NMR Study of the Reactions of Tin(II) Difluoride and Antimony(III) Trifluoride with Niobium Pentachloride

The reactions of SnF₂and SbF₃with NbCl₅in acetonitrile or dimethyl sulfoxide were studied by ¹⁹F, ⁹³Nb, and ¹¹⁹Sn NMR spectroscopy. The products of reaction in acetonitrile are anionic, while those in di-methyl sulfoxide are neutral octahedral niobium chlorofluoride complexes. Tin(II) difluoride and antimony(III) trifluoride are powerful sources of fluoride ions in the preparation of metal chlorofluoride and fluoro complexes.     

NMR Study of the Interaction of Tin(II) and Antimony(III) Fluorides with Phosphorus Chlorides

Reactions of SnF₂ and SbF₃ with POCl₃ and PCl₅ in acetonitrile were studied by ¹⁹F, ³¹P, and ¹¹⁹Sn NMR. Tetrahedral compounds POF₂Cl and POF₃ form in the reaction with POCl₃. Interaction of SnF₂ and SbF₃ with PCl₅ yields higher (in terms of fluorine) octahedral complexes [PF₅ · MeCN] and [PF₆]^–. In all cases, fluorine-free phosphorus compounds are found in the acetonitrile solution.     

Reactions of Tin(II) Fluoride with Halogens

By oxidative-addition of X₂ (X = Cl, Br) to SnF₂ in acetonitrile, monomeric SnF₂Cl₂(MeCN)₂ and polymeric or oligomeric SnF₂Br₂(MeCN)₂ are obtained. The corrected v CN IR frequencies provide a good indication of the Sn–N bond strength. The reactions of SnF₂ with Br₂ and I₂ in the presence of DMSO, and with I₂ in the presence of pyridine yield the disproportionation products rather than the mixed-halide compounds. That suggests that the stability of the mixedhalide compounds decreases when the difference between the halides increases. The reaction of SnF₂ with I₂ in acetonitrile gives rise to SnF₄(MeCN)₂, and provides a simple and inexpensive route to SnF₄ and its complexes, as MeCN is lost under mild conditions or substituted by other ligands. In this way we have prepared SnF₄L₂ (L = DMF, DMSO, THF, Py). The structure of the compounds is discussed in terms of the IR and ¹¹⁹Sn Mössbauer spectra and, in the case of SnF₄L₂, the Mössbauer isomer shift and the IR v Sn–F compared to the corresponding SnCl₄L₂ compounds.     

Reactions of Tin and Lead with Tricarbonylcyclopentadienylmolybdenum(II) and Tricarbonylcyclopentadienyltungsten(II) Chlorides

Tin was oxidized with tricarbonylcyclopentadienylmolybdenum and tricarbonylcyclopentadienyltungsten chlorides to obtain polynuclear organometallic compounds [⁵-C₅H₅M(CO)₃]₂SnCl₂ (M = Mo, W). The reactions of the above-mentioned oxidants with lead gave lead chloride and [⁵-C₅H₅M(CO)₃]₂ dimers. Formal-kinetic regularities of tin oxidation with tricarbonylcyclopentadienylmolybdenum chloride in N,N-dimethylformamide were found. Thermodynamic parameters of adsorption of the reagent on the metal surface were determined.     

Tin(II) Halide Insertion or Halogen Exchange in the Reactions of Dihaloplatinum(II) Complexes with Tin(II) Halide

Reactions of SnCl₂ with the complexes cis‐[PtCl₂(P₂)] (P₂=dppf (1,1′‐bis(diphenylphosphino)ferrocene), dppp (1,3‐bis(diphenylphosphino)propane=1,1′‐(propane‐1,3‐diyl)bis[1,1‐diphenylphosphine]), dppb (1,4‐bis(diphenylphosphino)butane=1,1′‐(butane‐1,4‐diyl)bis[1,1‐diphenylphosphine]), and dpppe (1,5‐bis(diphenylphosphino)pentane=1,1′‐(pentane‐1,5‐diyl)bis[1,1‐diphenylphosphine])) resulted in the insertion of SnCl₂ into the Pt? Cl bond to afford the cis‐[PtCl(SnCl₃)(P₂)] complexes. However, the reaction of the complexes cis‐[PtCl₂(P₂)] (P₂=dppf, dppm (bis(diphenylphosphino)methane=1,1′‐methylenebis[1,1‐diphenylphosphine]), dppe (1,2‐bis(diphenylphosphino)ethane=1,1′‐(ethane‐1,2‐diyl)bis[1,1‐diphenylphosphine]), dppp, dppb, and dpppe; P=Ph₃P and (MeO)₃P) with SnX₂ (X=Br or I) resulted in the halogen exchange to yield the complexes [PtX₂(P₂)]. In contrast, treatment of cis‐[PtBr₂(dppm)] with SnBr₂ resulted in the insertion of SnBr₂ into the Pt? Br bond to form cis‐[Pt(SnBr₃)₂(dppm)], and this product was in equilibrium with the starting complex cis‐[PtBr₂(dppm)]. Moreover, the reaction of cis‐[PtCl₂(dppb)] with a mixture SnCl₂/SnI₂ in a 2 : 1 mol ratio resulted in the formation of cis‐[PtI₂(dppb)] as a consequence of the selective halogen‐exchange reaction. ³¹P‐NMR Data for all complexes are reported, and a correlation between the chemical shifts and the coupling constants was established for mono‐ and bis(trichlorostannyl)platinum complexes. The effect of the alkane chain length of the ligand and Sn^II halide is described.     

