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1.  Synthetic, Structural, and Biochemical Studies of Organotin(IV) With Schiff Bases Having Nitrogen and Sulphur Donor Ligands 
Three bidentate Schiff bases having nitrogen and sulphur donor sequences were prepared by condensing S-benzyldithiocarbazate (NH2NHCS2CH2C6H5) with heterocyclic aldehydes. The reaction of diphenyltin dichloride with Schiff bases leads to the formation of a new series of organotin(IV) complexes. An attempt has been made to prove their structures on the basis of elemental analyses, conductance measurements, molecular weights determinations, UV, infrared, and multinuclear magnetic resonance (1H, 13C, and 119Sn) spectral studies. Organotin(IV) complexes were five- and six-coordinate. Schiff bases and their corresponding organotin complexes have also been screened for their antibacterial and antifungal activities and found to be quite active in this respect.
PMCID: PMC1686295  PMID: 17497003
2.  Spectral Studies and Bactericidal, Fungicidal, Insecticidal and Parasitological Activities of Organotin(IV) Complexes of Thio Schiff Bases Having no Donor Atoms 
Metal-Based Drugs  1995;2(6):297-309.
Twelve new organotin(IV) complexes of the type RnSnLm [where n = 3, m = 1, R = CH3 or C6H5; n = 2, m = 2, R = C6H5 or C4H9 ; L = anion of Schiff bases derived from the condensation of 2-amino-5-(o-anisyl)-l,3,4-thiadiazole with salicylaldehyde (HL-1), 2- hydroxynaphthaldehyde (HL-2) and 2-hydroxyacetophenone (HL-3)] have been synthesized and characterized by elemental analysis, molar conductances, electronic, infrared, far-infrared, 1H NMR and 119Sn Mössbauer spectral studies. Thermal studies of two complexes, viz., Ph3Sn (L-1) and Ph2Sn(L-2)2 have been carried out in the temperature range 25-1000∘C using TG, DTG and DTA techniques. All these complexes decompose gradually with the formation of SnO2 as an end product. In vitro antimicrobial activity of the Schiff bases and their complexes has also been determined against Streptococcus faecalis, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus Penicillin resistance (2500 units), Candida albicans, Cryptococcus neoformans, Sporotrichum schenckii, Trichophyton mentagrophytes and Aspergillus fumigatus. The Schiff bases (HL-1), (HL-2) and the organotin(IV) compounds have also been tested against various important herbicidal, fungicidal, insecticidal species and also for parasitological activity against freeliving nematode.
PMCID: PMC2364992  PMID: 18472781
3.  Synthesis, Characterization, Semiempirical and Biological Activities of Organotin(IV) Carboxylates with 4-Piperidinecarboxylic Acid 
Organotin (IV) carboxylates with the general formulae R2Sn(Cl)L [R = Me (1), n-Bu (2), Ph (3)] and R3SnL [R = Me (4), Ph (5)] have been synthesized by the reaction of 4-piperidinecarboxylic acid (HL) with KOH and R2SnCl2 (R = Me, n-Bu, Ph)/R3SnCl (R = Me, Ph) in methanol under stirring conditions. The metal ligand binding site, structure, and stability of complexes have been verified by FT-IR, (1H, 13C) NMR, EI-MS technique, and semiempirical study. The FT-IR data indicate the bidentate chelating mode of the carboxylate ligand which is also confirmed by semiempirical study. In solution state, five and four coordinated geometry around tin was confirmed by NMR spectroscopy. The EI-MS data agreed well with the molecular structure of the complexes. Thermodynamic parameters and molecular descriptors were calculated by using semiempirical PM3 method. HOMO-LUMO calculations show that chlorodiorganotin complexes are more susceptible to nucleophilic attack as compared to triorganotin complexes. Computed negative heat of formation indicates that complexes 1–4 are thermodynamically stable. The organotin(IV) carboxylates displayed powerful antimicrobial activities against various strains of bacteria and fungi and their minimal inhibitory concentration were also evaluated. The complexes exhibited comparatively higher hemolytic activity as compared to free ligand.
PMCID: PMC4274932  PMID: 25548551
4.  The Proteasome Is a Molecular Target of Environmental Toxic Organotins 
Environmental Health Perspectives  2008;117(3):379-386.
