Synthesis and spectroscopic study of transition metal complexes of tridentate ligand formed by direct condensation of o-vanillin and 2-aminophenol: X-ray structural characterization of the zinc(II) complex

Abstract

The reactions of the Schiff base 2-((2-hydroxyphenylimino)methyl)-6-methoxyphenol (H2L), obtained by direct condensation of 2-aminophenol and 2-hydroxy-3-methoxybenzaldehyde, with some transition metal ions (Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)) afforded complexes of general formulae [M2(L)2(solvent)x] (M: Mn, Co, Ni, Cu or Zn; Solvent: DMSO or H2O). These compounds were characterized by elemental analysis, UV-Vis, IR, 1H- and 13C-NMR spectroscopies, molar conductivity and room temperature magnetic measurements. The structure of zinc(II) complex has been determined by X-ray crystallography. Crystal data for C32H34N2O8S2Zn2 (M =769.47 g/mol): Orthorhombic, space group Pbca (no. 61), a = 16.3176(7) Å, b = 9.1247(3) Å, c = 21.8274(10) Å, V = 3250.0(2) Å3, Z = 4, T = 173(2) K, μ(MoKα) = 1.658 mm-1, Dcalc = 1.573 g/cm3, 28116 reflections measured (4.5° ≤ 2Θ ≤ 60.3°), 4457 unique (Rint = 0.0409, Rsigma = 0.0371) which were used in all calculations. The final R1 was 0.0307(0.0466) and wR2 was 0.0649 (0.0701) (all data). The coordination sphere of the Zn center is best described as a trigonal bipyramid.

Design, synthesis, structural inspection, and DFT calculation of some novel imine ciprofloxacin metal chelates: A novel approach for pharmaceutical applications and DNA interaction

“…On the other hand, signals that show up in the 7.5–7.9 ppm region are thought to be aromatic proton (Ar‐H). Additionally, the singlet signal seen at δ 8.75 ppm suggests the involvement of imine proton in hydrogen bond interaction 43 . The peaks’ positions showed a lack of unique signals in the ligand between 2.4 and 2.9 ppm, which is explained by the amine group’s deprotonation during the azomethine bond formation, confirming the production of the Schiff base ligand.…”

Fabrication, Preparation, Physicochemical Characterization, and Theoretical Studies of Some Novel Schiff Base Ciprofloxacin Metal Complexes: DNA Interaction and Biomedical Applications

“…On the other hand, signals that show up in the 7.53–7.89 ppm region are thought to be aromatic proton (Ar‐H). Additionally, the singlet signal seen at δ 8.65 ppm suggests the involvement of amine proton in hydrogen bond interaction [67, 68]. The peaks’ positions showed a lack of unique signals in the ligand between 2.4 and 2.9 ppm, which is explained by the amine group’s deprotonation during the azomethine bond formation, confirming the production of the Schiff base ligand.…”

Synthesis, characterization, DFT studies and evaluation of the potential anti-tumour activity of nicotinic hydrazide based Schiff base using in vitro and molecular docking techniques

“…N [ 30 ]. A low intensity band between 3080 and 3000 cm −1 represents aromatic ν (C–H) [ 31 ]. There is a sharp peak at 1664 cm −1 which is due to the presence of C = 0 group of the ligand.…”