Antimicrobial studies of newly synthesized organotin(IV) complexes of dihydrobis(2-mercaptothiazolinyl)borate

Four organotin(IV) complexes of dihydrobis(2-mercaptothiazolinyl)borate were synthesized and characterized by elemental analysis and spectroscopic techniques (IR, ¹H-NMR, ¹³C-NMR, ¹¹B-NMR, and ¹¹⁹Sn-NMR). All the compounds were screened against bacterial, fungal, and cyanobacterial strains. Among the complexes, triorganotin(IV) complexes show better inhibition growth as compared to diorganotin(IV) complexes.     

Tributyltin(IV) Schiff base complexes with amino acid derivatives: synthesis,characterization and biological activity

The synthesis in one‐pot reactions and structural characterization of six new tri‐n‐butyltin(IV) derivatives of Schiff bases are reported. The compounds are derived from a condensation reaction between l ‐alanine, l ‐valine, l ‐isoleucine, l ‐methionine, l ‐phenylalanine or l ‐tryptophan and 3,5‐di‐tert‐butyl‐2‐hydroxybenzaldehyde. Characterization was completed using elemental analysis, infrared spectroscopy, mass spectrometry, one‐ and two‐dimensional solution NMR (¹H, ¹³C and ¹¹⁹Sn) as well as solid‐state ¹¹⁹Sn NMR. In addition, the crystal structures of three of the compounds were confirmed using single‐crystal X‐ray diffraction. Although five‐coordinated and polymeric in the solid state, the tin compounds are four‐coordinated and monomeric in solution. The coordination environment around the triorganotin units comprises three carbon atoms and two oxygen atoms from two ligands in a trigonal bipyramidal geometry. The anti‐proliferative effect of these compounds on the cervical carcinoma cell lines HeLa, CaSki and ViBo was screened in vitro, the compounds showing cytotoxic activity against all three strains and null or low cytotoxic activity (necrotic) as well. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis and Crystal Structure of 3-{[（1E） 1-（2- Hydroxyphenyl） methylidene]amino}-4-cyanopyrazole

The title Schiff base compound （C11H8N4O）, a derivative of pyrazole, has been synthesized by the reaction of salicylaldehyde and 3-amino-4-cyanopyrazole in absolute ethanol and characterized by elemental analyses, IR, ^1H NMR and X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P21/n, with a = 7.5594（7）, b = 18.3342（19）, c = 22.461（2） A^°, β = 98.419（2）°, V = 3079.5（5） A^°3, Mr = 212.21, Z = 12, F（000） = 1320, Dc = 1.373 g/cm^3, T = 298（2） K, 2 = 0.71073 A^°, the final R = 0.0571 and wR = 0.0493. A total of 5412 unique reflections were collected, of which 1612 with I 〉 2σ（I） were observed. The molecular structure adopts a trans configuration about the C=N double bond. The preliminary biological tests show that the compound has high antibacterial activities.     

Coordination compounds of copper(II) with substituted 3-{[(2-hydroxyphenyl)methylidene]amino}propane-1,2-diols

3-{[(2-Hydroxyphenyl)methylidene]amino}propane-1,2-diol, its 5-chloro-,5-bromo-, 5-nitro-, 3-methoxy derivatives, and 3-{[(2-hydroxynaphthyl-1)methylidene]amino}propane-1,2-diol react with hydrates of copper(II) chloride, bromide and nitrate in ethanol to form coordination compounds Cu(L)X·nH₂O. Template condensation reaction between 3-aminopropane-1,2-diol and 2,3-, 2,4- or 2,5-dihydroxybenzaldehyde in the presence of copper(II) nitrate trihydrate results in similar compounds Cu(L)NO₃·nH₂O. Structure of some of the condensation products was identified by X-ray analysis. Thermolysis of the substances obtained occurs through the dehydration step (70–90°C) and complete thermal decomposition (290–560°C).     

Homobimetallic organotin(IV) complexes with succinohydrazide Schiff base: Synthesis,spectroscopic characterization,and biological screening

Russian Journal of General Chemistry - Six new bis-diorganotin(IV) complexes, [(Me2Sn)2L] (1), [(Et2Sn)2L] (2), [(n-Bu2Sn)2L] (3), [(Ph2Sn)2L] (4), [(n-Oct2Sn)2L] (5), and [(tert-C4H9)2Sn)2L] (6),...     