Because of the vital importance of the proteasome pathway, chemicals affecting proteasome activity could disrupt essential cellular processes. Although the toxicity of organotins to both invertebrates and vertebrates is well known, the essential cellular target of organotins has not been well identified. We hypothesize that the proteasome is a molecular target of environmental toxic organotins.
Our goal was to test the above hypothesis by investigating whether organotins could inhibit the activity of purified and cellular proteasomes and, if so, the involved molecular mechanisms and downstream events.
We found that some toxic organotins [e.g., triphenyltin (TPT)] can potently and preferentially inhibit the chymotrypsin-like activity of purified 20S proteasomes and human breast cancer cellular 26S proteasomes. Direct binding of tin atoms to cellular proteasomes is responsible for the observed irreversible inhibition. Inhibition of cellular proteasomes by TPT in several human cell lines results in the accumulation of ubiquitinated proteins and natural proteasome target proteins, accompanied by induction of cell death.
The proteasome is one of the molecular targets of environmental toxic organotins in human cells, and proteasome inhibition by organotins contributes to their cellular toxicity.
PMCID: PMC2661907  PMID: 19337512
cell death; molecular target; organotins; proteasome; proteasome inhibitors; TPT
5.  Intramolecular chalcogen-tin interactions in [(o-MeE-C6H4)CH2]2SnPh2-nCln; E = S, O, CH2, n = 0, 1, 2 and intermolecular chlorine-tin interactions in the meta and para-methoxy isomers 
Inorganic chemistry  2010;49(3):960-968.
Organotin(IV) compounds of the type [(o-MeE-C6H4)CH2]2SnPh2-nCln were synthesized, E = O, n = 0 (1), n = 1 (2), n = 2 (3), E = S, n = 0 (4), n = 1 (5), n = 2 (6) and E = CH2, n = 0 (7), n = 1 (8), n = 2 (9). The dichloro compounds 3 and 6 have been investigated by single crystal X-ray diffraction and exhibit bi-capped tetrahedral geometry at the tin atom as a consequence of significant intramolecular Sn⋯O (3) and Sn⋯S (6) secondary bonding, in monomolecular units. Compound 3 when crystallized from a hexane/thf solvent mixture shows two different conformers, 3′ and 3″, in the crystal structure, 3′ has two equivalent Sn⋯O interactions, while 3″ has two non-equivalent Sn⋯O interactions. Upon recrystallization of 3 from hexane only a single structural form is observed, 3′. The Sn⋯E distances in 3′, 3″, and 6 are 71.3; 73.5, 72.9; and 76.3% of the ΣvdW radii, respectively. The meta and para-substituted isomers of 3 (10, 11) exhibit a distortion at the tin atom due to self-association via intermolecular Sn⋯Cl interactions resulting in polymeric structures. 119Sn NMR spectroscopy suggests that the intramolecular Sn⋯E interactions persist in solution for the dichloride compounds 3 and 6.
PMCID: PMC2847510  PMID: 20047301
19Sn NMR; tin-oxygen coordination; tin-sulfur coordination; chloride-tin coordination; intramolecular contacts; intermolecular contacts
6.  Synthesis, Spectroscopic, Molecular Structure, and Antibacterial Studies of Dibutyltin(IV) Schiff Base Complexes Derived from Phenylalanine, Isoleucine, and Glycine 
New series of organotin(IV) complexes and Schiff bases derived from amino acids have been designed and synthesized from condensation of 1H-indole-2,3-dione, 5-chloro-1H-indole-2,3-dione, and α-amino acids (phenylalanine, isoleucine, and glycine). All compounds are characterized by elemental analyses, molar conductance measurements, and molecular weight determinations. Bonding of these complexes is discussed in terms of their UV-visible, infrared, and nuclear magnetic resonance (1H, 13C, and 119Sn NMR) spectral studies. The results suggest that Schiff bases behave as monobasic bidentate ligands and coordinate with dibutyltin(IV) in octahedral geometry according to the general formula [Bu2Sn(L)2]. Elemental analyses and NMR spectral data of the ligands with their dibutyltin(IV) complexes agree with their proposed distorted octahedral structures. Few representative compounds are tested for their in vitro antibacterial activity against Gram-positive (B. cereus, Staphylococcus spp.) and Gram-negative (E. coli, Klebsiella spp.) bacteria. The results show that the dibutyltin complexes are more reactive with respect to their corresponding Schiff base ligands.
