119Sn 13C Research Articles

Synthesis, structure, and cytotoxicity of some triorganotin(iv) complexes of 3-aminobenzoic acid-based Schiff bases

Abstract Six new triorganotin(iv) complexes of 3-aminobenzoic acid-based Schiff bases, 3-(R′-CH═N)C6H4COOSnR3 (1–6) (R′, R = 5-Br-2-HOC6H3, Ph (1); 3,5-Br2-2-HOC6H2, Ph (2); 4-NEt2-2-HOC6H3, Cy (3); 3-OCH3-2-HOC6H3, Cy (4); 2-HOC10H6, Ph (5); 2-HOC10H6, Cy (6)), have been synthesized by the one-pot reaction of equimolar 3-aminobenzoic acid, substituted 2-hydroxybenzaldehyde (or 2-hydroxy-1-naphthaldehyde) and triorganotin(iv) hydroxide, and characterized by elemental analysis, FT-IR, NMR spectroscopy, and X-ray single crystal diffraction. The NMR data (1 J(119Sn–13C) and 119Sn chemical shifts) suggested that these organotin(iv) complexes are all four-coordinated in CDCl3 solution. In the crystalline state, the tin atoms in 1–4 and 6 are four-coordinated and possess a distorted tetrahedral geometry. Complex 5 with crystalline solvents (CH3OH and CHCl3) exhibits a zigzag chain, and the five coordination atoms on the tin atom are arranged in a trigonal bipyramidal geometry in which the carboxylate oxygen atom and the phenolic oxygen atom of the adjacent ligand occupy the axial positions. In all complexes, the 3-(arylmethyleneamino)benzoate ligands are coordinated with tin atoms in monodentate mode. Their cytotoxicity against two human cancer cell lines (A549 and HeLa), UV-Vis, and fluorescence have been determined, and the results reveal that complexes 1–6 have higher cytotoxicity than cisplatin and may be explored for potential blue luminescent materials.

Diorganotin complexes of carboxylates: synthesis and characterization

Diorganotin complexes of monoisopropyl and monomethyl nadiate, succinate, and phthalate were synthesized and characterized by elemental analysis, FT-IR, 1H NMR, 13C NMR, and 119Sn NMR spectroscopic techniques. The spectroscopic investigation demonstrated that carboxylate is bidentate in the diorganotin complexes. On the basis of 1 J(119Sn–13C) and 2 J(119Sn–1H) values, C–Sn–C bond angles were also calculated. The newly synthesized complexes were also screened for their antibacterial activities against Gram-positive and Gram-negative pathogenic strains of bacteria.

The small-scale preparation and NMR characterization of isotopically enriched organotin compounds

Synthetic methods for the small-scale laboratory preparation of isotopically enriched dibutyltin dichloride, dibutyltin di-iodide, tributyltin chloride, tributyltin iodide, diphenyltin dichloride, triphenyltin chloride and triphenyltin iodide have been successfully established. Organotin iodides were prepared from redistribution reactions between tin(IV) iodide and the corresponding tetraorganotin, with the exception of dibutyltin di-iodide, which was prepared directly from the reaction between tin metal and iodobutane. The development of novel procedures for the dealkylation/dearylation of tetraorganotins by acid hydrolysis produced superior yields of tributyltin chloride and diphenyltin dichloride in comparison with redistribution reactions. Organotin iodide redistribution reaction products were converted to their chloride analogues via the fluoride salts using an aqueous ethanolic solution of potassium fluoride. The insolubility of organotin fluoride salts was exploited to isolate and purify the isotopically enriched compounds, and to prevent losses during the purification procedure. The nuclear magnetic resonance (NMR) spectroscopic study of ‘natural abundance’ and isotopically enriched organotin compounds gave proton (1H) and carbon-13 (13C) spectra for butyltins, Bu4−nSnXn, and phenyltins, Ph4−nSnXn (X = I, Cl), allowing the assignment of ­1H and 13C chemical shifts, and 119Sn–13C and 117Sn–13C coupling constants. The 13C NMR spectroscopic analysis of 117Sn-enriched organotin compounds has allowed the assignment of certain resonances and tin–carbon coupling constants which were previously unobservable. The spectral patterns show that Δ(1H) and Δ(13C) values are sensitive to structural changes, and that 13C shielding decreases with an increase in the electronegativity of the substituent. The tin–carbon coupling constants are also sensitive to structural changes, and for alkyl and aryl compounds the couplings decrease in the order 1J > 3J > 2J > 4J. The 13C chemical shift values and the magnitude of tin–carbon coupling constants are shown to be solvent-dependent. The 13C spectra of the isotopically enriched compounds show that the degree of isotopic enrichment and the nature of the isotope used (magnetic or non-magnetic) are reflected in the spectral pattern obtained. Copyright © 2000 John Wiley & Sons, Ltd.

