Di- and trinuclear CoII complexes of a bis-β-diketone ligand with variable conformation: structure and magnetic studies

Abstract

The bis-β-diketone-phenol ligand H₃L reacts with Co(OAc)₂ to become part of di- or trinuclear complexes in various conformations, depending on the nature of the co-ligand present in the reaction. Thus, the following series of complexes have been synthesized: [Co₂(HL)₂(Solv)₄] (Solv = py, 1; MeOH, 2), [Co₂(HL)₂(LL)₂] (LL = bpy, 3; bpya, 4; Ph₂bpy, 5; phen, 6) and [Co₃(HL)₃] (7), of which 1, 3, and 7 have been crystallographically characterized. The solvent-controlled interconversion between the trinuclear complex and dinuclear complexes 1 or 2 has been demonstrated. The distortion of the Co^II coordination geometry within 1, 3, and 7 has been evaluated through Continuous Shape Measures, whereas their magnetic data have been treated with models that include spin–orbit coupling effects.