The Oxidation of Some Aryldialkylamines with Thallium (III) Nitrate (TTN) in Various Solvents

The oxidation of organic substrates with thallium (III) nitrate (TTN) has been summarised in a recent review¹. No systematic study is available using aromatic tertiary amines as substrates. We showed in two previous reports^2,3 that these compounds undergo oxidative dealkylation and nitration when oxidised with cerium (IV) ammonium nitrate (CAN).     

Role of Tin Difluoride and Gallium Trifluoride in Glass Formation in SnF2–GaF3–BaF2

The structure of glasses in SnF₂–GaF₃ and SnF₂–GaF₃–BaF₂ systems was investigated by IR spectroscopy. It is shown that the glass structure in systems of this type is formed by two glass-forming agents: gallium trifluoride and tin difluoride. The introduction of 5 mole % barium difluoride shifts the edge of the absorption band to the low-frequency region.     

An Organogold(III) Difluoride with a trans Arrangement

The trans isomer of the organogold(III) difluoride complex [PPh₄][(CF₃)₂AuF₂] has been obtained in a stereoselective way and in excellent yield by reaction of [PPh₄][CF₃AuCF₃] with XeF₂ under mild conditions. The compound is both thermally stable and reactive. Thus, the fluoride ligands are stereospecifically replaced by any heavier halide or by cyanide, the cyanide affording [PPh₄][trans‐(CF₃)₂Au(CN)₂]. The organogold fluoride complexes [CF₃AuF_x]^? (x=1, 2, 3) have been experimentally detected to arise upon collision‐induced dissociation of the [trans‐(CF₃)₂AuF₂]^? anion in the gas phase. Their structures have been calculated by DFT methods. In the isomeric forms identified for the open‐shell species [CF₃AuF₂]^?, the spin density residing on the metal center is found to strongly depend on the precise stereochemistry. Based on crystallographic evidence, it is concluded that Auⁱⁱⁱ and Agⁱⁱⁱ have similar covalent radii, at least in their most common square‐planar geometry.     

Features of Reactions of Radical (Co)Polymerization of Methacryloylguanidine Trifluoroacetate in Various Solvents

A method for the synthesis of methacryloylguanidine trifluoroacetate was developed for the first time and its radical (co)polymerization was carried out in various solvents. The polymerization proceeds homogeneously in water, methanol, and DMSO up to high conversion and heterogeneously in acetone after reaching 20% conversion. For the first time, methacryloylguanidine trifluoroacetate and methylmethacrylate copolymers were synthesized in acetone and DMSO; the copolymerization constants for this system in acetone were determined to be r₁ = 1.41 ± 0.24 and r₂ = 0.11 ± 0.01. Preliminary biological tests showed a fairly high biocidal and fungicidal activity of the synthesized copolymers.     

Spectrochemical Properties of Cobalt(II) Complex with Bidentate Schiff Base in Various Solvents

As a continuation of our previous studies on copper(II) complexes with a bidentate Schiff base derived from 5-bromosalicylaldehyde and -aminopyridine, we have investigated the electronic spectra of the cobalt(II) complex with this ligand. The complex is a red crystalline compound soluble in common solvents, such as chloroform, dioxane, dimethyl formamide, dimethyl sulfoxide, and methanol. The time-elapsed spectral measurements of the complex and ligand, as well as conductivities of the complex in chloroform and dioxane solutions, are presented and discussed. Molar conductivities indicate that the complex exists as a nonelectrolyte in nonpolar solvents and as a 1:1 or 1:2 electrolyte in polar solvents. The ligand-field parameters (CFM/AOM) for the complex in chloroform solution are estimated and discussed.     

