The matrix isolation technique has been employed to investigate the reactions of Cl4MoO and MoCl2O2 with CH3OH and C2H5OH. Using twin jet deposition, the initial intermediate in the mechanism was identified as a weakly bound molecular complex, characterized by perturbations to the Mo=O and O-H stretching modes. The complex between Cl4MoO and CH3OH was destroyed by near-UV irradiation, producing the novel Cl-3-Mo(O)OCH3 species and cage-paired HCl. The complex between CH3OH and MoCl2O2 was not photosensitive. Merged jet deposition of CH3OH and Cl4MoO, with a 70 degreesC reaction zone, led to complete conversion to Cl3Mo(O)OCH3, the same product observed in after irradiation of the 1:1 complex. This species was identified by use of extensive isotopic labeling, by the observation of HCl (or DCl) as an additional reaction product, and by comparison to density functional calculations. Most of the fundamental vibrational modes of this species that lie above 400 cm(-1) were observed, some with very high intensities. C2H5OH reacted in a very similar manner with Cl4MoO, yielding Cl3Mo(O)OC2H5 and HCl. In contrast, the merged jet co-deposition of CH3OH with MoCl2O2 did not yield any reaction product.