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• Synthesis and spectroscopic studies of some metal-phenylacetohydrazide Schiff base complexes. • X-ray and Hirshfeld surface analysis of the silver complex. • DFT and reactivity descriptors of certain complexes were reported. • Antibacterial activities and molecular docking studies of some complexes. The coordination complexes of a tridentate-phenylacetohydrazide Schiff base (2-hydroxybenzylidene-2-phenylacetohydrazide, HL) with metal ions, namely, iron(II), zinc(II), palladium (II), silver(I) and cadmium(II), were synthesized and investigated using various analytical and spectroscopic techniques. A single-crystal X-ray diffraction analysis was performed on the silver derivative. The HL ligand and Ag complex were also characterized via Hirshfeld surface analyses. Both X-ray and Hirshfeld surface analysis revealed intriguing structure and geometric characteristics, as well as remarkably intramolecular and intermolecular hydrogen bonding. All metal ions, with the exception of palladium one, bonded to two molecules of ligand without deprotonation of the hydroxyl moieties. In addition, 1H NMR studies of the diamagnetic complexes and X-ray analysis of the silver complex revealed the presence of the unprotonated OH. DFT-B3LYP calculations were used to determine the energy-minimized molecular geometric arrangements of the Pd(II), Ag(I), and Cd(II) derivatives. Quantum global reactivities of the complexes were also computed. Antibacterial and molecular docking studies of complexes were carried out to examine the potential applications of derivatives as therapeutic reagents. The Ag(I) complex showed the highest antibacterial inhibition towards the tested bacteria with zone diameter = 21.7, 21.0, 19.3 and 15.7 mm. Molecular docking analysis revealed that the complexes have high binding affinities against the selected receptors (PDB: 1BNA and 5AEP) and demonstrated different DNA binding potencies. [ABSTRACT FROM AUTHOR]

Abstract Thermal reaction of Ni(NO 3) 2.6H 2 O, PdCl 2 , PtCl 2 , Mo(CO) 6 and Ru 3 (CO) 12 with the prepared Schiff base ligand N-(2-hydroxy-1-naphthylidene)-2-aminothiophenol (H 2 L) resulted in the formation of the five complexes; [Ni(HL) 2 ], 1 ; [Pt(H 2 L)Cl 2 ], 2 ; [Pd 2 (HL) 2 Cl 2 ], 3 ; [Mo(O 2)(H 2 L)], 4 ; and [Ru(CO) 3 (HL)], 5. The studied compounds were characterized using different spectroscopic techniques (IR, 1H NMR, mass) elemental analyses, magnetic measurement, molar conductance, and thermal analysis. The kinetic and thermodynamic parameters of the complexes were computed. The geometry of studied 1:1 Pt(II)-, Pd(II)- Mo(IV)- and Ru(I)- complexes and 1:2 Ni(II)- complex were investigated at the B3LYP/GENECP level of theory. The geometries of the studied complexes are non-planner as indicated from the dihedral angles between central metal ion and coordinated atoms of the ligand. DFT calculations have been also carried out to calculate the global properties; hardness (η), global softness (S) and electronegativity (χ). The mean first-order hyperpolarizability (<β>) was calculated and compared with Urea as a reference material. The results of the mean first-order hyperpolarizability (<β>) showed that the ligand and the studied complexes are excellent candidates to NLO materials. Also, the interaction of the reported compounds with calf thymus DNA (CT-DNA) by different techniques revealed that the complexes could bind to CT-DNA by intercalative mode. The binding of the reported complexes to calf thymus DNA has been investigated using fluorescence and UV–Vis absorption spectra. The results indicated a much lower binding affinity of the ligand than that of the complexes. Biological activities of the compounds have been studied. Graphical abstract Optimized structures, numbering system, bond lengths', bond angles and the vector of the dipole moment of square planar structures of Pd-complexes. Image 1 Highlights • Synthesis, characterization of new transition metal complexes. • DNA-complex binding studies by UV–Vis and fluorescence spectroscopy. • Antimicrobial activity studies suggested positive results. • The HOMO and LUMO energies were computed and discussed. • The NLO study proves promising optical properties for complexes. [ABSTRACT FROM AUTHOR]

Thermal reactions of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Ru(III) metal ions with a novel Schiff base ligand (HL) derived from the condensation of 2-aminothiazole and 2-hydroxy-1-naphthaldehyde resulted in the formation of a series of metal complexes, [Co(L)2(H2O)2]·2H2O (1), [Ni(L)(CH3COO)(H2O)2] (2), [Cu(L)2(H2O)2] (3), [Zn(L)2] (4), [Cd(L)(CH3COO)]·2H2O (5), and [Ru(L)2(H2O)2]Cl (6). The ligand and its complexes were characterized by means of elemental and thermal analyses, molar conductance, and magnetic moment measurements along with different spectroscopic techniques. The structure of the ligand was determined by X-ray crystal structure analysis and revealed that it crystallized in the orthorhombic space group P21cn with a Z value of 4. Theoretical calculations based on accurate DFT approximations were used to verify the structures of ligand and complexes. The relative reactivities were estimated using chemical descriptors analysis. The biological activities of the compounds were examined. The antioxidant activity against DPPH radical was evaluated in vitro by using spectrophotometric methods; the experiments showed potent antioxidant activity. Also, the interaction of the reported compounds with calf-thymus DNA (CT-DNA) by different techniques revealed that the complexes could bind to CT-DNA by intercalative mode. [ABSTRACT FROM AUTHOR]

