects: Bonding; Deformation; Density; Insertion; Mathematical analysis; Orbitals; Stretching; Vinylidene
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp207423q

Laser-ablated ruthenium atoms undergo reaction with acetylene during condensation in excess neon and argon matrices to form a metallacycle complex, insertion into the C-H bond, and rearrangement to the vinylidene complex. The subject molecules were identified by super(13)C sub(2)H sub(2 ) and C sub(2)D sub(2), isotopic substitutions and density functional theory (DFT) frequency calculations. The HRuCCH molecule is described by Ru-H, CH, and CC stretching modes and CCH deformation modes. A very strong CC double bond stretching, weak CH stretching, and CCH deformation frequencies were observed for the Ru=C=CH sub(2) complex. The metallacycle Ru- eta super(2)-(C sub(2)H sub(2)) is characterized through CC double bond stretching, CH stretching and CCH deformation modes. The reaction mechanism for formation of the Ru=C=CH sub(2) complex was investigated by B3LYP internal reaction coordinate calculations, and the hydrido-alkyny complex is the rate-determining step. The delocalized three-center-four-electron pi bond using the Ru 4d sub(xz) electron pair contributes to the C-C pi * orbital and provides stabilization energy ( Delta E super((2)), second-order perturbation) for the vinylidene Ru=C=CH sub(2) complex.