Toxicological and pesticidal studies on novel bioactive sulfonamide imine organotin(IV) complexes

Toxicological, pesticidal and stereochemical aspects of organotin(IV) complexes with a sulfonamide imine ligand having an N^∩N donor system are described with the support of elemental analysis, IR, UV, ¹H NMR, ¹³C NMR and ¹¹⁹Sn NMR spectroscopy. The spectral data suggest that the ligand acts in a monobasic bidentate manner coordinating through the nitrogen atom. The complexes have been characterized on the basis of molecular weight determinations, conductivity measurements, and magnetic measurements. The isolated products are coloured solids, soluble in dimethylsulfoxide, dimethylformamide (DMF) and methanol. All the complexes are monomeric in nature, as indicated by their molecular weight determinations. Conductivity measurements in dry DMF show them to be non‐electrolytes. From the analyses of these studies the donor sites of the ligand are located and the geometries of the donor environment around the tin(IV) acceptor centres proposed. The ligand and its metal complexes are tested in vitro against a number of pathogenic fungal and bacterial strains and the findings are discussed. Emphasis has been given to the nematicidal properties. Copyright © 2003 John Wiley & Sons, Ltd.     

Biologically potent sulphonamide imine complexes of organotin(IV): Synthesis, spectroscopic characterization and biological screening

Coordination behaviour of a biologically potent sulphonamide-imine having N^∩N donor moiety towards the diorgano and triorganotin(IV) have been investigated. The unimolar and bimolar reactions of di-and triorgano-tin(IV) chlorides with monobasic bidentate imine resulted in the formation of colored solids, soluble in DMSO, DMF and MeOH, which have been characterized by elemental analyses, molecular weight determinations and conductance measurements. Structures of the resulting complexes have been proposed using IR, ¹H, ¹³C and ¹¹⁹Sn NMR spectral studies. All the complexes are monomeric in nature as indicated by their molecular weight determinations. Conductivity measurements in dry DMF show them to be non-electrolytes. The pathogenicity and virulence of certain microbial infections associated with ions of the complexes have been found to be potent and like broad spectrum antibiotics. These results made it desirable to delineate a comparison between the ligand and its metal complexes. Emphasis has been given to the nematicidal properties.     

Antimicorbial effects of newly synthesized organotin(IV) and organolead(IV) derivatives

Triorganotin(IV) and triorganolead(IV) derivatives of the types Me₃Sn(SCZ) and Ph₃Pb(SCZ) (where SCZ^? is the anion of a semicarbanzone ligand) have been synthesized by substitution reactions of trimethyltin chloride and triphenyl-lead chloride with semicarbazones derived from heterocyclic ketones. The resulting complexes have been characterized by elemental analyses, molecualr weight determinations and conductivity measurements. The mode of bonding has been established on the basis of infrared and ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopic studies. Some respresentative complexes have also been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria; the results of these investigations have been reported in the present paper.     

Bioactive versatile azomethine complexes of organotin(IV) and organosilicon(IV)

Diorganotin(IV) and diorganosilicon(IV) derivatives of the types R₂MCl(TSCZ) and R₂M(TSCZ)₂ (where TSCZ is the anion of a thiosemicarbazone ligand, R=Ph or Me and M=Sn or Si) have been synthesized and characterized by elemental analyses, molecular weight determinations and conductivity measurements. The mode of bonding has been established on the basis of IR and ¹H, ¹³C ²⁹Si and ¹¹⁹Sn NMR spectroscopic studies. Some of the representative complexes have also been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria in vivoas well as in vitro.The results of these investigations are reported. © 1998 John Wiley & Sons, Ltd.     

