New Polydentate Ligand and Catalytic Properties of the Corresponding Ruthenium Complex During Sulfoxidation and Alkene Epoxidation.

Bis(diimine)-ruthenium complexes constitute a class of catalysts with good activity for oxidn. reactions, such as sulfoxidn. and epoxidn. The synthesis and the full characterization of a new ruthenium complex [Ru(L5pyr)(CH3CN)][PF6]2 bearing an original pentadentate ligand (L5pyr = 2,6-bis-(6-ethyl-2,2'-bipyridyl)-pyridine) is reported. Comparison of its activity with regard to [Ru(bpy)2(CH3CN)2]2+ and [Ru(bpy)2(py)(CH3CN)]2+ during alkene and sulfide oxidn. allowed us to conclude that the addn. of a fifth pyridine ligand in the coordination sphere improves the efficiency of the catalyst. Moreover, under these oxidn. conditions a hydroxylation of the ligand L5pyr led to a better activity than its analog [Ru(bpy)2(py)(CH3CN)]2+, esp. during epoxidn. of alkenes by PhI(OAc)2. [on SciFinder(R)]


Soumis le 12 avril 2018