Synthesis,characterization, biological activities,crystal structure and DNA binding of organotin(IV) 5-chlorosalicylates

New organotin(IV) carboxylates, R₂SnL₂ (R=n-Bu: 1), R₂Sn(Cl)L (R=n-Bu: 2), and R₃SnL (R=Me: 3; n-Bu: 4; Ph: 5) have been synthesized by stirring 5-chloro-2-hydroxybenzoic acid HL with KOH and R₂SnCl₂ (R=n-Bu)/R₃SnCl (R=Me, n-Bu, Ph) in methanol at room temperature. The complexes along with ligand have been characterized by FTIR, (¹H, ¹³C) NMR, EI-MS, and single-crystal XRD crystallography. FTIR data indicated bidentate coordination of carboxylate. NMR data suggested six- or five-coordinate geometry of organotin(IV) carboxylates. Single-crystal XRD of 1 demonstrated skew-trapezoidal geometry around the tin center, with the basal plane occupied by four oxygens and the two butyl groups lying in distorted axial position. Complexes 1, 2, and 5 exhibited interaction with SS-DNA (salmon sperm) and suggests intercalating mode of binding. The complexes displayed significant antimicrobial activities against bacterial and fungal strains as compared to free ligand. The hemolytic activity of the complexes was lower compared to Triton-X 100 (positive control, 100% lysis) and higher than phosphate-buffered saline (negative control, 0% lysis). Complex 4 was the most potent inhibitor of bacterial/fungal growth.     

Synthesis and spectroscopic studies on organotin(IV) complexes of some pyrazoles and pyrazol-5-ones and their antibacterial activity

A series of organotin(IV) complexes of the general formula R_xSnCl_4?x.L (where R=Me, n?Bu, Ph; x = 2 or 3; L = pyrazole or pyrazol-5-one) have been prepared and characterized by elemental analyses, IR and NMR spectroscopy. The ligands used were found to coordinate with R₃SnCl species as monodentate ligands via the more reactive nitrogen atom, to give pentacoordinate tin complexes, whilst they may coordinate with R₂SnCl₂ species as bidentate ligands through the N–N linkage to give hexacoordinate tin complexes. These were demonstrated mainly by spectroscopic data. The tautomeric behaviour of organotin complexes of pyrazol-5-one ligands in inert (CDCl₃) and donor (DMSO-d₆) solvents were also studied. The complexes were screened against six species of bacteria.     

Structural and antimicrobial studies of potassium hydrotris(2-mercaptobenzathiazolyl)borate and its organotin(IV) derivatives

Potassium hydrotris(2-mercaptobenzathiazolyl)borate (KL) was formed by the solid state reaction of potassium borohydride and 2-mercaptobenzathiazoline. This ligand was reacted with R _n SnCl_4?n (R =?methyl, butyl and phenyl, n =?2 and 3) in dichloromethane and four different neutral organotin(IV) complexes were obtained. All compounds were characterized by elemental analyses, FT-IR and multinuclear NMR (¹H, ¹³C, ¹¹ B and ¹¹⁹Sn) spectroscopy. Spectroscopic data indicate the six-coordinated nature of tin in its di and triorganotin(IV) complexes.

To check the toxic potential of the ligand and its organotin(IV) complexes, selected bacterial (E. coli, S. epidemidis and S. dysenteriae) and fungal (A. niger, C. albicanes and A. flaves) species were screened. The results were compared with standard drugs kinamycine and miconazole for bacterial and fungal activity, respectively. The toxicity of the organotin(IV) complexes depends on the number and nature of organic groups attached to the tin atom; triorganotin(IV) complexes exhibit better inhibition than diorganotin(IV) complexes. All compounds were also screened on the cyanobacterial strains (Aulosira fertillissma, Anabaena variabilis, Anabaena species and Nostoc muscorum). Results show that the compounds inhibit the growth of organisms at very low concentration.     

Di- and Tri-organotin(IV) Complexes of N-Acetyltriglycine and N-Benzoyltriglycine: Synthesis and Spectroscopic Characterization

Di- and tri-organotin(IV) derivatives of N -acetyltriglycine and N -benzoyltriglycine (HA) were obtained by refluxing equimolar mixtures of the ligand and the organotin(IV) oxide or hydroxide in methanol or acetone. According to the spectroscopic data, triorganotin(IV) derivatives adopt a trigonal-bipyramidal structure in which the planar R₃Sn^IV unit is bonded by a monodentate carboxylate group and a donor group, presumably the amide CO. The reaction of HA with the appropriate diorganotin(IV) compounds gave both dicarboxylates R₂SnA₂, with six-coordinated tin, and dimeric tetraorganodistannoxanes {[R₂SnA]₂O}₂, in which the tin atoms are essentially five-coordinated.     