PMCID: PMC4265522  PMID: 25525422
7.  Synthesis and Antifungal Activity of Some Organotin(IV) Carboxylates 
Metal-Based Drugs  1998;5(4):233-236.
Six diorganotin(IV) carboxylates prepared by reacting diorganotin(IV) dichlorides with the respective silver carboxylate have been tested for antifungal activity against Aspergillus. niger, Aspergilluus flavus and Pencillium. citrinum in Sabourand dextrose broth. The compounds generally exhibit greater fungitoxicity than the diorganotin(IV) dichlorides and the carboxylic acids from which they were synthesized. In keeping with the generally accepted notion that the organotin moiety plays an important role in deciding the antifungal activity of an organotin compound, the diphenyltin(IV) compounds were more active than their di-n-butyltin(IV) analogues. However, the order of increasing fungitoxicity of the compounds parallels that of the uncomplexed carboxylic acids. The implications of the results are discussed.
PMCID: PMC2365116  PMID: 18475848
8.  Activation of RXR-PPAR heterodimers by organotin environmental endocrine disruptors 
EMBO Reports  2009;10(4):367-373.
The nuclear receptor RXRα/PPARγ heterodimer was recently reported to play a major role in mediating the deleterious effects of organotin compounds which are ubiquitous environmental contaminants. However, because organotins are unrelated to known RXRα and PPARγ ligands, the mechanism by which these compounds bind and activate the RXRα/PPARγ heterodimer at nanomolar concentrations has remained elusive. Here, we show that tributyltin (TBT) activates all three RXR/PPARα, γ, δ heterodimers primarily through its interaction with RXR. Moreover, the 1.9 Å resolution structure of the RXRα ligand-binding domain in complex with TBT reveals a covalent bond between the tin atom and residue C432 of helix H11. This interaction largely accounts for the high binding affinity of TBT which occupies the RXRα ligand-binding pocket only partially. Our data allow understanding of the binding and activation properties of the various organotins and suggest a mechanism by which these tin compounds could affect other nuclear receptor signaling pathways.
PMCID: PMC2672886  PMID: 19270714
Cell Line; Chromatography, Liquid; Crystallography, X-Ray; Endocrine Disruptors; chemistry; pharmacology; Fluorescence Polarization; Humans; Mass Spectrometry; Models, Biological; Molecular Structure; Peroxisome Proliferator-Activated Receptors; chemistry; metabolism; Protein Multimerization; drug effects; Protein Structure, Secondary; Retinoid X Receptors; chemistry; metabolism; Trialkyltin Compounds; chemistry; pharmacology; nuclear receptor; 3D structure; organotins; environment
9.  Preparation, Characterization, and Antimicrobial Activities of Bimetallic Complexes of Sarcosine with Zn(II) and Sn(IV) 
Heterobimetallic complexes of Zn(II) and Sn(IV) with sarcosine have been synthesized at room temperature under stirring conditions by the reaction of sarcosine and zinc acetate in 2 : 1 molar ratio followed by the stepwise addition of CS2 and organotin(IV) halides, where R = Me, n-Bu, and Ph. The complexes were characterized by elemental analysis, FT-IR and NMR (1H, 13C) spectroscopy. IR data showed that the ligand acts in a bidentate manner. NMR data revealed the four coordinate geometry in solution state. In vitro antimicrobial activities data showed that complexes (3) and (4) were effective against bacterial and fungal strains with few exceptions.
PMCID: PMC3819876  PMID: 24235910
10.  Diagnosis and treatment of organotin poisoned patients 
With the development of industry and agriculture, organotin compounds have been widely used in China. Organotin compounds cause a common occupational poisoning. The toxicity of organotin was reported in animal studies; however the reports about human organotin intoxication are very rare. In this study we retrospectively analyzed the clinical manifestations of 15 organotin-poisoned patients who had been treated at our hospital from 2002 through 2007.
Fifteen patients with organotin poisoning were admitted to Sir Run Run Shaw Hospital Affiliated to Zhejiang University School of Medicine from 2002 to 2007. They were 9 males and 6 females, aged from 25 to 52 years. Clinical manifestations and Glasgow Coma Scales showed that the poisoning was mild in 4 patients, moderate in 6 and severe in 5. The severe patients were given glucocorticoid after hospitalization by intravenous guttae of 500 mg methylprednisolone for the first day, followed by 160 mg methylprednisolone per day for three days, and then 80 mg methylprednisolone per day for another three days. Potassium glutamate and sodium glutamate were intravenously dripped to reduce blood ammonia; intravenous guttae plus oral administration of potassium 9 g/day was used to correct intractable hypokalemia; sodium bicarbonate was used to correct metabolic acidosis, and sedatives were used to control spasm and twitch; mechanical ventilators were used in 4 patients with dyspnea.
