Hanaa A. El-Boraey

Structural studies and anticancer activity of a novel (N6O4) macrocyclic ligand and its Cu(II) complexes

A novel (N6O4) macrocyclic ligand (L) and its Cu(II) complexes have been prepared and characterized by elemental analysis, spectral, thermal (TG/DTG), magnetic, and conductivity measurements. Quantum chemical calculations have also been carried out at B3LYP/6-31+G(d,p) to study the structure of the ligand and one of its complexes. The results show a novel macrocyclic ligand with potential amide oxygen atom, amide and amine nitrogen atoms available for coordination. Distorted square pyramidal ([Cu(L)Cl]Cl·2.5H2O (1), [Cu(L)NO3]NO(3)·3.5H2O (2), and [Cu(L)Br]Br·3H2O (4) and octahedral ([Cu(L)(OAc)2]·5H2O (3)) geometries were proposed. The EPR data of 1, 2, and 4 indicate d1x2(-y)2 ground state of Cu(II) ion with a considerable exchange interaction. The measured cytotoxicity for L and its complexes (1, 2) against three tumor cell lines showed that coordination improves the antitumor activity of the ligand; IC50 for breast cancer cells are ≈8.5, 3, and 4 μg/mL for L and complexes (1) and (2), respectively.

Reversible and irreversible thermochromism of some Schiff base metal complexes

SummaryNickel(II) and copper(II) complexes of Schiff bases derived from salicylaldehyde, 2-hydroxy-1-naphthaldehyde, 2,4-dihydroxybenzaldehyde, 2,3-dihydroxybenzaldehyde or 5-chlorosalicylaldehyde and 8-aminoquinoline have been prepared and characterized. Several of the complexes are thermochromic in the solid state. The origin of the thermochrornism is discussed in terms of changes in ligand field strength and coordination geometry. These changes were studied by means of thermal and spectral methods.

Coordination behavior of tetraaza [N4] ligand towards Co(II), Ni(II), Cu(II), Cu(I) and Pd(II) complexes: Synthesis, spectroscopic characterization and anticancer activity

Novel eight Co(II), Ni(II), Cu(II), Cu(I) and Pd(II) complexes with [N(4)] ligand (L) i.e. 2-amino-N-{2-[(2-aminobenzoyl)amino]ethyl}benzamide have been synthesized and structurally characterized by elemental analysis, spectral, thermal (TG/DTG), magnetic, and molar conductivity measurements. On the basis of IR, mass, electronic and EPR spectral studies an octahedral geometry has been proposed for Co(II), Ni(II) complexes and Cu(II) chloride complex, square-pyramidal for Cu(I) bromide complex. For Cu(II) nitrate complex (6), Pd(II) complex (8) square planar geometry was proposed. The EPR data of Cu(II) complexes in powdered form indicate d(x2-y2) ground state of Cu(II) ion. The antitumor activity of the synthesized ligand and some selected metal complexes has been studied. The palladium(II) complex (8) was found to display cytotoxicity (IC(50)=25.6 and 41 μM) against human breast cancer cell line MCF-7 and human hepatocarcinoma HEPG2 cell line.

Thermal behaviour of some aromatic diamine complexes

Abstract The Co(II) and Ni(II) complexes of some aromatic diamines were prepared and characterised by different analytical and spectral methods. The thermal behaviour of the investigated complexes was also studied. The thermal stabilities of the complexes were discussed in terms of chelate ring size and localised electron model.

Thermal investigation of iron(III) and manganese(II,III) complexes of dianils derived from 6-formylkhellin

Manganese and iron complexes of Schiff bases derived from 6-formylkhellin were prepared and characterized. Complexes of o-phenylenediamine derivative (ligand (I)) are monomeric or dimeric whereas those of p-phenylenediamine derivative (ligand (II)) are polymeric. The complexes obtained are characterized by a lower magnetic moment values. The complexes also have different solvent of crystallization with different nature of interaction. The thermal behaviour of the ligands and their metal complexes was investigated by means of DTA, TG, IR and X-ray diffraction spectroscopy. Ligand (I) shows different thermal behaviour from that of ligands (II) and (III). The complexes of ligand (II) give abnormal oxides as a final product during their thermal decomposition.

