pH Dependent formations of dinuclear molybdenum(V) and incomplete cubane molybdenum(IV) complexes with nitrilotriacetate

Nitrilotriacetato oxomolybdenum(V) dinuclear complex (NH4)4[cis-Mo2O4(nta)2] · 7H2O (1) (H3nta = nitrilotriacetic acid) and its incomplete cubane-type trinuclear molybdenum(IV) complex [Mo3O(OH)3(Hnta)3] · Cl · 3H2O (2) are isolated in a weak acidic and an acidic solutions, respectively (pH 4.5 and 1.0). The nitrilotriacetate ligand in the anion 1 or the cation 2 displays tridentate mode through the nitrogen atom and the oxygen atoms of β-carboxy groups. Unusual protonations of bridged oxygen atoms in 2 have not effect on the skeleton of molybdenum(IV) cap Mo3O unit. There are obvious dissociations of molybdenum(V) complexes based on 13C NMR observations in solution.

Formations of nitrilotriacetato oxomolybdenum(V) dinuclear complex (NH4)4[cis-Mo2O4(nta)2] · 7H2O and its incomplete cubane-type trinuclear molybdenum(IV) complex [Mo3O(OH)3(Hnta)3] · Cl · 3H2O show a pH dependent reaction pattern.Figure optionsDownload as PowerPoint slide