Synthesis, spectral characterization, thermal studies and biological activity of (Z)‐5‐((1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)diazenyl)‐6‐hydroxy‐2‐mercaptopyrimidin‐4(3H)‐one and its metal complexes

Abstract

Z)-5-((1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)diazenyl)-6hydroxy-2-mercaptopyrimidin-4(3H)-one (H 3 L) was exploited as a ligand for the synthesis of a series of metal complexes, where the metal was Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), Cr(III) and Ru(III). The structural features of the ligand and the synthesized complexes were characterized using various analytical, spectral and thermal measurements. Infrared spectra showed that the ligand coordinates to all metal ions in a neutral keto-enol-thiol manner. It behaves in a tetradentate fashion in all binuclear complexes except the Cr(III) complex, where it is hexadentate, and in a tridentate fashion in mononuclear complexes. The azo group participates in chelation only in the case of binuclear complexes. All complexes exhibit octahedral geometry except Pd(II) and Cu(II) acetate which are square planar and square pyramidal, respectively. Kinetic parameters were computed from thermal decomposition data. Axial electron spin resonance spectra were obtained for Cu(II) complexes indicating (d x 2 −y 2 ) 1 as a ground state with small g || values affording strong interaction between the ligand and metal ions. The biological measurements reveal that the ligand has antioxidant activity relative to the metal complexes, while the metal complexes have cytotoxicity in comparison to the free ligand. KEYWORDSantioxidant and anticancer activity, azodye ligand, metal complexes, spectral methods, thermal studies

Synthesis and Characterization of VO2+, Co2+, Ni2+, Cu2+ and Zn2+ Complexes of a Schiff base ligand derived from ethyl 2‐amino‐6‐ethyl‐4,5,6,7‐tetrahydrothieno[2,3‐c]pyridine‐3‐carboxylate and their Investigation as fungicide Agents

“…These possess a vital role in organic, inorganic, medicinal chemistry and biological field owing to their structures; furthermore, these have an imperative role in the theme of coordination chemistry, particularly in the development of complexes owing to its facility to produce stable organo‐metal compounds with transition metal ions. Schiff bases and their complexes are versatile extensively used for industrial goals and expose a contrasting broad range of biological activities include, antifungal, antibacterial, Anti‐leishmanial, anti‐molluscicidal, antimalarial, anti‐proliferative, anti‐inflammatory, antitumor, anti‐amoebic, antiviral, antioxidant and antipyretic properties. The Schiff base ligands derived from o ‐vanillin connected with Pd atom forming metal complexes showed a cytotoxic effect on three cancer cell lines: breast (MCF‐7), lung (A549) and ovarian (SKOV3) .…”

Structural characterization, thermal investigation and biological activity of metal complexes containing Schiff Base ligand (Z)‐3‐(1‐((4,6‐dimethyl‐1H‐pyrazolo[3,4‐b] pyridin‐3‐yl)imino)ethyl)‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one

“…All metal complexes are stable, non‐hydroscopic and partially soluble in aprotic organic solvents, but they are freely soluble in DMF and DMSO. The molar conductance values are recorded within range; 10–48 Ω −1 cm 2 mol −1 , revealing to non‐electrolytic nature for complexes ( 1 , 2 , 4 , 6 and 7 ) along with 1:1 electrolyte for complexes ( 3) and ( 5 ) …”

Synthesis, structural, spectroscopic, and thermal studies of some transition‐metal complexes of a ligand containing the amino mercapto triazole moiety

“…Moreover, the HL spectrum displays strong and medium bands at 1602, 961, 627 and 426, and 1542 and 1498 cm −1 assignable to aromatic ν(C=C), pyridine ring breathing, C–H in‐plane and out‐of‐plane pyridine ring bending along with triazole ring stretching, and NH in‐plane deformation vibration, respectively . In addition, the IR spectrum of HL ligand illustrates strong and medium bands at 1661 and 1125, 583 cm −1 attributed to the C=O stretching and in‐plane, out‐of‐plane bending vibrations (υ and δ, γ) of the antipyrine carbonyl group, respectively . For the free ligand, four bands appeared at 1542, 1333, 1073, and 827 cm −1 attributable to thioamide I {δ (NH) + ν(C=N)}, thioamide II {ν(C=N) + ν as (C=S)}, thioamide III{ν(C–N) + ν s (C=S)}, and thioamide IV that is mainly from δ(C=S) .…”