Nano‐sized Co(II), Ni(II), and Zr(IV) complexes of quinaldine‐based azo dye for promising therapeutic and catalytic applications: Synthesis, characterization, density functional theory studies and molecular docking

Abstract

Novel azo dye containing the heterocyclic quinaldine nucleus, 3‐((2‐methylquinolin‐4‐yl)diazenyl)naphthalen‐2‐ol HL, and its Co(II), Ni(II) and Zr(IV) nano‐sized metal chelates have been synthesized and fully characterized by alternative analytical and spectral techniques. The finding indicated that the ligand coordinated as a monobasic bidentate via azo nitrogen and hydroxyl oxygen atom, resulting in octahedral geometry towards Co(II) and Zr(IV) complexes, and square planer geometry towards Ni(II) metal ion. Theoretical studies by DFT/B3LYP/6‐311+G(d,p)/LANLDZ including energetic parameters, geometrical optimization, dipole moment, and HOMO–LUMO energy gap were applied to support the geometrical arrangement of the complexes. The produced complexes were generated at the nanoscale, as evidenced by the average particle size from TEM. The average particle size calculated from TEM images for Co(II), Ni(II), and Zr(IV) complexes is 6.0, 12.0, and 5.5 nm, respectively. The antibacterial activity of the ligand compared with its metal complexes shows enhanced activity over the metal complexes against different types of bacteria. Antitumor efficacy of the compounds was tested against A‐549 and PANC‐1 cells, compared with the vinblastine standard. The cytotoxic efficiency of both Co(II) and Ni(II) complexes exceeded that of vinblastine. The anticancer activity of the Zr complex was then studied using molecular docking to determine the interactions between this molecule and PANC‐1. Docking studies revealed that the Zr complex produces four hydrogen bond contacts with the active amino acid residues Arg 136 and Asp 140, two hydrophobic interactions with Val 50 and Leu 147, and two electrostatic interactions with Arg 136. Also, the catalytic property of the free ligand and nanocomplexes were tested on the oxidative degradation of methyl violet 2B dye in the presence of H2O2. The following arrangement was observed for the pseudo‐first‐order rate constants: Co(II) complex (0.068 min−1) > Ni(II) complex (0.066 min−1) > Zr(IV) complex (0.061 min−1) > HL (0.037 min−1).

Synthesis, structural characterization, density functional theory, anticancer, and antimicrobic studies of Ni2+ and Cu2+ complexes encompassing tridentate ONS‐donor azo‐thiosemicarbazone

“…This outcome agrees with the FMO idea of the electron density distribution. From the above, it may be concluded that a compound's biological activity can be described by its quantum chemical properties, which are confirmed by MEPs 40,106 …”

“…The EI‐mass spectrum of azo‐thiosemicarbazone (H 4 Azo‐STC, 1) exhibited a precise peak corresponding to m/z 299 amu; this matches with the chemical formula (C 14 H 13 N 5 OS) and aligns well with the computed molecular weight at m/z = 299.3 amu. Furthermore, the mass spectrum exhibited several peaks associated with the progressive deterioration of the azo‐thiosemicarbazone (H 4 Azo‐STC, 1) , as observed through the fragmentation pathway illustrated in Figure S15 40 . The mass spectra of metal complexes (Figures S9–S14) revealed that the bond between metal and ligand was broken, resulting in the formation of molecular ion peaks distinct to the parent azo‐thiosemicarbazone (H 4 Azo‐STC, 1) .…”

“…The values of Cu 2+ complexes' corrected magnetic moment ranged from 1.88 to 2.19 BM, which is coherent with the attendance of one unpaired electron in a Cu 2+ cations in a square planar geometry 89 . The magnetic moment result showed that the Ni 2+ complex is diamagnetic, referring to dsp 2 hybridization and demonstrating that the Ni 2+ complex has a square planar structure 40 …”

“…The medicinal characteristics of azo‐synthetics were uncovered for a sulphonamide‐connected azo‐dye called Prontosil, which is employed as a medicine to treat microbic infections 33,34 . The azo‐synthetics' biological properties have garnered interest due to their potential as anti‐inflammatory, 35 antiviral (HIV), 36 anti‐oxidant, 37 anticancer, 38–40 bactericidal, 39–41 and fungicidal, 42–44 agents. The azo‐thiosemicarbazone ligand was created by combining the azo‐dyes moiety (‐N=N‐) with thiosemicarbazone that has a thionic moiety (‐C=N–NH–C(=S)–NH 2 ).…”