Naser Eltaher Eltayeb

Synthesis of nickel(II) complexes of isatin thiosemicarbazone derivatives: in vitro anti-cancer, DNA binding, and cleavage activities

Six new nickel(II) complexes of thiosemicarbazone Schiff base with isatin moiety [Ni(L1)2–Ni(L6)2] were synthesized through reaction of Ni(II) with (Z)-2-(2-oxoindolin-3-ylidene)-N-phenylhydrazinecarbothioamide (L1H), (Z)-2-(5-methyl-2-oxoindolin-3-ylidene)-N-phenylhydrazinecarbothioamide (L2H), (Z)-2-(5-fluoro-2-oxoindolin-3-ylidene)-N-phenylhydrazinecarbothioamide (L3H), (Z)-N-methyl-2-(5-nitro-2-oxoindolin-3-ylidene)hydrazinecarbothioamide (L4H), (Z)-N-methyl-2-(5-methyl-2-oxoindolin-3-ylidene)hydrazinecarbothioamide (L5H), and (Z)-N-ethyl-2-(5-methyl-2-oxoindolin-3-ylidene)hydrazinecarbothioamide (L6H). The structures of the Ni complexes were characterized through elemental analysis, infrared, and mass spectral data. The structure of the NiL2 complex was further characterized through single-crystal X-ray diffraction. The interaction of these complexes with calf thymus (CT-DNA) exhibited high intrinsic binding constants (Kb = 1.4 × 105–2.4 × 106 M−1), which reflected their intercalative activity toward CT-DNA. This result was also confirmed by viscosity data. Electrophoresis studies revealed that these complexes could cleave the DNA through the oxidative pathway. The in vitro anti-proliferative study establishes the anticancer potency of these compounds against human colorectal carcinoma cell line. Graphical Abstract

A new thio-Schiff base fluorophore with copper ion sensing, DNA binding and nuclease activity

Copper ion recognition and DNA interaction of a newly synthesized fluorescent Schiff base (HPyETSC) were investigated using UV-vis and fluorescent spectroscopy. Examination using these two techniques revealed that the detection of copper by HPyETSC is highly sensitive and selective, with a detection limit of 0.39 μm and the mode of interaction between HPyETSC and DNA is electrostatic, with a binding constant of 8.97×10(4) M(-1). Furthermore, gel electrophoresis studies showed that HPyETSC exhibited nuclease activity through oxidative pathway.

4-Methyl-N-[2-(pyridin-2-yl)ethyl-carbamo-thio-yl]benzamide.

In the title compound, C16H17N3OS, the dihedral angle between the planes of the benzene and pyridine rings is 71.33u2005(15)°. An intramolecular N—H⋯O hydrogen bond is present. In the crystal, weak aromatic C—H⋯O hydrogen bonds link the molecules into chains extending along a.

Methyl 5-(4-hy­droxy­phen­yl)-6-oxo-1,6-di­hydro­pyrazine-2-carboxyl­ate

The title compound, C12H10N2O4, is approximately planar, with dihedral angles of 5.53u2005(9) and 2.48u2005(13)°, respectively, between the benzene and pyrazine rings, and between the pyrazine ring and the methyl carboxylxadate plane. An intraxadmolecular C—H⋯O hydrogen bond with an S(6) ring motif is observed. In the crystal, interxadmolecular O—H⋯O and N—H⋯O hydrogen bonds link molxadecules into a layer parallel to the ab plane. Adjacent layers interxadpenetrate each other through a π–π interxadaction [centroid–centroid distance of 3.4746u2005(11)u2005A].

Crystal structures of (E)-1-naphthaldehyde oxime and (E)-phenanthrene-9-carbaldehyde oxime

The aldoximes (E)-1-naphthaldehyde oxime (I) and E-phenanthrene-9-carbaldehyde oxime (II) were synthesized and characterized using NMR and XRD. The crystal structures of both (I) and (II) are similar with a single intermolecular O—H⋯N hydrogen-bonding interaction, giving rise to the formation of one-dimensional polymeric chains extending along the 21 (b) screw axes in each.

Crystal structure of trans-di­chloridobis­[N-(5,5-di­methyl-4,5-di­hydro-3H-pyrrol-2-yl-κN)acetamide]palladium(II) dihydrate

The synthesis and crystal structure of the complex trans-[dichlorido-bis(N-(4,5-dihydro-5,5-dimethyl-3H-pyrrol-2-yl)acetamide)]palladium(II) dihydrate is described.

Methyl 5-(4-hy­droxy­phen­yl)-6-oxo-1,6-di­hydro­pyrazine-2-carboxyl­ate monohydrate

In the title hydrate, C12H10N2O4·H2O, the dihedral angle between the benzene and pyrazine rings is 37.70u2005(10)°. In the crystal, molxadecules are connected by hydrogen bonds (N—H⋯O, O—H⋯O and O—H⋯O) to generate (1-10) sheets. Aromatic π–π stacking [centroid–centroid separation = 3.7070u2005(13)u2005A] links the sheets into a three-dimensional network.

(Z)-2-(5-Fluoro-2-oxoindolin-3-yl­idene)-N-methyl­hydrazinecarbo­thio­amide

In the title compound, C10H9FN4OS, which is approximately planar with a maximum deviation of 0.0881u2005(10)u2005A from the mean plane of the non-H atoms, an intraxadmolecular N—H⋯O hydrogen bond generates an S(6) ring. In the crystal, molxadecules are linked via N—H⋯O hydrogen bonds, forming a helical chain along the a axis. The chains are linked by N—H⋯S, C—H⋯S and C—H⋯F hydrogen bonds and C—H⋯ π interxadactions into a three-dimensional network.