Organotin(IV) Carboxylates of Substituted α‐Cinnamic Acid,RnSn(OCOC(R2)=CHR1)4 – n: Synthesis,Spectroscopic Characterization and Biological Evaluation

Di‐ and triorganotin(IV) carboxylates, R_nSn(OCOC(R²)=CHR¹)_4–n (n = 2 and 3; R = Me, Et, n‐Bu, Ph; R¹ = 3‐CH₃O‐4‐OHC₆H₃, R² = C₆H₅) were prepared by reacting the corresponding organotin(IV) chloride with the silver salt of the (E)‐3‐(4‐hydroxy‐3‐methoxyphenyl)‐2‐phenylpropenoic acid. The title compounds were investigated and characterized by elemental analysis, infrared (FT‐IR), multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR, and mass spectrometry, and possible structures were proposed. The complexes and ligand acid ( HL ) have been evaluated in vitro against various bacteria and fungi. The results noticed during the biocidal activity screenings proved their in vitro biological potential. They were also tested for cytotoxicity.     

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.     

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.     

ORGANOGERMANIUM(IV) O,O,ALKYLENEDI-THIOPHOSPHATES

Abstract

Tri- and di-organogermanium(IV) O,O-alkylenedithiophosphates R_4-n ,Ge(S₂PO₂G)_n (where R = Ph. Bu, Et. G =—C(CH₃)₂C(CH₃)₂[sbnd], [sbnd], CH₂C(CH₃)₂CH₂[sbnd], [sbnd]CH—CH₃CH₂C(CH₃)₂[sbnd], n= 1, 2) were synthesized by treatment of organogermanium(IV) chlorides with ammonium O,O-alkylenedithiophosphates in benzene. These are volatile, liquids except the phenyl ones which are solids. All of these are miscible in organic solvents and monomeric in refluxing benzene. Like dialkyldithiophosphate derivatives of organogermanium these cyclic ones also appear to be tetrahedral with the ligands behaving as unidentate ones.     

Differential pulse polarographic determination of some organotin(IV) compounds in dimethyl sulfoxide

The differential pulse polarographic behavior of two series of organotin(IV) compounds having the general formula R_xSnCl_{4 − x} (R = Me, Ph; x = 1, 2, 3, 4) has been investigated in DMSO. The peaks obtained are recommended for the trace determination of these compounds. Linear calibration curves are obtained over the concentration range 10⁻⁴ –10⁻⁶ M.     

Syntheses and Structures of Organotin(IV) Thioesters of N‐Phthaloylamino Acids

Five organotin(IV) thioesters of N‐phthaloyl amino acids with the general formulae R₃SnL (R = Me, Ph) and nBu₂SnL₂ were synthesized with L = N‐phthaloyl‐thioalanine and N‐phthaloyl‐thioleucine. The structures of trimethyltin(IV) N‐phthaloyl‐thioleucinate ( 1 ), trimethyltin(IV) N‐phthaloyl‐thioalaninate ( 2 ), triphenyltin(IV) N‐phthaloyl‐thioleucinate ( 3 ), triphenyltin(IV) N‐phthaloyl‐thioalaninate ( 4 ), and di‐n‐butyltin(IV) di‐N‐phthaloyl‐thioalaninate ( 5 ) were characterized by means of X‐ray diffractometry. Quantumchemical investigations served to clarify several structural peculiarities of the isolated compounds.     

Synthesis,characterziation, semi-empirical quantum-mechanical study and biological activity of organotin(IV) complexes with 2-ethylanilinocarbonylpropenoic acid

Seven different organotin(IV) complexes have been synthesized by reacting 2-ethylanilinocarbonylpropenoic acid with R₂SnCl₂/R₃SnCl under reflux conditions. The organotin(IV) complexes along with ligand have been characterized by different techniques including elemental analysis, FT-IR and multinuclear NMR (¹H and ¹³C). IR data show that complexation occurs through -COO site and the ligand is bidentate which is also confirmed by the semi-empirical quantum-mechanical study. ¹H and ¹³C NMR data confirm the tetrahedral geometry of complexes in solution. The complexes as well as the ligand were also checked for various     

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.     

Spermatocyte chromosome alterations in truncatella subcylindrica (L., 1767) (Mollusca,Mesogastropoda) following exposure to dibutyltin(IV) and tributyltin(IV) chlorides

In order to analyze chromosomes for possible numerical and structural alterations in response to exposure to organotin(IV) compounds, gastropod Truncatella subcylindrica specimens were treated with dibutyltin(IV) and tributyltin(IV) chloride solutions with different exposure times. Experimental evidence suggests that tributyltin(IV) chloride is more toxic to this organism than dibutyltin(IV) dichloride at low concentrations. Furthermore, the toxicity responses to these organotin(IV) derivatives seem to be proportional to both concentration and exposure time. The following structural lesions have been identified by comparative analysis of spermatocyte chromosomes from untreated specimens and specimens treated with organotin(IV) compounds: (1) breakages; (2) bridging; (3) irregular outline; and (4) light areas after staining with acetic orcein. In this respect, dibutyltin(IV) and tributyltin(IV) chlorides seem to have an effect similar to that of colchicine.     

