Hydrogen-bonded complexes of ethynethiol and hydrogen cyanide trapped in low-temperature argon matrices

Abstract

Hydrogen bonding is one of the exciting and interesting research themes because it plays important roles in biomolecules, plant cells, and so on. Here we report hydrogen-bonded complexes among the photodecomposition products of thiazole, being studied by a joint use of infrared (IR) spectroscopy and density-functional-theory (DFT) calculations. Three types of hydrogen-bonded complexes of ethynethiol (HSCCH) and hydrogen cyanide (HCN), which are photodecomposed by two cleavages of the NC–SC and CN–CC single bonds of thiazole in argon matrices, have been identified by comparison of the observed IR spectra with the corresponding calculated spectral patterns. In addition, another complex with weak interaction between S atom and HCN, which are photoproduced by cleavages of the three single bonds of thiazole, is detected by comparison with the wavenumbers previously reported in literature. The reaction mechanisms to form these complexes are discussed based on the analysis of IR spectra and the DFT calculations.