Spectral characterization, cyclic voltammetry, morphology, biological activities and DNA cleaving studies of amino acid Schiff base metal(II) complexes

Metal complexes are synthesized with Schiff bases derived from o-phthalaldehyde (opa) and amino acids viz., glycine (gly) l-alanine (ala), l-phenylalanine (pal). Metal ions coordinate in a tetradentate or hexadentate manner with these N(2)O(2) donor ligands, which are characterized by elemental analysis, molar conductance, magnetic moments, IR, electronic, (1)H NMR and EPR spectral studies. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). Based on EPR studies, spin-Hamiltonian and bonding parameters have been calculated. The g-values calculated for copper complexes at 300K and in frozen DMSO (77K) indicate the presence of the unpaired electron in the dx2-y2 orbital. The evaluated metal-ligand bonding parameters showed strong in-plane sigma- and pi-bonding. X-ray diffraction (XRD) and scanning electron micrography (SEM) analysis provide the crystalline nature and the morphology of the metal complexes. The cyclic voltammograms of the Cu(II)/Mn(II)/VO(II) complexes investigated in DMSO solution exhibit metal centered electroactivity in the potential range -1.5 to +1.5V. The electrochemical data obtained for Cu(II) complexes explains the change of structural arrangement of the ligand around Cu(II) ions. The biological activity of the complexes has been tested on eight bacteria and three fungi. Cu(II) and Ni(II) complexes show an increased activity in comparison to the controls. The metal complexes of opapal Schiff base were evaluated for their DNA cleaving activities with calf-thymus DNA (CT DNA) under aerobic conditions. Cu(II) and VO(II) complexes show more pronounced activity in presence of the oxidant.     

Self-assembly of extended Schiff base amino acetate skeletons, 2-{[(2Z)-(3-hydroxy-1-methyl-2-butenylidene)]amino}phenylpropionate and 2-{[(E)-1-(2-hydroxyaryl)alkylidene]amino}phenylpropionate skeletons incorporating organotin(IV) moieties: Synthesis,spectroscopic characterization,crystal structures,and in vitro cytotoxic activity

The organotin(IV) compounds, [Ph₃SnL¹H]_n · nCCl₄ (1), [Me₂SnL²(OH₂)] (2), [ⁿBu₂SnL²] (3), [Ph₂SnL²]_n (4), [Ph₃SnL²H]_n (5) and [Ph₃SnL³H]_n (7) (L¹ = 2-{[(2Z)-(3-hydroxy-1-methyl-2-butenylidene)]amino}phenylpropionate and L²⁻³ = 2-{[(E)-1-(2-hydroxyaryl)alkylidene]amino}phenylpropionate), were synthesized by treating the appropriate organotin(IV) chloride(s) with the potassium salt of the ligand in a suitable solvent, while [ⁿBu₂SnL³(OH₂)] (6) was obtained by reacting the acid form of L³ (generated in situ) with ⁿBu₂SnO. These complexes have been characterized by ¹H, ¹³C, ¹¹⁹Sn NMR, ESI-MS, IR and ^119mSn Mössbauer spectroscopic techniques in combination with elemental analyses. The crystal structures of 1 and 4–7 were determined. The crystal structures of complexes 1, 5 and 7 reveal that the complexes exist as polymeric chains in which the L-bridged Sn-atoms adopt a trans-R₃SnO₂ trigonal bipyramidal configuration with R groups in the equatorial positions and the axial locations occupied by a carboxylate oxygen from the carboxylate ligand and the alcoholic or phenolic oxygen of the next carboxylate ligand in the chain. The carboxylate ligands coordinate in the zwitterionic form with the alcoholic/phenolic proton moved to the nearby nitrogen atom. A polymeric zig-zag cis-bridged chain structure is observed for 4, without considering the weak Sn⋯O interaction, the Sn-atom having a slightly distorted trigonal bipyramidal coordination geometry with the two O atoms of the tridentate amino propionate ligand in axial positions. On the other hand, the structure of 6 reveals a monomeric molecule in which the Sn-atom has a distorted octahedral coordination geometry involving the tridentate carboxylate ligand, two n-butyl ligands occupying trans-positions and one water ligand. The in vitro cytotoxic activity of triphenyltin(IV) compounds, viz., 1, 5 and 7 against WIDR, M19 MEL, A498, IGROV, H226, MCF7 and EVSA-T human tumor cell lines are also reported.     

