Solvent dependent formation of Cu (II) complexes based on isonicotinamide ligand

Abstract

Five solvent-dependent Cu(II) compounds have been synthesized with [Cu(μ-OAc)(μ-Pip)(MeOH)]2 (OAc = acetate; Pip = 1,3-benzodioxolecarboxylate) and isonicotinamide (Isn) as an auxiliary ligand in different solvents. In all the compounds, Pip units are displaced resulting in dimeric [Cu(μ-OAc)(OAc)(Isn)2(solvent)]2 (solvent = MeOH (2a), dmf and H2O (3) or H2O and HPip (4a)), paddle-wheel [Cu(μ-OAc)2(Isn)]2·2dmso (5) or monomeric compounds [Cu(OAc)2(HOAc)(Isn)2]·HOAc (6). All of them have been characterized by analytical and ATR-FTIR techniques and their X-ray crystal structures solved. The OAc anions construct different arrays and exhibit different coordination modes depending on the solvent used. The supramolecular expansion is constantly determined by the amide-amide pattern and the role of the occluded solvent molecules. This tendency is confirmed by Hirshfeld Surface analysis. Finally, the thermal stability of compound 4a has been analyzed.