New complexes of zinc( ii ) and copper( ii ) with 2-furoic acid (Hfur), acetic acids and N-donor ligands with the compositions [Zn ₂ (fur) ₄ ] _n , [Zn ₂ (fur) ₄ (NH ₂ py) ₂ ], [Zn(fur) ₂ (neoc)], [Zn(OAc) ₂ (neoc)], and [Cu(fur) ₂ (neoc)(H ₂ O)] were synthesized.

A new silver(I) cluster [Ag₈L₄(Py)(Pype)]·4Py·11H₂O (I) with 3-benzyl-4-phenyl-1,2,4-triazol-5-thiol (L) was synthesized via the direct reaction of AgNO₃ and L in MeOH, followed by recrystallization from a pyridine–piperidine mixture. The compound I was isolated in a monocrystal form and its crystal structure was determined via single crystal X-ray diffraction. The complex forms a “butterfly” cluster with triazol-5-thioles. The purity of the silver complex and its stability in the solution was confirmed via NMR analysis. Excitation and emission of the free ligand and its silver complex were studied at room temperature for solid samples. The in vitro biological activity of the free ligand and its complex was studied in relation to the non-pathogenic Mycolicibacterium smegmatis strain. Complexation of the free ligand with silver increases the biological activity of the former by almost twenty times. For the newly obtained silver cluster, a bactericidal effect was established.