Synthesis, characterization, crystal structures and in vitro antistaphylococcal activity of organotin(IV) derivatives with 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidine

Abstract

New organotin(IV) complexes of 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp) and 5,7-diphenyl-1,2,4-triazolo [1,5-a]pyrimidine (dptp) with 1:1 and/or 1:2 stoichiometry were synthesized and investigated by X-ray diffraction, Sn Mössbauer in the solid state and by 1 H and 13 C NMR spectroscopy, in solution. Moreover, the crystal and molecular structures of Et 2 SnCl 2 (dbtp) 2 and Ph 2 SnCl 2 (EtOH) 2 (dptp) 2 are reported. The complexes contain hexacoordinated tin atoms: in Et 2 SnCl 2 (dbtp) 2 two 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine molecules coordinate classically the tin atom through N(3) atom and the coordination around the tin atom shows a skew trapezoidal structure with axial ethyl groups. In Ph 2 SnCl 2 (EtOH) 2 (dptp) 2 two ethanol molecules coordinate tin through the oxygen atom and the 5,7-diphenyl-1,2,4-triazolo [1,5-a]pyrimidine molecules are not directly bound to the metal center but strictly H-bonded, through N (3), to the \OH group of the ethanol moieties; Ph 2 SnCl 2 (EtOH) 2 (dptp) 2 has an all-trans structure and the C-Sn-C fragment is linear. On the basis of Mössbauer data, the 1:2 diorganotin(IV) complexes are advanced to have the same structure of Et 2 SnCl 2 (dbtp) 2 , while Me 2 SnCl 2 (dptp) 2 to have a regular all-trans octahedral structure. A distorted cis-R 2 trigonal bipyramidal structure is assigned to 1:1 diorganotin(IV) complexes. The in vitro antibacterial activities of the synthesized complexes have been tested against a group of reference pathogen micro-organisms and some of them resulted active with MIC values of 5 μg/mL, most of all against staphylococcal strains, which shows their inhibitory effect.

Organotin(IV) derivatives with 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidine and their cytotoxic activities: The importance of being conformers

“…Significant bond distances and angles are reported in Table 2. In agreement with IR and Mössbauer evidences [13], n Bu 2 SnCl 2 (dptp) is a five-coordinated Sn species; X-ray diffraction studies confirm a distorted trigonal bipyramidal geometry with N, Cl as axial atoms and Cl and butyl groups in the equatorial plane. The triazolopyrimidine unit coordinates to the Sn atom through N(3) in a monodentate mode, with Sn-N(3) bond distance of 2.576(8) and 2.556(8) Å for molecule A and B respectively, trans to Cl(2), Sn-Cl(2) 2.439(4) and 2.436(4) Å for molecule A and B respectively (Fig.…”

“…The apoptosis of HepG2 cells induced by the most active complexes was also investigated using flow cytometry as well as fluorescence microscopy. Moreover, crystal structure of n Bu 2 SnCl 2 (dptp), 7, whose spectroscopical parameters have been previously reported [13], is also discussed. Crystals of 7, suitable for the X-ray diffraction studies, were grown on slow evaporation of a methanol solution of the complex (Fig.…”

“…Recently, we described complexes of diorganotin(IV) dichlorides with the heterocyclic ligands [1,2,4] [12], 5,7-ditertbutyl-1,2,4-triazolo [1,5-a]pyrimidine (dbtp) and 5,7-diphenyl-1,2,4-triazolo [1,5-a]pyrimidine (dptp) [13] that exhibit antibacterial activity against a group of reference pathogen micro-organisms, thus showing antibacterial activities against a group of reference pathogen micro-organisms, which shows their inhibitory effect. In vitro antimicrobial tests showed that n Bu 2 SnCl 2 (dmtp) [12] has interesting properties as anti Grampositive and antibiofilm agent.…”

“…We here investigate inhibitory effects of complexes with triazolopyrimidine on the growth of a number of human malignant cell lines and assess the influence of the substituents (tert-butyl or phenyl) attached to the heterocyclic ring and the type of alkyl or phenyl groups attached to the tin atom, on their biological activity. The formerly characterized organotin(IV) compounds [13] (9). All complexes were evaluated for their in vitro anti-proliferative activity against three human cancer cell lines: HepG2 (human hepatocellular carcinoma), HeLa (human cervix adenocarcinoma) and MCF-7 (human breast cancer).…”

Synthesis of platinum complexes with 2-(5-perfluoroalkyl-1,2,4-oxadiazol-3yl)-pyridine and 2-(3-perfluoroalkyl-1-methyl-1,2,4-triazole-5yl)-pyridine ligands and their in vitro antitumor activity

“…This activity has been attributed to their DNA-binding properties [22]. In the same way, triazole rings have been widely studied as bioactive moieties [23] and also have been used as ligands in order to synthesize cytotoxic platinum, palladium and organotin(IV) complexes [24][25][26][27].…”