Synthesis, characterization and crystal structures of polymeric and dimeric triphenyltin(IV) complexes of 4-[((E)-1-{2-hydroxy-5-[(E)-2-(2-carboxyphenyl)-1-diazenyl]phenyl}methylidene)amino]aryls

Tributyltin(IV) Butyrate: A Novel Epigenetic Modifier with ER Stress- and Apoptosis-Inducing Properties in Colon Cancer Cells

Organotin(IV) compounds are a class of non-platinum metallo-conjugates exhibiting antitumor activity. The effects of different organotin types has been related to several mechanisms, including their ability to modify acetylation protein status and to promote apoptosis. Here, we focus on triorganotin(IV) complexes of butyric acid, a well-known HDAC inhibitor with antitumor properties. The conjugated compounds were synthesized and characterised by FTIR spectroscopy, multi-nuclear (1H, 13C and 119Sn) NMR, and mass spectrometry (ESI-MS). In the triorganotin(IV) complexes, an anionic monodentate butyrate ligand was observed, which coordinated the tin atom on a tetra-coordinated, monomeric environment similar to ester. FTIR and NMR findings confirm this structure both in solid state and solution. The antitumor efficacy of the triorganotin(IV) butyrates was tested in colon cancer cells and, among them, tributyltin(IV) butyrate (BT2) was selected as the most efficacious. BT2 induced G2/M cell cycle arrest, ER stress, and apoptotic cell death. These effects were obtained using low concentrations of BT2 up to 1 μM, whereas butyric acid alone was completely inefficacious, and the parent compound TBT was poorly effective at the same treatment conditions. To assess whether butyrate in the coordinated form maintains its epigenetic effects, histone acetylation was evaluated and a dramatic decrease in acetyl-H3 and -H4 histones was found. In contrast, butyrate alone stimulated histone acetylation at a higher concentration (5 mM). BT2 was also capable of preventing histone acetylation induced by SAHA, another potent HDAC inhibitor, thus suggesting that it may activate HDACs. These results support a potential use of BT2, a novel epigenetic modulator, in colon cancer treatment.

Di-butyltin(iv) complexes with azo-carboxylates: synthesis, characterization, crystal structures and their anti-diabetic assay

The results of the anti-diabetic test of the compounds against the alpha glucosidase enzyme showed that2exhibits promising activity.

Selective sensing of a Cu(ii) ion by organotin anchored keto-enamine ligands

New organotin carboxylates [{(n-Bu)₂Sn(HL)}₂O]₂ (1), [(t-Bu)₂Sn(HL)₂] (2) and [Ph₃Sn(HL)] (3) have been synthesized and used for sensing of Cu(ii) ion. Complex 3 shows highest binding constant and better limit of detection than other complexes.

Synthesis, characterization and anti-diabetic assay of diorganotin(iv) azo-carboxylates: crystal structure and topological studies of azo-dicarboxylic acid ligand and its cyclic tetranuclear dimethyltin(iv) complex

Two novel cyclic tetranuclear and a cyclic dimeric diorganotin(iv) azo-dicarboxylates have been reported. The complexes exhibited effective anti-diabetic activity.

Synthesis, chemical characterization, computational studies and biological activity of new DNA methyltransferases (DNMTs) specific inhibitor. Epigenetic regulation as a new and potential approach to cancer therapy

This work deals with the synthesis, the chemical characterization of dibutyltin(IV) complex of caffeic acid (Bu2Sn(IV)HCAF, caf1) and its cytotoxic action on tumor cells. The coordination environment at the tin center was investigated by FTIR, (119)Sn{(1)H} cross polarization magic angle spinning, electrospray ionization mass spectroscopy in the solid state and UV-vis, fluorescence and (1)H, (13)C and (119)Sn NMR spectroscopy in solution phases. Density functional theory study confirmed the proposed structures in solution phase and indicated the most probably stable conformation. The effects on viability of breast cancer MDA-MB231, colorectal cancer HCT116, hepatocellular carcinoma HepG2 and Chang liver cells, an immortalized non-tumor hepatic cell line, have been investigated. The effect of a variation in structure of caf1 was found to lead to a change in the respective antiproliferative properties: caf1 induces loss of viability in HCT116, MDA-MB-231, and HepG2; the complex shows only moderate effects in non-tumor Chang liver cells. caf1 exerts lower cytotoxic activity than Bu2SnCl2, suggesting that the binding with H3CAF modulates the marked cytotoxic activity exerted by Bu2SnCl2; caf1 displays a considerably more pronounced antitumoural effect towards cell lines than caffeic acid. It is known that caffeic acid can modulate DNA (cytosine-5)-methyltransferases 1 (DNMT1) mediated DNA methylation. In this paper we demonstrate that caf1 treatment was able to induce a time-dependent reduction of global DNA methylated status. This effect was also confirmed by a concomitant reduction DNMT1 expression level. The effect induced by caf1 was more evident not only with respect to untreated cells but also compared to H3CAF treated cells.

