1:1 hydrogen bonded complexes of HCl with CrCl 2 O 2 and OVCl 3 have been isolated in argon matrices and characterized by infrared spectroscopy. For both complexes, the H-Cl stretching mode was observed, shifted 52 and 47cm - 1 , respectively, from parent HCl. Deuterium substitution, leading a ν H /ν D ratio=1.38, verified the identification and band assignment. For the OVCl 3 .HCl complex, the shifted V O stretching mode was observed, suggesting that the site of interaction for the hydrogen bond is with the oxo group. The shift of the H-Cl stretching mode is quite small compared to many HCl complexes and represents approximately a 3.5% decrease in the H-Cl stretching force constant. These results suggest that the initial step in the oxidation of many organic substrates containing a heteroatom and an acidic hydrogen (e.g. CH 3 OH) may be coordination of the substrate to the transition metal center rather than a hydrogen bonding interaction with the oxo group.