Spectroscopy, molecular structure, and electropolymerization of Ni(ii) and Cu(ii) complexes containing a thiophene-appending fluorinated Schiff base ligand. Issue 13 (10th March 2023)

• Record Type: Journal Article
• Authors: Ahumada, Guillermo; Hamon, Paul; Roisnel, Thierry; Dorcet, Vincent; Fuentealba, Mauricio; Hernández, Loreto A.; Carrillo, David; Hamon, Jean-René; Manzur, Carolina
• Is Part Of: Dalton transactions. Volume 52:Issue 13(2023)
• Page Start: 4224
• Page End: 4236
• Publication Date: 2023-03-10
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d3dt00224a
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Electropolymerization of the title compounds yields golden-colored deposits, with the Cu(ii ) monomer enabling the formation of thicker coatings with increased conductivity in both CV and chronoamperometry voltammetric profiles. Abstract : In this contribution, we describe the preparation, characterization, and electrochemical behavior of a series of four new mononuclear M(ii ) complexes featuring a symmetric substituted N2 O2 -tetradentate Schiff base ligand, bearing either trifluoromethyl and p -bromophenyl (M = Ni, 3 ; Cu, 4 ) or trifluoromethyl and the π-extended p -(2-thienyl)phenylene (M = Ni, 5 ; Cu, 6 ) substituents. Complexes 3 and 4 were readily synthesized by reacting the diprotic fluorinated Schiff base proligand 2 with the appropriate hydrated metal(II) acetates, whereas 5 and 6 were obtained upon Stille cross-coupling reaction of 3 and 4 with 2-(tributylstannyl)-thiophene, respectively. Compounds 3–6 were isolated as neutral, air, and thermally stable-coloured solids, with yields ranging from 60 to 80%. The four complexes, the diimine precursor 1 and its trifluoroacetylated derivative 2, were identified using analytical (EA, ESI-MS), spectroscopic (IR, 1 H, 13 C, and 19 F NMR), and X-ray crystallographic methods. X-ray crystal structure determination of complexes 3–5 revealed that both four-coordinate Ni(ii ) and Cu(ii ) metal ions adopt a square planar geometry. The magnetic properties of powdered samples of the Cu(ii ) derivatives 4 and 6 have been investigated (2–300 K) and found consistent in both cases with a single isolated copper(ii ) ion ( s = 1/2). DFT calculations were used to examine the optimal geometries of complexes 5 and 6, allowing for a consistent perspective of their structure and characteristics. The primary aspects of the UV-vis spectra were interpreted using TD-DFT computations. Finally, electrochemical data indicate that complexes 5 and 6 polymerize at high anodic potentials in acetonitrile (greater than 2.0 V vs. Ag/AgCl). Cyclic voltammetry, scanning electron microscopy, and energy-dispersive X-ray spectroscopy (SEM-EDS) analyses were used to characterize the obtained films poly-5 and poly-6 .