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.     

Syntheses and structural characterization of organotin(IV) complexes derived from reaction of 2,3-diphenylpropionic acid and various alkyltin salts

Five new organotin(IV) complexes, [(R₃Sn)(O₂C₁₅H₁₃)] _n (R?=?Me: 1; nBu: 2), [RSn(O)(O₂C₁₅H₁₃)]₆ (R?=?Ph: 3), [(R₂Sn)₂(O₂C₁₅H₁₃)₂(μ ₃-O)]₂ (R?=?Me: 4), and [(R₂Sn)(O₂C₁₅H₁₃)₂] (R?=?nBu: 5), have been prepared by the reaction of 2,3-diphenylpropionic acid and the corresponding organotin chloride with sodium ethoxide in methanol. All the complexes were characterized by elemental analysis, FT-IR, NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopy, TGA, and X-ray crystallography. The structural analyses reveal that 1 and 2 are 1-D infinite polymeric chains with Sn in syn–anti conformation. Complex 3 has a drum structure with six Sn centers. Complex 4 has a supramolecular chain-like ladder through weak intermolecular Sn?···?O interactions. Complex 5 is a monomer, connected into a 1-D polymer through intermolecular C–H?···?O interactions. Complexes 1 and 5 crystallize in the orthorhombic space groups P212121 and P21212, which are chiral space groups.     

Synthesis and coordination chemistry of organotin(IV) complexes of 2,3-methylenedioxyphenylpropenoic acid

The synthesis, spectroscopy, and antitumor behavior of organotin(IV) complexes of 2,3-methylenedioxyphenylpropenoic acid are described. The spectroscopic data indicate 1 : 2 and 1 : 1 metal to ligand stoichiometry in case of di- and trioganotin(IV) compounds and hypervalency of Sn(IV) in trigonal bipyramidal and octahedral modes. Mass spectrometric and elemental analysis data support the solid and solution spectroscopic results. The complexes have been evaluated in vitro against crown gall tumor and bio-activity screenings showed in vitro biological potential. The nature of covalent attachments (methyl, ethyl, n-butyl, phenyl, and n-octyl) of Sn(IV) played a decisive role for bioactivity. All the compounds have been studied in solution by NMR (¹H, ¹³C) and also in solid state using FTIR, mass spectrometry, and by X-ray crystallography. The molecular structure of Et₂Sn(IV) and Me₃Sn(IV) derivatives confirm the behavior of di- and tri-organotin(IV) compounds in solid state. Mono-organotin derivatives are octahedral both in solid and solution.     

Polymeric seven-coordinated organotin(IV) complexes derived from 5-amino-2-chlorobenzoic acid and in vitro anti-cancer studies

Cancer cases are alarmingly increasing worldwide, and newer chemotherapeutic agents are needed. Recent analogs of cisplatin (carboplatin, lobaplatin, nedaplatin and oxaliplatin) and their marketing as advanced chemotherapeutic drugs have furthered the interest in metal-based anti-cancer drugs. In the current study, two new polymeric organotin(IV) carboxylate complexes (1 and 2) have been synthesized and characterized. Spectroscopic studies showed that coordination took place via carboxylates. Furthermore, X-ray crystallographic study on 1 indicated that it possesses a monomeric structure and exists in polymeric formation due to additional Sn–N coordination, assigning seven coordinations to each metal ion. Both the complexes were tested against three cancerous (human colon cancer, HCT 116; breast cancer, MCF-7; and leukemia, K562) and one non-cancerous (3T3-L1) cell lines. Complex 1 showed exceptional cytotoxicity against cancerous cell lines (IC₅₀ = 1.0 μM for HCT 116; 258.7 nM for MCF-7; and 46.7 nM K562) and remained comparatively non-toxic against normal cells (IC₅₀ = 37.0?μM). This shows that both complexes have selective cytotoxicity against cancer cells.     

