M. Ibrahim M. Tahir

Synthesis, characterization, antibacterial, and cytotoxic activities of organotin(iv) complexes derived from n (4)-cyclohexylthiosemicarbazone: x-ray crystal structure of [ph 2sncl(l)]

Reaction of organotin(IV) chloride(s) with 2-benzoylpyridine-N(4)-cyclohexylthiosemicarbazone, [HL] (1) yielded [MeSnCl2(L)] (2), [BuSnCl2(L)] (3), [Me2SnCl(L)] (4), and [Ph2SnCl(L)] (5). The ligand (1) and its organotin(IV) complexes have been characterized by CHN analyses, molar conductivity, UV-Vis, FT-IR, 1H, 13C, and 119Sn NMR spectral studies. The molecular structure of 5 was also determined by X-ray diffraction. There are two independent molecules in the asymmetric unit and the central tin(IV) atom is six-coordinate in distorted octahedral geometry. The ligand (1) and complexes were screened for their in vitro antibacterial activities. The cytotoxic activities of 1–5 were tested against A2780 and A2780/Cp8 cancer cell lines. The compounds have better antibacterial activities than the free ligand; 2–5 are more potent cytotoxic agents than 1, while the diphenyltin(IV) 5 is more active with IC50 values of 0.05 and 0.54 µmol L−1 against A2780 and A2780/Cp8 cell lines, respectively.

Synthesis and characterization of mixed-ligand copper(II) saccharinate complexes containing tridentate NNS Schiff bases. X-ray crystallographic analysis of the free ligands and one complex

Abstract Four new Schiff bases containing N and S heteroatoms (HL1–HL4) have been prepared and characterized, including determination of the X-ray crystal structures of HL1 and HL3. Spectroscopic evidence indicates that these Schiff bases behave as uninegatively charged tridentate NNS ligands in complexes of general formula [Cu(Ln)sac] (Ln is the anionic form of NNS, and sac represents saccharinate anion). Crystals of both HL1 and [Cu(L4)sac)(H2O)]·Hsac crystallized in triclinic system with P

Benzyl N′-[1-(3-pyridyl)ethylidene]hydrazinecarbodithioate

\bar{1}

Benzyl N-[(Z)-(1-methyl-2-sulfanyl­propyl­idene)amino]­carbamodithio­ate

1¯ space group, while HL3 crystallized in monoclinic system with P 21/c space group. [Cu(L4)sac)(H2O)]·Hsac has a distorted square-pyramidal structure with a non-bonded saccharin molecule present in the outer coordination sphere. The tridentate NNS ligands are coordinated to Cu through pyridine nitrogen, azomethine nitrogen and thiolate sulfur atoms, while the fourth and fifth coordination positions are occupied by the N-bonded saccharinate anion and a water ligand, respectively.

2-Naphthylmethyl N-(3-pyridylmethylene) hydrazinecarbodithioate.

Two bidentate Schiff base ligands having nitrogen sulphur donor sequence were derived from the condensation of S-benzyldithiocarbazate (SBDTC) with 2-chloroacetophenone and 4-chloroacetophenone to give S-benzyl-β-N-(2-chlorophenyl)methylenedithiocarbazate (NS2) and S-benzyl-β-N-(4-chlorophenyl)methylenedithiocarbazate (NS4) isomers. Each of the ligands was then chelated with Cd2+, Zn2+, Cu2+, and Ni2+. The compounds were characterized via IR spectroscopy and melting point while the structure of NS4 was revealed via X-ray crystallography. Finally, the compounds were screened for antimicrobial activity to investigate the effect that is brought by the introduction of the chlorine atom to the benzene ring. X-ray crystallographic analysis showed that the structure of NS4 is planar with a phenyl ring that is nearly perpendicular to the rest of the molecules. The qualitative antimicrobial assay results showed that NS4 and its complexes lacked antifungal activity while Gram-positive bacteria were generally inhibited more strongly than Gram-negative bacteria. Furthermore, NS4 metal complexes were inhibited more strongly than the ligand while the opposite was seen with NS2 ligand and its complexes due to the partial solubility in dimethyl sulfoxide (DMSO). It was concluded that generally NS2 derivatives have higher bioactivity than that of NS4 derivatives and that the Cd complexes of both ligands have pronounced activity specifically on K. rhizophila.

2-Quinolylmethyl N′-[1-(m-tol­yl)ethyl­idene]hydrazinecarbodithio­ate

The title compound, C15H5N2S2, crystallizes as a trans–cis conformer. The thione sulfur is in a trans position with the methyl pyridyl fragment with respect to the C—N bond but adopts a cis position with the benzyl ring across the C—S bond. The dihedral angle between the planar quinoline ring and the dithiocarbazate unit is 103.70 (1). The inclination of the dithiocarbazate unit with the benzyl group is 17.20 (1).There are strong – stacking interactions between pairs of dithiocarbazate units and also pairs of pyridine rings [3.27 (5)and 3.28 (5) A ° , respectively]. A long-distance intermolecular N—H N hydrogen bond [3.171 (2) A ° ] also stabilizes the structure.

Synthesis and characterization of cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes of benzyl N-[1-(thiophen-2-yl)ethylidene] hydrazine carbodithioate and benzyl N-[1-(thiophen-3-yl)ethylidene] hydrazine carbodithioate and the X-ray crystal structure of bis {benzyl N-[1-(thiophen-2-yl)ethylidene] hydrazine carbodithioate }nickel(II)

The title compound, [Ni(C13H11N4S2)2], was obtained by the reaction of S-2-picolyldithiocarbazate and pyridine-2-carbaldehyde with nickel(II) acetate. The NiII atom is located on a twofold rotation axis and is bonded to four N atoms at distances of 2.037 (8) and 2.109 (9) Å, and to two S atoms at a distance of 2.406 (3) Å, leading to a distorted octahedral coordination. The angle between the mean planes of the coordinating moieties of the two symmetry-related tridentate ligands is 83.3 (2)°. In the crystal, complex molecules are linked by weak C—H⋯S hydrogen bonds, π–π interactions between the pyridine rings [centroid–centroid distance = 3.775 (9) Å] and C—H⋯π interactions. The hydrogen-bonding interactions lead to the formation of layers parallel to (010); π–π interactions link these layers into a three-dimensional network.

Synthesis, characterization and bioactivity of mixed-ligand Cu(II) complexes containing Schiff bases derived from S -benzyldithiocarbazate and saccharinate ligand and the X-ray crystal structure of the copper-saccharinate complex containing S -benzyl-β-N-acetylpyrid-2 -yl)methylenedithiocarbazate

The title compound, C12H16N2S3, was obtained by the condensation reaction of S-benzyl dithiocarbazate and 3-mercaptobutan-2-one. The phenyl ring and thiol (SH) group are approximately perpendicular [S—C—C—C and N—C—C—S torsion angles = 67.8 (3) and 116.9 (2)°, respectively] to the rest of the molecule. In the crystal, molecules are linked by weak S—H⋯S and N—H⋯S hydrogen bonds, π–π interactions between the benzene rings [centroid–centroid distance = 3.823 (2) Å] and C—H⋯π interactions.