Omyma A.M. Ali

Synthesis, spectroscopic, fluorescence properties and biological evaluation of novel Pd(II) and Cd(II) complexes of NOON tetradentate Schiff bases

The solid complexes of Pd(II) and Cd(II) with N,N/bis(salicylaldehyde)4,5-dimethyl-1,2-phenylenediamine (H2L(1)), and N,N/bis(salicylaldehyde)4,5-dichloro-1,2-phenylenediamine (H2L(2)) have been synthesized and characterized by several techniques using elemental analysis (CHN), FT-IR, (1)H NMR, UV-Vis spectra and thermal analysis. Elemental analysis data proved 1:1 stoichiometry for the reported complexes while spectroscopic data indicated square planar and octahedral geometries for Pd(II) and Cd(II) complexes, respectively. The prepared ligands, Pd(II) and Cd(II) complexes exhibited intraligand (π-π(∗)) fluorescence and can potentially serve as photoactive materials. Thermal behavior of the complexes was studied and kinetic parameters were determined by Coats-Redfern method. Both the ligands and their complexes have been screened for antimicrobial activities.

Palladium(II) and zinc(II) complexes of neutral [N2O2] donor Schiff bases derived from furfuraldehyde: Synthesis, characterization, fluorescence and corrosion inhibitors of ligands

Metal complexes of Schiff bases derived from furfuraldehyde and 4,5-dimethyl-1,2-phenylendiamine (L1) or 4,5-dichloro-1,2-phenylendiamine (L2) have been reported and characterized based on elemental analyses, IR, 1H NMR, UV-Vis, magnetic moment, molar conductance and thermal analysis. The complexes are found to have the formulae [PdL1-2]Cl2 and [ZnL1-2](AcO)2·H2O. The molar conductance data reveal that Pd(II) and Zn(II) chelates are ionic in nature and are of the type 2:1 electrolytes. The spectral data are consistent with a square planar and tetrahedral geometry around Pd(II) and Zn(II), respectively, in which the ligands act as tetradentate ligands. The thermal behavior of some chelates is studied and the activation thermodynamic parameters are calculated using Coats-Redfern method. The corrosion inhibition of stainless steel types 410 and 304 in 1 M HCl using the synthesized Schiff bases as inhibitors have been studied by weight loss method. The obtained data considered these ligands as efficient corrosion inhibitors. The ligands and their metal complexes exhibited considerable antibacterial activity against Staphylococcusaureus, and Escherichiacoli and antifungal activity against Candida albicans.

Group VI Dinuclear Oxo Metal Complexes of Salicylideneimine‐2‐anisole Schiff Base

Interaction of the Schiff base salicylideneimine‐2‐anisole (salanH) with Cr(CO)6 yielded the dicarbonyl derivative Cr2O2(CO)2(salan)2. The dinuclear oxo complex M2O4(salan)2, M˭Mo and W, was isolated from the reaction of M(CO)6 with salanH. Elemental, spectroscopic and magnetic studies of the reported complexes allowed structures to be proposed. The thermal properties of the complexes were investigated by thermogravimetry.

Spectroscopic, thermal and X-ray crystal structure studies of some bis-(pyrazine-2-carboxylato) nickel(II) complexes

Three nickel(II) complexes [Ni(PC)2(H2O)2], 1, [Ni(PC)2(TU)2], 2 and [Ni(PC)2(ABI)2]· 2(H2O), 3, PC = pyrazine-2-carboxylate, TU = thiourea and ABI = 2-aminobenzimidazole, were synthesized and characterized by elemental analysis, IR spectroscopy and thermal analysis. The complexes were also investigated by single crystal X-ray diffraction analysis. Structures of the monomeric complexes showed nickel(II) chelated to two PC ions from an oxygen atom of carboxylate ion and the adjacent hetero nitrogen atom. The three complexes were crystallized in a monoclinic system with P2 1 /c space group for 1, while 2 and 3 had C2/c space groups. The structure of 1 showed two coordinated water molecules occupying the trans positions of a slightly elongated octahedron. The structure of 2 consisted of two PC ions and two thiourea molecules in trans positions. The structure of 3 was different and showed a highly distorted octahedron with two ABI molecules chelated to the nickel ion in cis positions through their hetero nitrogen atoms. Two water molecules of crystallisation were shown in the structure of 3.

