Selective oxidation of C (sp3)-H bonds enabled by ruthenium clusters containing pyridine-alkoxide ligands

Reactions of Ru-3(CO)(12) with 6-methyl-2-pyridinyl-ethanol ligands 6-CH3-2-(PyCH2CRROH)-R-1-O-2 [R-1(sic)H, R-2(sic)2-CH3OC6H4 (L1H); R-1(sic)H, R-2(sic)2-CF3C6H4 (L2H); R-1(sic)R-2(sic)CH3 (L3H); and R-1(sic)H, R-2(sic)2,6-(CH3O)(2)C6H3 (L4H)] in refluxing THF afforded the corresponding trinuclear ruthenium clusters (6-CH3-2-(PyCH2CRRO)-R-1-O-2)(mu(2)-H)Ru-3(CO)(9) [R-1(sic)H, R-2(sic)2-CH3OC6H4 (1); R-1(sic)H, R-2(sic)2-CF3C6H4 (2); R-1(sic)R-2(sic)CH3 (3); and R-1(sic)H, R-2(sic)2,6-(CH3O)(2)C6H3 (4)], respectively. All the four new clusters were well characterized by elemental analysis, IR, H-1, and C-13 nuclear magnetic resonance. Furthermore, their crystal structures were determined by single-crystal X-ray diffraction analysis. The ruthenium clusters were proved to be efficient catalysts for the oxidation of saturated C-H bonds with tert-butyl hydroperoxide (TBHP) as the oxidant in CH3CN/H2O (1:4) at room temperature.

Automated summary

Reactions of Ru-3(CO)(12) with 6-methyl-2-pyridinyl-ethanol ligands resulted in the formation of trinuclear ruthenium clusters. The clusters were characterized by various techniques and their crystal structures were determined by X-ray diffraction analysis. The clusters exhibited efficient catalytic activity for the oxidation of saturated C-H bonds.