Synthesis and characterization of Cu(II), Ni(II) and Zn(II) metal complexes of bidentate NS isomeric Schiff bases derived from S-methyldithiocarbazate (SMDTC): Bioactivity of the bidentate NS isomeric Schiff bases, some of their Cu(II), Ni(II) and Zn(II) complexes and the X-ray structure of the bis[S-methyl-β-N-(2-furyl-methyl)methylenedithiocarbazato]zinc(II) complex.

Two new isomeric Schiff bases, S-methyl-β-N-(2-furylmethyl)methylenedithiocarbazate (NS′) and S-methyl-β-N-(5-methyl-2-furyl)methylenedithiocarbazate (NS″) have been prepared. Bis-chelated complexes of these two bidentate ligands, [M(NS)2], [M=Cu(II), Ni(II) and Zn(II)], were synthesized. The Schiff bases and their metal complexes have been characterized by a variety of physico-chemical techniques. X-ray crystallographic analysis shows that the Zn(II) complex, [Zn(NS′)2], is four-coordinate and has a distorted tetrahedral structure with the ligand coordinated to the Zn(II) ion as an uninegatively charged bidentate chelating agent via the azomethine nitrogen and the mercaptide sulfur atoms. The Cu(II) complexes are paramagnetic with a square-planar stereochemistry. The Ni(II) and [Zn(NS″)2] complexes have a square-planar and tetrahedral structure, respectively, however, they are diamagnetic. Only Cu(NS′)2 showed clear activity against the bacteria, Subtilis mutant (B28), while both NS′ and NS″ Schiff bases were strongly antifungal against Saccharomyces cereviceae (20341), Candida albicans, Candida lypolytica (2075) and Aspergillus ochraceous (398). Cu(NS′)2 and Ni(NS′)2 showed clear inhibition of C. albicans and S. cereviceae (20341), respectively. The Cu(NS′)2, Ni(NS′)2 and Zn(NS′)2 complexes showed very good activity against human cell T-lymphoblastic leukemia [CEM-SS] cells with CD50 values of 1.6, 2.1 and 3.0 μg ml−1, respectively. The remainder of the Schiff bases and complexes were inactive towards CEM-SS cells. None of the compounds showed any activity towards colon cancer cells (HT-29). Only the Cu(NS′)2 and Zn(NS′)2 complexes were highly active against cervical cancer cells (HELA cells) with CD50 values of 1.5 and 2.1 μg ml−1, while the Ni(NS′)2 complex was weakly active towards HELA cells with a CD50 value of 23.0 μg ml−1

Coordination chemistry and bioactivity of some metal complexes containing two isomeric bidentate NS schiff bases derived from S-benzyldithiocarbazate and the x-ray crystal structures of S-benzyl-β-N-(5-methyl-2-furylmethylene)dithiocarbazate and bis[S-benzyl-β-N-(2-furylmethylketone)dithiocarbazato]cadmium(II).

someric bidentate ligands having nitrogen–sulfur donor sequence were prepared by condensing S-benzyldithiocarbazate (SBDTC) with 5-methyl-2-furyladehyde (NS) and 2-furylmethylketone (NS′). Complexes of these ligands with lead, tin, iron, cobalt and cadmium gave complexes of [M(L)2] (M=Pb, Fe and Cd) and [M(L)2]Cln (M=Sn, n=2 and Co, n=1) (L=NS and NS′). The compounds have been characterized by spectroscopic studies (infrared, 1H NMR and electronic spectra). X-ray crystallographic analysis of S-benzyl-β-N-(5-methyl-2-furylmethylene)dithiocarbazate shows the presence of two independent molecules in the asymmetric unit. The molecule adopts a trans–cis configuration, as was observed in other analogues, such as SBDTC where the furylmethylene and benzyl groups are trans and cis about the N-C and C-S bonds, respectively. The molecular structure of bis[S-benzyl-β-N-(2-furylmethylketone)dithiocarbazato]cadmium(II) shows a tetrahedral geometry about the central cadmium atom with the bidentate ligand coordinating through the thioketo sulfur and the azomethine nitrogen atoms. The lead(II) complex of the NS ligand was highly cytotoxic against leukemic cells (CEM-SS) with a CD50 of 3.25 μg cm−3 while antimicrobial screening showed that the [Fe(NS)2]Cl2·H2O complex was effective against Aspergillus achraceous

Synthesis, characterization and bio-activity of metal complexes of bidentate N-S isomeric Schiff bases derived from S-methyldithiocarbazate (SMDTC) and the X-ray structure of the bis[S-methyl-β-N-(2-furyl-methylketone) dithiocarbazato]cadmium(II) complex.

