Synthesis, crystal structure, antimicrobial activity and electrochemistry study of chromium(III) and copper(II) complexes based on semicarbazone Schiff base and azide ligands

A tridentate NNO donor Schiff base ligand HL [HL: C5H4NCH=NNHCONH2] was obtained by condensation of pyridine 2-carbaldehyde with semicarbazide. The HL and azide ligands with Cr(III) and Cu(II) ions have been used to synthesize a dinuclear complex [Cr(L)(N3)(OCH3)]2(1) and a coordination polymer complex [Cu(L)(N3)]n(2). The ligand, 1 and 2 were clearly characterised by elemental analysis, FT-IR, UV–Vis spectral studies and the structures of the 1 and 2, have been studied by single crystal X-ray diffraction analysis. The results of X-ray diffraction analysis revealed Cr(III) and Cu(II) center are coordinated in a distorted octahedral and a square pyramidal geometries for 1 and 2 respectively. The ligand and the complexes were tested for their efficiency towards antimicrobial activity and the MIC data revealed that the HL, 1 and 2 have not strong activity in comparison to the standard drugs. The electrochemistry of the HL and its complexes were studied by cyclic voltammetry.

Graphical abstractThe HL [HL: C6H5CHCNNHCONH2] and azide ligands have been used to synthesise a dinuclear complex [Cr(L)(N3)(OCH3)]2(1) and a coordination polymer complex [Cu(L)(N3)]n(2). The results of X-ray diffraction analysis revealed Cr(III) and Cu(II) centers are coordinated in distorted octahedral and square pyramidal geometries for 1 and 2 respectively.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We synthesized a tridentate NNO donor Schiff base HL ligand. ► New complexes [Cr(L)(N3)(OCH3)]2 (1) and [Cu(L)(N3)]n (2) were synthesized with HL an azide. ► The compounds 1, 2 and HL were characterized by elemental analysis and spectral studies. ► In 1 Cr(III) center is coordinated in distorted octahedral geometry. ► In 2 Cu(II) center is coordinated in distorted square pyramide geometry.