Peculiarities of Chemical Binding in Anhydrous Lead(II) and Tin(II) Hexacyanoferrates(II,III)

The electronic structure and chemical binding of anhydrous lead and tin hexacyanoferrates(II,III) Pb₂Fe(CN)₆, Pb_1.5Fe(CN)₆, and Sn₂Fe(CN)₆ were studied by the linear muffm-tin orbital (tight binding approximation) and extended Hückel theory methods. The general tendencies of variation for the stability of the Pb–N, Sn–N, Fe–C, and C–N bonds were determined for Pb₂Fe(CN)₆, Pb_1.5Fe(CN)₆, and Sn₂Fe(CN)₆ crystals. Peculiarities of Pb(Sn)–N chemical interactions in the structure of the phases have been found.     

Fluorination of Organic Compounds with Cobalt Trifluoride and Elemental Fluorine in the Presence of Cobalt Trifluoride

Fluorination of organic compounds with cobalt trifluoride and elemental fluorine in the presence of cobalt trifluoride was studied. Fluorination with elemental fluorine proceeds under external-kinetic control at a constant rate. Examples of fluorination with elemental fluorine of certain fluorinated olefins and polyfluorinated paraffins in the presence of CoF₃ are presented.     

ChemInform Abstract: Divergent Electronic Structures of Isoelectronic Metalloclusters: Tungsten(II) Halides and Rhenium(III) Chalcogenide Halides

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Anion Recognition with Antimony(III) and Bismuth(III) Triaryl-Based Pnictogen Bonding Receptors

The synthesis and characterisation of a library of acyclic antimony(III) and bismuth(III) triaryl pnictogen bonding (PnB) receptor systems are reported. In the first-generation receptor series, quantitative ¹H NMR chloride titration experiments in THF solvent media reveal halide anion binding potency is intimately correlated with both the electronic-withdrawing nature of the aryl- substituent and the polarisability of the PnB donor. Further extensive anion binding investigations with the most potent Sb- and Bi-based PnB receptors: 1⋅Sb^2CF3 and 1⋅Bi^2CF3 , reveal novel selectivity profiles, both displaying Cl⁻ selectivity relative to the heavier halides and, impressively, to a range of highly basic oxoanions. The synthesis and preliminary chloride anion binding studies of a series of novel tripodal tris-proto-triazole triaryl Sb(III) and Bi(III) mixed PnB-HB receptor systems are also described. Whereas parent triphenyl Sb(III) and Bi(III) compounds are incapable of binding Cl⁻ in THF solvent media, the PnB-triazole HB host systems exhibit notable halide affinity.     

Tin(II) sulphate as a new reductimetric titrant--direct titration of thallium(III) with use of ion-pair and redox indicators

The use of tin(II) sulphate as a direct reductimetric titrant for thallium(III) has been investigated, with potentiometric and visual detection of the end-point. Some azure dyes are used as redox indicators and Methylene Blue is used as both a redox and an ion-pair indicator.     

Competition of Different Addition and Cycloaddition Processes During Reaction of Phosphorus(II) and (III) Halides with Alkynes

Abstract

Addition of P-halogenophosphaalkenes to I-alkoxyalkynes provides either 2-phosphabutadienes 2 or P(II1)-substituted allenes 3. The reaction o f P-halogenophosphaalkenes I with I-aminoalkynes leads to the phosphetines 4 wa 5 - the product of 1,2-addition reaction.     

Flow-Injection Study and Analytical Applications of the Reactions of Palladium(II) and Platinum(IV) with Tin(II) Chloride in Hydrochloric Acid Solutions

The interaction of palladium(II) and platinum(II) with tin(II) chloride in hydrochloric acid solutions was studied by flow-injection (FI) spectrophotometry. It was found using kinetic measurements in the stopped flow mode that the composition of detected products and the rate of their formation depend on the concentrations of tin(II) and chloride ions in the reaction zone and on the acidity of the solution. Optimal FI conditions were found, and the selectivity of interaction of palladium(II) with tin(II) chloride was estimated for the detection of the signal at 407 nm (yellow form) and 646 nm (green form). It was demonstrated that the reaction of the formation of yellow platinum(IV) complexes is slower than that for palladium(II), especially at rather low concentrations of hydrochloric acid in the reaction flow. Based on the detection of green complexes of palladium(II) with tin(II) chloride, a flow injection method was proposed for the selective spectrophotometric determination of palladium(II) in the presence of other platinum-group metals. The height of the recorded peak is directly proportional to the concentration of palladium(II) in the injected solution in the range of 0.028–0.300 mM. The method was used for the analysis of pharmaceuticals and industrial catalysts.