Synthesis, Characterization, DFT of novel, symmetrical, N/O-donor tetradentate Schiff’s base, its Co(II), Ni(II), Cu(II), Zn(II) complexes and their in-vitro human pathogenic antibacterial activity

Abstract

A NOVEL tetradentate Schiff's base ligand Bis(furfural)-1,8-naphthalenediimine (L) was synthesized and characterized by physical, analytical and spectral data. Complexes of Co(II), Ni(II), Cu(II) and Zn(II) of general composition MLX 2 [L = C 20 H 14 N 2 O 2 and X = Cl-, NO 3 and OAc-] have been synthesized in 1:1 molar ratio of metal to ligand. The elemental analysis, molar conductance measurements, magnetic susceptibility measurements, Mass, IR, UV-Visible, NMR and EPR spectral studies of the compounds led to the conclusion that the ligand acts in a tetradentate manner in Co(II), Ni(II) and Cu(II) complexes, while in bidentate fashion in Zn(II) complex. Octahedral geometry was assigned to Co(II) and Ni(II) complexes, Tetragonal geometry for Cu(II) complexes and tetrahedral geometry for Zn(II) complexes of the Schiff's base ligand. The thermal studies suggested that the complexes are more stable as compared to ligand and absence of coordinated water molecules in metal complexes. The geometries of Schiff's base and metal complexes were optimized with respect to the energy taking the 6-31+g(d,p) basis set in Gaussian 09W programme in gaseous phase. The antibacterial studies of the compounds were examined against the human pathogenic, Gram negative bacteria i.e. Escherichia coli, Yersinia enterocolitica, Klebsiella pneumoniae, and Salmonella typhi and Gram positive bacteria i.e. Listeria monocytogenes and Enterococcus faecalis.

New heterocyclic Schiff base‐metal complex: Synthesis, characterization, density functional theory study, and antimicrobial evaluation

“…Chemical reactivity and other properties of the prepared compounds were identified by density functional theory (DFT) using Becke three‐parameter hybrid exchange and Lee–Yang–Parr correlation functional (B3LYP/3‐21G) for ligand and B3LYP/LANL2DZ for metal complexes using GAUSSIAN09 program [ 14,15 ] . The Gaussian files obtained through this method were visualized using Gauss‐View 05 molecular visualization program.…”

New Charge-Transfer Complexes of Organochalcogenide Compound Based on Aryl Acetamide Group with Quinones: Synthesis, Characterization, Antioxidant, and Computational Study

“…The difference between the HOMOs gives the energy band gap (E g ) as a crucial property in solids because it can predict whether it is a conductor, insulator, or semiconductor. The energy band represents the energy difference between lower virtual and higher full energy levels [35]. Table 5 displays the comparison of HOMO and LUMO energies.…”

“…It corresponds to the energy required to remove one electron from a negative ion. According to Koopman's theorem, the ionization potential and electron affinity depend on the energies of the valence and conduction bands [23], Table 6 shows the values of ionization potential and electron affinity for compounds I-VIII, according to Koopman's VII > VIII > III > II > I > VI > V > IV It is beneficial that less energy is required for electrons to escape from the surface [34][35]. The electron affinity (A) decreased as follows:…”

Novel Schiff Bases Ligands and Their Complexes: Thermal Analysis, Antibacterial Activity, and Molecular Docking

“…Tetradentate β-ketoenamine Schiff base ligands that have been produced via the condensation of β-diketone with diamine or monoamine contain N2O2 donor atoms [2][3][4][5][6][7][8][9][10][11]. Moreover, polydentate and macrocycle Schiff base ligands that have various donor atoms; such asN2S2, N2O2, N4,and N2O [12][13][14] ;are known to cooperatewell with a variety of metal ions [15][16][17][18]. A wealth of articles that extend from pure synthesis to contemporary physically-and biochemically-relevant investigations indicate that the metal complexes of β-ketoenamine ligands have played an essential role incoordination chemistry-based studies [19][20][21][22][23][24][25].…”