Asymmetrische diorganoalkoxyzinnhydride und ihre anwendung als stereoselektive reduktionsmittel

The asymmetric diorgano(alkoxy)tin halides RR′Sn(OC₁₀H₁₉)X and RR′Sn-(OC₁₀H₁₇)X were synthesized by the reaction of diorganotin halides with sodium l(?)mentholate and sodium l(?)borneolate. Reduction of these asymmetric diorgano(alkoxy)tin halides yields the optically active diorgano(alkoxy)tin hydrides RR′Sn(OC₁₀H₁₉)H and RR′Sn(OC₁₀H₁₇)H, which are used for the asymmetric reduction of racemic haloalkanes.     

三丁基锡羧酸酯的结构表征及其生物活性研究

合成了三十个三丁基锡羧酸酯Bu3SnO2CR(R=烷基、芳基、芳氧甲基和呋喃基)。通过对它们的红外光谱、核磁共振谱(^1^3C, ^1^1^9Sn)的研究, 表明羰基红外吸收频率与锡原子的配位数有密切关系, 同样分子上的微小变化明显地表现在δ119Sn上, 对位取代基苯甲酸酯的δ119Sn与苯环上取代基的Hammett常数(σ)之间存在良好的线性关系:δ119Sn=19.11σ+110.612 n=7, γ=0.9955着重研究了部分化合物在经济作物上的抗病原菌能力, 结果表明, 这是一类具有广谱性的有机锡化合物, 抗菌活性优于对比药剂朴海因, 接近或相当于多菌灵, 它们同时具有较强的除草活性。     

Study of tin dioxide–sodium stannate composite obtained by decomposition of peroxostannate as a potential anode material for lithium-ion batteries

A tin dioxide–sodium stannate composite has been obtained by the thermal treatment of sodium peroxostannate nanoparticles at 500°C in air. X-ray powder diffraction study has revealed that the composite includes crystalline phases of cassiterite SnO₂, sodium stannate Na₂Sn₂O₅, and sodium hexahydroxostannate Na₂Sn(OH)₆. Scanning electron microscopy has shown that material morphology does not change considerably as compared with the initial tin peroxo compound. Electrochemical characteristics have been compared for the anodes of lithium-ion batteries based on tin dioxide–sodium stannate composite and anodes based on a material manufactured by the thermal treatment of graphene oxide–tin dioxide–sodium stannate composite at 500°C in air.     

Investigation of redox properties of different PtSn/Al2O3 catalysts.

Alumina-supported Sn and PtSn particles are studied by 119Sn M?ssbauer spectroscopy after oxidation and reduction under various conditions. The observed species of Sn(IV), Sn(II) and Sn(0) are grouped in several categories, each being characterised by distinct structural properties. Tin phases in contact with the support or with platinum are identified. The results are used to establish a model describing the phase transformations occurring in PtSn particles under oxidising or reducing conditions. Particular attention is paid to the reduction/reoxidation mechanisms governing H2/O2 double titrations. An increased reactivity of tin towards oxygen, induced by the contact with platinum, is demonstrated. It is shown that tin contributes to the oxygen uptake VO1 of a first titration cycle by platinum-catalysed transformation of Sn(II) into an oxometallic phase Pt(x)Sn(O). The oxygen titre VO2 of a second cycle is due to O2 chemisorption on platinum only.     

Influence of Sn4+ on the structural and electronic properties of Ti1-xSnxO2 nanoparticles used as photocatalysts

Ti(1-x)Sn(x)O(2) nanocrystalline materials employed for photocatalysis have been characterised by means of X-ray diffraction, Raman, X-ray absorption (XANES and EXAFS) and UV-Vis spectroscopy and high resolution transmission electron microscopy. Single-phase samples with anatase or rutile type structures and similar tin contents permitted a separate study of the effect of Sn(4+) ions on these crystalline forms, whereas materials composed of anatase and rutile mixtures were used to investigate the distribution of the dopant cations when both phases coexist. The results obtained from the single-phase doped TiO(2) samples indicate that the presence of tin causes a different effect when doping anatase or rutile in both their structural and electronic properties. While a random substitution of Sn(4+) for Ti(4+) seems plausible for the rutile phase, some kind of gradient in Sn(4+) concentration is possible in anatase. On the other hand, when anatase and rutile coexist, effects of doping are visible in both phases. Regarding chemical composition, a homogeneous distribution of tin was found in both calcined and hydrothermal multiphase samples. Photocatalytic experiments show that both tin-doping and coexistence of different phases have a beneficial effect on the activity of the catalysts.     

