Wydział Chemii

K. S. Rutkowski

S. M. Melikova

Jerzy Jański

Aleksander Koll

2010

Chemical Physics

375

92-100

10.1016/j.chemphys.2010.07.028

Naukowa

Angielski

Artykuł

The FTIR spectra of C₂H₂ in mixtures with trimethylamine (TMA) have been studied in liquefied Kr in the frequency range of ∼800–7000 cm⁻¹. The data obtained for C₂H₂ subunit suggest the formation of 1:1 complexes stabilized by a moderate strength conventional H-bond. CH and CN stretching vibrations, related to the vicinal bonds of proton acceptor, were found to shift in opposite directions – blue in the former and red in the latter case. New weak bands, revealed in the range of ∼6000–7000 cm⁻¹, were ascribed to the overtone and combination bands of CH stretching vibrations of acetylene which participates in the H-bond formation. The relative stability of the complex has been determined in a series of temperature (T = 118–157 K) measurements of integrated intensities of vibrational bands ascribed to monomer and complex species. Ab initio MP2/6-311++G(2d,2p) a priory counterpoise corrected calculations, made for acetylene, TMA, and the complex reproduce the main spectroscopic observations. They suggest that the most stable non-linear structure of the complex is very floppy. Evaluations of anharmonic effects on position and integrated intensity of selected bands of CH stretching modes of C₂H₂ subunit have been made within perturbation theory on the basis of single point potential energy surface (PES) and dipole moment function calculations.

Hydrogen bond, Anharmonicity, CH⋯B interactions, Trimethylamine, Acetylene, Liquefied Kr

https://doi.org/10.1016/j.chemphys.2010.07.028

http://www.elsevier.com