Catalytic sulfoxidation and epoxidation using oxomolybdenum compounds generated from tricarbonyl(1-methylimidazole)molybdenum(0)

The scope of molybdenum carbonyl precatalysts has been expanded to include [Mo(CO) 3 (1-mim) 3 ] ( 1 ) (1-mim = 1-methylimidazole) for application in epoxidation and sulfoxidation processes, using relatively ecofriendly and industrially used oxidants. The mechanisms of conversion of 1 to active species were investigated by systematically combining catalytic and characterization studies. With tert -butylhydroperoxide (TBHP), 1 gives the functionalized polyoxomolybdate (1-Hmim) 4 [Mo 8 O 26 (1-mim) 2 ]·2H 2 O ( 2 ), which then leads to the stable salt (1-Hmim) 4 [Mo 8 O 26 ]·2H 2 O ( 3 ) containing β -octamolybdate molecular anions. With H 2 O 2 , 1 gives a structurally distinct octamolybdate, (1-Hmim) 4 [Mo 8 O 26 ] ( 4 ), with characterization data that point to the presence of [Mo 8 O 26 ] n 4 n − chains. In the reactions of cis -cyclooctene or dl-limonene with H 2 O 2 , 4 is a reaction-induced self-separating catalyst, i.e., in the initial stages it dissolves to give a homogeneous solution, but then self-precipitates once the oxidant is consumed. In the sulfoxidation of methyl phenyl sulfide, 4 was effective in producing the sulfoxide selectively with TBHP, and the sulfone with H 2 O 2 . • Application of [Mo(CO) 3 (1-methylimidazole) 3 ] ( 1 ) in epoxidation and sulfoxidation. • Ex situ and in situ studies to characterize oxidative decarbonylation pathways of 1 . • Three different 1-methylimidazolium octamolybdate hybrids isolated starting from 1 . • (1-Hmim) 4 [Mo 8 O 26 ] ( 4 ) acts as a reaction-induced self-separating catalyst with H 2 O 2 . • 4 /H 2 O 2 system effective for producing diol from dl-limonene and sulfone from PhSMe.