Disproportionation of triorganotin species,R3SnX

Triorganotin compounds, R₃SnX, have found extensive use as a biological agents in such areas as agrochemicals, marine antifoulants and timber preservatives. In contrast, di(R₂SnX₂) and tetraorganotin derivatives (R₄Sn) possess less biological activity than do their triorganotin counterparts. It has been shown that disproportionation of R₃SnX species (i.e. to produce R₂SnX₂ and R₄Sn) can occur especially when X is a chelating or bridging group such as oxide, carboxylate, hydroxy ketone or hydroxyquinoline. This process has implications for the industrial applications and analysis of R₃SnX compounds.     

Synthesis,spectroscopic characterization and fungicidal activity of triphenyltin derivatives of N,N-dimethylglycine: Crystal structure of [dimethyl(carboxylatomethyl)ammonium]-chlorotriphenylstannate

The new triorganotin complexes formulated as Me₂HNCH₂COO · Ph₃SnX, X = Cl, NCS were prepared and spectroscopically characterized, and their fungicidal properties against Ceratocystis ulmi were determined. An X-ray structure for [dimethyl(carboxylatomethyl)ammonium] chlorotriphenylstannate is also reported.     

Tolerance of aggressive and non-aggressive isolates of Ceratocystis ulmi to organotin fungicides

The effect of triorganotin compounds, R₃SnX, on the growth of three wild strains of Ceratocystis ulmi (C. ulmi) fungus, two aggressive and one non-aggressive strains, was evaluated in shake culture. In all cases, the triphenyltins were the more effective organotins for the inhibition of C. ulmi in vitro. The anionic group, X, did not have a significant role in the inhibition, suggesting that the species involved in the inhibition is the triphenyltin moiety (Ph₃Sn⁺) or the hydrated triphenyltin moiety (Ph₃Sn(H₂O)⁺₂). It is further suggested that the triphenyltin species Ph₃SnOH and Ph₃SnOAc are the preferred compounds for the control of Dutch elm disease. The tolerance of aggressive isolates to fungitoxins appears to depend more on the nature of the fungicide than on the type of fungus.     

Group IB Organometallic chemistry : XV. Arylcopper compounds ArnCun as intermediates in organometallic synthesis. One-step synthesis of triorganotin halides of the type Ar3SnX and Ar3-nRnSnX

A new method for the one-step preparation of triorganotin halides is described. Triphenyltin halides are synthesized via the reaction of pure phenylcopper with SnX₄ or with Ph₂SnX₂. Me₂NCH₂, Me₂N and OMe-substituted phenylcopper react with Me₂(or Ph₂)SnBr₂ to give novel (substituted-phenyl)-diorganotin bromides in high yields. The selective arylation of tin halides by organocopper compounds is based upon the low reactivity of RCu towards the SnX bond in triorganotin halides. The selectivity of the arylation by the corresponding phenyllithium derivatives is connected with intra- or inter-molecular SnN (or O) coordination and/or of steric factors exerted by substituents ortho to the SnC(phenyl) bond.     

Changes in fungal and bacterial populations in soil treated with two triorganotin(IV) compounds

The effects of two triorganotin(IV) compounds, diphenylbutyltin bromide (Ph₂BuSnBr) and triphenyltin chloride·triphenylphosphine oxide (Ph₃SnCl·Ph₃PO), on soil bacterial and fungal populations were compared with that of Thiram and the commercial triorganotin fungicide ‘Brestan’ (triphenyltin acetate, Ph₃SnOAc). Soil fungal populations were reduced most by Thiram, then by Ph₃SnCl·Ph₃PO, Ph₂BuSnBr and Ph₃SnOAc, in that order. Following the application of the compounds, there was a marked increase in the bacterial population in soil, the increase being greatest with Thiram and least with Ph₃SnCl·Ph₃PO. The triorganotin(IV) compounds were less harmful to soil fungi than Thiram. In Thiram-treated soil, recolonization was slower than in soil treated with the triorganotin(IV) compounds. More species of fungi were tolerant to and persisted after application of the triorganotin(IV) compounds compared with Thiram. Among the fungi that were tolerant to the triorganotin(IV) compounds were cellulolytic species such as Trichoderma.     