Organosilicon(IV) and organotin(IV) complexes as biocides and nematicides: synthetic,spectroscopic and biological studies of N∩N donor sulfonamide imine and its chelates

A brief account is given of the synthesis and stereochemistry and the antibacterial, antifungal, nematicidal and insecticidal behaviour of organosilicon(IV) and organotin(IV) complexes of a biologically potent ligand, 2‐acetylfuransulfaguanidine. The unimolar and bimolar substitution products have been characterized by elemental analyses, conductance measurements, molecular weight determinations, and spectral studies, viz. IR, ¹H NMR, ¹³C NMR, UV, ²⁹Si NMR and ¹¹⁹Sn NMR spectra. The data support the binding of the nitrogen atom to the metal atom in R₃M(N^∩N), [R₂M(N^∩N)₂ and R₂M(N^∩N)Cl [(R = Me/Ph and M = Si(IV) and Sn(IV)] types of complex. Based on these studies, with coordination number five and six a trigonal bipyramidal and an octahedral geometry have been proposed for the resulting derivatives. The free ligand (N^∩NH) and its respective metal complexes were tested in vitro against a number of microorganisms to assess their antimicrobial properties. The results are indeed positive. In addition to these studies, the complexes also show good nematicidal and insecticidal properties. The results of these findings have been discussed in detail. Copyright © 2004 John Wiley & Sons, Ltd.     

Microwave‐assisted synthesis and insecticidal properties of biologically potent organosilicon(IV) compounds of a sulfonamide imine

Microwave‐assisted synthesis and spectroscopic studies of dimethyl‐, diphenyl‐ and triphenyl‐silicon(IV) chelates derived from the reactions of organochlorosilanes with the sodium salt of a biologically active nitrogen donor ligand N^∩NH are described. The resulting products have been isolated and characterized by elemental analyses, molecular weight determinations and conductance measurements. On the basis of electronic, infrared, ¹H, ¹³C and ²⁹Si NMR spectral studies, trigonal bipyramidal and octahedral geometries have been suggested for the resulting complexes. The biological activity of the ligand and its corresponding complexes has been examined with regard to antifungal and antibacterial activity against pathogenic fungi and bacteria, and the results are quite encouraging. All the compounds have also been found to act as nematicides and insecticides, by reducing the number of nematodes (Meloidogyne incognita) and insects (Trogoderma granarium). Copyright © 2005 John Wiley & Sons, Ltd.     

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

The 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.     

Mn (II) and Zn (II) complexes of a benzimidazole ligand having undecyl chains: Crystal structures,photophysical and thermal properties

A new tridentate benzimidazole ligand (L‐C¹¹) containing undecyl chains and its Mn (II) and Zn (II) complexes were synthesised and characterized by spectroscopic and analytical methods. Molecular structures of complexes [Mn(L‐C¹¹)Cl₂] and [Zn(L‐C¹¹)Cl₂] were evaluated by X‐ray diffraction studies. The X‐ray data showed metal ions in both complexes are five‐coordinate with distorted square pyramidal geometry around the metal centres. The undecyl chains in the structure of the complexes are aligned in an interdigitated manner (head to tail) forming a non‐polar domain. The aggregation properties of the ligand and its complexes were investigated by UV–Vis. absorption and emission spectroscopies in DMF‐water mixtures. The emission spectral data revealed that the compounds showed aggregation induced quenching (AIQ) in DMF‐water solutions. Moreover, thermal properties of the compounds were investigated by TG, DTG and DSC analysis.     

Spectroscopic,DFT and antimicrobial activity of Zn(II), Zr(IV), Ce(IV) and U(VI) complexes of N,N‐ chelated 4,6‐bis (4‐chlorophenyl)‐2‐amino‐1,2‐dihydropyridine‐3‐carbinitrile

Four novel metal complexes of 4,6‐bis (4‐chlorophenyl)‐2‐amino‐1,2‐dihydropyridine‐3‐carbinitrile (H₂L) with Zn(II), Zr(IV), Ce(IV) and U(VI) were synthesized. The structure was elucidated using elemental analysis, melting point, molar conductivity; spectroscopic techniques (IR, ¹H NMR, UV–Vis., mass spectra) as well as thermo gravimetric analysis. The spectroscopic data proved that H₂L chelated with the metal ions as a bidentate ligand through N_amino and N_carbinitrile atoms. The molecular structure of the complexes was determined using density functional theory (DFT). The central metal ion in each complex is six‐coordinate and the angles around it vary from 62.74° to 166.46°; these values agree with distorted octahedral geometry. The calculated total energy of the complexes found in the region – 406.342 to ?459.717 au and the dipole moment change from 4.675 to 13.171D. The antibacterial and antifungal activities of the ligand, metal salts and complexes were estimated on some microorganisms. The complexes showed significant antibacterial profile in comparison to the free ligand.     