New 15-membered tetraaza (N4) macrocyclic ligand and its transition metal complexes: Spectral, magnetic, thermal and anticancer activity

Novel tetraamidemacrocyclic 15-membered ligand [L] i.e. naphthyl-dibenzo[1,5,9,12]tetraazacyclopentadecine-6,10,11,15-tetraoneand its transition metal complexes with Fe(II), Co(II), Ni(II), Cu(II), Ru(III) and Pd(II) have been synthesized and characterized by elemental analysis, spectral, thermal as well as magnetic and molar conductivity measurements. On the basis of analytical, spectral (IR, MS, UV-Vis, (1)H NMR and EPR) and thermal studies distorted octahedral or square planar geometry has been proposed for the complexes. The antitumor activity of the synthesized ligand and some complexes against human breast cancer cell lines (MCF-7) and human hepatocarcinoma cell lines (HepG2) has been studied. The complexes (IC50=2.27-2.7, 8.33-31.1μg/mL, respectively) showed potent antitumor activity, towards the former cell lines comparable with their ligand (IC50=13, 26μg/mL, respectively). The results show that the activity of the ligand towards breast cancer cell line becomes more pronounced and significant when coordinated to the metal ion.

Spectroscopic, thermal and toxicity studies of some 2-amino-3-cyano-1,5-diphenylpyrrole containing Schiff bases copper (II) complexes.

AbstractTwo novel Schiff base ligands of 2-amino-3-cyano-1,5-diphenylpyrrole and salicylaldehyde (HL1) or 2- hydroxy1-naphthylaldehyde (HL2) and their copper(II) complexes have been synthesized and characterized by elemental analyses, spectral (UV-Vis, IR, EPR, Mass (for ligands)), thermal (DTA-TGA) methods, magnetic and conductance measurements. IR results demonstrate the bidentate binding of the Schiff base ligands involving azomethine nitrogen, phenolic or naphtholic oxygen and suggest the presence of HL2 and complexes (1, 2, 4 and 8) in enolimine-ketonamine tautomeric forms in the solid state. The EPR spectral data of complexes (2, 5, 6) show that the metal — ligand bonds have considerable covalent character. The thermal studies show that complexes (1, 2, 4 and 8) that are present in enolimine-ketonamine tautomeric forms exhibit lower thermal stability. The effect of synthesized ligands (HL1, HL2) and complexes (1, 5) were tested on the mortality of entomopathogenic nematodes (EPN) (Heterorhabditis bacteriophora and Steinernema carpocapsae). The study shows that the mortality of the nematodes increased with increasing concentrations of copper(II) ion, ligands and complexes. Copper(II) ion was the most toxic for EPN.

Preparation of highly insulating dimeric and polymeric metal complexes with higher thermal stability in the solid state

Abstract Cobalt(II), nickel(II) and copper(II) complexes of Schiff bases derived from isoniazide (pyridylhydrazone) and salicylaldehyde were prepared and characterised. The study indicates that the ligand coordinates in its keto form (except for complex 4 obtained from the reaction of nickel acetate) to give monomeric (2 and 5) and polymeric (1, 3, and 4) complexes. The keto form of the ligand in the complexes transforms into enol one through the loss of HCl or HNO 3 upon heating in the solid state. The monomeric complexes of nickel and copper are thermochromic in both solid state and DMF. The thermochromism obtained is discussed in terms of geometrical and structural changes. The two complexes change their colours from yellow and orange into red and green, respectively, upon heating in the solid state. The dimeric red form and polymeric green form are characterised by higher thermal stability as well as insulating properties.

Transition metal complexes of a new 15-membered [N5] penta-azamacrocyclic ligand with their spectral and anticancer studies

Novel penta-azamacrocyclic 15-membered [N5] ligand [L] i.e. 1,5,8,12-tetetraaza-3,4: 9,10-dibenzo-6-ethyl-7-methyl-1,12-(2,6-pyrido)cyclopentadecan-5,7 diene-2,11-dione and its transition metal complexes with Co(II), Ni(II), Cu(II), Ru(III) and Pd(II) have been synthesized and structurally characterized by elemental analysis, spectral, thermal as well as magnetic and molar conductivity measurements. On basis of IR, MS, UV-Vis 1H NMR and EPR spectral studies an octahedral geometry has been proposed for all complexes except Co(II), Cu(II) nitrate complexes and Pd(II) chloride complex that adopt tetrahedral, square pyramidal and square planar geometries, respectively. The antitumor activity of the synthesized ligand and some complexes against human breast cancer cell lines (MCF-7) and human hepatocarcinoma cell lines (HepG2) has been studied. The complexes (IC50=2.04-9.7, 2.5-3.7 μg/mL) showed potent antitumor activity comparable with their ligand (IC50=11.7, 3.45 μg/mL) against the above mentioned cell lines, respectively. The results evidently show that the activity of the ligand becomes more pronounced and significant when coordinated to the metal ion.

Effect of precipitation on the thermochromic behaviour of nickel(II) complexes in the solid state

SummaryNiII-8-aminoquinolinato complexes have been prepared. The structures of the complexes were investigated by different analytical and spectral methods. The thermochromic behaviour of the complexes in the solid state is discussed in terms of structural phase change and ligand field strength. The observed phase change was investigated by means of X-ray powder diffraction and the temperature dependence of the electrical conductivity.