Most of the patients showed elevated level of blood ammonia, decreased level of blood potassium and metabolic acidosis, but some had demyelination changes shown by CT and MRI. Treatments included correction of metabolic acids, blood potassium and ammonia, and mechanical ventilation when necessary. For patients with injuries of the nervous system, glucocorticoids were given immediately after hospitalization. These patients showed intractable hypokalemia and metabolic acidosis during the treatment. Forteen patients recovered completely without long-term side-effect. One patient in the aphasiac stage restored the linguistic capacity during a 6-month follow-up.
Elevated level of blood ammonia, decresed level of blood potassium, and metabolic acidosis are common in patients with organotin poisoning. Demyelination can be observed in patients with severe poisoning. The abnormalities of the patients are reversible after suitable treatments.
PMCID: PMC4129753  PMID: 25214954
Organotin; Poisoning; Blood ammonia; Demyelination
11.  Organotin Compound Derived from 3-Hydroxy-2-formylpyridine Semicarbazone: Synthesis, Crystal Structure, and Antiproliferative Activity 
The novel diphenyltin(IV) compound [Ph2(HyFoSc)Sn] (2), where H2HyFoSc (1) is 3-hydroxy-2-formylpyridine semicarbazone, was prepared and characterized by vibrational and NMR (1H, 13C) spectroscopy. The structure of [Ph2(HyFoSc)Sn] was confirmed by single-crystal X-ray crystallography. The doubly deprotonated ligand is coordinated to the tin atom through the enolic-oxygen, the azomethine-nitrogen, and phenolic-oxygen, and so acts as an anionic tridentate ligand with the ONO donors. Two carbon atoms complete the fivefold coordination at the tin(IV) center. Intermolecular hydrogen bonding, C–H → π, and π → π interactions combine to stabilize the crystal structure. Compounds 1 and 2 have been evaluated for antiproliferative activity in vitro against the cells of three human tumor cell lines: MCF-7 (human breast cancer cell line), T24 (bladder cancer cell line), A549 (nonsmall cell lung carcinoma), and a mouse fibroblast L-929 cancer cell line.
PMCID: PMC2869176  PMID: 20490260
12.  Biological and Spectral Studies of Newly Synthesized Triazole Schiff Bases and Their Si(IV), Sn(IV) Complexes 
The Schiff bases HL1-3 have been prepared by the reaction of 5-bromothiophene-2-carboxaldehyde with 4-amino-5-mercapto-3-methyl/propyl/isopropyl-s-triazole, respectively. Organosilicon(IV) and organotin(IV) complexes of formulae (CH3)2MCl(L1-3), (CH3)2M(L1-3)2 were synthesized from the reaction of (CH3)2MCl2 and the Schiff bases in 1 : 1 and 1 : 2 molar ratio, where M = Si and Sn. The synthesized Schiff bases and their metal complexes have been characterized with the aid of various physicochemical techniques like elemental analyses, molar conductance, UV, IR, 1H, 13C, 29Si, and 119Sn NMR spectroscopy. Based on these studies, the trigonal bipyramidal and octahedral geometries have been proposed for these complexes. The ligands and their metal complexes have been screened in vitro against some bacteria and fungi.
PMCID: PMC3150780  PMID: 21826133
13.  Hexa-μ2-acetato-hexa-n-butyl­hexa-μ3-oxido-tin(IV) toluene monosolvate 
The title compound, [Sn6(C4H9)6(CH3COO)6O6]·C7H8, has one half-toluene mol­ecule and one half-organotin mol­ecule in the asymmetric unit. The latter is situated about an inversion centre and belongs to the class of hexa­meric monoorganooxo­tin carboxyl­ates with a hexa­gonal prismatic or ‘drum-like’ motif of the central tin–oxygen core. Two Sn3O3 rings in a flat-chair conformation are linked via six Sn—O bonds and six bridging acetate groups. All Sn atoms have approximate octa­hedral coordination geometry. The Sn—O bonds which are trans to the alkyl group are significantly shorter than the others. One butyl group is disordered over two different sites, with occupancies of 0.9:0.1. Very large atomic displacement parameters of the toluene mol­ecule indicate an unresolvable disorder about the twofold axis.
