Département de chimie moléculaire

This study deals with the unprecedented reactivity of dinuclear nonheme MnII-thiolate complexes, [Mn2(L)(HL)], with O2, which dependent on the protonation state of the initial MnII dimer selectively generates either a di-μ-oxo or μ-oxo-μ-hydroxo MnIV complex [Mn2(O)2(L)2] (HL = 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(1,1'-diphenylethanethiol)). Both dimers were characterized by different techniques including single-crystal x-ray diffraction and mass spectrometry. Oxygenation reactions carried out with labeled 18O2 unambiguously show that the oxygen atoms present in the MnIV dimers originate from O2. Based on exptl. observations and DFT calcns., evidence is provided that these MnIV species comproportionate with a MnII precursor to yield μ-oxo and/or μ-hydroxo MnIII dimers. The work highlights the delicate balance of reaction conditions to control the synthesis of nonheme high-valent μ-oxo and μ-hydroxo Mn species from MnII precursors and O2. [on SciFinder(R)]