Synthesis, Characterization and Properties of Organotin Complexes Dibutyltin（Ⅳ） Bis（heteroaromatic carboxylate） and Crystal Structure of Dibutyltin（Ⅳ） Bis（2-thiazolylcarboxylate）

The six organotin complexes dibutyltin(IV) bis(heteroaromatic carboxylate) were synthesized by the reaction of (n‐Bu)2SnO with heteroaromatic carboxylic acid in 1:2 molar ratio. These complexes have been characterized by elemental analysis, IR, ¹H, ¹³C and ¹¹⁹Sn NMR. The crystal structure of dibutyltin(IV) bis(2‐thiazolylcarboxylate) was determined by X‐ray single crystal diffraction. This compound is a weakly bridged dimer through weak interaction Sn···O between molecules. The tin atoms took six‐coordinate skew‐trapezoidal bipyramidal geometry. The crystal of complex 3 belongs to monoclinic symmetry with space group P2₁/c, a=1.863(2) nm, b=2.220(3) nm, c=1.0395(10) nm, β=90.275(16)°, Z=8, V=4.292(8) nm³, D_c=1.514 Mg/m³, μ=1.406 mm^‐1, F(000)=1968, S=0.999, R=0.0549, wR=0.1011.     

Synthesis,Spectroscopy, Semi‐empirical and Biological Activities of Organotin(IV) Complexes with o‐Isopropyl Carbonodithioic Acid

New organotin(IV) complexes have been synthesized by treating potassium o‐isopropyl carbonodithioate with R₂SnCl₂/R₃SnCl in 1 : 2/1 : 1 M/L ratio. All complexes have been characterized by IR and NMR (¹H, ¹³C) spectroscopy. IR results shows that ligand acts as bidentate which is also confirmed by semi‐empirical study. NMR data reveals four coordinated geometry in solution. Computed positive heat of formation shows that complex 5 is thermodynamically unstable. UV/visible spectroscopy was used to assess the mode of interaction and binding of the complexes with DNA which shows that complex 5 exhibits higher binding constant as compared to complex 3 . In protein kinase inhibition assay, compound 3 was found most active, while other biological activities shows that triorganotin(IV) complexes are biologically more active as compared to diorganotin(IV) complexes.     

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.     

Application of computational modeling to analyze reactive organotin(IV) species

Abstract  

Computational optimization modeling (COM) is a research method that uses advanced computers and specialized software (e.g., Gaussian) to generate extremely detailed analyses of molecular properties and structures with a goal of depicting models with values for molecular properties that match either (a) selected experimentally determined properties or (b) computationally determined conformers with lowest energies of formation over many properties. Determination and effects of various COM treatments on three series of medium-sized organotin(IV) molecules (a) (C₆H₄)S(CH₂)(Me)(Ph _x Cl _y Sn) (where x + y = 3), (b) three R₂SnCl₂ structures, where x + y = 2 and R = methyl or phenyl, and (c) MeSnCl₃ and Me₃SnCl, where Me = methyl were researched relative to X-ray crystallography and solid-state NMR. Also, a reliable COM was determined for a bimolecular organotin(IV) system to compute the energy reduction due to system formation. In summary, this research determined for organotin(IV) molecules: (a) reliable COMs, (b) validation methods, (c) complexities of creating reliable models, (d) comparative analyses of molecules in a series, (e) a substitution method to control intramolecularity and hypercoordination, and (f) pre-optimization COM treatments and pre-optimization conformation changes that may influence final conformations.     

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.     

Synthesis,characterization, semi-empirical study,and biological activities of organotin(IV) and transition metal complexes with o-methyl carbonodithioate

Three transition metal and six organotin(IV) complexes have been synthesized by treating potassium o-methyl carbonodithioate with ZnCl₂/CdCl₂/HgCl₂ and R₂SnCl₂/R₃SnCl under stirring. The complexes were characterized by IR, ¹H, and ¹³C NMR spectroscopies. IR results show that the ligand is bidentate in 1–3 while monodentate in 4–9, which is also confirmed by semi-empirical study. NMR data reveal four-coordinate geometry in solution. HOMO–LUMO study shows that 7 and 9 are thermodynamically unstable. The enzyme inhibition study shows that 1 is a potent inhibitor of ALP, EC 3.1.3.1, resulting in very slow rate of formation and breakdown of enzyme–substrate complex. UV/visible spectroscopy was used to assess the mode of interaction and binding of the complexes with DNA which shows that 9 exhibits higher binding constant when compared to 6. In protein kinase inhibition assay, 1 was active, while antifungal activity shows that organotin(IV) complexes are more active than transition metal complexes.