Mode of action of tin-based anti-proliferative agents: Biological studies of organotin(IV) derivatives of fatty acids

Some organotin(IV) carboxylates of the general formula RnSn(L)m [n=3, m=1, R=Me, Pr, Bu and Ph; n=2, m=2, R=Me, Bu and Oct; L=anion of lauric (HLA), stearic (HSA) and myristic acid (HMA)] have been synthesized and characterized by various spectroscopic studies. Tri- and diorganotin(IV) carboxylates adopt trigonal-bipyramidal and octahedral geometry around tin atom, respectively. They have been screened in vitro for anti-tumor activity against cancer cell lines of human origin, viz. MCF-7 (mammary), HEK-293 (kidney), PC-3 (prostate), HCT-15 (colon) and HepG-2 (liver). Enzyme assays viz. lipid peroxidase, glutathione peroxidase, glutathione reductase and total glutathione assay have been carried out to explore the cause of their cytotoxiciy. The results indicate that ROS (reactive oxygen species) generation may be responsible for their cytotoxicity but elevation in LDH (lactate dehydrogenase) suggests that necrosis cannot be excluded. Further, DNA (deoxyribonucleic acid) fragmentation, acridine orange and comet assay support the fact that the apoptosis is the main cause of cytotoxicity of organotin(IV) carboxylates, whereas the necrosis plays a minor role. The anti-inflammatory activity evaluation shows that the complexes possess moderate activity. Results of acute toxicity of the complexes have also been discussed.

Synthetic, spectral, thermal and powder X-ray diffraction studies of bis(O-alkyldithiocarbonato-S,S') antimony(III) dialkyldithiocarbamates

Compounds of antimony(III) with mixed sulfur donor ligands of the type [(ROCS2)2SbS2CNR'2] (where, R=C2H5, and (i)C3H7; R'=CH3, C2H5, and CH2CH2) have been synthesized using anhydrous acetone as a solvent by the one pot reaction of antimony(III) tris(O-alkyldithiocarbonato-S,S'), antimony(III) chloride and sodium/ammonium salt of dialkyldithiocarbamate in 2:1:3molar ratios. These compounds have been characterized by physicochemical [melting points, molecular weight determinations, elemental analyses (C, H, N, S, and Sb)], spectral [UV, IR, Far-IR and NMR ((1)H and (13)C)] studies. In IR spectra strong band was observed at 1028-1051cm(-1) which indicates anisobidentate mode of bonding of both the ligands with antimony metal. NMR spectral data of these compounds show expected proton resonance due to corresponding moieties. The powder XRD, ESI-Mass and thermal (TG and DTA) studies have also been performed to get the information about geometrical parameters, fragmentation pattern and last thermal decomposition product, respectively. The powder XRD studies lead to the structural properties of the synthesized compounds and show the nanorange crystallite size and monoclinic crystal system. Thermal data of these compounds indicate the formation of antimony sulfide (Sb2S3) as a final thermal degradation product which is used in a number of ways like switching devices television cameras and microwave devices.

Structural investigation on toluene-3,4-dithiolatoantimony(iii) alkyldithiocarbonate complexes: thermal, powder XRD and biological studies

On thermal decomposition of the mixed sulfur donor antimony(iii) complexes, we obtained antimony sulfide at 600 °C, which was confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX).

Synthetic aspects, spectral, thermal studies and antimicrobial screening on bis(N,N-dimethyldithiocarbamato-S,S')antimony(III) complexes with oxo or thio donor ligands

The bis(N,N-dimethyldithiocarbamato-S,S')antimony(III) complexes have been obtained by the reaction of chloro bis(N,N-dimethyldithiocarbamato-S,S')antimony(III) with corresponding oxo or thio donor ligands such as sodium benzoate 1, sodium thioglycolate 2, phenol 3, sodium 1-propanethiolate 4, potassium thioacetate 5, sodium salicylate 6, ethane-1,2-dithiolate 7 and disodium oxalate 8. These complexes have been characterized by the physicochemical [melting point, molecular weight determination and elemental analysis (C, H, N, S and Sb)], spectral [UV-Visible, FT-IR, far IR, NMR (1H and 13C)], thermogravimetric (TG & DTA) analysis, ESI-Mass and powder X-ray diffraction studies. Thermogravimetric analysis of the complexes confirmed the final decomposition product as highly pure antimony sulfide (Sb2S3) and powder X-ray diffraction studies show that the complexes are in lower symmetry with monoclinic crystal lattice and nano-ranged particle size (11.51-20.82 nm). The complexes have also been screened against some bacterial and fungal strains for their antibacterial and antifungal activities and compared with standard drugs. These show that the complexes have greater activities against some human pathogenic bacteria and fungi than the activities of standard drugs.