Structures of medium sized tin cluster anions

The structures of medium sized tin cluster anions Sn(n)(-) (n = 16-29) were determined by a combination of density functional theory, trapped ion electron diffraction and collision induced dissociation (CID). Mostly prolate structures were found with a structural motif based on only three repeatedly appearing subunit clusters, the Sn(7) pentagonal bipyramid, the Sn(9) tricapped trigonal prism and the Sn(10) bicapped tetragonal antiprism. Sn(16)(-) and Sn(17)(-) are composed of two face connected subunits. In Sn(18)(-)-Sn(20)(-) the subunits form cluster dimers. For Sn(21)(-)-Sn(23)(-) additional tin atoms are inserted between the building blocks. Sn(24)(-) and Sn(25)(-) are composed of a Sn(9) or Sn(10) connected to a Sn(15) subunit, which closely resembles the ground state of Sn(15)(-). Finally, in the larger clusters Sn(26)(-)-Sn(29)(-) additional bridging atoms again connect the building blocks. The CID experiments reveal fission as the main fragmentation channel for all investigated cluster sizes. This rather unexpected "pearl-chain" cluster growth mode is rationalized by the extraordinary stability of the building blocks.     

One-dimensional Infinite Chain Organotin Compounds: Synthesis and Structural Characterization of Triphenyltin Thiazole-2-carboxylate and Triphenyltin 3-Pyridinylcarboxylate

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Effect of the Support on the Structural Characteristics of Tin

Tin oxide was supported on alumina, titania, magnesia and silica, treated with hydrogen at different temperatures and characterized by Mössbauer spectroscopy and X-ray diffraction. For the samples calcined at 773 K, tin is present as SnO₂ on alumina, magnesia and silica, but it occupies Ti sites on titania. After hydrogen treatment at high temperatures, tin is reduced from Sn(IV) to Sn(II) on alumina and titania, from Sn(IV) to Sn(0) on silica, but practically not reduced on magnesia. These results show the different degree of interaction between tin and the supporting material.     

Materials based on group IVA elements for alloying-type sodium storage

There are five elements in group IVA of the periodic table, i.e., carbon (C), silicon (Si), germanium (Ge), tin (Sn) and lead (Pb), of which Si, Ge, and Sn can be used as alloying-type electrode materials for sodium-ion batteries. Pb is also capable of alloying with sodium, but it is generally ruled out as the cause of toxicity. In recent years, materials based on Si, Ge, and Sn have been intensively exploited as sodium anodes because of their abundant resource and large capacity with reasonable working voltages. However, successful deployment of these anode materials needs to overcome kinetic and thermodynamic issues related to poor electrochemical activity, particle pulverization associated with large volume swelling, and formation of unstable solid-electrolyte interphase. A diversity of material strategies has been employed to address these difficulties, mainly leveraging on the knowledge recently advanced for lithium anodes. This review highlights such issues and provides valuable insights for possible solutions, which serves as a guide and inspiration for future material innovation for rechargeable batteries.     

Speciation Analysis of Butyltin Species in Water by Gas Chromatography with Flame Photometric Detection Using Quartz Surface-induced Tin Emission

A flame photometric detector using quartz surface-induced tin emission was designed and evaluated for quantification analysis of butyltin species. It has been demonstrated that this quartz surface-induced tin emission, centred at 390 nm, is more sensitive than the commonly used gas-phase emission at 610 nm. The dependence of detector response on quartz enclosure was studied. The operational variables such as hydrogen–air flow rate, carrier-gas flow rate and purge-gas flow rate were optimized. An analytical procedure for speciation analysis of butyltin species in water using simultaneous hydride generation with sodium borohydride and extraction into dichloromethane was established. The detection limits (defined as the signals that equal three times the deviations of the noise) were 0.3 pg of Sn for tetrabutyltin (TeBT), 5 pg of Sn for monobutyltin (MBT), 18 pg of Sn for dibutyltin (DBT) and 2 pg of Sn for tributyltin (TBT), which are approximately 10- to 30-fold better than those reported for using more commonly used gas-phase emission centred at 610 nm.     

{Sn9[Si(SiMe3)3]3}− and {Sn8Si[Si(SiMe3)3]3}−: variations of the E9 cage of metalloid group 14 clusters

The disproportionation reaction of the subvalent metastable halide SnBr proved to be a powerful synthetic method for the synthesis of metalloid cluster compounds of tin. Hence, the neutral metalloid cluster compound Sn(10)[Si(SiMe(3))(3)](6) (3) was synthesized from the reaction of SnBr with LiSi(SiMe(3))(3). In the course of the reaction anionic clusters might also be present, and we now present the first anionic cluster compound {Sn(8)E[Si(SiMe(3))(3)](3)}(-) (E = Si, Sn), where one position in the cluster core is occupied by a silicon or a tin atom, giving further insight into structural variations of E(9) cages in metalloid group 14 cluster compounds.     

