Oxidative Atom-Transfer to a Trimanganese Complex To Form Mn_6(μ~6-E) (E = O, N) Clusters Featuring Interstitial Oxide and Nitride Functionalities

摘要

Utilizing a hexadentate ligand platform, a trinuclear manganese complex of the type (~HL)Mn_3(thf)_3 was synthesized and characterized ([~HL]~(6-) = [MeC-(CH_2N(C_6H_4-o-NH))_3]~(6-)). The pale-orange, formally divalent trimanganese complex rapidly reacts with O-atom transfer reagents to afford the μ~6 -oxo complex (~HL)_2Mn_6-(μ~6-O)(NCMe)_4, where two trinuclear subunits bind the central O-atom and the (~HL) ligands cooperatively bind both trinuclear subunits. The trimanganese complex (~HL)Mn_3-(thf)_3 rapidly consumes inorganic azide ([N_3]NBu_4) to afford a dianionic hexanudear nitride complex [(~HL)_2Mn_6-(μ~6 -N)] (NBu_4)_2, which subsequently can be oxidized with elemental iodine to (~HL)_2Mn6(μ~6-N)(NCMe)_4. EPR and alkylation of the interstitial light atom substituent were used to distinguish the nitride from the oxo complex. The oxo and oxidized nitride complexes give rise to well-defined Mn(II) andMn(III) sites, determined by bond valence summation, while the dianionic nitride shows a more symmetric complex, giving rise to indistinguishable ion oxidation states based on crystal structure bond metrics.