Microwave-assisted synthesis of nitrogen-sulfur and nitrogen-oxygen donor ferrocene-containing ligands and their organotitanium(IV) and organozirconium(IV) complexes

The synthetic routes and spectroscopic studies of organotitanium(IV) and organozirconium(IV) complexes derived from azomethines, 1-acetylferrocenethiosemicarbazone (L¹H) and 1-acetylferrocenesemi-carbazone (L²H), have been carried out in 1 : 1 and 1 : 2 stoichiometric ratios. Azomethines and their complexes have been characterized by elemental analyses, conductance measurements, molecular weight determinations, and spectral studies. The electronic, IR, and ¹H NMR and ¹³C NMR spectral data indicate that azomethines act as bidentate ligands and coordinate to the metal (Ti or Zr) via nitrogen and the sulfur or oxygen atoms giving trigonal bipyramidal and octahedral geometries for the resulting complexes. All the ligands and their complexes have been screened for their biological activity on several pathogenic fungi and bacteria and were found positive in this respect. The text was submitted by the authors in English.     

Ecofriendly synthesis,antimicrobial and antispermatogenic activity of triorganotin(IV) complexes with 4′‐nitrobenzanilide semicarbazone and 4′‐nitrobezanilide thiosemicarbazone

New series of triorganotin(IV) complexes with 4′‐nitrobenzanilide semicarbazone (L¹H) and 4′‐nitrobenzanilide thiosemicarbazone (L²H) of the type [R₃Sn(L)] (R = ‐CH₃, ‐C₆H₅ and n‐C₄H₉) were synthesized under microwave irradiation. All the complexes were characterized by elemental analysis, conductance measurements, molecular weight determinations and spectral data, viz., IR, UV–vis, ¹H, ¹³C and ¹¹⁹Sn NMR. The central tin atoms of these complexes are all five‐coordinated with trigonal bipyramidal geometry. In order to assess their growth inhibitory potency semicarbazone, thiosemicarbazone and their triorganotin(IV) complexes were tested in vitro against some pathogenic fungi and bacteria. Also the ligands and their organotin(IV) complexes were studied to assess the effects of long‐term ingestion of these compounds on fertility, body and reproductive organ weights. The biochemical analyses were also performed on blood samples and reproductive organs of male rats. The findings have been presented in this paper. Copyright © 2009 John Wiley & Sons, Ltd.     

New mononuclear diorganotin(IV) dithiocarboxylates: synthesis,characterization and study of their cytotoxic activities

Since organotin complexes have been reported to show fewer side effects relative to other heavy metal anticancer compounds, in the present study we report for the first time four novel organotin(IV) derivatives with the general formula R₂SnL₂, where R = methyl (1), n‐butyl (2), phenyl (3), benzyl (4) and L = morpholine‐1‐carbodithioate (MCDT). The newly synthesized ligand was monodentate or bidentate, coordinating through a sulfur atom. The complexes were synthesized by directly mixing, refluxing and stirring the ligand, with diorganotin(IV) dichlorides in a suitable solvent. The complexes were found to be pure and their solid and solution phase structural configuration was investigated by FT‐IR, multinuclear NMR (¹ H, ¹³ C, ¹¹⁹Sn) and mass spectrometry. Complex 2 was also studied for its thermal decomposition by thermogravimetry and differential thermal analysis. The results obtained on the basis of these techniques are in full concurrence with the proposed 1:2 (Sn:L) stoichiometry. The cytotoxic activity of the MCDT and diorganotin(IV) complexes (1–4) was tested against tumor cell lines – human cervix carcinoma HeLa and human myelogenous leukemia K562 – and normal immunocompetent cells: peripheral blood mononuclear cells PBMC. Results of bioassay demonstrated that organotin derivatives were in general more active than the anticancer drug cisplatin. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthetic, structural, and antimicrobial studies of organotin(IV) complexes of semicarbazone, thiosemicarbazone derived from 4-hydroxy-3-methoxybenzaldehyde

