Synthesis, crystal structure, characterisation, and antifungal activity of 3-thiophene aldehyde semicarbazone (3STCH), 2,3-thiophene dicarboxaldehyde bis(semicarbazone) (2,3BSTCH2) and their nickel (II) complexes

The reaction of nickel (II) chloride and bromide with 3-thiophene aldehyde semicarbazone (3STCH) and 2,3-thiophene dicarboxaldehyde bis(semicarbazone) (2,3BSTCH2) leads to the formation of a series of new complexes: [NiCl2(3STCH)2], [NiBr2(3STCH)2], [NiCl(2,3BSTCH2)(H2O)]Cl, and [NiBr(2,3BSTCH2)(H2O)]Br respectively. The crystal structures of the two ligands 3STCH, 2,3BSTCH2 and of the complex [NiBr(2,3BSTCH2)(H2O)]Br have been determined by X-ray diffraction methods. For all these complexes, the central ion is coordinated through the oxygen atom of the carbonyle and the azomethine nitrogen atom of the semicarbazone. The antifungal activity of the complexes and their corresponding ligands was evaluated against some strains of respectively, Candida albicans, Candida glabrata and Aspergillus fumigatus. The complexes with 3STCH and 2,3BSTCH2 revealed interesting CMI80 values specifically against C. glabrata. Cytotoxicity assay was also carried out in vitro on MRC5 cells.

Graphical abstractThe reaction of nickel (II) chloride and bromide with 3-thiophene aldehyde semicarbazone (3STCH) and 2,3-thiophene dicarboxaldehyde bis(semicarbazone) (2,3BSTCH2) leads to the formation of complexes: [NiCl2(3STCH)2], [NiBr2(3STCH)2], [NiCl(2,3BSTCH2)(H2O)]Cl, and [NiBr(2,3BSTCH2)(H2O)]Br shown in this crystal structure.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Use of thiophene 3-carboxaldehyde semicarbazone. ► Use of 2,3-thiophene dicarboxaldehyde bis(semicarbazone). ► Crystal structure of the two ligands. ► Crystal structure of the nickel(II) bromide complex with bis(semicarbazone).