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

Abstract

A new series of transition‐metal complexes of Schiff base ligand containing the amino mercapto triazole moiety (HL) was prepared. The Schiff base and its metal complexes were elucidated by different spectroscopic techniques (infrared [IR], 1H nuclear magnetic resonance, UV–Visible, mass, and electron spin resonance [ESR]), and magnetic moment and thermal studies. Quantum chemical calculations have been carried out to study the structure of the ligand and some of its complexes. The IR spectra showed that the ligand is chelated with the metal ion in a neutral, tridentate, and bidentate manner using NOS and NO donors in complexes 1–6, 10–12, and 7 and 8, respectively, whereas it behaves in a monobasic tridentate fashion using NOS donor sites in copper(II) nitrate complex (9). The magnetic moment and electronic spectra data revealed octahedral and square pyramidal geometries for complexes 2, 11, 12, and 5–8 and 10, respectively. However, the other complexes were found to have tetrahedral (4), trigonal bipyramidal (1 and 3), and square planar (9) structures. Thermal studies revealed that the chelates with different crystallized solvents undergo different types of interactions and the decomposition pathway ended with the formation of metal oxygen (MO) and metal sulfur (MS) as final products. The ESR spectrum of copper(II) complex 10 is axial in nature with hyperfine splitting with 2B1g as a ground state. By contrast, complexes 7 and 8 undergo distortion around the Cu(II) center, affording rhombic ESR spectra. The HL ligand and some of its complexes were screened against two bacterial species. Data showed that complex 12 demonstrated a better antibacterial activity than HL ligand and other chelates.

Synthesis, characterization, and density functional theory studies of hydrazone–oxime ligand derived from 2,4,6‐trichlorophenyl hydrazine and its metal complexes searching for new antimicrobial drugs

“…Magnetic susceptibilities have been measured at 25°C by the Gouy method using mercuric tetra‐thiocyanatocobaltate (II) as the magnetic susceptibility standard were calculated by published equation. [ 29 ] Diamagnetic corrections have been estimated from Pascal's constant. [ 30 ] Molar conductance has been performed on a Tacussel type CD 6 NG conductivity bridge using 10 −3 M DMF solutions and were calculated according to published equation.…”

Synthesis, spectroscopic, electrochemical characterization, density functional theory (DFT), time dependent density functional theory (TD‐DFT), and antibacterial studies of some Co(II), Ni(II), and Cu(II) chelates of (E)‐4‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)‐1‐(3‐hydroxynaphthalen‐2‐yl)methylene) thiosemicarbazide Schiff base ligand

“…Calculated and experimental 1 H chemical shifts (ppm) of (E)-4-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-1-(3-hydroxynaphthalen-2-yl)methylene) thiosemi-carbazide(H 2 L) in deuterated dimethyl sulfoxide (DMSO-d 6 ) Figure S5), and new bands at 745 and 755 cm −1 owing to υ(C-S) indicated the participation of te thiolate sulfur atom through enolization and subsequent deprotonation. [42,43] The spectrum of the acetato chelate, [Cu (HL) (OAc)].2H 2 O, showed two bands at 1625 and 1425 cm −1 due to ν as (COO − ) and ν sy (COO − ), respectively, while the corresponding bending modes were seen at 670 and 630 cm −1 . The large separation Δν = ν as -ν sy = 200 cm −1 is indicative for the monodentate geometry of the acetate ligand bonded to Cu (II).…”

Divalent manganese, cobalt, copper and cadmium complexes of (Z)‐N‐benzoyl‐N′‐(1H‐1,2,4‐triazol‐3‐yl)carbamimidothioic acid: Preparation, characterization, computational and biological studies

“…[3][4][5] The interest of the thiourea derivatives chemistry is enhanced by the fact that coordination to metal ions improve the antimicrobial, [6] antioxidants [2,6] and anticancer [6,7] activity. Triazole ligands and their derivatives also play a significant role as an antimicrobials, [8,9] anticancer [9] and antitumoural. [10] Due to the extensive range of biological properties [8][9][10][11][12][13][14] of triazole and thiourea derivatives, in the current study, we report the synthesis of a new carbonyl thiourea derivative and its Co(II), Cu(II), Mn(II) and Cd(II) complexes.…”

“…Triazole ligands and their derivatives also play a significant role as an antimicrobials, [8,9] anticancer [9] and antitumoural. [10] Due to the extensive range of biological properties [8][9][10][11][12][13][14] of triazole and thiourea derivatives, in the current study, we report the synthesis of a new carbonyl thiourea derivative and its Co(II), Cu(II), Mn(II) and Cd(II) complexes. Different modes of chelation were proposed for the metal complexes, based on the spectral and theoretical studies.…”