Chelating behavior of 3-amino-4,6-dimethyl-1H-pyrazolo[3,4-b]pyridine ligand towards some metal ions, spectral and thermal measurements as well as molecular modeling and biological studies

Abstract The 3-amino-4,6-dimethyl-1H-pyrazolo [3,4-b]pyridine ligand and its Mn(II), Pd(II), Fe(III), Cr(III), Ru(III), Hf(IV), Zr(IV) and UO2(II) metal complexes were synthesized and characterized by means of elemental analysis, spectral studies and thermal investigation. Also, the theoretical studies that done by Spartan ‘14 V1.1.4 software supported the experimental studies. The infrared data suggest that the ligand coordinates to the metal ions as a neutral monodentate moiety through nitrogen atom of amino group. The complexes are formed with 1:2 and 1:3 (M:L) molar ratios. All complexes possesses octahedral geometry except the Pd(II) complex that presents a square planar geometry. Thermal analyses (TGA and DTG) of ligand and its metal complexes are performed in order to identify the external solvents molecules and thermal stability ranges of the complexes. The X-ray diffraction studies suggest orthorhombic structure of P type lattice for Pd(II) complex and monoclinic structure of P type lattice for Cr(III) and Zr(IV). Theoretical calculations are performed to corroborate the experimental results. Some theoretical parameters are reported in order to compare the reactivity of the compounds. The cytotoxic activity of the ligand and its Pd(II) and Ru(III) complexes is evaluated against breast MCF-7 cell line. Pd(II) complex presents a higher activity. The synthesized ligand and its Pd(II), Cr(III) and Zr(IV) metal complexes also are screened for antibacterial activity. The ligand and its tested complexes has weak activity towards a Gram-positive bacteria and no activity towards Gram-negative bacteria except Pd(II) complex.