ICP-AES法测定锡精矿中锡、铜、铅、铁的含量

建立了过氧化钠熔融分解样品、电感耦合等离子发射光谱法（ICP-AES）测定锡精矿中锡、铜、铅、铁的新方法。对试样分解方法、过氧化钠用量、元素分析谱线等进行了讨论。选择过氧化钠用量为2．0g,样品熔融温度为850~C,锡、铜、铅、铁分析谱线分别为189．991,324．754,220．353,259．940nm。将该方法应用于标准样品（BY0107—1）中Sn,Cu,Pb,Fe的测定,待测元素的回收率在92．0％-101．6％之间,检出限为分别为0．006,0．002,0．005,0．001μg／mL,测定结果的相对标准偏差为0．16％～2．11％（n=5）。     

N → Sn coordination in the complexes of tin halides with pyridine: A comparison between Sn(II) and Sn(IV)

The experimentally well‐known complexation of tin(II) and tin(IV) halides with pyridine (py) leads to structures showing N → Sn coordination. In the present work, the complexes SnX_n·mpy (where X = F, Cl, Br, I; n = 2, 4; m = 1, 2) possessing this kind of coordination were studied using a computational quantum chemical approach. Various aspects in the theoretical picture of these complexes were examined to find similarities and differences in their N → Sn coordination. The aspects included, among others, the physical nature of intermolecular interactions, and their role in establishing the structure and energetic stabilization of the complexes. In this context, the effect of tin valency was inspected in great detail. As proven by several theoretical methods, a largely ionic character with a certain covalent component can be attributed to the studied N → Sn coordination, irrespective of tin valency. All complexes are destabilized by py‐py and three‐body interactions, but the Sn(II) complexes experience it to a greater extent. Marked differences are observed in the structural behavior of N → Sn and SnX_n during complex formation. This affects the energetics of complexation and, in consequence, the penta‐coordinated Sn(IV) center shows a higher propensity to expand its coordination number, compared with the tri‐coordinated Sn(II) center. The present study supplements the experimental characterization of SnX_n·mpy and, in general, it sheds light on the coordination of heteroaromatic nitrogen to tin. The survey of the Cambridge Structural Database revealed that such coordination occurred in a number of crystal structures.     

Tin-chalcogen double-bond compounds, stannanethione and stannaneselone: synthesis, structure, and reactivities

The first isolation of diarylstannanethione (tin-sulfur double-bond compound) and diarylstannaneselone (tin-selenium double-bond compound), Tbt(Ditp)Sn=X (Tbt = 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl; Ditp = 2,2' '-diisopropyl-m-terphenyl-2'-yl; X = S and Se) was accomplished by dechalcogenation of the corresponding highly hindered tetrachalcogenastannolanes, Tbt(Ditp)SnX(4). The (119)Sn NMR of stannanethione, Tbt(Ditp)Sn=S, and stannaneselone, Tbt(Ditp)Sn=Se, showed only one low-field broad signal at 531 and 440 ppm, respectively, characteristic of a tricoordinated tin, and hence, the stannanethione and stannaneselone display an intrinsic nature of tin-chalcogen double-bond compounds. The X-ray crystallographic analysis of the isolated stannaneselone, Tbt(Ditp)Sn=Se 5a, revealed a completely trigonal geometry around the central tin with a remarkably short Sn-Se bond length, indicative of structural similarity to a ketone.     

激光共振电离质谱法测量锡的同位素比

采用实验室研制的激光共振电离质谱仪,建立了锡(Sn)同位素的激光共振电离质谱分析方法.测量了锡原子的自电离态光谱,确认了锡的一条三色三光子共振电离路径,其各步激发/电离的激光波长分别为λ1=286.4 nm、λ2=811.6 nm、λ3=823.7 nm;通过将样品与氧化石墨烯溶液混合制样,有效提高了锡样品的电热原子化效率,1μg锡的总探测效率达到3×10-5以上,是直接滴样方式的4.5倍左右.采用本方法对锡、锑、硫(1:1:1,m/m)混合模拟样品进行测试,实现了锡的选择性电离,有效避免了测量过程中锑、硫对锡的同量异位素干扰,样品中主要同位素比116 Sn/120 Sn,117 Sn/120 Sn,118 Sn/120 Sn和119 Sn/120 Sn测量的相对标准偏差均°1%.结果表明,本方法能够有效解决TIMS、ICP-MS等商业质谱仪在锡同位素质谱分析过程中的同量异位素干扰难题,有望应用于反应堆乏燃料中裂变产物121m Sn、126 Sn的测量.     

