Nighat Fahmi

Coordination behavior and biopotency of N and S/O donor ligands with their palladium(II) and platinum(II) complexes

Some metal complexes of Schiff bases have been prepared by the interactions of palladium(II) and platinum(II) chloride with 5-chloro-1,3-dihydro-3-[2-(phenyl)-ethylidene]-2H-indol-2-one-hydrazinecarbothioamide(L1H) and 5-chloro-1,3-dihydro-3-[2-(phenyl)-ethylidene]-2H-indol-2-one-hydrazinecarboxamide(L2H), in bimolar ratios. All the new compounds have been characterized by elemental analyses, conductance measurements, molecular weight determinations, IR and 1H NMR spectral studies. The spectral data are consistent with a square planar geometry around Pd(II) and Pt(II) in which the ligands act as neutral bidentate and monobasic bidentate ligands, coordinating through the nitrogen and sulfur/oxygen atoms. Free ligands and their metal complexes were screened for their antimicrobial activity on different species of pathogenic fungi and bacteria and their biopotency has been discussed.

Microwave assisted synthesis, characterization and biological evaluation of palladium and platinum complexes with azomethines

Reactions of 3-acetyl-2,5-dimethylthiophene with thiosemicarbazide and semicarbazide hydrochloride resulted in the formation of new heterocyclic ketimines, 3-acetyl-2,5-dimethylthiophene thiosemicarbazone (C(9)H(13)N(3)OS(2) or L(1)H) and 3-acetyl-2,5- dimethylthiophene semicarbazone (C(9)H(13)N(3)OS or L(2)H), respectively. The Pd(II) and Pt(II) complexes have been synthesized by mixing metal salts in 1:2 molar ratios with these ligands by using microwave as well as conventional heating method for comparison purposes. The authenticity of these ligands and their complexes has been established on the basis of elemental analysis, melting point determinations, molecular weight determinations, IR, (1)H NMR and UV spectral studies. These studies showed that the ligands coordinate to the metal atom in a monobasic bidentate manner and square planar environment around the metal atoms has been proposed to the complexes. Both the ligands and their complexes have been screened for their antimicrobial activities. The antiamoebic activity of both the ligands and their palladium compounds against the protozoan parasite Entamoeba histolytica has been tested.

Coordination Behavior of Unsymmetrical Ligand Complexes of Diorganotin and Diorganosilicon Derived From Schiff Bases

Hexacoordinated organotin and organosilicon derivatives have been prepared and characterized by analytical and spectroscopic techniques including UV, IR, 1 H NMR, and 13 C NMR spectra. The ligands used in the present account were derived by the condensation of thiosemicarbazide and 1H-Indol-2,3-dione, 1,3-dihydro-3-[2-(4-fluorophenyl)-2-oxo-ethylidene]-2H-indol-2-one, and 1,3-dihydro-3-[2-(4-fluoro-3-methyl-phenyl)-2-oxo-ethylidene]-2H-indol-2-one under microwave irradiation as well as by conventional heating. Newly synthesized complexes with their corresponding ligands were tested for their antifungal and antibacterial activities. The aim of the present study is to synthesize some novel ecofriendly fungicides and bactericides that have important pharmacodynamic significance.

SULFUR BONDED PALLADIUM(II) AND PLATINUM(II) COMPLEXES OF BIOLOGICALLY POTENT THIOAMIDES

Abstract Sulfur bonded square planar complexes of the type, [M(NSH)2]Cl2 and [M(NS)2], where, M=PdII and PtII and NSH = 2-[1-furanyl)-ethyledene]hydrazinecarbothioamide, 2-[1-(2-thienyl)-ethyledene]hydrazinecarbothioamide, 2[1-(2-naphthenyl)ethyledene]-hydrazinecarbothioamide with sulfur donor ligands have been synthesised and characterised. Chemical analysis, IR, UV-visible, 1H NMR, magnetic measurements, conductance measurements and molecular weight determinations have been utilised for establishing the geometries of the free ligands and their metal complexes. The spectral data are consistent with a square planar geometry around PdII and PtII in which the ligand acts as a neutral bidentate and monoanionic bidentate ligand coordinating through nitrogen and sulfur atoms. To discuss bioinorganic aspects of the complexes, representative free ligands and their metal complexes were tested in vitro against a number of microorganisms and in vivo on male albino rats. Findings are positive.

Synthetic, spectral, and antimicrobial aspects of biologically relevant coordination compounds of dioxomolybdenum(VI) and oxovanadium(V)

Heterocyclic ketimines, 5-nitro-3-(indolin-2-one)hydrazinecarbothioamide (L1H), 5-nitro-3-(indolin-2-one)hydrazinecarboxamide (L2H), 6-nitro-3-(indolin-2-one)hydrazinecarbo-thioamide (L3H), and 6-nitro-3-(indolin-2-one) hydrazinecarboxamide (L4H), were prepared by the condensation of thiosemicarbazide and semicarbazide hydrochloride (in the presence of sodium acetate) in ethanol with the respective ketones. The dioxomolybdenum(VI) complexes and oxovanadium(V) complexes have been prepared by mixing dioxobis(2,4-pentanedinato)molybdenum(VI) in 1: 2 molar ratios and vanadium oxytrichloride in 1: 1 and 1: 2 molar ratios with monobasic bidentate ketimines. The resulting complexes have been characterized by elemental analysis, conductance measurements, and spectral studies, including IR, 1H NMR, and UV spectra. The ketimines and their corresponding metal complexes have been tested on a number of pathogenic bacteria and fungi in order to assess their growth inhibition potency at different concentrations.

