Synthesis, structure and biological activity of nickel(II) complexes of 5-methyl 2-furfural thiosemicarbazone

5-Methyl 2-furfuraldehyde thiosemicarbazone (M5HFTSC) with nickel(H) leads to three types of complexes: [Ni(M5HFTSC)(2)X-2], [Ni(M5FrSC)(2)] and [Ni(M5FTSC)(2)]. 2DMF. In the first type the ligand remains in thione form, while in the two other, the anionic thiolato form is involved. The species [Ni(M5HFTSC)(2)X-2] has been characterized spectroscopically. The structures of [Ni(M5FrSC)(2)]. 2DMF and [Ni(M5FFSC)(2)] have been solved using X-ray diffraction. Biological studies of [Ni(M5HFTSC)(2)Cl-2] have been carried out in vitro for antifungal activity on human pathogenic fungi, Aspergillus fumigatus and Candida albicans, and in vivo for toxicity on mice. The results are compared to those of the ligand, the metal salt and a similar copper complex [Cu(M5HFTSC)Cl-2]. (C) 2001 Elsevier Science B.V. All rights reserved.