Insecticidal effects of organotin(IV) compounds on Plutella xylostella (Linnaeus) larvae I: Topical application toxicity and antifeedant effect

Structure–activity relationship studies were conducted with early fourth-instar larvae of a highly resistant strain of the diamondback moth, Plutella xylostella (Linnaeus) on (1) toxicity by topical appliction of 43 organotin compounds, and (2) the antifeedant effect of a selected number (17) of these compounds on treated Brassica chinensis (Chinese cabbage) leaves. The toxicity data revealed that the triorganotins (R₃SnX) were, without exception, more toxic than the commercial sample of malathion (84% active ingredient) used in the tests. Among the diorganotins, phenylcyclopentyltin oxide proved to be as active as malathion. Within the triorganotin series, the tricyclohexyltins were generally more toxic than the triphenyltins, the most active tricyclohexyltin compound being (c-C₆H₁₁)₃Sn(2-pyridinethiolato N-oxide) (LC₅₀ 0.03 μg μl^?1), which was almost 500-fold more active than malathion. The most active compound in the triphenyltin class was O, S-bis(triphenyltin)mercaptoacetate (LC₅₀ 0.30 μg μl^?1). Variations in the anionic X group resulted only in marginal changes in activity in the (c-C₆H₁₁)₃Sn series, but significant changes in activity were obtained with the Ph₃Sn compounds, especially the ring-substituted phenoxyacetates, (4-ZC₆H₄)OCH₂(O)COSnPh₃. In the mixed triorganotin compounds an increase in activity was observed when one of the phenyl groups in Ph₃SnOH was replaced by the p-chlorophenyl group. In the antifeedant tests, the tricyclohexyltins were found to be generally more effective than the triphenyltins. In most cases, antifeedant activity paralleled the toxicity by topical application trends in the (c-C₆H₁₁)₃Sn series, but in the Ph₃Sn series an inverse trend was observed. The diorganotin compound (c-C₅H₉)PhSnO exerted a relatively pronounced antifeedant activity which was comparable with that of a number of triphenyltin derivatives. It was established from histological studies of the mid-gut cross-sections of the treated larvae that, in most cases, the organotins affected the columnar cells physiologically; an exception was noted for Ph₃SnOC(O)C₆H₄COOH-4 which, like malathion, caused severe morphological damage to the cell membrane.     

Synthesis,spectral and antimicrobial studies of triorganotin(IV) 3(2′-hydroxyphenyl)-5-(4-substituted phenyl) pyrazolinates

Triorganotin(IV) pyrazolinates of the type R₃Sn(C1₅H₁₂N₂O?·?X) [where C₁₅H₁₂N₂O?·?X?= 3(2′-hydroxyphenyl)-5(4-X-phenyl)pyrazoline {where X?=?H (a); CH₃ (b); OCH₃ (c); Cl (d) and R?=?Me, Pr ⁿ and Ph}] have been synthesized by the reaction of R₃SnCl with the sodium salt of pyrazolines in a 1?:?1 molar ratio, in anhydrous benzene. These newly synthesized derivatives have been characterized by elemental analysis (C, H, N, Cl and Sn), molecular weight measurement as well as spectral studies [IR and multinuclear NMR (¹H, ¹³C and ¹¹⁹Sn)]. The bidentate behaviour of the ligands was confirmed by IR, ¹H and ¹³C NMR spectral data. Trigonal bipyramidal structure around tin(IV) atom for R₃Sn(C₁₅H₁₂N₂O?·?X) has been suggested. The free pyrazoline and a few triorganotin(IV) pyrazolinates have also been screened for their antibacterial and antifungal activities. Some triorganotin(IV) pyrazolinates exhibit higher antibacterial and antifungal effects than free pyrazoline and some of the antibiotics.     

Coordination behaviour of the 2‐(N,N‐dimethylaminomethyl)phenyl ligand towards the di‐t‐butylchlorotin(IV) moiety

{2‐(N,N‐Dimethylaminomethyl)phenyl}(di‐t‐butyl)tin(IV)chloride, {2‐[(CH₃)₂NCH₂]C₆H₄}Sn(t‐Bu)₂ Cl, has been prepared and characterized using NMR and crystallography. This is the first example of a triorganotin(IV) halide containing the 2‐[(CH₃)₂NCH₂]C₆H₄—group as a C,N‐chelating ligand with a weak intramolecular Sn—N interaction because of the steric hindrance of t‐butyl groups. The interatomic Sn—N distance is elongated to 2.904(14) Å and the central tin atom is distorted trigonal bipyramidal. Copyright © 2004 John Wiley & Sons, Ltd.     