Reaction of dibutyltin dichloride, dimethyltin dichloride, and tributyltin chloride with ligands derived from thiosemicarbazone and semicarbazone leads to the formation of a new series of organotin(IV) complexes of general formula R₂SnCl₂·L and R₃SnCl·L (where L ligands derived from the condensation of thiosemicarbazide and semicarbazide with 4-hydroxy-3-methoxybenzaldehyde). The authenticity of these ligands and their metal complexes have been established on the basis of elemental analysis, conductance measurements, molecular weight determinations, infrared, ¹H NMR, ¹³C NMR, ¹¹⁹Sn NMR, and UV spectral studies. These studies showed that the ligands coordinate to the metal atom in a bidentate. An octahedral structure is proposed for the organotin(IV) complexes. The ligands and its metal complexes are screened for their antimicrobial activities against some Gram-positive and Gram-negative bacteria, and fungus. The studies demonstrated that metalation can increase the antimicrobial activity rather than the free ligands.     

Pesticidal and antifertility activities of triorganogermanium(IV) complexes synthesized using a green chemical approach

Microwave chemistry is a green chemical method that improves reaction conditions and product yields while reducing solvent amounts and reaction times. This paper deals with the synthesis, spectral and biological studies of germanium(IV) complexes with chelating hydrazones derived from 1‐(pyridine‐2‐yl)ethanone (F₁) and 1‐(furan‐2‐yl)ethanone (F₂) with isonicotinohydrazide (INH). The complexes have been synthesized under a microwave–green chemical approach and investigated using a combination of microanalytical analysis, melting point, IR spectra, ¹H NMR spectra and ¹³C NMR spectra. Trimethylgermanium(IV)chloride and triphenylgermanium(IV)chloride interact with the hydrazones in a 1:1 molar ratio (metal:ligand), resulting in the formation of coloured products. On the basis of conductance and spectral evidence, a pentacoordinated structure for germanium(IV) complexes has been assigned for these products. The ligand is coordinated to the germanium(IV) via the azomethine nitrogen atom and the enolic oxygen atom. The free ligands and their metal complexes have been tested in male rats in order to assess their antifertility properties. Ligands and their metal complexes have also been tested in vitro against a number of pathogenic microorganisms in order to assess their antimicrobial and pesticidal properties. Both the ligands and their complexes were found to possess appreciable antifertility activity and other activities, which have been discussed in brief. Copyright © 2013 John Wiley & Sons, Ltd.     

Diorganotin(IV) Complexes with Monohydrate Disodium Salt of Iminodiacetic Acid: Synthesis,Characterization, Crystal Structure and Biological Activities

Diorganotin(IV) derivatives have been synthesized by the reaction of R₂SnL₂ (R=n‐Bu 1 , Ph 2 ) with monohydrate disodium salt of iminodiacetic acid ( Na₂L ) in 1 : 1 M/L ratio under reflux conditions. The compounds have been characterized by FT‐IR, NMR (¹H and ¹³C) spectoscopy, electron ionization mass spectrometry (EIMS), thermogravimetric analyses (TGA) and single crystal XRD. FTIR data indicates a mono‐dentate binding mode of the carboxylic acid group as well as participation of the amino nitrogen and aqua oxygen in coordination with organotin(IV) moieties. NMR data demonstrates a tetra‐coordinated environment around tin(IV) in solution. Mass spectrometric and thermogravimetric analyses verify the close similarities between the molecular structures of both complexes. The thermal stability of diphenyltin(IV) derivative ( 2 ) was found slightly higher than that of the free ligand ( Na₂L ). Single crystal X‐ray analysis of the complex 1 have shown a hexa‐coordinated geometry around Sn(IV) with trans configuration. There are evidences for the existence of intermolecular hydrogen bonding in the structure of the complexes. The products displayed significant antibacterial and antifungal activities in contrast to the biologically inactive ligand precursor. However, the hemolytic cytoxicity of the complexes was comparatively high than the free ligand.     