PMCID: PMC3588278  PMID: 23476337
14.  Synthesis, Characterization, and Biological Studies of Organotin(IV) Derivatives with o- or p-hydroxybenzoic Acids 
Organotin(IV) complexes with o- or p-hydroxybenzoic acids (o-H2BZA or p-H2BZA) of formulae [R2Sn(HL)2] (where H2L = o-H2BZA and R = Me- (1), n-Bu- (2)); [R3Sn(HL)] (where H2L = o-H2BZA and R = n-Bu- (3), Ph- (4) or H2L = p-H2BZA and R = n-Bu- (5), Ph- (6)) were synthesized by reacting a methanolic solution of di- and triorganotin(IV) compounds with an aqueous solution of the ligand (o-H2BZA or p-H2BZA) containing equimolar amounts of potassium hydroxide. The complexes were characterized by elemental analysis, FT-IR, Far-IR, TGA-DTA, FT-Raman, Mössbauer spectroscopy, 1H, 119Sn-NMR, UV/Vis spectroscopy, and Mass spectroscopy. The X-ray crystal structures of complexes 1 and 2 have also been determined. Finally, the influence of these complexes 1–6 upon the catalytic peroxidation of linoleic acid to hydroperoxylinoleic acid by the enzyme lipoxygenase (LOX) was kinetically studied and the results showed that triorganotin(IV) complex 6 has the lowest IC50 value. Also complexes 1–6 were studied for their in vitro cytotoxicity against sarcoma cancer cells (mesenchymal tissue) from the Wistar rat, and the results showed that the complexes have high activity against these cell lines with triphenyltin((IV) complex 4 to be the most active one.
PMCID: PMC2669538  PMID: 19390627
15.  Tin-Carbon Cleavage of Organotin Compounds by Pyoverdine from Pseudomonas chlororaphis 
The triphenyltin (TPT)-degrading bacterium Pseudomonas chlororaphis CNR15 produces extracellular yellow substances to degrade TPT. Three substances (F-I, F-IIa, and F-IIb) were purified, and their structural and catalytic properties were characterized. The primary structure of F-I was established using two-dimensional nuclear magnetic resonance techniques; the structure was identical to that of suc-pyoverdine from P. chlororaphis ATCC 9446, which is a peptide siderophore produced by fluorescent pseudomonads. Spectral and isoelectric-focusing analyses revealed that F-IIa and F-IIb were also pyoverdines, differing only in the acyl substituent attached to the chromophore part of F-I. Furthermore, we found that the fluorescent pseudomonads producing pyoverdines structurally different from F-I showed TPT degradation activity in the solid extracts of their culture supernatants. F-I and F-IIa degraded TPT to monophenyltin via diphenyltin (DPT) and degraded DPT and dibutyltin to monophenyltin and monobutyltin, respectively. The total amount of organotin metabolites produced by TPT degradation was nearly equivalent to that of the F-I added to the reaction mixture, whereas DPT degradation was not influenced by monophenyltin production. The TPT degradation activity of F-I was remarkably inhibited by the addition of metal ions chelated with pyoverdine. On the other hand, the activity of DPT was increased 13- and 8-fold by the addition of Cu2+ and Sn4+, respectively. These results suggest that metal-chelating ligands common to pyoverdines may play important roles in the Sn-C cleavage of organotin compounds in both the metal-free and metal-complexed states.
