Tetrathiafulvalene Schiff base Cu(II) 1D coordination polymer upon a metallo-ligand approach

TTF-salicylaldehyde 1 has been prepared by Stille coupling between TTF-SnMe3 and 5-bromo-salicylaldehyde and characterized by single crystal X-ray structure analysis. A set of S center dot center dot center dot S, pi-pi and donoracceptor intermolecular interactions is observed in the solid state architecture of this precursor. Its condensation reaction with 2-ethanolamine provided the chelating electroactive ligand 4-TTF-2-((2-hydroxyethyl)iminomethyl)-phenol 2 (H2L1). Reaction with Cu(OAc)(2) in a 2:1 stoichiometry afforded the one-dimensional coordination chain-like polymer [Cu(HL1)(2)](n) 3 for which the solid state structure has been determined. The Cu(II) coordination sphere contains in the equatorial plane a N2O2 motif arising from two chelating imino-phenol units, while the axial positions are occupied by hydroxo ligands from the pendant hydroxy-ethyl arms of top and bottom neighbouring intra-chain complexes with quite larger Cu-O distances indicative of Jahn-Teller elongation. The TTF units form regular stacks within the chains and further interact laterally through short S center dot center dot center dot S contacts. Cyclic voltammetry measurements on ligand 2 and complex 3 indicate excellent electron donating properties of these multifunctional precursors. (C) 2017 Elsevier B.V. All rights reserved.