Dimethyltin(IV) complexes derived from hydroxamic acid and acylhydrazone ligands: Synthesis,DNA/bovine serum albumin interaction and cytotoxicity

Two novel dimethyltin(IV) complexes, Me₂SnL¹(PyCOO)(MeOH) ( 1 ) and Me₂SnL² ( 2 ) (HL¹ = 4‐pyridinehydroxamic acid and H₂L² = 2‐hydroxy‐N′‐[(2‐hydroxy‐5‐chlorophenyl)methylidene]benzoylhydrazone), were synthesized and characterized using elemental analyses, Fourier transform infrared and NMR (¹H, ¹³C) spectroscopies and single‐crystal X‐ray diffraction. In complex 1 the geometry around the tin atom is a six‐coordinated distorted octahedral configuration, while complex 2 exhibits five‐coordinated distorted trigonal bipyramid geometry. Preliminary in vitro cytotoxicity studies with two human cancer cell lines (HeLa and A549) using MTT assay show that complex 1 is more potent than complex 2 . The interactions of the two complexes with calf thymus DNA and bovine serum albumin were also investigated using UV–visible absorption spectral, thermal denaturation and viscosity measurements and docking analysis. Investigations indicate that the structures of the mixed ligands play an important role in the properties of the dimethyltin(IV) complexes, and, to some extent, the antitumor activities of the complexes are partly related to interactions with DNA and some proteins in cancer cells.     

The chemistry,properties, and characterization of organotin(IV) complexes of 2-(N-naphthylamido)benzoic acid

2-(N-naphthylamido)benzoic acid was synthesized by the reaction of phthalic anhydride with naphthylamine in glacial acetic acid at room temperature. Complexes 1–9 were synthesized under reflux in good yield with general formula R_{4? n} SnL _n (R = Me, n-Bu, Ph, n-Oct, Bz and n = 2, 3), which were studied by microanalysis, IR, NMR (¹H, ¹³C, ¹¹⁹Sn), and mass spectrometry. Cytotoxicity of the synthesized compounds was checked against Brine-shrimp larvae. In vitro activities against some Gram-positive and Gram-negative bacteria and fungi were also determined. Antimicrobial activities show that species with tetrahedral geometry in solution are more toxic.     

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.     

水相法合成双(环戊二烯基)钛氨基酸配合物的研究

以N-(取代苯基)氨基乙酸及盐与双(环戊二烯基)二氯化钛在水相及有机相反应,得到了五个双(环戊二烯基)钛氨基酸配合物,对配合物进行了熔点、元素分析、IR及^1HNMR的表征,确定了它们的结构。这些配合物在空气中稳定。经比较,水相中的合成反应速度快,操作简便,产物较易分离,产率高。     

Organoselenium compounds containing pyrazole or phenylthiazole groups: Synthesis,structure, tin(IV) complexes and antiproliferative activity

