Thiophene-containing β-diketonate complex of copper(II): X-ray crystal structure and electropolymerization

Abstract

International audienceIn this work, we report the synthesis of the asymmetrical β-diketone 1-(thiophen-2-yl)-3-(thiophen-3-yl)propane-1,3-dione (HL) and its corresponding bis(β-diketonate)copper(II) complex [Cu₁-(thiophen-2-yl)-3-(thiophen-3-yl)-1,3-propanedionate₂] (CuL2), isolated in 60 and 86% yields, respectively. These two new compounds have been characterized by elemental analysis, FT-IR and UV–Vis spectroscopy and, in the case of HL, by 1H and 13C NMR spectroscopy. Additionally, both compounds were authenticated by X-ray diffraction analysis. The β-diketone HL exists as its keto-enol tautomer both in solution and in the solid-state with the [sbnd]OH group adjacent to the 3-thienyl unit. The CuL2 is essentially flat and the Cu(II) center adopts a perfect square planar geometry. The CuL2 modified electrode was fabricated through the electropolymerization of the monomer in a 0.1 M of tetrabutylammonium tetrafluoroborate (TBATFB) in anhydrous acetonitrile solution, in the potential window −1.0 V to 1.6 V. The thin film Pt|(CuL2)n modified electrode response was studied employing a 0.1 M of TBATFB solution in CH3CN. Likewise, the potentiostatic method was also employed to synthesize the films on Fluorine Doped Tin Oxide electrode (FTO). Images from the electrode surface were obtained using Scanning Electron Microscopy (SEM)

Synthesis, structures, electrochemical and quantum chemical investigations of Ni(ii) and Cu(ii) complexes with a tetradentate Schiff base derived from 1-(2-thienyl)-1,3-butanedione

“…The 2-thienyl rings are strongly disordered thus precluding any further discussion of their metrical parameters. We previously observed such a disorder, albeit much weaker, in structures of thiophen-containing compounds solved at low temperature [18][19][20]. All close intermolecular contacts correspond to van der Waals interactions.…”

“…synthesized by us. 18,29,30 In any case, it should be noted that both deposits have a fully reversible charge response, as is the case with the other thiophene derivatives studied, they have been proposed to be tested as battery cathodes. 30,31 These results, which do not seem very auspicious in that sense, will allow to propose structural modifications in search of the preparation of metal containing polymers.…”

“…[15][16][17] In this context, we have recently disclosed the generation and characterization of a polythienyl-containing β-diketonate copper(II) compound and its deposition on an electrode, upon electropolymerization of the [Cu(II)-bis-{1-(2-thienyl)-3-(3-thienyl)propane-1,3-dionato}] complex using potentiodynamic method. 18 By contrast, no deposits of polymeric species on the electrode surface could be observed upon changing the thiophen-3-yl group for the more electron-withdrawing 4-fluorophenyl unit. 19 A similar observation was made with a series of cobalt(II), nickel(II) and copper(II) complexes of a fluorinated Schiff base ligand formally resulting from the condensation of 2-thenoyltrifluoroacetone (TTA) with 1,2diaminoethane; cyclic voltammograms of these complexes displayed indeed oxidation waves, but none of them formed polymer films upon repeated cycling.…”

Octahedral bis(2-thenoyltrifluoroacetonato)-ethylenediamine Co(II), Ni(II) and Cu(II) complexes: Synthetic, structural, electrochemical, and theoretical studies

“…This lack of massive deposit of polymer could be attributed to either the weak contribution of the 2-thienyl group to the spin density or to the electron-attracting effect of the CF 3 moieties that limits the extension of the electropolimerization and does only allow the formation of soluble short oligomers with low molecular weight. Very recently, we have shown that when the CF 3 substituent is absent in the thienyl-containing β-diketonate structure, polymeric massive deposits can be obtained on the electrode surface [55]. …”

Crystal structure of 4-amino-3-(thiophen-3-ylmethyl)-1H-1,2,4-triazole-5(4H)-thione

“…Recently, the synthesis, characterization and antifungal activities, together with crystal structure determinations, of thiophene-based heterocyclic chalcones have been investigated (Ming et al, 2017). Thiophene-containing -diketonate complexes of copper(II) have been studied and their deposits obtained by electropolymerization have been characterized (Oyarce et al, 2017). Combinations of the thiophene ring with other heterocyclic rings have also been investigated, such as a -keto-enol group embedded with thiophene and pyridine moieties giving interesting applications in the field of solidphase extraction (Radi et al, 2016).…”