Über tetraaryl-methan-analoga in der gruppe 14: III. Ar 4Sn/Pb (Ar  Ph, p-, m-, o-Tol, 2,4-Xyl und 2,5-Xyl): Gegenüberstellung von bindungslängen und winkeln, von NMR chemischen verschiebungen und kopplungskonstanten und von schwingungsdaten

The title compounds have been synthesized by Grignard reactions or pyrolysis of diplumbanes respectively. The crystal structures of m-Tol 4Pb and Ph 4Pb (redetermination) have been determined. All eight compounds (Ph/Tol) 4(Sn/Pb) are S 4 symmetric and contracted along this unique axis. The 13C-NMR chemical shifts and the couplings 1 J( 119Sn/ 207Pb 13C) as well depend additively upon the methyl substituents. The ratios 1 K( 207Pb 13C): 1 K( 119Sn 13C) of the reduced coupling constants are all near to 1.61; a comparison with values from the literature for alkyl, alkenyl and alkinyl substituents is given. The ratio δ( 207Pb):δ( 119Sn) results in 2.28. IR (700 down to 200 cm −1) and Raman (700 down to 50 cm −1) data are given.

Tin-nitrogen connection in triphenyltin chloride 2-(arylazo)pyridine complexes

Proton, 13C and 119Sn NMR data indicate that in complexes with triphenyltin chloride, the 2-(arylazo)pyridines behave as monodentate ligands with donation by the nitrogen atom of the pyridine ring. The observed low values of δ( 119Sn) and 1 J( 119Sn 13C) reveal that the complexes dissociate in solution. Mössbauer spectral data on these complexes support a trigonal bipyramidal geometry in the solid state.

Zur näheren Kenntnis des 1‐Camphenylsystems ‐ 1‐Camphenylverbindungen des Lithiums, Zinns und Quecksilbers

About the 1‐Camphenyl System – 1‐Camphenyl Compounds of Lithium, Tin and Mercury1‐Camphenyl lithium, 1‐camphenyl isobutyl mercury an 1‐camphenyl triethyl tin were synthesized and characterized by their 13C n.m.r. spectra. The lithium compound contains σ,η1‐bonded allyl groups and suggests a weak interaction between the exocyclic double bonds and the metal atoms. The coupling constants 1J(199Hg‐13C) and 1J(119Sn–13C) in the spectra of the mercury and the tin compound allow to compare the donor strength of 1‐camphenyl anion with those of other carbanions.

Structural studies of diorganotin(IV) bischelates. Crystallographic evidence of seven-coordinate tin in bis(2-carbomethoxyethyl)bis ( N,N-dimethyldithiocarbamato)tin(IV), [MeOC(O)(CH 2) 2] 2Sn[SC(S)NMe 2] 2

The crystal structure of bis(2-carbomethoxyethyl)bis( N,N-dimethyldithiocarbamato)tin(IV) was determined from 2495 observed Mo- K α reflections and refined to an R factor of 0.053 (space group P2 1/ c; a 15.629(4), b 10.574(3), c 16.118(4) Å; β 117.00(2)°; V 2373(1) Å 3; Z = 4). The compound is monomeric and the tin is seven-coordinate in a distorted pentagonal bipyramid with the organic groups in apical positions (CSnC 154.3(3)°; the pentagonal girdle is made up of the four sulfur atoms of the anisobidentate dithiocarbamato ligands and the carbonyl oxygen atom of a bent apical organic group (SnS (short) 2.571(2), 2.598(2); SnS (long) 2.848(2), 2.913(2); SnO 2.751(5) Å). The oxygen atom and one sulfur atom are displaced equally but oppositely by 0.24(3) Å from the pentagonal least-squares plane, and the tin atom by 0.054(1) Å. The compound is six-coordinate in CDCl 3 solution, as shown by ambient 13C NMR data; the one-bond coupling constant, 1 J( 119Sn 13C), has the value 794.2 Hz, consistent with the lower coordination state. There is some evidence, however, of retention of the seven-fold coordination in pyridine solution.

