Condensation Of S-benzyldithiocarbazate Research Articles

Cadmium(II) Schiff base Complex Containing 5-Fluoroisatin Moiety: Synthesis, Characterization, Antibacterial Activity and Structural Studies

The Schiff base ligand, HSB5FISA (H1), obtained by the condensation of S-benzyldithiocarbazate with 5-fluoroisatin, has been employed to synthesize a new cadmium(II) complex, Cd(SB5FISA)2 (2) (SB5FISA = monoanionic form of H1). The complex has been characterized by elemental analysis, molar conductivity, magnetic susceptibility, inductively coupled plasma atomic emission spectroscopy (ICP-AES), Fourier-transform infrared spectroscopy (FT-IR) and ultraviolet-visible spectroscopy (UV-Vis). The crystallographic study of Cd(SB5FISA)2×2DMSO (2a) (DMSO = dimethyl sulfoxide) was conducted using single-crystal X-ray diffraction. The crystal structure of 2a confirmed the presence of 6-coordinated cadmium in a distorted octahedral environment. Ligand H1 behaves in a tridentate monoanionic fashion, coordinating to a cadmium(II) metal centre through the thiolate sulfur, azomethine nitrogen and carbonyl oxygen. The antibacterial activity of both H1 and 2 was examined against 4 different bacterial strains using the disc diffusion method. Complex 2 showed significant inhibitory effect against Bacillus subtilis with an inhibition zone of 14 mm, comparable to the standard antibiotic streptomycin.
 HIGHLIGHTS 
 
 Cd(II) complex of 5-fluoroisatin Schiff base was synthesized
 Structural studies of compound determined via single crystal X-ray diffraction
 Compound exhibited significant antibacterial activity towards Bacillus subtilis
 
 GRAPHICAL ABSTRACT

XRD/HSA, noncovalent interactions and influence of solvent polarity on spectral properties of dithiocarbazate schiff base and its cis-Cu(II) complex: Experimental and theoretical studies

A N,S-bidentate ligand (LH) was synthesized via the condensation of S-benzyldithiocarbazate with acetophenone. The produced Schiff base ligand was reacted with a copper(II) salt to yield a neutral cis-Cu(II) complex. The influence of solvent polarity on spectral properties were demonstrated for the new complex in different organic solvents. The global reactivity parameters were estimated by means of energy values of the frontier molecular orbitals. Both the desired LH and its complex have been characterized by XRD-crystal analysis. In solid state the LH exists in a thione tautomeric form, while the deprotonated form of is chelated to the Cu(II) center through neutral nitrogen of azomethine and ionic sulfur of thiol, giving rise to tetrahedrally distorted square planar geometry around the metal center, in which the two ligands coordinated in cis-configuration. The noncovalent interactions were evaluated via Hirshfeld surface analysis (HSA), reflecting the presence of four position of short contacts for both the free ligand and its complex. Moreover, the formation of hydrogen bonds of the types NH⸱⸱⸱S=C and CH⸱⸱⸱S=C were observed in the ligand structure, while H⸱⸱⸱Caromatic interactions were perceived in both structures of the ligand and complex, approved by the XRD-packing results.

Synthesis, Characterization and Biological Activity of a Bidentate NS Schiff Base Containing S-Benzyl Dithiocarbazate and Its Zr(IV), Sn(II) Complexes

Zr (IV) and Sn (II) complexes were prepared with bidentate ligand, benzyl 2-(3-phenylallylidene) hydrazinecarbodithioate, derived from the condensation of S-benzyldithiocarbazate (SBDTC) with cinnamaldehyde and characterized by microanalysis, molar conductance and magnetic measurements, IR, electronic and ESI-MS studies. It was found that the ligand coordinated to the metal center through azomethine nitrogen and thiol sulfur atoms to form octahedral complexes with both the metal ions. The antimicrobial activities of the ligand and its complexes were investigated against the gram-positive and gram-negative bacteria and the fungus strain. The metal complexes showed strong activity than the free ligand.

SBDTC Derived Schiff Base Metal Complexation: Synthesis, Physicochemical, and Spectral Studies with Antibacterial Activity

A Schiff base ligand derived from condensation of S-benzyldithiocarbazate (SBDTC) and salicylaldehyde, and its U(VI), Th(IV) and Zr(IV) complexes have been synthesized. The compounds are characterized by elemental analysis, molar conductance, magnetic moments, UV-Vis, FT-IR and 1H NMR spectra. The Schiff base ligand coordinates via azomethine nitrogen, thiol sulfur and/or the phenolic OH group, and acts as bidentate in case of U(VI) and Zr(IV) ions and tridentate with Th(IV) ion. The U(VI) and Th(IV) complexes are 1 : 2 electrolytes whereas Zr(IV) complex is non-electrolytic. All the compounds have been tested for their antibacterial activity against four pathogenic bacteria, two Gram-negative Escherichia coli and Shigella dysenteriae and two Gram-positive Staphylococcus aureus and Bacillus subtilis using Kanamycin (K-30) as a standard. The U(VI) and Th(IV) complexes exhibit stronger antibacterial activity than the Zr(IV) complex against all tested organisms.

