Thermal behaviour of some biologically active species based on complexes with a triazolopyrimidine pharmacophore

Abstract

A series of complexes of type M(pmtp)(CH 3 COO) 2 ÁnH 2 O ((1) M: Co, n = 4.5; (2) M: Ni, n = 3.5; (3) M: Cu, n = 0.5; (4) M: Zn, n = 0; pmtp: 5-phenyl-7-methyl-1,2,4-triazolo[1,5-a]pyrimidine) were synthesised by one-pot condensation. The complexes were characterized by elemental analysis, ESI-MS, IR, UV-Vis-NIR, EPR spectra, magnetic susceptibility at room temperature as well as thermogravimetric analysis. The modifications in the IR spectra of complexes are in accordance with the condensation process and indicate the triazolopyrimidine coordination as unidentate. The electronic and EPR spectra together with magnetic moments indicate an octahedral stereochemistry for paramagnetic ions, except for Cu(II) with a square pyramidal geometry. Processes such as water elimination, acetate into carbonate transformation, as well as oxidative degradation of the triazolopyrimidine derivative were evidenced during thermal decomposition. The complexes exhibited an improved antimicrobial activity in comparison with the ligand, on both planktonic and biofilm-embedded microbial cells. The best antimicrobial activity in both susceptible and resistant strains was obtained for complex (3) followed by complex (1), which can be related to both oxidation state and stereochemical versatility. At high concentrations, the Cu(II) complex exhibits both cytotoxicity on HT 29 tumour cell line and anti-inflammatory activity.

Coordination behaviour, molecular docking, density functional theory calculations and biological activity studies of some transition metal complexes of bis‐Schiff base ligand

“…This assignment and the general observation were in agreement with the fact that the Cu (II) d–d transitions are normally close in energy. Note that the magnetic moment of this complex was 2.8 BM, which falls within the range normally observed for octahedral Cu (II) complexes …”

“…Its diffuse reflectance spectrum showed three bands at 15 345 (ν 1 ), 16 267 (ν 2 ) and 21 475 cm −1 (ν 3 ), which were assigned to 3 A 2g (F)→ 3 T 2g (F), 3 A 2g (F)→ 3 T 1g (F) and 3 A 2g (F)→ 3 T 1g (P) transitions, respectively. The spectrum of the Mn (II) complex showed three bands at 15554, 17475 and 26877 cm −1 which correspond to 4 T 1g → 6 A 1g , 4 T 2g (G) → 6 A 1g and 4 T 1g (D) → 6 A 1g transitions, respectively . The complex had a magnetic moment value 5.58 BM, which confirmed octahedral geometry around the Mn (II) ion.…”

Coordination behaviour and biological activity studies involving theoretical docking of bis‐Schiff base ligand and some of its transition metal complexes

“…The study of complexes containing iron ions with azomethine ligand has been of particular interest and the solvent in the reaction medium was one of the most important factors governing both the yield and the structure of the products. The nitrogen donor atoms present in the structure of Schiff base ligands act as good chelating agents for metal ions . Coordination of such Schiff base ligands with transition metal ions often leads to an increase in activity .…”

Synthesis, Spectroscopic Characterization, Molecular Docking, and Evaluation of Antibacterial Potential of Transition Metal Complexes Obtained Using Triazole Chelating Ligand

“…e subtle reflectance spectra for Fe(III) complex indicated a signal at 21,362 cm − 1 , possibly specified toward 6 A lg ⟶ T 2g (G) conversion into octahedral geometry belonging to complex [33][34][35]. e transition 6 A 1g ⟶ 4 T 2g (G) and 6 A 1g ⟶ 4 T 1 g was split into two signals at 17,642 and 12,784 cm − 1 .…”