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

The bis-beta-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: [Co-2(HL)(2)(Solv)(4)] (Solv = py, 1; MeOH, 2), [Co-2(HL)(2)(LL)(2)] (LL = bpy, 3; bpya, 4; Ph(2)bpy, 5; phen, 6) and [Co-3(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.