Spectroscopic, structural, electrochemical and computational studies of some new 2-thienyl-containing β-diketonate complexes of cobalt(II), nickel(II) and copper(II)

摘要

AbstractIn this work, we present the synthesis of the unsymmetrical β-diketone 1-(2-thienyl)-3-(4-fluorophenyl)-propane-1,3-dione(HL) and its corresponding Co(II), Ni(II) and Cu(II)bis(β-diketonato) complexes1–3, respectively. The four new compounds were isolated in good yields (65–70%), and characterized by mass spectrometry, elemental analysis, FT-IR and UV–Vis spectroscopy and, in the case of HL, by1H,13C and19F NMR spectroscopy. In addition, the molecular identities and the geometries of the β-diketone HL and complex3were confirmed by X-ray diffraction analysis. The dicarbonyl derivative HL does exist as the diketo tautomeric form in DMSO solution and as its keto-enol tautomer in the solid-state with the OH group adjacent to the 4-fluorophenyl unit. The keto-enol isomer was computed to be more stable by 8.2?kcal/mol in free energy at room temperature. In3, the Cu(II) center adopts a perfect square-planar geometry. Two reduction processes were observed in the cyclovoltammogram of3?at??1.30 and??1.80?Vvs.Fc/Fc+, with copper deposit on the surface of the electrode. DFT and TD-DFT calculations on HL and complex3allow rationalizing their stability, bonding and properties.Graphical abstractDisplay OmittedHighlights?Synthesis of 1-(2-thienyl)-3-(4-fluorophenyl)- propane-1,3-dione? Synthesis ofbis(β-diketonate) Co(II), Ni(II) and Cu(II) complexes?Crystal structures of ligand precursor and ofbis(β-diketonate) Cu(II) complex?Geometry optimization and analysis of electronic structure using DFT calculations?Interpretation of the major features of UV-vis spectra using TDDFT calculations]]>