Thermal reaction of [Ru 3 (CO) 12 ] with 2-picolinic acid (Hpic) in the absence and presence of a secondary ligand (pyridine, Py, bipyridine, Bipy, or thiourea, Tu) was investigated. Four complexes with molecular formulae: [Ru(CO) 3 (Hpic)], 1 , [Ru 2 (CO) 5 (Hpic)(Py)], 2 , [Ru 2 (CO) 5 (Hpic)(Tu)], 3 and [Ru 2 (CO) 4 (Hpic)(Bipy)], 4, were isolated. All complexes were characterized based on elemental analyses, IR, 1 H NMR, magnetic studies, mass spectrometry and thermal analysis. The ligand and its complexes have been screened for antibacterial activities. Density Functional Theory (DFT) calculations at the B3LYP/6-311G (d,p)_ level of theory have been carried out to investigate the equilibrium geometry of the ligands. The optimized geometry parameters of the complexes were evaluated using B3LYP method and LANL2DZ basis set. The extent of natural charge population (core, valence and rydberg), exact electronic configuration, total Lewis and total non-Lewis are estimated and discussed in terms of natural bond orbitals (NBO) analysis. [ABSTRACT FROM AUTHOR]

Thermal reactions of Mo(CO)6with the Schiff base 4-nitro-N-(pyridine-2-yl-methylene)aniline (NPMA) in THF in absence and presence of triphenyl phosphine (PPh3), pyridine (py) or thiourea (Tu) gave the four carbonyl complexes, [Mo(CO)4(NPMA)] (1), [Mo(CO)3(NPMA)(PPh3)] (2) [Mo2(O)2(CO)2(NPMA)2(Py)2] (3), and [Mo2(O)2(CO)4(NPMA)(Tu)2] (4), respectively. Thermal reaction of W(CO)6with NPMA in THF gave the two complexes [W2(O)6(NPMA)] (5) and [W2(O)6(NPMA)(Py)2] (6) in absence and presence of pyridine, respectively, while under sunlight irradiation the complex [W2(CO)6(NPMA)2] (7) was isolated. Magnetic susceptibility, elemental analyses, and IR, mass, and1H NMR spectroscopy were studied. Thermal, cyclic voltammetry, catalytic epoxidation, and biological activity were also investigated. [ABSTRACT FROM AUTHOR]

Thermal reaction of M(CO) 6 (M = Cr, Mo or W) with a Schiff base (DMPA) derived from the condensation of 4,5-dimethyl-1,2-phenylenediamine and pyridine-2-carboxaldehyde in THF in absence and presence of a secondary ligand; 2-aminobenzimidazole (Abz), thiourea (Tu) or 2-(2′-pyridyl)benzimidazole (pybz) were studied. The reaction of Cr(CO) 6 gave the four complexes Cr 2 (CO) 2 (DMPA) 2 ; 1 , Cr(DMPA) 2 (Abz) 2 ; 2 , Cr 2 (CO) 4 (DMPA) 2 (Tu) 2 ; 3 and Cr(DMPA) 2 (Pybz); 4 , while the thermal reaction of Mo(CO) 6 resulted in the formation of the two complexes Mo 2 (O) 6 (DMPA) 2 ; 5 , and Mo 2 (O) 2 (CO) 2 (DMPA) 2 (Tu) 2 ; 6 . Thermal reaction of W(CO) 6 and the Schiff base DMPA gave the complex W(O) 2 (DMPA) 2 ; 7 . The ligand DMPA and its metal complexes have been reported and characterized based on elemental analyses, IR, 1 H NMR, magnetic measurements, and thermal analysis. Cyclic voltammetry and biological activity were also investigated. [ABSTRACT FROM AUTHOR]

A new cobalt(II) cyanato complex, [Co(NCO)2(H2O)2(hmt)] (I) where hmt is hexamethylenetetramine, has been synthesized and structurally characterized. The electronic spectra of the solid compound suggest octahedral cobalt and IR spectra revealed monodentate N-cyanato groups and aqua ligands, while hmt is a bridging N, N'-bidentate leading to a 1-D infinite polymeric chain. The structure has been confirmed from single crystal X-ray diffraction. Crystal data for I : Fw 319.20, a = 9.234(2), b = 11.252(2), c = 12.576(3) Å, β = 107.75(3)°, V = 1244.5(4) Å3, Z = 4, T = 100 K. Crystal system : monoclinic, space group : C2/c. Hydrogen bonds of the type O-H ··· O and O-H ··· N between aqua molecules and O atom of the terminal N-cyanato groups or an N atom of hmt ligands consolidate and extend the structure to a 3-D network. The thermal properties of I are reported. [ABSTRACT FROM AUTHOR]