Synthesis, spectroscopic, thermal and antimicrobial studies of toluene-3,4-dithiolatoarsenic(III) derivatives with some oxygen and sulphur donor ligands

Replacement reactions of toluene-3,4-dithiolatoarsenic(III) chloride with oxygen and sulphur donor ligands like benzoic acid, thiobenzoic acid, anhydrous sodium acetate, thioacetic acid, phenol, thiophenol, sodium salicylate and thio glycolic acid in 1:1 molar ratio as well as disodium oxalate in 2:1 molar ratio in refluxing anhydrous benzene yielded toluene-3,4-dithiolatoarsenic(III) mono oxo or thio carboxylic or phenolic derivatives of the general formula SC(6)H(3)(CH(3))SAsR {where R=OOCC(6)H(5), SOCC(6)H(5), OOCCH(3), SOCCH(3), OC(6)H(5), SC(6)H(5), OOCC(6)H(4)(OH), SCH(2)COOH} and SC(6)H(3)(CH(3))SAsOOC-COOAsS(CH(3))C(6)H(3)S. These synthesized derivatives are yellow, yellow-brown solids/ liquids and are soluble in common organic solvents like benzene, chloroform, dichloromethane, dimethyl formamide, dimethyl sulphoxide etc. These derivatives have been characterized by melting point determination, molecular weight determination, elemental analysis (C, H, S and As), spectral {UV, IR, NMR ((1)H and (13)C), ESI-Mass, SEM and powder X-ray diffraction} and thermal (TGA, DTA and DSC) studies. Some of these compounds have been screened for their antimicrobial activities using the disc diffusion method. These derivatives have shown good activity as antibacterial and antifungal agents on some selected bacterial and fungal strains, which increased on increasing the concentration. Chloroamphenicol and terbinafin were used as standards for the comparison.

Structural analysis of organometallic compounds with soft ionization mass spectrometry

The analysis of organometallic compounds with mass spectrometry has some special features in comparison with organic and bioorganic compounds. The first step is the choice of a suitable ionization technique, where the electrospray ionization is certainly the best possibility for most classes of organometallic compounds and metal complexes. Some ionization mechanisms of organometallic compounds are comparable to organic molecules, such as protonation/deprotonation, and adduct formation with sodium or potassium ions; however, in many cases, different mechanisms and their combinations complicate the spectra interpretation. Organometallics frequently undergo various types of adduct and polymerization reactions that result in significantly higher masses observed in the spectra in comparison to molecular weights of studied compounds. Metal elements typically have more natural isotopes than common organic elements, which cause characteristic wide distributions of isotopic peaks; for example, tin has ten natural isotopes. The isotopic pattern can be used for the identification of the type and number of metal elements in particular ions. The ionization and fragmentation behavior also depend on the type of metal atom; therefore, our discussion of mass spectra interpretation is divided according to the different type of organometallic compounds. Among various types of mass spectrometers available on the market, trap-based analyzers (linear or spherical ion-traps, Orbitrap) are suitable to study complex fragmentation pathways of organometallic ions and their adducts, whereas high-resolution and high-mass accuracy analyzers (time-of-flight-based analyzers, or Fourier transform-based analyzers-Orbitrap or ion cyclotron resonance mass spectrometers) provide accurate masses applicable for the determination of the elemental composition of individual ions.

Electrospray ionization-multistage tandem mass spectrometry of complex multitin organometallic compounds

The series of 14 complex organotin(IV) compounds containing many tin atoms and noncovalent bonds in the structure was characterized by electrospray ionization multistage tandem mass spectrometry (ESI-MS(n)). The mass spectra were measured in both polarity modes to obtain complementary structural information. The characteristic pattern of ten natural tin isotopes allowed the determination of the number of tin atoms in the molecular adducts and fragment ions by comparing theoretical and experimental isotopic distributions. Positive ion ESI spectra show unusual adduct formation depending on the type of organic solvent used for the direct infusion analysis owing to the ion-molecule reactions in the ion source. On the basis of the detailed spectral interpretation of organotin(IV) compounds, the fragmentation patterns of multitin organometallic compounds have been proposed. Noncovalent bonds in polymeric complexes are fragmented first, which is then followed by characteristic neutral losses in monomeric units.