PMCID: PMC143631  PMID: 12571007
16.  Novel Organotin(IV) Schiff Base Complexes with Histidine Derivatives: Synthesis, Characterization, and Biological Activity 
Five novel tin Schiff base complexes with histidine analogues (derived from the condensation reaction between L-histidine and 3,5-di-tert-butyl-2-hydroxybenzaldehyde) have been synthesized and characterized. Characterization has been completed by IR and high-resolution mass spectroscopy, 1D and 2D solution NMR (1H, 13C  and 119Sn), as well as solid state 119Sn NMR. The spectroscopic evidence shows two types of structures: a trigonal bipyramidal stereochemistry with the tin atom coordinated to five donating atoms (two oxygen atoms, one nitrogen atom, and two carbon atoms belonging to the alkyl moieties), where one molecule of ligand is coordinated in a three dentate fashion. The second structure is spectroscopically described as a tetrahedral tin complex with four donating atoms (one oxygen atom coordinated to the metal and three carbon atoms belonging to the alkyl or aryl substituents), with one molecule of ligand attached. The antimicrobial activity of the tin compounds has been tested against the growth of bacteria in vitro to assess their bactericidal properties. While pentacoordinated compounds 1, 2, and 3 are described as moderate effective to noneffective drugs against both Gram-positive and Gram-negative bacteria, tetracoordinated tin(IV) compounds 4 and 5 are considered as moderate effective and most effective compounds, respectively, against the methicillin-resistant Staphylococcus aureus strains (Gram-positive).
PMCID: PMC3707209  PMID: 23864839
17.  Pattern of organotin inhibition of methanogenic bacteria. 
Seven organotin compounds and tin chloride were tested for their effects on the methanogenic bacteria Methanococcus thermolithotrophicus, Methanococcus deltae delta LH, and Methanosarcina barkeri 227. The methanogens were strongly inhibited by triethyltin, tripropyltin, and monophenyltin compounds, generally at concentrations below 0.05 mM. Less inhibition by tributyltin and diphenyltin was observed at levels below 0.1 mM, but complete inhibition was observed at a 1 mM concentration. Tin chloride inhibited all methanogens, with nearly complete inhibition at a 1 mM concentration. There was no inhibition by tetra-n-butyltin and triphenyltin compounds even at 2 mM, the highest concentration tested. The 50 and 100% inhibitory concentrations of all compounds were estimated; these values varied with both the compound tested and the bacterium tested. The 50% inhibitory concentration estimate generally decreased (i.e., giving a higher toxicity) as the total surface area of the alkyltin molecules decreased. These results differ considerably from those reported previously for aerobic microorganisms (G. Eng, E. J. Tierney, J. M. Bellama, and F. E. Brinckman, Appl. Organometallic Chem. 2:171-175, 1988), where a clear correlation between increasing total molecular surface area and increasing toxicity was documented with a variety of organisms. Using the same procedures as for the methanogens, we examined the effects of organotin compounds on Escherichia coli growing aerobically or anaerobically. The E. coli inhibition pattern clearly resembled that seen in the data of Eng et al., under both aerobic and anaerobic conditions.
PMCID: PMC182866  PMID: 2059040
18.  Interaction of 5′-Guanosine Monophosphate with Organotin(IV) Moieties: Synthesis, Structural Characterization, and Anti-Inflammatory Activity 
ISRN organic chemistry  2012;2012:873035.
Reaction(s) of 5′-guanosine monophosphate (5′GMP) with di- and triorganotin(IV) chloride(s) led to formation of organotin(IV) derivatives of general formulae, [R2Sn(5′-GMP)·H2O]n and [(R′3Sn)2(5′-GMP)·H2O]n, where R = Me, n-Bu, and Ph; R′ = Me, i-Pr, n-Bu, and Ph; (5′-GMP)2− = 5′-guanosine monophosphate. An attempt has been made to prove the structures of the resulting derivatives on the basis of FT-IR, multinuclear 1H, 13C, and 119Sn NMR and 119Sn Mössbauer spectroscopic studies. These investigations suggest that both di- and triorganotin(IV)-5′-guanosine monophosphates are polymeric in which (5′-GMP)2− is bonded through phosphate group resulting in a distorted trigonal bipyramidal geometry around tin. The ribose conformation in all of the derivatives is C3′-endo, except diphenyltin(IV) and tri-i-propyltin(IV) derivatives where it is C2′-endo. All of the studied derivatives exhibited mild-to-moderate anti-inflammatory activity (~15.64–20.63% inhibition) at 40 mg kg−1 dose and LD50 values > 400 mg kg−1 in albino rats.