Synthesis, characterization, fluorescence and catalytic activity of some new complexes of unsymmetrical Schiff base of 2-pyridinecarboxaldehyde with 2,6-diaminopyridine.

The Schiff base, 2-[(pyridin-2-ylmethylidene)amino]-6-aminopyridine (L) was synthesized by 1:1 condensation of 2-pyridinecarboxaldehyde and 2,6-diaminopyridine. The ligand and its complexes were characterized by different physicochemical studies. The analytical and spectroscopic tools indicated that the synthesized complexes have the general formulae: [M(L)Cl2]·2H2O (M=Cu(II), Ni(II) and Co(II)), [La(L)3](NO3)3·3H2O and [Sm(L)(ClO4)3]·3H2O. Vibrational spectra indicated the coordination of L to metal ions through its pyridyl and azomethine nitrogen atoms. The presence of water molecules in all reported complexes has been supported by TG/DTA studies. Kinetic and thermodynamic parameters were computed using Coats and Redfern method. The prepared ligand and its complexes exhibited intraligand (π-π∗) fluorescence and can potentially serve as photoactive materials. The catalytic activity of the complexes toward the decomposition of hydrogen peroxide was investigated. Both the ligand and its complexes have been screened for antibacterial activities.

Ruthenium carbonyl derivatives of N-salicylidene-2-hydroxyaniline

The ruthenium tricarbonyl derivative [Ru(CO)3(sha)] (1), was synthesized from reaction of [Ru3(CO)12] with N-salicylidene-2-hydroxyaniline (shaH2) Schiff base. The corresponding reactions of the ruthenium cluster with shaH2 in presence of a secondary ligand L,L = pyridine and triphenyl phosphine resulted in the formation of the dicarbonyl derivatives [Ru(CO)2(shaH2)(L)] (2, 3). In the presence of L = 2-aminobenzimidazole or thiourea, two complexes [Ru(CO)2(sha)(L)] (4, 5) were formed and the shaH2 ligand bonded to ruthenium oxidatively. The bipyridine(bpy) derivative had the molecular formula [Ru(CO)2(shaH)(bpy)] (6), with shaH coordinated bidentate. All complexes were characterized by elemental analysis and mass, IR, 1H NMR and UV–Vis spectroscopy. The spectroscopic studies of these complexes revealed several structural arrangements and different tautomeric forms.

Spectroscopic and thermal studies of some Palladium complexes with certain Heterocyclic Nitrogen ligands

Mono- and binuclear palladium complexes were isolated from reactions of [PdCl4]2− with heterocyclic nitrogen donor ligands depending on the type of ligand. Bidentate ligands L–L, where L–L = 2-(2′-pyridyl)-benzimidazole (PBI), 2-pyrazinecarboxylic acid (PC) and 2-pyrazinecarboxamide (PCA) gave the monosubstituted [Pd(L-L)Cl2] complex. Binuclear palladium complexes [Pd(L)Cl2]2 were obtained from reactions with the monodentate ligands 2-aminothiazole (AT) or 2-aminobenzimidazole (ABI). Elemental analyses and spectroscopic studies of the reported complexes allowed structures to be proposed. The thermal properties of the complexes were also investigated by thermogravimetric techniques.

Synthesis and characterization of molybdenum complexes with salicylideneimine-2-anisole and certain heterocyclic nitrogen ligands

Reactions of Mo(CO)6 with salicylideneimine-2-anisole (Schiff-base, salanH), in the presence of certain heterocyclic nitrogen compounds in THF produced different complexes depending on the reaction conditions. In air, three dinuclear complexes [O2(salanH)Mo(μ-O)2MoO2L] were isolated, L = 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen) or 2,9-dimethy1-4,7-diphenyl-phenanthroline (dim). Under reduced pressure, the corresponding reactions resulted in the formation of the tetracarbonyl derivatives, [Mo(CO)4(salanH)](L). The complexes were characterized by elemental analyses, spectroscopic and magnetic studies. The thermal properties of the complexes were investigated using thermogravimetry.