Synthesis,structural characterization and in vitro cytotoxic activity of novel polymeric triorganotin(IV) complexes of urocanic acid

Two novel triorganotin carboxylate complexes of the biologically active urocanic acid have been synthesized and characterized. Elemental analysis, melting point, spectroscopic techniques – IR, ¹H, ¹³C and ¹¹⁹Sn NMR – mass spectrometry and X‐ray diffraction studies have been used for structural characterization. Crystal structures of the tin(IV) derivatives show that urocanic acid acts as a bridging bidentate ligand through its imidazole nitrogen atom and its carboxylic group, producing a polymeric one‐dimensional chain. The molecular structures of the complexes, catena‐poly‐tri(n‐butyl)tin(IV) 3‐(3H‐imidazol‐4‐yl)prop‐2‐enoate (1) and catena‐poly‐triphenyltin(IV) 3‐(3H‐imidazol‐4‐yl)prop‐2‐enoate (2), present a distorted trigonal–bipyramidal configuration. This is further confirmed by ¹¹⁹Sn NMR in the solid state. The tin(IV) derivatives form double‐stranded ribbons via N―H^…O―H bonds. Nevertheless, the compounds are essentially monomeric in solution, with a tetrahedral configuration as observed by ¹¹⁹Sn NMR in solution. The cytotoxic activity of the titled compounds has been tested against six human cell lines and the corresponding IC₅₀ values are reported. Both tin(IV) compounds have a high to very high in vitro cytotoxic activity against the tumor cell lines K562, HCT‐15 and MCF‐7. Compound 1 is 86 times more active than cisplatin in the HTC‐15 cell line. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis, structural elucidation and biological activities of organotin(IV) derivatives of (E)-3-(4-methoxyphenyl)-2-(4-chlorophenyl)-2-propenoic acid

A new series of di- and tri-organotin(IV) compounds with the general formula R_4?n SnL _n , where R?=?Me (1,2), Et (3), n-Bu (4,5), n-Oct (6), Ph (7) and L?=?(E)-3-(4-methoxyphenyl)-2-(4-chlorophenyl)-2-propenoate, were synthesized by reaction of silver salt of ligand or ligand acid with diorganotin dichloride/oxide and triorganotin chloride in 2:1 and 1:1 molar ratio, respectively. These compounds were characterized by elemental analyses, FT-IR, multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR and mass spectrometry. The spectroscopic results revealed that all the diorganotin(IV) compounds possess trigonal bipyramidal structures in solution and octahedral geometry in the solid state around the tin atom. A linear polymeric trigonal bipyramidal structure in the solid state and a tetrahedral environment around the tin atom in non-coordinating solvents has been proposed for the triorganotin(IV) compounds. All synthesized compounds were tested in vitro against a number of microorganisms to assess their biocidal activity. These studies revealed that ligand acid and some of its organotin compounds show promising activity against different strains of bacteria and fungi but lowered than reference drugs.     

Toxicity of triorganotin compounds to the brine shrimp,Artemia salina

The 14 triorganotin compounds that were screened against the brine shrimp, Artemia salina, were least effective against the first nauplii stage (24 h). This was attributed to the presence of a yolk membrane which reduced the contact between the triorganotin compounds and the organism. The data indicated that the species responsible for the toxicity is primarily the hydrated triorganotin cation. However, the anion X group may also play a minor role in the toxicity of these compounds. The observed order of activity for the triorganotins does not parallel their hydrophobicities, indicating that other factors must be involved in the toxicity mechanism. Copyright © 2000 John Wiley & Sons, Ltd.     

The effect of donor atom and ligand size on the molecular and solid state structure of selected tin (IV) compounds

The arrangement of bonded and nonbonded atoms surrounding the central tin atom in several methyltin halide and pseudohalide compounds has been calculated using a stereochemical model that takes into account the spatial requirements of atoms. Inherent in the analytical procedure is a parameter which provides a measure of the validity of the calculations when applied to a particular compound. The technique calculates an optimum ligand arrangement based upon a balancing of nonbonded intramolecular interactions; the procedure is then completed by calculating the distances of the Sn…X intermolecular interactions that occur when the approach of the associating atom is restricted only by the van der Waals contacts of the ligands on the central tin atom. In general, the calculations reproduce or account for the structural features of the methyltin compounds of known structure. The calculations show that the (CH₃)₃SnX, (CH₃)₂SnX₂, and CH₃SnX₃ molecules have ligand arrangements that may accommodate, 1, 2, or 3 strong intermolecular interactions, respectively. This agrees with the known tendency of (CH₃)₃SnX compounds to possess five-coordination and (CH₃)₂SnX₂ compounds to exhibit six-coordination. The calculated strengths of the intermolecular interactions vary in the order Sn…F > Sn…Cl > Sn…Br > Sn…I. Also, the strength of a particular type of Sn…X intermolecular interaction in a series of (CH₃)_nSnX_4?n compounds varies in the order (CH₃)₃SnX > (CH₃)₂SnX₂ > CH₃SnX₃. These calculations correlate with the observed variations in the discretely molecular or polymeric character of the solid states.     