Selektive Metallierung von Bicyclo[3.2.1]octa-2,6-dien: I. Monostannylierte Derivate

In contrast to earlier reports, bicyclo[3.2.1]octa-2,6-diene ( 1) can be deprotonated directly. The overall yield and the selectivity depend strongly on the reagent used n-BuLi/TMEDA metallates less than 5% of 1, whereas t-BuLi/TMEDA or n-BuLi/t-BuOK metallates 80 or 85% of 1. This was established from quenching of the carbanions with Me 3SnCl. The various stannylated isomers that have been obtained show that n-BuLi/t-BuOK attacks 1 exclusively at the allylic position 4 giving the exo/ endo-isomers 4a/ b. t-BuLi/TMEDA prefers the vinylic positions 6 and 7 and leads to the isomers 2a/ b (or 3a/ b having n-Bu 3Sn groups). No reaction occurs at the vinylic positions 2 and 3; this is shown by independent synthesis of the 3-stannylated derivative ( 7), 2a/ b, 3a/ b, 4a/ b and 7 were identified from the NMR parameter δ( 1H), δ( 13C), δ( 119Sn), n J( 1H 1H), 1 J( 13C 1H), n J( 119Sn 13C), and the isotope shifts n Δ 119Sn( 13C( i)). For 1 the 13C NMR signals were assigned unequivocally by analysis of the 13 C satellite spectrum which also gave 1 J( 13C 13C) and 1Δ 13C( i)( 13C( j)). The different reactivity shown by 1 is suggested to originate in the CH acidity and in the influence of Li + and K + on the transition state of the metallation. The isomer ratios could be traced back to the polarity of, and to torsional energies in 1.

Skew-trapezoidal bipyramidal diorganotin(IV) bischelates. Crystal structure of dimethylbis(2-pyridinethiolato- N-oxide)tin(IV)

Dimethylbis(2-pyridinethiolato- N-oxide)tin(IV), Me 2Sn(2-SPyO) 2, crystallizes in space group P2 1/ c with a 9.877(3), b 11.980(4), c 13.577(3) Å, β 109.1(2)° and Z = 4. The structure was refined to R F = 0.036 for 2263 Mo- K α observed reflections. The coordination geometry at tin is a skew-trapezoidal bipyramid, with the oxygen [SnO 2.356(3), 2.410(4) Å] and sulfur [SnS 2.536(1), 2.566(1) Å] atoms of the chelating groups occupying the trapezoidal plane and the methyl groups [SnC 2.106(6), 2.128(7) Å] occupying the apical positions. The methyl-tin-methyl skeleton is bent [CSnC 138.9(2)°]. The SSnS angle is 77.8(1)°, but the OSnO angle is opened to 136.7(1)° to accommodate the intruding methyl groups. The carbontincarbon angles predicted from quadrupole splitting ( 119mSn Mössbauer) and one-bond 119Sn 13C coupling constant (solution 13C NMR) data agree closely with the experimental value.

Dependence of | 1J( 119Sn 13C)| on the CSnC angle in n-butyltin(IV) compounds

Dependence of | 1J( 119Sn 13C)| on the CSnC angle in n-butyltin(IV) compounds

13C, 15N and 119Sn NMR spectral evidence for tin five-coordination in triorganotin(IV) oxinates

The 13C and 119Sn NMR spectra of tri(1-butyl)tin(IV) and triphenyltin(IV) oxinates and 1-naphthoxides in neat liquid and deuteriochloroform, pentadeuteriopyridine and hexamethylphosphortriamide solutions, and the 15N NMR spectra of both the oxinates and 8-methoxyquinoline in deuteriochloroform have been recorded. From the comparison of chemical shifts δ( 13C), δ( 15N) and δ( 119Sn) and coupling constants nJ ( 119Sn 13C) of the compounds it is concluded that the triorganotin(IV) oxinates, both as the neat liquid and in solution, form complexes containing five-coordinate tin atoms. In the neat liquid and in deuteriochloroform (a non-coordinating solvent) oxinates form chelate complexes with a cis-trigonal bipyramid arrangement. In coordinating solvents (pentadeuteriopyridine, hexamethylphosphortriamide) these are equilibria involving the formation of small amounts of oxinate complexes with one solvent molecule. These complexes have trans-trigonal bipyramid geometry with butyl or phenyl groups in equatorial plane and the monodentate oxinate group and a solvent molecule in axial positions.