Spectral studies of the newly synthesized azomethine derivatives of zirconium(IV)

Equimolar and bimolar reactions of zirconium isopropoxide with bibasic tridentate azomethine (AZH₂) having the donor system ONO have been carried out and derivatives of the type Zr(OPr¹)₂(AZ) and Zr(AZ)₂ [Where AZ²⁻ is the anion of the azomethine molecule] have been isolated. The labile nature of the isopropoxy groups in 1∶1 derivatives has been shown by carrying out exchange reactions with equimolar amount of 2-methylpentane-2,4-diol. All the newly synthesized derivatives have been characterized on the basis of elemental analysis, conductance measurements, molecular weight determinations and infrared, ultraviolet, visible and proton magnetic resonance spectral studies.     

Synthesis of methyl 4-aryl-2-{[4-(carbamimidoylsulfamoyl)- phenyl]amino}-4-oxobut-2-enoates

Methyl aroylpyruvates reacted with 4-amino-N-carbamimidoylbenzene-1-sulfonamide in acetic acid–ethanol (1: 1) to give methyl 4-aryl-2-{[4-(carbamimidoylsulfamoyl)phenyl]amino}-4-oxobut-2-enoates which were found to exist in solution as mixtures of Z and E isomers.     

Preparation and structural studies of organotin(IV) complexes formed with organic carboxylic acids

The complexes of six organic carboxylic acids (containing {O,O} donor atoms) with Bu₂Sn(IV)²⁺ and Ph₃Sn(IV)⁺ with ligand to metal ratios of 1 : 1 and 1 : 2, were prepared by two different methods. The FtIR and Raman spectra clearly demonstrated that the organotin(IV) moieties react with the {O,O} atoms of the ligands. It was found that in most cases the -COO^-group was chelated to the central metal ions, but monodentate coordination was also sometimes observed. Complex formation was accompanied by a rearrangement of the hydrogen-bonding network existing in the ligands. The complexes probably have polymeric structures. Comparison of the experimental Mössbauer D values with those calculated on the basis of the point charge model formalism revealed that the organotin(IV) moiety has a trigonal-bipyramidal (tbp) geometry, and in certain cases a tetrahedral (tetr) geometry too. Finally, the local structure of the maleic acid complex formed with Bu₂Sn(IV)²⁺ was determined by an EXAFS method.     

2-{[1-(3,4-Dihydroxyphenyl)methylidene]amino}benzoic acid immobilized Amberlite XAD-16 as metal extractant

2-{[1-(3,4-Dihydroxyphenyl)methylidene]amino}benzoic acid (DMABA) was loaded on Amberlite XAD-16 (AXAD-16) via azo linker and the resulting resin AXAD-16-DMABA explored for enrichment of Zn(II), Mn(II), Ni(II), Pb(II), Cd(II), Cu(II), Fe(III) and Co(II). The optimum pH values for extraction are 6.5-7.0, 5.0-6.0, 5.5-7.5, 5.0-6.5, 6.5-8.0, 5.5-7.0, 4.0-5.0 and 6.0-7.0, respectively. The sorption capacity was found between 97 and 515 μmol g⁻¹ and the preconcentration factors from 100 to 450. Tolerance limits for foreign species are reported. The kinetics of sorption is fast as t_1/2 is ≤5 min. The chelating resin can be reused for 50 cycles of sorption-desorption without any significant change (<1.5%) in the sorption capacity. The limit of detection values (blank +3 s) are 1.12, 1.38, 1.76, 0.67, 0.77, 2.52, 5.92 and 1.08 μg L⁻¹ for Zn(II), Mn(II), Ni(II), Pb(II), Cd(II), Cu(II), Fe(III) and Co(II), respectively. The enrichment on AXAD-16-DMABA coupled with monitoring by flame atomic absorption spectrometry (FAAS) is used to determine all the metal ion ions in river and synthetic water samples, Co in vitamin tablets and Zn in milk samples.     

