2, 6‐Bis((E)‐((5‐benzoyl‐2‐thioxo‐4‐phenylpyrimidin‐1(2H)‐yl)imino)methyl)‐4‐(methyl)phenol and its Metal(II) Complexes: Synthesis, Spectroscopy, Biological Activity, and Photoluminescence Features

Abstract

The preparation, characterization, magnetic measurements, antimicrobial activity, and photoluminescence properties of a number of metal complexes with a Schiff base ligand derived from 2, 6‐diformyl‐4‐methylphenol and 1‐amino‐5‐benzoyl‐4‐phenyl‐1H‐pyrimidine‐2‐thione are reported herein. UV/Vis spectra and magnetic measurements infer square planar stereochemistry for PdII and PtII complexes, and octahedral arrangement for the other metal complexes. The compounds results in intense emission (where λmax = 402 nm) upon irradiation by UV light. The photoluminescence quantum yields and long excited‐state lifetimes of the ligand and its complexes were calculated as 42 % and 3.94 ns, respectively. The photoluminescence intensities and quantum yields of metal complexes changed upon complexation with various metal ions. The ligand and its complexes are of interest as organic emitting materials for electroluminescent devices. The complexes were additionally evaluated for in vitro the antimicrobial activity against bacterial and fungal strains. While CuII, CoII, and PtII complexes have good antifungal efficiency against yeast (MICs, 80 μg·mL–1), only the complex [Cu(L)(AcO)]·4H2O had effective and selective antimicrobial activity against all tested microorganisms with MIC values in the range of 40–80 μg·mL–1, except for E. coli ATCC 4230. This study suggests that the complex [Cu(L)(AcO)]·4H2O may be a new potential antimicrobial substance towards bacteria and fungi.

In Vitro Biomolecular Interaction Studies and Cytotoxic Activities of Newly Synthesised Copper(II) Complexes Bearing 2‐Hydroxynaphthaldehyde‐Based Thiosemicarbazone

“…The band corresponds to ν (C=N) slightly lowered while that of ν (C=S) was slightly shifted to higher energy for both complexes C1 and C2 . This shift showing the coordination ligands via the azomethine nitrogen and the thionyl sulphur with the Cu(II) ion . A new band observed at 448 cm −1 for both complexes was assigned to ν (M–N), farther confirmed the coordination of azomethine nitrogen.…”

“…For both L1 and L2 , the appearance of the band in the 3397–3401 cm −1 region affirmed the presence of hydroxyl group on the ligand. In addition, a band was observed at 1223 cm −1 for L1 and 1238 cm −1 for L2 , which was assigned to C−O stretching vibration . The stretching of the azomethine moiety ν (C=N) appeared at 1549 and 1540 cm −1 in their respective spectra of L1 and L2 .…”

Novel Fluorescent Schiff Base Derivatives of 4‐Aminoantipyrine with Large Stokes Shifts and Dual Emission Properties: Crystal Structure, Molecular Interactions, Molecular Surfaces, Conformational and DFT Analyses

“…IR spectra also showed a characteristic band at 1644-1648 cm −1 due to the presence of >C O group and at 1594-1603 cm −1 which was attributed to the azomethine (CH N) group. 29 The 1 H NMR spectra of 3a and 3b showed characteristic sharp singlets at δ 10.01 and 9.73 ppm, respectively, confirming the presence of the azomethine ( CH N ) proton, and two singlets at δ 2.46-2.47 ppm (assigned to the CH 3 group attached to the carbon atom of the pyrazolone ring) and δ 3.16−3.20 ppm (assigned to the CH 3 group attached to the nitrogen atom of the pyrazolone ring). 18 Aromatic protons were also observed as expected δ 7.30-8.17 ppm as multiplets or doublets.…”

“…13 Regarding the structure of 3a, the five-membered antipyrine ring (N1-C1-C3-C2-N2) was almost planar, with an rms deviation for fitted atoms of 0.0480 Å and a dihedral angle of 67. 29 with its attached phenyl ring (C4-C9). The dihedral angles N2-N1-C4-C5 and N2-N1-C4-C9 were 150.4(2) and −32.5 (4) , respectively.…”