Structural studies in main group chemistry : XI. Tin-119m mössbauer investigations of triorganotin derivatives of substituted pyridines

Tin-119m Mössbauer and selected infrared and ¹H NMR data are reported for twenty four triorganotin derivatives of substituted pyridines and related ligands, and conclusions concerning structure inferred. Mössbauer quadrupole splittings in the ranges 3.09–3.38 mm sec^?1 and 2.92–3.22 mm sec^?1, respectively, for the 2- and 3-pyridone derivatives indicate five-coordinate trans-R₃SnX₂ trigonal bipyramidal configurations at tin with planar R₃Sn moieties. In the case of the derivatives of 2-pyridone, the extra coordination to give linear chain structures arises from bridging oxygen atoms, but bridging via either oxygen or the pyridyl nitrogen atom may occur in the derivatives of 3-pyridone. Similar oxygen-bridged chain structures are also postulated for the triorganotin derivatives of 2-pyridylalcohol and 2-pyridylaldehyde oxime, but lower splittings values of 2.63(5)–2.93 mm sec^?1 indicate some relaxation from planarity of the R₃Sn group towards tetrahedral. The splittings are observed to decrease in the order Me > Et > Pr, illustrating that the deviation from planarity and the bond distance of the coordinate O?Sn bond increase with the steric bulk of R. Much lower splittings of 1.60–2.27 mm sec^?1 are observed for the derivatives of 2-thiopyridone and 8-hydroxyquinoline, which, with the presence of three tin—carbon stretching modes in the infrared spectrum for the methyltin compounds, are consistent with the alternative five-coordinate cis-R₃SnX₂ geometry at tin. The very high splitting values, together with the low values of the anti-symmetric OCO stretching vibration of the carboxylate group and the multiple tin—carbon stretching modes observed for the methyltin compounds in the infrared, have been interpreted in terms of the six-coordinate mer-R₃SnX₃ stereochemistry for the triorganotin esters of 2-pyridylcarboxylic and 2,6-pyridyldicarboxylic acids. The low and almost constant value of the two-bond coupling constant ²J(¹HC¹¹⁹Sn) for the methyltin derivatives indicate that n solution either four or five-coordinate cis-R₃SnX₂ structures are adopted.     

Structure–Activity relationships of effect of aryltin compounds on Ceratocystis ulmi

The effect of aryltin compounds (Ar₄Sn and Ar₃SnCl) on the growth of Ceratocystis ulmi, the causative agent of Dutch elm disease, was studied in shake culture. In all cases, the triaryltins were more effective than the tetra-aryltins as inhibitors of C. ulmi in vitro. Furthermore, substitution on the phenyl ring at the meta- and para- positions in the triaryltins did not have a major effect on the biocidal activity for the substituted triaryltins. Quantitative structure–activity relationships (QSARs) gave support to the idea that the species responsible for the inhibition of the fungus is the triaryltin cation. The QSARs further suggest that the interaction of the triaryltin cation with the fungal cell wall of C. ulmi is by a non-specific mechanism.     

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.     

Synthesis,structural and biocidal activity studies of triorganotin(IV) compounds of some N-protected amino-acids

Seven new triorganotin(IV) complexes of the type R₃SnL (L=N-phthaloyl derivatives of glycine, DL-alanine or N-acetyl- and N-benzoyl-glycine and -cysteine; R-n-C₄H₉ or C₆H₅) have been prepared by reacting the sodium salt of the ligand and the triorganotin(IV) chloride in 1:1 molar ratio in methanol. The complexes have been characterized by elemental analysis, molecular mass determination, IR and ¹H NMR spectroscopy. The complexes are monomeric in molten camphor and are moderateely soluble in the common organic solvents. The spectral data support cis five-coordinate complexes with an unsymmetrical bidentate coordination of the carboxylate group to tin. The complexes exhibit some insecticidal effect on Bean Weevils (Sitophilus granaria) even at low concentration and they also show fungicidal activity on Aspergillus niger and Helminthosporium taulosum. Some of the complexes are found to be more effective than tri-n-butyltin and triphenyltin chlorides.     