Synthesis, characterization and biological activity of Cu(II), Zn(II) and Re(I) complexes derived from S-benzyldithiocarbazate and 3-acetylcoumarin.

Cu(II), Zn(II) and Re(I) complexes have been synthesized with the Schiff base, N'-[1-(2-oxo-2H-chromen-3-yl)-ethylidene]-hydrazinecarbodithioic acid benzyl ester (SBCM-H) which was prepared by condensation of S-benzyldithiocarbazate and 3-acetylcoumarin. The metal complexes were characterized on the basis of various physico-chemical and spectroscopic techniques including elemental analysis and electrochemical studies, and FT-IR, UV-Vis, NMR, EPR and mass spectroscopy. The Schiff base was found to behave as a bidentate ligand coordinating with Cu(II) and Zn(II) in the thiolate form with 1:2 metal to ligand stoichiometry. Crystals suitable for X-ray diffractometry (XRD) were obtained from the reaction of ReCl(CO)5 with SBCM-H forming a centrosymmetric dimeric complex Re2L2(CO)6 linked by Re-S-Re bridges, where S is the thiolate sulfur of the N,S-bidentate ligand. This Re(I) complex is the first metal carbonyl complex with a bidentate dithiocarbazate ligand to have been characterized by XRD. Cytotoxicity assays revealed enhancement of the bioactivity of SBCM-H upon complexation. Both Cu(II) and Re(I) complexes are found to be active against human breast adenocarcinoma cancer cell lines MDA-MB-231 and MCF-7. TOC diagram.

Synthesis, Characterization, and Bioactivity of Schiff Bases and TheirCd2+,Zn2+,Cu2+, andNi2+Complexes Derived from Chloroacetophenone Isomers with S-Benzyldithiocarbazate and the X-Ray Crystal Structure of S-Benzyl-β-N-(4-chlorophenyl)methylenedithiocarbazate

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.

Coordination behavior of three geometric isomers of indole-based S-benzyldithiocarbazone ligands towards nickel, zinc and cadmium divalent ions

Three indolyl-imine ligands have been synthesized through the condensation of S-benzyldithiocarbazate with indole-2-carbaldehyde, indole-3-carbaldehyde and indole-7-carbaldehyde. Treatment of these Schiff bases with acetate salts of Ni(II), Zn(II) and Cd(II) in ethanol yielded a series of complexes of 2:1 type (ligand/metal ratio) in which the ligands coordinated to the metal ions as monoanionic NS bidentate chelates. While the 2-imineindole and 3-imineindole formed the expected five-membered chelate rings, the X-ray crystal structure of [Cd(HL3)(py)2], (HL3=the mono-deprotonated 7-imineindole), revealed an unusual mode of coordination, namely formation of four-membered rings with the metal atom. Reaction of the 7-imineindole with the metal ions in the presence of potassium hydroxide produced complexes of the type [M(L3)(H2O)] in which the Schiff base acts as a dianionic NNS tridentate ligand.

Synthesis, Spectral, and 3D Molecular Modeling of Tin(II) and Organotin(IV) Complexes of Biologically Active Schiff Bases Having Nitrogen and Sulfur Donor Ligands

Reaction of tin(II) chloride and dimethyltin dichloride with Schiff bases derived from S-benzyldithiocarbazate leads to the formation of a new series of tin(II) and organotin(IV) complexes of general formula SnCl 2 .L and Me 2 SnCl 2 .L (where L = Schiff bases are derived from the condensation of S-benzyldithiocarbazate with heterocyclic aldehydes). An attempt has been made to prove the structures of the resulting complexes on the basis of elemental analysis, conductance measurements, molecular weight determinations, infrared, and multinuclear magnetic resonance ( 1 H, 13 C, and 119 Sn NMR) spectral studies. A few representative ligands and their tin complexes have also been screened for their antibacterial and antifungal activities and found to be quite active in this respect.

Coordination chemistry and bioactivity of Ni 2+, Cu 2+, Cd 2+ and Zn 2+ 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 CD 50 value of 2.0 μg cm −3, while [Cd(NS) 2] was moderately active with a CD 50 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.