The diorganodiselenides (pzCH₂CH₂)₂Se₂ ( 1 ) and (PhtzCH₂)₂Se₂ ( 2 ) were prepared by reacting Na₂Se₂ with 1‐(2‐bromoethyl)‐1H‐pyrazole and 4‐(chloromethyl)‐2‐phenylthiazole, respectively, while the reactions between 1‐(2‐bromoethyl)‐1H‐pyrazole or 4‐(chloromethyl)‐2‐phenylthiazole and the lithium organoselenolates [2‐(Et₂NCH₂)C₆H₄]SeLi and [2‐{O(CH₂CH₂)₂NCH₂}C₆H₄]SeLi in a 1:1 molar ratio resulted in the heteroleptic diorganoselenium(II) compounds [2‐(Et₂NCH₂)C₆H₄](R)Se (R = pzCH₂CH₂ ( 3 ) or PhtzCH₂ ( 5 )) and [2‐{O(CH₂CH₂)₂NCH₂}C₆H₄](R)Se (R = pzCH₂CH₂ ( 4 ) or PhtzCH₂ ( 6 )). The diorganotin(IV) bis(organoselenolato) derivatives of type R₂Sn(SeCH₂CH₂pz)₂ (R = 2‐(Me₂NCH₂)C₆H₄ ( 7 ) or Me ( 8 )) were obtained by reacting (pzCH₂CH₂)SeNa with the appropriate diorganotin(IV)dichloride in a 2:1 molar ratio. All compounds were investigated using NMR spectroscopy (¹H, ¹³C, ⁷⁷Se, ¹¹⁹Sn as appropriate) and ESI+ mass spectrometry. The molecular structures of 2 and 6 were determined using single‐crystal X‐ray diffraction. The formation of a 10–Se–3 hypercoordinated species was evidenced for 6 in the solid state, as a consequence of the C,N coordination behaviour of the 2‐{O(CH₂CH₂)₂NCH₂}C₆H₄ group. Compounds 1 , 7 and 8 were investigated for their antiproliferative activity towards the mouse colon carcinoma C26 cell line with the preliminary results showing a better activity than 5‐fluorouracil.     

Synthesis and crystal structure of diorganotin(IV) complexes with pyruvic acid benzoylhydrazone and pyruvic acid salicylhydrazone

Six diorganotin esters of Schiff-base ligands formulated as [R₂SnLY]₂, where L₁ is C₆H₅CON₂C(CH₃)CO₂ with Y?=?CH₃CH₂OH, R?=?mClC₆H₄CH₂ (1), oFC₆H₄CH₂ (2), pFC₆H₄CH₂ (3) and L₂ is 2-HOC₆H₄CON₂C(CH₃)CO₂ with Y?=?CH₃OH, R?=?oFC₆H₄CH₂ (4), pFC₆H₄CH₂ (5), mClC₆H₄CH₂ (6) have been prepared and characterized by elemental analysis, IR, ¹H and ¹¹⁹Sn NMR spectra. The crystal structures of complexes 1 and 4 have been determined by X-ray single crystal diffraction. The structure analyses reveal that the Sn atom in both 1 and 4 is seven-coordinate in distorted pentagonal bipyramid geometries with a planar SnO₄N unit and two apical aryl carbon atoms, thus forming a dimeric molecule, which sits on a crystallographic center of symmetry. Intramolecular or intradimeric hydrogen bonds contribute to the stability and compactness of the crystal structures.     

(n‐Bu2Sn)2O(CO3): An active,robust and recyclable organotin(IV) for the direct synthesis of linear organic carbonates from carbon dioxide and alcohols

Organotin(IV) compounds are known to promote the direct synthesis of organic carbonates from carbon dioxide and alcohols. In the past, structural studies have highlighted that the carbonato moiety is a recurring ligand of tin species collected during CO₂ pressurized reactions. In a mimetic approach and in order to achieve an available and recyclable precursor, the title compound (n ‐Bu₂Sn)₂O(CO₃) ( 1 ) was prepared in a single step by reacting commercial di‐n ‐butyltin dichloride with an aqueous solution of sodium carbonate. Compound 1 was characterized using infrared spectroscopy and thermogravimetric and elemental analyses. Multinuclear NMR investigations in solution were also conducted. Compound 1 was then evaluated for the direct carbonation of alcohols (methanol, ethanol, n ‐butanol and isopropanol) under CO₂ pressure. Recycling experiments were performed showing the efficient reuse of 1 without loss of activity. Furthermore, the infrared fingerprint of 1 was preserved even after several runs demonstrating a good stability. The effects of pressure and of reaction time on dimethyl carbonate formation were also studied.     

