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.     

Determination of Germanium and Tin and Inorganic Tin Species by Hydride Generation in Situ Trapping Flame Atomic Absorption Spectrometry

The analytical performances of a coupled hydride generation, integrated atom trap (HG-IAT) atomizer flame atomic absorption spectrometry (FAAS) system were evaluated for determination of Ge and Sn and inorganic tin species in environmental samples. Germanium and tin hydrides were atomized in air-acetylene flame-heated IAT. A new design of HG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangements (a water-cooled single silica tube, double-slotted quartz tube) permitting construction of an “integrated trap” was investigated. For the estimation of Sn(II) and Sn(IV) concentrations in samples, the difference between the analytical sensitivities of the absorbance singnals obtained for tin hydride without and with previous treatment of samples with L-cysteine could be used. The concentration of Sn(IV) was calculated by the difference between total Sn(tot) and Sn(II). An improvement in limit of detection was achieved compared with that obtained using any of the aforementioned atom trapping techniques separately. The concentration limits of detection were 25 and 8 ng mL^?1 for Ge and Sn, respectively. For a 2 min in situ preconcentration time, sensitivity enhancement, compared to FAAS, were 10 and 14 folds for Ge and Sn, respectively, using hydride generation atom trapping technique. The sensitivity can be further improved by increasing the collection time. The relative standard deviations (RSDs) are of the order of 5–10% for this hyphenated technique. The designs studied include slotted tube, single silica tube, and integrated atom trap water-cooled atom traps. The accuracy of this method was tested by analyses of BCS-CRM No.346 (Alloy), GBW 07302 (Stream Sediment), PACS-1 (Marine Sediment), NBS SRM 1633a (Coal Fly Ash), and NIST SRM 1643e (Trace Element in Water) certified reference materials. Agreement between analytical results and certified values for the test elements Ge and Sn (in the range of 1.7–91.0 µg g^?1) were in agreement with recommended values. The measured Ge and Sn contents in five referenced materials were in satisfactory agreement with the certified values. The hyphenated technique was applied for germanium and tin determination in coal fly ash, soil, sediment, garlic, sewage, and river water.     

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.     

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.     

HG-AFS 法测定多金属矿中的痕量锡

研究了酒石酸介质中氢化物发生原子荧光光谱法 ( HG- AFS)测定多金属矿中痕量锡的方法 ,考察了不同酸介质和浓度对氢化物发生效率的影响 ,试验了共存元素的干扰情况。方法的检出限为 1 .4× 1 0 - 10 g/ m L,精密度 ( n=5)为3.71 %～ 5.38%。     

Hydride generation induced chemiluminescence for the determination of tellurium (IV)

In the present work, hydride generation, as one of widespread application techniques in elemental analysis with the advantage of the excellent matrix separation, was attempted into the chemiluminescence. The experiment exhibited that the strong chemiluminescence emission can be obtained during the reaction between hydrogen telluride and luminol in basic medium, and a novel sensitive hydride generation-chemiluminescence (HG-CL) methodology for the determination of tellurium was proposed. Under the optimized conditions, the linear range of CL intensity versus concentration of tellurium (IV) was 10-200 μg L^− 1, with a coefficient (R) of 0.997 and a limit of detection (S/N = 3) of 2 μg L^− 1. The results showed that the method provided superior performance with respect to tolerance to various coexisting ions such as Mg²⁺, Ca²⁺, Fe³⁺, Zn²⁺, Pb²⁺, As³⁺, Ge²⁺, and Hg²⁺. The proposed method has the advantages of simplicity, selectivity, and sensitivity, with a potential of detecting tellurium in environmental and biological samples.     

Reactions of Unsaturated Ketones with Bis(trimethylsilyl) Hypophosphite

Bis(trimethylsilyl) hypophosphite reacts with unsaturated ketones (methyl vinyl ketone and mesityl oxide) to give, depending on the reaction conditions, 1: 1 or 1: 2 adducts after hydrolysis. It was found that the intramolecular cyclization of the 1: 2 reaction product with mesityl oxide, trimethylsilyl bis(2-methyl-4- oxopentan-2-yl)phosphinate, yields, after hydrolysis, a phosphorinane with exocyclic carbonyl and hydroxyl groups.     

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.     

A Bis‐Sulfonyl O,C,O Aryl Pincer Ligand and its Tin(II) Complex: Synthesis,Structural Studies,and DFT Calculations

The efficiency of the deprotonated aryl bis‐sulfone [2,6‐{(p‐tolyl)SO₂}₂C₆H₃]⁻ as an O,C,O‐coordinating pincer‐type ligand was described. The bis‐sulfone precursor was synthesized using a straightforward palladium‐catalyzed cross‐coupling reaction. As a result of directed ortho metalation (DoM) through sulfonyl groups, a selective lithiation of the aryl group was achieved and the corresponding carbanion was isolated and its structure determined by single‐crystal X‐ray diffraction analysis. A heteroleptic tin(II) complex has been prepared by a nucleophilic substitution reaction. Crystallographic analysis and DFT calculations indicate that the bis‐sulfonyl moiety acts as a new O,C,O‐coordinating pincer‐type ligand with intramolecular SO coordination to a tin(II) center. The cis form with the two nonbonded oxygen atoms of the sulfonyl groups on the same side is preferentially obtained.