Synthesis,characterization, EPR,electrochemical, and in situ spectroelectrochemical studies of salen-type oxovanadium(IV) and copper(II) complexes derived from 3,4-diaminobenzophenone

A new half unit and some new symmetrical or asymmetrical VO(IV) and Cu(II) complexes of tetradentate ONNO Schiff base ligands were synthesized. The probable structures of the complexes have been proposed on the basis of elemental analyses and spectral (IR, UV–Vis, electron paramagnetic resonance, ESI-MS) data. VO(IV) and Cu(II) complexes exhibit square pyramidal and square-planar geometries, respectively. The complexes are non-electrolytes in dimethylformamide (DMF) and dimethylsulfoxide. Electrochemical behaviors of the complexes were studied using cyclic voltammetry and square wave voltammetry. Half-wave potentials (E _1/2) are significantly influenced by the central metal and slightly influenced by the nature of substituents on salen. While VO(IV) complexes give VO^IV/VO^V redox couples and a ligand-based reduction process, Cu(II) complexes give only a ligand-based reduction. In situ spectroelectrochemical studies were employed to determine the spectra of electrogenerated species of the complexes and to assign the redox processes. The g-values were calculated for all these complexes in polycrystalline state at 298?K and in frozen DMF (113?K). The evaluated metal–ligand bonding parameters showed strong in-plane σ-bonding for some Cu(II) complexes.     

Synthesis of stannic(IV) complexes: Their structural elucidation in solid and solution state and antimicrobial activity

A series of organotin(IV) thiocarboxylates have been synthesized with the general formula R₂SnL₂ and R₃SnL (R = Ph₂(I), Me₃(II), n‐Bu₃(III), Ph₃(IV), Cy₃(V), Me₂(VI), n‐Bu₂(VII), and L = piperidine‐1‐thiocarboxylic acid) in anhydrous toluene under the reflux conditions. The complexes were characterized by microanalysis, IR, ¹H and ¹³C NMR, mass spectrometry, and XRD. NMR data revealed that thiocarboxylic acid acts as bidentate, and complexes exhibit the four‐coordinated geometry in solution state. In solid state, diorganotin complexes exhibit the hexa‐coordinated geometry whereas the triorganotin(IV) compounds show the five‐coordinated geometry. These complexes were also tested for their antimicrobial activity along with the ligand against different animals, plant pathogens, and Artemia salina. All complexes with few exceptions show high activity as compared to the ligand. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:664–674, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20380     

Biologically active organotin(IV) schiff base complexes

Organotin(IV) complexes with the general formulae R₃ML [R: alkyl (Et, Ph and Bz), M: Sn and L: 1,3-bis(2- hydroxybenzylidene)thiourea were synthesized. The newly synthesized schiff base and its complexes were characterized by elemental analysis, melting point, molecular weight determination, IR and NMR [¹H, ¹³C and ¹¹⁹Sn] spectral methods. In the light of these techniques, a tetrahedral geometry around the tin atom is proposed for the synthesized complexes. The experimental data have been compared with those in the literature which were found to coincide very well with the assigned structures. The ligands and their tin(IV) complexes were screened in vitro for their antibacterial activities. It was found that they possessed significant antibacterial activity and the effect of Ph₃SnL was possibly superior to those of Et₃SnL, Bz₃SnL and ligand. These findings add new insights onto the synthesis of antibacterial drugs as the synthesized compounds showed promising antimicrobial activity.     

UO<Subscript>2</Subscript>(VI), Sn(IV), Th(IV) and Li(I) complexes of 4-azomalononitrile antipyrine

UO₂(VI), Sn(IV), Th(IV) and Li(I) complexes of 4-azomalononitrile antipyrine (L) have been isolated and characterized based on IR spectra, ¹H NMR, elemental analyses, molar conductance and thermal analysis (DTA/TG). The study revealed that the ligand behaves as a neutral bidentate one and coordination takes place via the carbonyl atom of pyrazolone ring >C=O and the azomethine nitrogen >C=N. The thermal stability of the metal complexes were investigated by thermogravimetry (TG), differential thermal analysis (DTA) techniques and infrared spectra, and correlated to their structure. The thermal study revealed that Th(IV) complexes show lower thermal stability than both UO₂(VI) and Sn(IV) complexes.