Synthesis,crystal structure,and bioactivity of two triphenylantimony derivatives with benzohydroxamic acid and N-phenylbenzohydroxamic acid

Reaction of triphenylantimony dichloride with benzohydroxamic acid or N-phenylbenzohydroxamic acid in 1?:?1 stoichiometry yielded two new triphenylantimony derivatives formulated as [Ph₃SbL₁L₂] (L₁?=?benzohydroxamato, L₂?=?methoxide, 1; L₁?=?N-phenylbenzohydroxamato, L₂?=?Cl, 2), which have been characterized by FT-IR, NMR spectroscopy, elemental analysis, and melting point. Single-crystal X-ray diffraction analyses for 1 and 2 reveal that the antimony is six-coordinate adopting distorted octahedral geometry with one phenyl and methoxide or chloride in axial positions. In the supramolecular structure, a double-chain is shown for 2 constructed by C–H?···?X (X?=?O, C or π) weak interactions, while 1 exhibits a 1-D-chain structure connected by O–H?···?O and N–H?···?N hydrogen bonds. In vitro antitumor study reveals that 1 and 2 display activities against two human tumor cell lines – A549 and HCT-8. To explore the antitumor activity mechanism, DNA binding properties of 1 and 2 with calf thymus DNA (ct-DNA) have been investigated by fluorescence spectra, indicating that 1 and 2 bind to ct-DNA via intercalation, which could induce the death of cancer cells.     

Structural chemistry of mononuclear, tetranuclear and hexanuclear organotin(IV) carboxylates from the reaction of di-n-butyltin oxide or diphenyltin oxide with rhodanine-N-acetic acid

Three new organotin(IV) carboxylates, {[n-Bu₂Sn(O₂CC₄H₄NOS₂)]₂O}₂ (1), n-Bu₂Sn(O₂CC₄H₄NOS₂)₂ (2) and [PhSn(O)O₂CC₄H₄NOS₂]₆ · 3H₂O (3) were synthesized by the reaction of di-n-butyltin/diphenyltin oxide and rhodanine-N-acetic acid. The complexes 1-3 are characterized by elemental, IR, ¹H, ¹³C and ¹¹⁹Sn NMR and X-ray crystallography diffraction analyses. The complex 1 has a tetranuclear structure based on a planar four-membered Sn₂O₂ ring, while complex 2 is a hexa-coordinated monomer. As for complex 3, it adopts the hexameric drum-shaped structure. The supramolecular structure of 1 has been found to consist of one-dimensional molecular chain built up by intermolecular non-bonded S?O interactions. The salient feature of the supramolecular structure of complex 2 is that of a one-dimensional polymer, in which intermolecular Sn?O, S?O and S?S interactions are recognized.     

Synthesis and characterization of new organotin(IV) complexes with polyfunctional ligands

New mono-, di- and tri-organotin(IV) derivatives containing the neutral bis(2-pyridylthio)methane ligand, [(pyS)₂CH₂] and tris(2-pyridylthio)methane ligand, [(pyS)₃CH] have been synthesized from reaction with SnR_nCl_4−n (R = Me, ⁿBu, Ph and Cy, n = 1-3) acceptors. Mono-nuclear adducts of the type {[(pyS)₂CH₂]R_nSnCl_4−n} and {[(pyS)₃CH]R_nSnCl_4−n} have been obtained and characterized by elemental analyses, FT-IR, ESI-MS, multinuclear (¹H and ¹¹⁹Sn) NMR spectral data. The ¹H and ¹¹⁹Sn NMR and ESI-MS data suggest for the triorganotin(IV) derivatives a complete dissociation of the compounds in solution. The mono- and di-organotin(IV) derivatives show a greater stability in solution, and their spectroscopic data are in accordance with the existence of six-coordinated RSnCl₃N₂ or R₂SnCl₂N₂ species.     