Linear correlation analysis of 13C chemical shifts, 13C 119Sn coupling constants and solvatochromic parameters with trimethyl tin chloride

The 13C chemical shifts and 1 J 119Sn 13C values for trimethyl tin chloride in 22 solvents are reported. Linear correlation analysis of 1 J with the solvatochromic parameters π* and β gave only a fair correlation ( r = 0.960). A better correlation was obtained for the 13C chemical shift with π* and α ( r = 0.985).

Correlation of one-bond 15N 13C, 15NM, 29SiX (M = 11B, 29Si, 119Sn, X = 1H, 13C) nuclear spin-spin coupling constants with the structure of metallatranes in solution

The 15N 13C, 15N 11B, 15N 29Si, 29Si 1H and 29Si 13C one-bond coupling constants in 15N-labelled boratranes, silatranes and germatranes were measured and considered together with the literature data on 15N 119Sn and 119Sn 13C couplings in stannatranes. The quantitative pattern of structural variations in metallatranes revealed by analysis of X-ray data was used for the interpretation of the results. 1 J( 15N 13C) coupling constants quantitatively describe the increase in nitrogen pyramidality with the strengthening of the donor—acceptor (DA) bond N → M in solution. The coupling constants of the DA bond N → M were interpreted in terms of the Fermi contact interaction. 1 J( 15N 29Si) values were used to predict the bond order and the length of the N → Si bond in silatranes. In silocanes, bicyclic analogues of silatranes, a linear correlation was found between the 1 J( 15N 29Si) values and the free activation energy for DA bond cleavage in solution. The latter was used to estimate the energy of the DA bond N → Si in silatranes (50–70 kJ/mol). The coupling constant 2J( 15NSi 1H) depends greatly on the size of the corresponding valence angle, whose increase from 90 to 180° results in a sharp reduction of the coupling constant 2 J( 15NSi 1H) from ∼ 8 to 0 Hz. The effect of the substituents' electronegativity on the coupling constant through the covalent and DA bonds was found to be the opposite.

The 13C and 119Sn NMR spectra of some four- and five-coordinate tri-n-butyltin(IV) compounds

The 13C and 119Sn NMR spectra of a set of tri-n-butyltin(IV) compounds and their complexes in coordinating and non-coordinating solvents have been studied. The chemical shifts δ( 119Sn) and δ( 13C) and the coupling constants 1 J( 119Sn 13C) depend significantly on the coordination number of the tin atom and on the geometry of its coordination sphere. Approximate ranges of these characteristic NMR parameters for various types and configurations of tri-n-butyltin(IV) compounds have been defined. The data for these compounds are discussed in comparison with those for triphenyltin(IV) compounds.

13C and 119Sn NMR study of some triphenyltin(IV) carboxylates

The 13C and 119Sn NMR of CDCl 3 solutions of aliphatic and aromatic triphenyltin(IV) carboxylates of type Ph 3SnOCOR (Ph = phenyl; R = H, Ch 3, C 2H 5, C(CH 3) 3, CF 3, CH 2Cl, CHCl 2, CCl 3, CH 2Br and CHBr 2) and of the type Ph 3SnOCOC 6H 4X (X = H, 4-NH 2, 4-OCH 3, 4-C(CH 3) 3, 4-CH 3,4-NHCOCH 3, 4-OH, 4-SH, 4-I, 4-Cl, 4-CN, 4-NO 2, 2-OH and 2_NH 2) have been recorded. The value of the chemical shifts δ( 119Sn) and δ( 13C) ipso and the coupling constants 1 J( 119Sn 13C) of the triphenyltin(IV) group provide evidence that the compounds are monomeric species in the solutions irrespective of their structure in the solid state.

Untersuchungen zum elektronischen einfluss von organylliganden: IV. 13C-NMR-spektroskopische untersuchung der gegenseitigen beeinflussung von organylliganden in triethylzinnorganylverbindungen

By means of 13C NMR spectroscopy, the coupling constants 1 J( 119Sn 13C Et) of 18 compounds of the SnEt 3R type (R = organo group) have been measured. These coupling constants have been shown to reflect the change induced by R in the s-content of the tin hybrid orbitals of the SnC Et bonds. The series of the influence of R obtained on the basis of the coupling constant mentioned as a parameter is compared with a trans-influence series of R obtained on organo-mercury compounds. Occurring differences are attributed to different modes of bonding of the group R at the central atom.