Gravimetric determination of tin with sodium cyclotetramethylenedithiocarbamate and its applications in metal analysis

A gravimetric determination of tin is proposed with sodium cyclotetramethylenedithiocarbamate as precipitant at pH 5.0–5.5. By optimizing the reaction conditions the theoretical conversion factor 0.1687 can be used for determining ≥5% of Sn. Its standard deviation (n=10) at the level of 20 mg of Sn was found to be 0.08 mg. Effects of diverse cationic species can be eliminated by a clear-cut group precipitation at pH 9 with DDTC in the presence of tartrate and subsequent masking with EDTA. Provision is also made for removal of individual species in occasional cases. Hence, the proposed method is flexible and versatile and was successfully applied to the macro-determination of Sn in diverse alloys.     

二[氧合-二(3-二茂铁基丙烯酸二正丁基锡(Ⅳ))]配合物的合成及谱学表征

由FcCH=CHCO2H和(n Bu)2SnO反应合成了{[(FcCH=CHCO2)Sn(n Bu)2]2O}2(A)新配合物[其中Fc=(η5 C5H5)Fe(η5 C5H4)].经红外光谱和核磁共振(1H、13C、119Sn)谱学研究, 确定其组成和结构.提出 [(RCOOSnR′2)2O]2类化合物中一一指认与内环锡、外环锡键连的两类烷基R′中各个碳峰的原则.     

用于锂离子电池负极材料的锡/碳复合材料研究

采用分散聚合的方法在氧化锡的表面包覆聚对位二乙烯基苯,再热解制备了锡基颗粒在碳基体中均匀分散的锡/碳复合材料.该复合材料具有良好的循环性能.在该复合材料中无定形碳起到了至关重要的作用,它一方面保证了复合材料的导电性能,另一方面有效地抑制了锡基颗粒的团聚与粉化.只有当小尺寸的锡基颗粒均匀地分散在碳基体中时,锡/碳复合材料才具有稳定的电化学性能.     

DFT calculations of the electric field gradient at the tin nucleus as a support of structural interpretation by 119Sn Mössbauer spectroscopy

DFT calculations, using an all-electron basis set and with full geometry optimization, were performed on 34 Sn(II) and Sn(IV) compounds of known structure and (119)Sn M?ssbauer parameters, to obtain the theoretical values of the electric field gradient components, V(xx), V(yy), and V(zz), at the tin nucleus. These were used to determine the quantity V = V(zz)[1+ 1/3((V(xx) - V(yy))/((V(zz))(2)](1/2), for each investigated compound, which is related to the quadrupole splitting (DeltaE) parameter according to DeltaE = 1/2eQV, where e is the electronic charge and Q is the quadrupole moment of the tin nucleus. The linear fitting of the correlation plot of the experimental DeltaE, versus the corresponding calculated V values, produced a slope that is equal to 0.93 +/- 0.03 and a correlation coefficient R = 0.982. The value of Q obtained, 15.2 +/- 4.4 fm(2), is in agreement with that previously experimentally determined or calculated by analogous procedures. The calculation method is able to establish the sign of the electric field gradient component V(zz), in agreement with the sign of DeltaE determined experimentally by M?ssbauer-Zeeman spectroscopy. The calculated structural parameters are in good agreement with the corresponding experimental data, determined by X-ray crystallography in the solid state, with average structural deviations of about 3 % for bond lengths and angles in the tin environment. Calculated values of DeltaE were obtained from the calibration fitting constant and from the values of V. By comparing experimental and calculated DeltaE parameters, the structure assignment of configurational isomers was successful in two test cases, in agreement with the experimental X-ray crystallographic structures. These results indicate that the method can be used as a tool to support the routine structure interpretation of tin compounds by (119)Sn M?ssbauer spectroscopy.     

Reactions of sodium 3,4,5-triphenyl-1,2-diphosphacyclopentadienide with alkyl halides and silicon and tin chlorides

Reactions of sodium 3,4,5-triphenyl-1,2-diphosphacyclopentadienide with primary alkyl bromides, secondary alkyl iodides, and silicon and tin chlorides gave stable 1-substituted 1,2-diphospholes. In a solution of 3,4,5-triphenyl-1-trimethylstannyl-1,2-diphosphacyclopenta-2,4-diene, the Me3Sn group migrates between two phosphorus atoms.