Kinetic studies of the interaction between organotin(IV)chlorides and tetraaza Schiff bases: Synthesis and characterization of some novel tin(IV) Schiff base complexes

In this article the kinetics of the interaction between the teteraaza Schiff bases as donor with organotin(IV)chlorides as acceptor was studied in acetonitrile. Teteraaza Schiff bases are (Me₄‐Bzo₂[14]tetraeneN₄) (tmtaa), (Me₄‐4‐CH₃Bzo₂[14]tetraeneN₄) (Metmtaa), (Me₄‐4‐ClBzo₂[14]tetraeneN₄) (Cltmtaa), i.e., [(Me₄‐Bzo₂[14]tetraeneN₄)] means that (5,7,12,14‐tetramethyldibenzo[b,i][1,4,8,11] tetraazacyclotetradecine) (tmtaa) and organotin(IV)chlorides are methyltin(IV) trichloride, phenyltin(IV)trichloride, dimethyltin (IV)dichloride, diphenyltin(IV) dichloride, and dibutyltin(IV)dichloride. The kinetic parameters and the second‐order k₂ rate constants show the donor properties of tetraaza Schiff bases as Me₄‐4‐CH₃Bzo₂[14]tetraeneN₄ > Me₄‐Bzo₂[14]tetraeneN₄ > Me₄‐4‐ClBzo₂[14]tetraeneN₄ and also the acceptor properties of organotin(IV)chlorides as PhSnCl₃ > MeSnCl₃ > Ph₂SnCl₂ > Me₂SnCl₂ > Bu₂SnCl₂. An excellent linearity of k_obs vs. the molar concentration of the acceptor, the high span of k₂ values, the large negative values of ΔS^≠, and the low ΔH^≠ values suggest an associative (A) mechanism for the acceptor–donor interaction. © 2011 Wiley Peiodicals, Inc. Int J Chem Kinet 43: 247–254, 2011     

Biological studies of organotin(IV) complexes with 2-mercaptopyrimidine

The known organotin(IV) complexes with 2-mercaptopyrimidine (L) [Me₂SnL₂] (1), [Buⁿ ₂SnL₂] (2), [Ph₂SnL₂] (3), and [Ph₃SnL] (4) were synthesized using a new approach. The effect of the synthesized compounds on peroxidation of fatty acids (oleic and linoleic) was studied. Complexes 1–4 promote the peroxidation of oleic acid. Their effect on the enzymatic peroxidation of linoleic acid with lipoxygenase was compared with that of cisplatin and in vitro cytoxicity against sarcoma cancer cells was determined. The antiproliferative effect of complexes 2–4 was demonstrated. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 737–743, April, 2007.     

Schiff base supported mononuclear organotin(IV) complexes: Syntheses,structures and fluorescence cell imaging

Three mononuclear organotin(IV) complexes supported by Schiff bases have been synthesized. The complexes [(C₆H₅)₂Sn(L)] ( 1 ), [(t‐Bu)₂Sn(L)] ( 2 ) and [(t‐Bu)₂Sn(L')] ( 3 ) (L, L' = deprotonated Schiff bases) were obtained in good yield by the reaction of Schiff bases H ₂ L or H ₂ L′ with corresponding diorganotin dichlorides respectively. All newly synthesized complexes were characterized by means of FT‐IR spectroscopy, elemental analysis and multinuclear (¹H, ¹³C and ¹¹⁹Sn) NMR spectroscopy. In addition, single crystal X‐ray diffraction analyses were employed to establish the solid state molecular structures of these complexes. The structures of 1 – 3 reveal that all complexes are mononuclear with a five‐coordinated tin(IV) centre in it. The absorption and emission properties of all complexes have been investigated. Moreover, cytotoxicity and fluorescence cell imaging studies of theses complexes have been performed.     

Biologically potent organotin(IV) complexes of 2-maleimidoacetic acid

The in vitro LD₅₀, anti-bacterial, anti-fungal and anti-yeast bio-tests are carried out, which proved them to be powerful biocides. The in vitro anti-tumour and analgesic activities also displayed excellent potential of the title compounds. Series of organotin(IV) complexes are synthesized and characterized. Based on spectroscopic analysis and literature evidences, the compound 1 is tetrahedral and 2 distorted octahedral or trigonal bipyramidal in nature wherein the compounds 3 and 4 are tetrahedral in solid and polymeric trigonal bipyramidal geometry in solution. Beside to ¹H, ¹³C and ¹¹⁹Sn NMR, the FT-IR is successfully applied to verify the bonding mode of endo and exo status of tin(IV) of compound 2.     

