Trinuclear oxothiomolybdenum(IV) glycolates (H(2)glyc, glycolic acid) with 2-methylimidazole (2-mim), 4-methylimidazole (4-mim), and sulfite, Na-2 [Mo-3(IV)(mu(3)-S) (mu(2)-O)(3)(glyc)(3)(2-mim)(3)]center dot 1.5H(2)O (1), (4-Hmim)(6) [Mo-3(IV)(mu(3)-S)(mu(2)-O)(3)(glyc)(3)(4-mim)(3)](2) [(MoO2)-O-IV(glyc)(2)] (2), and Na-3(4-Hmim)[Mo-3(IV)(mu(3)-S)(mu(2)-O)(3)(SO3)(glyc)(3)(4-mim)]center dot 8H(2)O (3), have been isolated in reduced media, where 4-methylimidazole trinuclear oxothiomolybdenum(IV) glycolates in 2 coprecipitate with dioxomolybdenum(VI) glycolate, exhibiting unusual mixed valences of 4+ and 6+. Large downfield shifts of glycolates have been observed in solid-state and solution C-13 (H-1) NMR spectra with coordination to Mo, indicating obvious dissociation of soluble 1 and 3 in solution. Investigations of the coordination modes and conversions among the three complexes give insight into the reactivities of trinuclear oxothiomolybdenum(IV) complexes. Channels with 3.1 x 7.0 angstrom(2) diameters exist in 2, showing reversible O-2 absorption of 65.03 mg at 29.9 bar compared with little or no adsorption of N-2, H-2, CO2, and CH4 at room temperature, respectively. Moreover, trinuclear 2- or 4-methylimidazole oxothiomolybdenum(IV) glycolates 1 and 3 show only a few adsorptions for O-2 under the same conditions.