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

Guillermo Ahumada, Mauricio Fuentealba, Thierry Roisnel, Samia Kahlal, Ricardo Córdova, David Carrillo, Jean Yves Saillard, Jean René Hamon, Carolina Manzur

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

In 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) complexes 1–3, 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, by 1H, 13C and 19F NMR spectroscopy. In addition, the molecular identities and the geometries of the β-diketone HL and complex 3 were 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. In 3, the Cu(II) center adopts a perfect square-planar geometry. Two reduction processes were observed in the cyclovoltammogram of 3 at −1.30 and −1.80 V vs. Fc/Fc+, with copper deposit on the surface of the electrode. DFT and TD-DFT calculations on HL and complex 3 allow rationalizing their stability, bonding and properties.

Original languageEnglish
Pages (from-to)531-539
Number of pages9
JournalJournal of Molecular Structure
Volume1150
DOIs
StatePublished - 15 Dec 2017
Externally publishedYes

Keywords

  • Cobalt(II)
  • DFT and TD-DFT calculations
  • Diketonate complex
  • Nickel(II) and copper(II)
  • Single-crystal X-ray diffraction
  • Thiophene

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