Synthesis and characterization of tribenzyltin(IV) and dibenzyltin(IV) complexes of 2-{[(2Z)-3-hydroxy-1-methyl- 2-butenylidene]amino}acetic acid: Crystal structure of tribenzyl{2-{[(2Z)-3-hydroxy-1-methyl-2-butenylidene] amino}acetato}tin(IV)

Reactions of equimolar quantities of potassium 2-{[(2Z)-3-hydroxy-1-methyl-2-butenylidene]amino}acetate, with R _n SnX_4?n (R: benzyl– and n=2 or 3) in methanol yielded products of compositions LHSn(PhCH₂)₃ and LSn(PhCH₂)₂, respectively. The complexes were characterized by microanalysis, IR, NMR (¹H, ¹³C, ¹¹⁹Sn) and ^119mSn Mössbauer spectroscopy. A full characterization of the structure of the complex, tribenzyl{2-{[(2Z)-3-hydroxy-1-methyl-2-butenylidene]amino}acetato}tin(IV), was carried out by single crystal X-ray crystallography. The compound exists as centrosymmetric dimers in which two ligand molecules bridge the two tin centres. Each of the tin atoms in the dimeric unit is five coordinate in an approximately trigonal bipyramidal configuration, with carbon atoms in the equatorial positions and oxygen atoms arranged axially.     

Synthesis,spectral and biological studies of organotin(IV) complexes of heteroscorpionate

A heteroscorpionate ligand, potassium hydrobis(benzoato)(salicylaldehyde)borate (KL), has been synthesized. This was converted into organotin complexes R₂SnL₂ and R₃SnL complexes by mixing and stirring with a methanolic solution/suspension of organotin chloride. The ligand and its complexes were characterized by elemental analyses and spectral studies (IR, ¹H NMR, ¹³C NMR, ESI mass spectra and Thermo gravimetric analysis (TGA)). Antibacterial and antifungal studies of these compounds were evaluated by the disc diffusion method at variable concentration against three species of bacteria (Staphylococcus aureus, Klebsiella pneumonia and Bacillius subtillis) and two species of fungi (Asperjillius fiavus and Candida albicans). It was found that triorganotin derivatives (R₃SnL) of the ligand were more effective as compared with diorganotin derivatives (R₂SnL₂). The organotin complexes of borates were tested for their algicidal activity on the cyanobacterial strains Aulosira fertilissma, Anabaena species, Anabaena variabilis and Nostoc muscorum and showed high to moderate toxicity towards the above species. The ligand and its complexes were also tested for its pH effect on soil in vitro for a duration of more than one month and it was found that they are able to kill pests without damaging the soil quality. Copyright © 2006 John Wiley & Sons, Ltd.     

Ligational,density functional theory,and biological studies on some new Schiff base 2-(2-hydroxyphenylimine)benzoic acid (L) metal complexes

The metal ions Co(II), Ni(II), Zn(II), Zr(IV), and Hg(II) reacted with synthesized Schiff base (L) in mole ratios 1:2 (M:L) formed metal complexes. The structure of the prepared compounds was identified based on the data obtained from elemental analyses, magnetic measurement, melting point, conductivity, Fourier-transform infrared, UV–Vis., nuclear magnetic resonance spectroscopy, X-ray diffraction (XRD) spectra, and thermal analysis (TG/DTG [thermogravimetric/differential thermal analysis]). The results indicate that the L bound as bidentate through the oxygen atom of the hydroxyl group and nitrogen atom of the azomethine group with the metal ions and the complexes is electrolyte in nature. TG/DTG studies confirmed the chemical formula for complexes. The kinetic and thermodynamic parameters such as E^*, ΔH^*, ΔS^*, and ΔG^* were determined by using Coats–Redfern and Horowitz–Metzger methods at n = 1 and n ≠ 1. The XRD patterns exhibited a semicrystalline nature lying between the amorphous and crystalline nature for L, (D), and (E), but the complexes (A), (B), and (C) possessed a crystalline character. Density functional theory confirmed the structural geometry of the complexes. In vitro antimicrobial activities were performed for L and its metal complexes.