INFRARED-SPECTRA AND RELATIVE STABILITY OF HYDROGEN-CHLORIDE VAN-DER-WAALS COMPLEXES WITH VARIOUS ALKYL CHLORIDES IN LIQUEFIED NOBLE-GASES

Mid-infrared spectra (4000-400 cm-1) of mixtures of HCl with ethyl-d5, n-propyl, isopropyl-d7, or tert-butyl chloride, dissolved in liquefie d argon (95-117 K) and liquefied krypton (122-148 K) have been investi gated. In all cases the formation of a 1:1 van der Waals molecule betw een HCl and the alkyl chloride was observed. At higher concentrations, a new absorption band, due to a 1:2 complex (RCl).(HCl)2 was found. T he association enthalpy in liquefied argon was determined to be -9.8 /- 0.6 kJ mol-1 for C2D5Cl.HCl, -10.0 +/- 0.5 kJ mol-1 for gauche-n-C3 H7Cl.HCl and -10.8 +/- 0.5 kJ mol-1 for iso-C3D7Cl.HCl. The DELTAH0 fo r the C2D5Cl.HCl species in liquefied krypton was determined to be -9. 4 +/- 0.5 kJ mol-1. For the formation of the 1:2 complex from the 1:1 complex and hydrogen chloride, the DELTAH0 was determined to be -3.7 /- 0.4 kJ mol-1 for the ethyl-d5 chloride complex and -4.5 +/- 0.3 kJ mol-1 for the isopropyl-d7 chloride complex.