1,1-Azido bridge driven aggregation of a centrosymmetric trinuclear linear CoIIICoIICoIII complex

Reactions of Co(OAc)2 · 4H2O with NaQ (sodium salt of 8-quinolinol) in methanol in absence and presence of NaN3 give the mononuclear complex mer-CoQ3 · MeOH (1) and a linear trinuclear mixed valence complex [Co3(N3)4Q4(OH2)2] · 2H2O (2). Presence of N3- ions prevents the formation of tris chelate leading to an aggregation to 2. Four N3- anions bridges three cobalt ions all in μ-1,1 coordination mode, resulting in a trinuclear structure with a center of inversion. The complex contains a high-spin CoII and two terminal low-spin CoIII.

A trinuclear mixed valence linear Co2IIICoII complex with only EO azido bridge has been assembled and identified in the solid state from a reaction of metal salt and ligand in presence of N3- ions. In absence of N3- ions the mononuclear tris chelate is formed exclusively.Figure optionsDownload as PowerPoint slide