PMCID: PMC3767334  PMID: 24052853
19.  Metal-Based Antibacterial and Antifungal Agents: Synthesis, Characterization, and In Vitro Biological Evaluation of Co(II), Cu(II), Ni(II), and Zn(II) Complexes With Amino Acid-Derived Compounds 
A series of antibacterial and antifungal amino acid-derived compounds and their cobalt(II), copper(II), nickel(II), and zinc(II) metal complexes have been synthesized and characterized by their elemental analyses, molar conductances, magnetic moments, and IR, and electronic spectral measurements. Ligands (L1)−(L5) were derived by condensation of β-diketones with glycine, phenylalanine, valine, and histidine and act as bidentate towards metal ions (cobalt, copper, nickel, and zinc) via the azomethine-N and deprotonated-O of the respective amino acid. The stoichiometric reaction between the metal(II) ion and synthesized ligands in molar ratio of M : L (1 : 1) resulted in the formation of the metal complexes of type [M(L)(H2O)4]Cl (where M = Co(II), Cu(II), and Zn(II)) and of M : L (1 : 2) of type [M(L)2(H2O)2] (where M = Co(II), Cu(II), Ni(II), and Zn(II)). The magnetic moment data suggested for the complexes to have an octahedral geometry around the central metal atom. The electronic spectral data also supported the same octahedral geometry of the complexes. Elemental analyses and NMR spectral data of the ligands and their metal(II) complexes agree with their proposed structures. The synthesized ligands, along with their metal(II) complexes, were screened for their in vitro antibacterial activity against four Gram-negative (Escherichia coli, Shigella flexeneri, Pseudomonas aeruginosa, and Salmonella typhi) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains and for in vitro antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani, and Candida glaberata. The results of these studies show the metal(II) complexes to be more antibacterial/antifungal against one or more species as compared to the uncomplexed ligands. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties. Five compounds, (3), (7), (10), (11), and (22), displayed potent cytotoxic activity as LD50 = 8.974 × 10−4, 7.022 × 10−4, 8.839 × 10−4, 7.133 × 10−4, and 9.725 × 10−4 M/mL, respectively, against Artemia salina.
PMCID: PMC1800917  PMID: 17497020
20.  Nanoparticles of novel organotin(IV) complexes bearing phosphoric triamide ligands 
Four novel organotin(IV) complexes containing phosphoric triamide ligands were synthesized and characterized by multinuclear (1H, 31P, 13C) NMR, infrared, ultraviolet and fluorescence spectroscopy as well as elemental analysis. The 1H NMR spectra of complexes 1–4 proved that the Sn atoms adopt octahedral configurations. The nanoparticles of the complexes were also prepared by ultrasonication, and their SEM micrographs indicated identical spherical morphologies with particles sizes about 20–25 nm. The fluorescence spectra exhibited blue shifts for the maximum wavelength of emission upon complexation.
PMCID: PMC3596101  PMID: 23504649
luminescence; nanoparticles; organotin(IV) complexes; phosphoric triamide; ultrasonic
21.  Novel Organotin(IV)-Schiff Base Complexes: Synthesis, Characterization, Antimicrobial Activity, and DNA Interaction Studies 
Four organotin(IV) complexes with 2-(2-hydroxybenzylideneamino)isoindoline-1,3-dione (L1), and 4-(4-hydroxy-3-methoxybenzylideneamino-N-(pyrimidin-2-yl)benzenesulfonamide (L2) were synthesized and well characterized by analytical and spectral studies. The synthesized compounds were tested for antimicrobial activity by disc diffusion method. The DNA binding of the complexes 1 and 3 with CT-DNA has been performed with absorption spectroscopy, which showed that both the complexes are avid binders of CT-DNA. Also the nuclease activity of complexes 1 and 3 with plasmid DNA (pUC19) was studied using agarose gel electrophoresis. The complex 1 can act as effective DNA cleaving agent when compared to complex 3 resulting in the nicked form of DNA under physiological conditions. The gel was run both in the absence and presence of the oxidizing agent.
PMCID: PMC3021846  PMID: 21253533
22.  Toxicity and health effects of selected organotin compounds: a review. 
The toxicity of selected tin compounds is reviewed. Over the years, a variety of uses has been found for organic and inorganic tin compounds, as fungicides, as stablizers in plastics, moluscicides, and miticides; they have also been suggested as insect chemosterilants and for other industrial uses. Many of these products are unpalatable when mixed into diets and have been suggested as rodent repellents. Inhaling tin as dust or fumes may cause a benign pneumoconiosis in exposed workers. The organotin compounds can be divided into alkyltin and aryltin compounds. The trimethyl and triethyltin compounds are well absorbed from the gastrointestinal tract and are the most toxic in this group. Triethyltin particularly produces status spongiosus of the white matter of the central nervous system. Most of the other alkyl and aryl tin compounds are poorly absorbed from the gastrointestinal tract, and are less toxic when given orally than when given parentally. Only one compound, tricyclohexyltin hydroxide, is now registered by the Environmental Protection Agency as a miticide. This product produces skin irritation in rabbits. Studies should be conducted to determine whether it causes contact dermatitis in humans.
