Oxidative Atom-Transfer to a Trimanganese Complex To Form Mn6(μ6-E) (E = O, N) Clusters Featuring Interstitial Oxide and Nitride Functionalities

Utilizing a hexadentate ligand platform, a trinuclear manganese complex of the typEe (L-H)Mn-3(thf)(3) was synthesized and characterized ([L-H](6-) = [MeC-(CH2N(C6H4-o-NH))(3)](6-)). The pale-orange, formally divalent trimanganese complex rapidly reacts with O-atom transfer reagents to afford the mu(6)-oxo complex (L-H)(2)Mn-6-(mu(6)-O)(NCMe)(4), where two trinuclear subunits bind the central O-atom and the (L-H) ligands cooperatively bind both trinuclear subunits. The trimanganese complex (L-H)Mn-3-(thf)(3) rapidly consumes inorganic azide ([N-3]NBu4) to afford a dianionic hexanuclear nitride complex [(L-H)(2)Mn-6-(mu(6)-N)](NBu4)(2), which subsequently can be oxidized with elemental iodine to (L-H)(2)Mn-6(mu(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) and Mn(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.