Über zinn-haltige heterocyclen : V. Sn-phenyk-substituierte stannocane, Übergänge von tetraedrischer 4-Zu trigonal-bipyramidaler 5-koordination

A complete series of diphenyl and mixed methyl/chlorine/bromine/iodinephenyl substituted oxadithia- and trithiastannocanes has been prepared by reactions between the respective disodium dithiolates and tin dihalides. The 13C NMR chemical shifts of these compounds and the coupling constants J( 119Sn 13C) are dependent upon the magnetic anisotropy of the substituents and the bond angles at the tin atom. The crystal structure of 2,2-diphenyl-1,3,6-trithia-2-stannocane has been determined and refined to R = 0.039. The environment of Sn is a monocapped tetrahedron (transannular distance Sn⋯S 324.6(1) pm). This type of coordination, intermediate between a tetrahedron and a trigonal bipyramid, is discussed quantitatively and compared with a series of analogous compounds. The eight-membered ring has the boat-chair conformation.

The 119Sn 13C and 119Sn 1H couplings for methyl derivatives of tin in various solvents

The spin-spin coupling constants | 1J( 119 Sn 13 C)| and | 2J( 119Sn 1 H)| have been obtained from 13C and 1H NMR spectra of (CH 3) n SnHal 4− n ( n =1-4; Hat = Cl, Br) in various solvents (CCl 4, benzene, nitrobenzene, CD 3CN, acetone- d 6, dimethylformamide- d 7, dimethyl sulfoxide- d 6, pyridine, hexamethylphosphoramide). The data show that the relations between these constants as a function of solvent are not linear, and this indicates that other contributions besides Fermi contact terms are important in determining 119Sn 13C couplings.

The regio- and stereospecific synthesis of diarylpropenyllithium compounds from dimethylamino- and dimethylaminomethyl-substituted diarylacetylenes via transmetallation reactions involving diarylpropenylmagnesium and -tin compounds

Dimethylamino- and dimethylaminomethyl-substituted diarylacetylenes were prepared by the Pd(PPh 3) 4-catalyzed coupling reaction of dimethylamino- and dimethylaminomethyl-substituted aryl halides with arylacetylenes. Reaction of the asymmetric diarylacetylenes with methylmagnesium bromide in the presence of NiCl 2(PPh 3) 2 gave stereo- and regio-selectively cis addition products in which the aryl group bearing the built-in ligand (Me 2N or Me 2NCH 2) and the magnesium atom are bonded to the same unsaturated carbon atom. The E-diarylpropenylmagnesium bromides were converted in two successive transmetallation steps into the corresponding E-triphenyltin and Z-lithium compounds with retention of configuration. Depending on the type of solvent, complete inversion of configuration was observed for the Z-diarylpropenyllithium compounds. From the E-lithium compounds the corresponding Z-diarylpropenyltriphenyltin compounds were prepared (Scheme 1). Retention of configuration in the series of transmetallation reactions has unambiguously been established by comparison of the 119Sn 1H, 13C 1H and 119Sn 13C coupling constants observed in the 1H and 13C NMR spectra of the configurationally pure stereoisomeric pairs.

Carbon-13 fourier transform NMR studies of organotin compounds : III. Carbon-13 chemical shifts and tin-119—carbon-13 spin—spin coupling constants in acyclic, monocyclic and bicyclic organostannanes

Carbon-13 NMR parameters for 33 organotin compounds with a variety of structurul features were investigated in order to obtain information about the relationship between their structure and 13C NMR parameters. It was found that the substitution of a proton by a trialkyltin group generally produces an upfield shift for the directly bonded carbon. The γ-nuclei usually resonate at lower fields except where there is appreciable steric strain while the β-carbons undergo relatively constant shifts of approximately 3.5 to 4.5 ppm to lower fields. The magnitude of direct bond coupling Jz-sfnc; 1 J( 119Sn 13C)z-sfnc; is influenced by the hybridization of the tin and the directly attached carbon atoms. In rigid organitins, the vicinal coupling constants show a Karplus type variation. In aliphatic organotins, the values of the vicinal 119Sn 13C coupling indicates a flexible molecular framework with a clear cut preference for certain conformations.