PMCID: PMC1475111  PMID: 789069
23.  Organotin(IV) Derivatives of L-Cysteine and their in vitro Anti-Tumor Properties 
The synthesis and characterization of the organotin compounds [(n-C4H9)2Sn(cys)] (1), [(C6H5)2Sn(cys)] (2), [(C6H5)3Sn(Hcys).(H2o)] (3), {[(CH3)2Sn(Kcys)2].2(H20)} (4), {[(n-C4H9)2Sn(Kcys)2].2(H20)} (5) and {[(C6H5)2Sn(Kcys)2].2(H20)} (6) (where H2cys = L-cysteine) are reported. The compounds have been characterized by elemental analysis and 1H-NMR, Uv-Vis, FT-IR and MOssbauer spectroscopic techniques. Attempted recrystallization of (2) in DMSO/methanol 2:1 solution yielded after several days unexpectedly the dimeric compound bis(tri-phenyltin)sulphide {[(C6H5)3Sn]2S} (7) which has been characterized by x-ray analysis. The structure of the parent complex (2) as well as the mechanism of the decomposition of cysteine are being further investigated. The in vitro anticancer activity of complexes (I)- (6), against human leukemia (HL60), human liver (Bel7402), human stomach (BGC823) and human cervix epithelial human carcinoma (Hela), nasopharyngeal carcinoma (KB) and lung cancer (PG) tumor cells, were evaluated.
PMCID: PMC2267074  PMID: 18365068
24.  Control of heme and cytochrome P-450 metabolism by inorganic metals, organometals and synthetic metalloporphyrins. 
The heme-cytochrome P-450 complexes represent sensitive metabolic systems for examining the biological impact of metals on important cellular functions. Many metals, both in the inorganic form and bound to organic moieties, potently induce heme oxygenase, the rate limiting enzyme of heme degradation. The resulting increase in the rate of heme breakdown is reflected in a marked depression of cellular cytochrome P-450 content and impairment of the oxidative metabolism of natural and foreign chemicals dependent on this hemeprotein. Organometal complexes do not mimic in all their aspects the actions of the inorganic elements which they contain. For example, organotins, in contrast to inorganic tin, produce a prolonged induction response of heme oxygenase in the liver but not in the kidney. Co-protoporphyrin is a much more potent inducer of heme oxygenase in liver than is inorganic cobalt; and Sn-protoporphyrin inhibits heme oxygenase activity nearly completely, whereas inorganic tin is a powerful inducer of the renal enzyme. Contrasting effects on heme metabolism exist as well within the metalloporphyrin species as demonstrated by the effects in vivo of Co-protoporphyrin and Sn-protoporphyrin on heme oxygenase activity; the former induces the enzyme whereas the latter potently inhibits it. In vitro, however, both compounds competitively inhibit heme oxidation activity. These differences, among others which characterize metal actions in vivo and in vitro attest to the importance of pharmacokinetic, adaptive and other host factors in defining the responses of the heme-cytochrome P-450 systems to the impact of metals in the whole animal.
PMCID: PMC1568282  PMID: 6548701
25.  The Development of Novel Organotin Anti-Tumor Drugs: Structure and Activity 
Metal-Based Drugs  1998;5(4):179-188.
An overview of the development of anti-tumor organotin derivatives in selected classes of compounds is presented and discussed. High to very high in vitro activity has been found, sometimes equaling that of doxorubicin. Solubility in water is an important issue, dominating the in vivo testing of compounds with promising in vitro properties. The cytotoxicity of the compounds was increased by the presence of a bulky group, an active substituent or one or more polar substituents. Polar substituents may also improve the water solubility. Although organotin derivatives constitute a separate class of compounds, the comparison with cisplatin is inevitable. Among the observed toxicities, neurotoxicity, known from platinum cytostatics, and gastrointestinal toxicity, typical for many oncology drugs, have been detected. Further research to develop novel, useful organotin anti-tumor compounds should be carried out.
PMCID: PMC2365118  PMID: 18475842

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