Infrared spectra of hydrogen fluoride complexes with tetrachloromethane, trichloromethane, and dichloromethane in solid argon

Abstract

Hydrogen fluoride complexes with CCl{sub 4}, CHCl{sub 3}, and CH{sub 2}Cl{sub 2} were prepared in argon matrices and characterized by infrared spectroscopy. The spectra of CCl{sub 4} and HF revealed a strong CCl{sub 4}-HF complex absorption at 3876 cm{sup {minus}1} with a considerably weaker band at 3904 cm{sup {minus}1} due to the CCl{sub 4}-FH complex. Only one 1:2 complex, CCl{sub 4}-HF-HF, was observed at higher HF concentrations and matrix annealings. Similarly, the HF interaction with CH{sub 2}Cl{sub 2} produced two 1:1 complexes and one 1:2 complex. However, the major product absorption at 3901 cm{sup {minus}1} was assigned to the anti-hydrogen-bonded complex, Ch{sub 2}Cl{sub 2}-FH, while a less intense doublet due to the CH{sub 2}Cl{sub 2}-HF complex appeared at 3799 and 3793 cm{sup {minus}1}. The IR spectra of CHCl{sub 3} and HF were more complicated due to the presence of a third 1:1 complex. The CHCl{sub 3}-HF complex band at 3860 cm{sup {minus}1} was clearly the strongest product absorption. In addition, the ChCl{sub 3}- H complex produced a 3903-cm{sup {minus}1} absorption, while a triplet probably due to the HF-HCCl{sub 3} complex was observed at 3893, 3883, and 3875 cm{sup {minus}1}. Finally, the acid-base properties of these common solvents were considered. 31more » refs., 4 figs., 1 tab.« less