Synthesis and Crystal Structure of Di-n-butyltin(IV) Complex with 2-Oxo-propionic Acid (4-Pyridinecarbonyl) Hydrazone

Introduction The studies of diorganotin(IV) complexes are of current interest owing to their wide range of applica-tions such as biocides and homogeneous catalysts in industry.1 In recent years there have been more and more reports on the synthesis, antitumour activities and structural elucidation of various diorganotin(IV) deriva-tives of carboxylic acid.2-5 In particular, people take considerable interest in structural studies of diorgano-tin(IV) complexes of carboxylic acid, because there…     

Synthesis and characterization of pentagonal bipyramidal organotin(IV) complexes of 2,6-diacetylpyridine Schiff bases of S-alkyl- and aryldithiocarbazates

New organotin(IV) complexes with empirical formula Sn(SNNNS)R₂, where SNNNS is the dianionic form of 2,6-diacetylpyridine Schiff bases of S-methyldithiocarbazate (H₂dapsme) or S-benzyldithiocarbazate (H₂dapsbz) and R = Ph or Me, have been prepared and characterized by IR, UV-Vis, NMR and Mössbauer spectroscopic techniques and conductance measurements. The molecular structures of the Sn(dapsme)R₂ (R = Ph and Me) have been determined by single crystal X-ray diffraction techniques. Both complexes have a distorted pentagonal-bipyramidal geometry in which the tin is coordinated by a dinegatively charged pentadentate chelating agent via pyridine nitrogen, two azomethine nitrogens, and two thiolate sulfurs. The five donors (N₃S₂) provided by the Schiff base occupy the equatorial plane close to a pentagonal planar array while the carbanion ligands occupy axial sites.     

Diorganotin(IV) complexes of indole 3-acetic acid

Alkyl derivatives of indole 3-acetic acid (IAA) have been prepared and are suitable for investigating steric substituent effects on hormonal activity without major interference from electronic effects. Triorganotin(IV) derivatives of indole 3-acetic acid and N-methylindole 3-acetic acid have been reported to act as insecticidal, fungicidal and bactericidal agents. Me₃SnIAA is more active as a biocide than Cy₃SnIAA. The activity of these two compounds may be due to the fact that four-coordinated tin monomers or five-coordinated tin polymers are often more active than chelated five-coordinated tin species because these readily undergo hydrolysis to give R₃Sn(H₂O⁺)₂ species. The ligand affects the rate of formation of the ligand-free active organotin entity. Biocidal activity is expected from diorganotin(IV) pentacoordinated complexes of indole 3-acetic acid in the present case due to (i) the activity of pentacoordinated organotin species, (ii) the presence of an—NH moiety in the complexes, which is an active site for binding. The NH moiety may be deprotonated and nitrogen may coordinate with metal ions present in the physiological systems and thus destroy the activity of enzymes.     

Organometallic complexes with biological molecules: V. In vivo cytotoxicity of diorganotin(IV)-amoxicillin derivatives in mitotic chromosomes of rutilus rubilio (pisces,cyprinidae)

In Order to test in vivo cytotoxicity of diorganotin(IV)-amoxicillin (amox) derivatives, mitotic chromosomes of Rutilus rubilio (Pisces, Cyprinidae) have been analyzed using two different chromosome-staining techniques. Results gathered after exposure of fish to the free amox · 3H₂O, R₂SnClamox · 2H₂O, and R₂Snamox · ₂ 2H₂O (R = methyl, butyl and phenyl; amox⁻ = 6-[D(−)-β-amino-p-hydroxyphenylacetamido]penicillinate) suggest that methyl derivatives seem to exert a lower cytotoxicity than butyl and phenyl ones and that R₂Snamox · ₂ 2H₂O deriva-tives are more toxic than R₂SnClamox · 2H₂O at both 10⁻⁵ and 10⁻⁷mol dm⁻³ concentrations. The following structural lesions have been iden-tified by comparative analysis of mitotic chromo-somes from untreated specimens (controls) and specimens treated with diorganotin(IV)-amoxicillin derivatives: (1) differentially stained chromosome areas; (2) granular deeply stained zones along the chromosomal body; (3) arm breakages; and (4) side-arm bridges (pseudochiasmata).