C,N‐chelated triorganotin(IV) diesters of 4‐ketopimelic acid and their fungicidal activity

The set of four triorganotin(IV) diesters of 4‐ketopimelic acid containing {2‐[(CH₃)₂NCH₂]C₆H₄}‐ as a C,N‐chelating ligand was prepared. Their structures were studied by the help of IR, NMR and X‐ray crystallographic techniques in the case of {{2‐[(CH₃)₂NCH₂]C₆H₄}SnPh₂}₂[(OOCCH₂CH₂)₂C?]. All these compounds are monomeric both in solid state and solution with five‐coordinated tin atoms and medium strong intramolecular Sn? N connection. The antimycotical activity of these compound was studied and compared with the triorganotin(IV) derivatives of 4‐ketopimelic acid and antimycotical drugs in clinical use. Copyright © 2008 John Wiley & Sons, Ltd.     

Ecofriendly synthesis,antimicrobial and antispermatogenic activity of triorganotin(IV) complexes with 4′‐nitrobenzanilide semicarbazone and 4′‐nitrobezanilide thiosemicarbazone

New series of triorganotin(IV) complexes with 4′‐nitrobenzanilide semicarbazone (L¹H) and 4′‐nitrobenzanilide thiosemicarbazone (L²H) of the type [R₃Sn(L)] (R = ‐CH₃, ‐C₆H₅ and n‐C₄H₉) were synthesized under microwave irradiation. All the complexes were characterized by elemental analysis, conductance measurements, molecular weight determinations and spectral data, viz., IR, UV–vis, ¹H, ¹³C and ¹¹⁹Sn NMR. The central tin atoms of these complexes are all five‐coordinated with trigonal bipyramidal geometry. In order to assess their growth inhibitory potency semicarbazone, thiosemicarbazone and their triorganotin(IV) complexes were tested in vitro against some pathogenic fungi and bacteria. Also the ligands and their organotin(IV) complexes were studied to assess the effects of long‐term ingestion of these compounds on fertility, body and reproductive organ weights. The biochemical analyses were also performed on blood samples and reproductive organs of male rats. The findings have been presented in this paper. Copyright © 2009 John Wiley & Sons, Ltd.     

Syntheses and structures of diorgano(halo- orpseudohalo-)(1,3-dithiole-2-thione-4,5-dithiolato)-stannates (1-), [Q][RSnX(dmit)] (Q=onium cation; X=halide orpseudohalide)

Ionic compounds, [Q] [R₂SnX(dmit)][dmit=1,3-dithiole-2-thione-dithiolate; Q=1,4-dimethylpyridinium or tetraalkylammonium; R=Phor alkyl; X=Cl, Br, I, NCS, NCSe, or N₃] have been obtained by (a) from R₂SnX₂ and [Q]₂[Zn(dmit)₂] in the presence of excess QX,(b) from halide exchange reactions in acetone solution between [Q] [R₂SnCl(dmit)]and a halide or pseudohalide source, or (c) by addition of QX to [R₂Sn(dmit)]. Crystalstructure determinations of [NEt₄] [Ph₂SnI(dmit)] and [1,4-Me₂pyridiniuml [Ph₂SnBr(dmit)] as well as of the mixed halides, [1a, 1b, 4a, 2] [Ph₂SnCl_nI₁₋n(dmit)] (n=0.57, 0.42 or0.22), indicated that the tin atoms have distorted trigonal bipyramidal geometries in the anions,with the X ligand and a dithiolato atom in the axial sites. The [R₂SnX(dmit)]⁻ anions remain essentially intact in organic solvents, but lose X⁻ on extractionwith H₂O to give the neutral species, R₂Sn(dmit).     

Crystal structure and fungitoxicity of aquatributyltin N-phthaloylglycinate

The [nBu₃Sn(N-phthaloylglycinate)(OH₂)] compound has been prepared and characterized. The crystal structure reveals the tin atom, in each of the two molecules comprising the asymmetric unit, to exist in a distorted trigonal bipyramidal geometry in which the trigonal plane is defined by the three organic substituents and the axial sites are occupied by an oxygen atom derived from a monodentate carboxylate ligand and a coordinated water molecule. The [nBu₃Sn(N-phthaloylglycinate)(OH₂)] compound and three other triorganotin derivatives of N-phthaloyl-protected amino acids display marked toxicity against several economically important plant pathogenic fungi.