Syntheses, structures and spectral characterization of copper(II) and dioxidovanadium(V) complexes with salicylidene-aminoguanidine

The reaction of SalAG·HNO3 with Cu(OAc)2·H2O in the presence of NH4SCN and NaN3 resulted in formation of the complexes [Cu(SalAG–H)NCS] and [Cu2(SalAG–H)2(N3)2], respectively, while this ligand with NH4VO3 produced [VO2(SalAG–H)]. In the complexes, the ligand is coordinated as a monoanion, in a tridentate ONN mode, via phenolic oxygen atom and nitrogen atoms of azomethine and imino groups of the aminoguanidine fragment. The ligand and its complexes were characterized by elemental analysis, IR, NMR and UV–Vis spectroscopy, and single crystal X-ray diffraction analysis. Cyclic voltammetric studies of the ligand and copper(II) complexes in DMF show that electron transfers are complicated by following chemical reactions.

Graphical abstractSyntheses and characterization of the complexes [Cu(SalAG–H)NCS], [Cu2(SalAG–H)2(N3)2] and [VO2(SalAG–H)] with salicylidene-aminoguanidine (SalAG) are presented. Monoanionic SalAG−H is coordinated as a tridentate ONN ligand. Electrochemical characterization showed that the copper(II) complexes in DMF are present in two complex forms which may be reduced in separate electrode processes.Figure optionsDownload full-size imageDownload as PowerPoint slide