Synthesis and characterization of coordination compounds of organotin(IV) with nitrogen and sulfur donor ligands

AbstractThe reactions of dimethyltin dichloride with nitrogen and sulfur donor ligands derived by condensation of S‐benzyldithiocarbazate with indol‐3‐carboxylaldehyde, thiophene‐2‐aldehyde and furfuraldehyde have been investigated in 1:1 and 1:2 molar ratios in anhydrous alcohol. These ligands act as mononegatively charged bidentate species and coordinate to the central tin(IV) atom through the thiosulfur by proton exchange with the azomethine nitrogen. The newly synthesized complexes have been characterized by elemental analysis, conductance measurements and molecular weight determinations. The mode of bonding and the geometry of the complexes have been suggested on the basis of infrared, electronic and 1H, 13C and 119Sn NMR spectroscopy, and probable structures have been assigned to these complexes. A few representative ligands and their tin(IV) complexes have also been screened for their antifungal and antibacterial activities and found to be quite active in this respect. Copyright © 2001 John Wiley & Sons, Ltd.

Complexes of a tridentate ONS Schiff base. Synthesis and biological properties

Several new complexes of a tridentate ONS Schiff base derived from the condensation of S-benzyldithiocarbazate with salicylaldehyde have been characterised by elemental analyses, molar conductivity measurements and by i.r. and electronic spectra. The Schiff base (HONSH) behaves as a dinegatively charged ligand coordinating through the thiolo sulphur, the azomethine nitrogen and the hydroxyl oxygen. It forms mono-ligand complexes: [M(ONS)X], [M=NiII, CuII, CrIII, SbIII, ZnII, ZrIV or UVI with X = H2O, Cl]. The ligand produced a bis-chelated complex of composition [Th(ONS)2] with ThIV. Square-planar structures are proposed for the NiII and CuII complexes. Antimicrobial tests indicate that the Schiff base and five of the metal complexes of CuII, NiII, UVI, ZnII and SbIII are strongly active against bacteria. NiII and SbIII complexes were the most effective against Pseudomonas aeruginosa (gram negative), while the CuII complex proved to be best against Bacillus cereus (gram positive bacteria). Antifungal activities were also noted with the Schiff base and the UVI complex. These compounds showed positive results against Candida albicans fungi, however, none of them were effective against Aspergillus ochraceous fungi. The Schiff base and its zinc and antimony complexes are strongly active against leukemic cells (CD50 = 2.3–4.3 μg cm−3) while the copper, uranium and thorium complexes are moderately active (CD50 = 6.9–9.5 μg cm−3). The nickel, zirconium and chromium complexes were found to be inactive.

Syntheses and metal complexes of a quadridentate NNSS ligand derived from S-benzyl dithiocarbazate (H 2L) and crystal structure of the complex CuL

The quadridentate N 2S 2 Schiff base ligand, H 2L, prepared by the condensation of S-benzyl dithiocarbazate with 1,4-bis (2′-formylphenyl)-1,4-dioxabutane in a 2:1 molar ratio, reacts with divalent metal ions to form the neutral metal complexes, ML (M=Ni, Cu, Zn). The complexes have been characterized by physico-chemical techniques and the single crystal X-ray structure of the Cu (II) complex shows the geometry around the metal atom to be distorted square planar. The monomeric units are weakly associated into dimers via a long Cu–S interaction [2.9519 (8) Å].

Peroxo complexes of zirconium(IV), thorium(IV), molybdenum(VI), tungsten(VI) and uranium(VI) ions containing a quadridentate SNNS Schiff base

New peroxo complexes of zirconium(IV), thorium(IV), molybdenum(VI), tungsten(VI) and uranium(VI) containing a quadridentate Schiff base, formed by the condensation of S-benzyldithiocarbazate and benzil, have been synthesized and characterized. The complexes have the general formulae [M(O 2)(SNNS)] (M = Zr IV and Th IV) and [M 1(O)(O 2)(SNNS)] (M 1 = Mo VI, W VI and U VI). These peroxo complexes were found to be inert towards oxidation. The size of the metals as well as the electronic effect derived from the quadridentate Schiff base influence the mode of coordination of the peroxo moiety. The frequency of the v 1 mode of the M(O 2) grouping decreases with an increase in the atomic number of the metals in a particular group and in the σ-donor electronic nature of the quadridentate Schiff base used.

Synthesis of Novel Coordination Compounds of Niobium(V) with Sulphur Donor Ligands+

Abstract The reactions of niobium pentaisopropoxide with the sulphur donor ligands derived by the condensation of S-benzyl dithiocarbazate with salicylaldehyde, o-hydroxy acetophenone, 2,4-pentanedione or 1-phenyl-1,3-butanedione have been investigated in 1:1, 1:2, 2:5 and 1:3 molar ratios in anhydrous benzene. These ligands act as dinegatively charged tridentate species, and coordinate to the central niobium(V) atom through the thiolo-sulphur by proton exchange the azomethine nitrogen and the hydroxo/keto oxygen. On the basis of vibrational, electronic and proton nuclear magnetic resonance spectroscopy, conductance, thermogravimetric and magnetic susceptibility measurements, probable structures have been assigned to these complexes.