Condensation of SMDTC with 2-furyl-methylketone and 5-methyl-2-furaldehyde gave isomeric Schiff bases, (NS) and (NS'). The metal complexes of these uninegatively charged bidentate Schiff base ligands with cadmium, tin, iron, lead and cobalt have been prepared. The complexes have been characterized by a variety of physico-chemical techniques. X-ray crystallographic analysis shows that the Cd(II) complex, bis[S-methyl-β-N-(2-furylmethylketone)dithiocarbazato]cadmium(II), consists of two molecules with distorted octahedral structure. The Co(II) complexes are paramagnetic with a square-planar stereochemistry. The diamagnetic Sn(II), Fe(III) and Pb(II) complexes also have square-planar structures while the diamagnetic [Cd(NS')2]. 3H2O complex is tetrahedral. The [Cd(NS')2].3H2O, [Sn(N'S)2) and [Co(NS)2] showed clear inhibition of almost all bacteria and fungi tested However, [Cd(NS)2], [Fe(NS)]Cl2, [Pb(NS)2] and [Pb(NS')2] were inactive against all bacteria assayed while [Cd(NS)2], [Fe(NS)]Cl2 and [Pb(NS)2] showed clear inhibition of some fungi. The [Cd(NS)2], [Cd(NS')2].3H2O and [Co(NS)2] were found to be very active against Human cell T-lymphoblastic leukemia (CEM-SS) and cervical cancer cells (HELA) with CD50 values between 1.8 and 3.6 μl cm-3

Coordination chemistry and bioactivity of Ni2+, Cu2+, Cd2+ and Zn2+ complexes containing bidentate schiff bases derived from S-benzyldithiocarbazate and the X-ray crystal structure of bis[S-benzyl-β-N-(5-methyl-2-furylmethylene)dithiocarbazato]cadmium(II).

New bidentate isomeric NS and NS′ Schiff bases were derived from the condensation of S-benzyldithiocarbazate (SBDTC) with 5-methyl-2-furyldehyde and 2-furyl-methylketone. Reaction of NS ligand with Ni(II), Cu(II), Cd(II) and Zn(II) salts gave solid complexes. Only the Ni(II) complex of the NS′ ligand was isolated. All complexes were characterized by a variety of physico-chemical techniques, viz. elemental analyses, molar conductivity, i.r. and electronic spectral studies. The Schiff bases behaved as uninegatively charged bidentate ligands. Square-planar structures have been proposed for the Cu(II) complex containing the NS Schiff base ligand and the Ni(II) complexes of the bidentate NS and NS′ Schiff base ligands. Single crystal X-ray diffraction study of [Cd(NS)2] showed that the complex was bis chelated with a distorted tetrahedral structure. The antimicrobial properties of the Schiff bases and their metal complexes indicate that the organic compounds are stronger antifungal agents than their complexes with the metals studied. However, the zinc complex of the Schiff base, S-benzyl-β-N-(5-methyl-2-furyl)methylenedithiocarbazate, (NS), was found to be highly active against CEM-SS (Human cell T-lymphoblastic leukemia) with a CD50 value of 2.0 μg cm−3, while [Cd(NS)2] was moderately active with a CD50 value of 4.95 μg cm−3. None of the compounds were found to be active against HT-29 (Human colon adenocarcinoma cells). The bioactivity of a previously reported tridentate NNS Schiff base (SBD1) and its metal complexes with nickel(II) and copper(II) are also discussed

Hard Single Diffraction in pbarp Collisions at root-s = 630 and 1800 GeV

Using the D0 detector, we have studied events produced in proton-antiproton collisions that contain large forward regions with very little energy deposition (``rapidity gaps'') and concurrent jet production at center-of-mass energies of root-s = 630 and 1800 Gev. The fractions of forward and central jet events associated with such rapidity gaps are measured and compared to predictions from Monte Carlo models. For hard diffractive candidate events, we use the calorimeter to extract the fractional momentum loss of the scattered protons.Comment: 11 pages 4 figures. submitted to PR

(2,2 `-Bipyridine-kappa N-2,N `)bis(N-ethyl-N-methyldithiocarbamato-kappa S-2,S `)zinc(II)

The complete molecule of the title compound, [Zn(C4H8NS2)(2)(C10H8N2)], is generated by crystallographic twofold symmetry, with the Zn atom lying on the rotation axis; the axis also bisects the central C-C bond of the 2,2'-bipyridine molecule. The metal atom is chelated by two S,S'-bidentate dithiocarbamate anions and the N,N'-bidentate heterocycle, resulting in a distorted cis-ZnN2S4 octahedral geometry. The methyl and ethyl groups of the anion are statistically disordered

Bis(N-isobutyl-N-propyldithiocarbamato-kappa S-2,S `)zinc(II)

In the title compound, [Zn(C8H16NS2)(2)], the Zn-II atom is chelated by two S,S'-bidentate dithiocarbamate ions in a very distorted tetrahedral geometry. The alkyl chains of the ligands are equally disordered over two sets of sites

Bis {-N-[1-(2-oxidophenyl) ethylidene] benzohydrazido} bis [(dimethylsulfoxide) zinc (II)]

The title compound, [Zn2(C15H12N2O2)2(C2H6OS)2], is a centrosymmetric dimer via a Zn-O bridge of 2.0038 (13) Å, with a Zn...Zn separation of 3.1370 (13) Å. The geometry of the five-coordinate environment of the Zn atoms is close to trigonal bipyramidal

Bis{μ-N-[1-(2-oxidophenyl)ethylidene]benzo-hydrazido} bis[(dimethylsulfoxide)zinc(II)]

The title compound, [Zn2(C15H12N 2O2)2(C2H6OS) 2], is a centrosymmetric dimer via a Zn-O bridge of 2.0038 (13) Å, with a Zn⋯Zn separation of 3.1370 (13) Å. The geometry of the five-coordinate environment of the Zn atoms is close to trigonal bipyramidal. © 2003 International Union of Crystallography Printed in Great Britain - all rights reserved