Coordination chemistry of rare earth metal complexes with coumarin-based imines: ecofriendly synthesis, characterization, antimicrobial, DNA cleavage, pesticidal, and nematicidal activity evaluations

Coordination and biocidal aspects of lanthanide(III) complexes with 3-formyl-4-chlorocoumarin hydrazinecarbothioamide (L1H) and 3-formyl-4-chlorocoumarin hydrazinecarboxamide (L2H) are described with the support of elemental analyses, molecular weight, melting point, and molar conductance determinations along with the IR, 1H NMR, EPR, UV spectral, and X-ray powder diffraction studies. The spectral data suggest that the ligands are monobasic bidentate, coordinating through nitrogen and sulfur/oxygen. The isolated products are colored solids, soluble in DMSO, DMF, and methanol. All the complexes are monomeric, as indicated by their molecular weight determinations. Conductivity measurements in dry DMF show them to be non-electrolytes. The antimicrobial, DNA cleavage, pesticidal, and nematicidal activities were examined and are discussed.

Synthesis, spectroscopic studies and electrochemistry of palladium (II) macrocyclic complexes derived from a new tetraazahalogen substituted ligands by template method and their antimicrobial and pesticidal activities.

A new series of Pd(II) macrocyclic complexes have been synthesized by template condensation of bis(benzil)4-chloro 1,2-phenylenediamine (ML1) and bis(benzil)4-fluro 1,2-phenylenediamine (ML2) respectively, with appropriate diamine i.e. 1,2-phenylenediamine, 4-chloro 1,2-phenylenediamine and 4-fluro 1,2-phenylenediamine in the presence of PdCl2 to form complexes of the type [Pd(C40H26N4ClF)]Cl2, [Pd(C40H27N4X)]Cl2 and [Pd(C40H26N4X2)]Cl2, where X=Cl, F. The complexes have been characterized with the help of elemental analysis, IR, 1H NMR, electronic spectra, conductance measurement, magnetic susceptibility, cyclic voltammetry and X-ray powder diffraction studies. On the basis of these studies a square planar geometry has been proposed around the metal ion. The newly synthesized ligands and their complexes have been screened for antimicrobial and pesticidal activities. The results obtained from bioassays indicate that this class of compounds can be utilized for the design of new substance with pesticidal activity and promising antimicrobial activity.

BIOCHEMICAL STUDIES ON BIOLOGICALLY ACTIVE THIO-LIGANDS BENZOTHIAZOLINES AND THEIR MANGANESE(II) COMPLEXES

Abstract The coordination behaviour of benzothiazolines having the donor group N⌢S towards manganese(II) has been studied. The unimolar and bimolar reactions of hydrated manganese acetate with monobasic bidentate benzothiazolines resulted in the formation of coloured solids which have been characterised by elemental analysis, molecular weight determinations conductance and magnetic measurements. The infrared, electronic and electron spin resonance spectral studies indicate a high spin tetrahedral geometry for the resulting complexes. All the ligands and their corresponding complexes have been screened for their fungicidal and bactericidal activity.

Microwave assisted synthesis, spectroscopic, electrochemical and DNA cleavage studies of lanthanide(III) complexes with coumarin based imines

The present work stems from our interest in the synthesis, characterization and biological evaluation of lanthanide(III) complexes of a class of coumarin based imines which have been prepared by the interaction of hydrated lanthanide(III) chloride with the sodium salts of 3-acetylcoumarin thiosemicarbazone (ACTSZH) and 3-acetylcoumarin semicarbazone (ACSZH) in 1:3 molar ratio using thermal as well as microwave method. Characterization of the ligands as well as the metal complexes have been carried out by elemental analysis, melting point determinations, molecular weight determinations, magnetic moment, molar conductance, IR, (1)H NMR, (13)C NMR, electronic, EPR, X-ray powder diffraction and mass spectral studies. Spectral studies confirm ligands to be monofunctional bidentate and octahedral environment around metal ions. The redox behavior of one of the synthesized metal complex was investigated by cyclic voltammetry. Further, free ligands and their metal complexes have been screened for their antimicrobial as well as DNA cleavage activity. The results of these findings have been presented and discussed.

Palladium(II) and platinum(II) derivatives of benzothiazoline ligands: Synthesis, characterization, antimicrobial and antispermatogenic activity.

A series of Pd(II) and Pt(II) complexes with two N(∩)S donor ligands, 5-chloro-3-(indolin-2-one)benzothiazoline and 6-nitro-3-(indolin-2-one)benzothiazoline, have been synthesized by the reaction of metal chlorides (PdCl2 and PtCl2) with ligands in 1:2 molar ratios. All the synthesized compounds were characterized by elemental analyses, melting point determinations and a combination of electronic, IR, 1H NMR and 13C NMR spectroscopic techniques for structure elucidation. In order to evaluate the effect of metal ions upon chelation, both the ligands and their complexes have been screened for their antimicrobial activity against the various pathogenic bacterial and fungal strains. The metal complexes have shown to be more antimicrobial against the microbial species as compared to free ligands. One of the ligands, 5-chloro-3-(indolin-2-one)benzothiazoline and its corresponding palladium and platinum complexes have been tested for their antifertility activity in male albino rats. The marked reduction in sperm motility and density resulted in infertility by 62-90%. Significant alterations were found in biochemical parameters of reproductive organs in treated animals as compared to control group. It is concluded that all these effects may finally impair the fertility of male rats.