Synthesis and characterization of tri(o-fluorobenzyl)tin esters of heteroaromatic carboxylic acid and crystal structures of tri(o-fluorobenzyl)tin esters of 4-pyridinecarboxylic acid and 3-pyridinecarboxylic acid

Reaction of tri(o-fluorobenzyl)tin chloride with sodium of heteroaromatic carboxylic acid in 1:1 stoichiometry yielded complexes of the type (2-F-Bz)₃SnOOCR (R=2-furanyl, 2-furanvingl, 2-thiophenyl, 2-pyridinyl, 3-pyridinyl, 4-pyridinyl, 3-indolyl, 3-indolmethyl and 3-indolpropyl), respectively. These complexes have been characterized by elemental analyses, IR and ¹H NMR spectroscopy. The crystal structures of tri(o-fluorobenzyl)tin esters of 4-pyridinecarboxylic acid (5) and 3-pyridinecarboxylic acid (6) were determined by single crystal X-ray diffraction. In the crystals of compounds 5 and 6, the tin atoms are rendered five-coordinate in a trigonal bipyramidal structure by coordinating with pyridine N atom of carboxylate group. The resulting structure is a one-dimensional linear polymer containing Sn-O bond lengths of 2.161(4), 2.202(9) Å and Sn-N bond lengths of 2.518(5), 2.454(10) Å.     

水杨酸及其氯代物的毛细管电泳分析研究

建立了分析水杨酸、５－氯代水杨酸、三氯水杨酸等水杨酸类化合物的毛细管区带电泳法（ＣＺＥ）。讨论了电压、缓冲溶液的浓度和ｐＨ值对分析结果的影响。其中缓冲溶液的ｐＨ值对分析结果的影响最为显著。ｐＨ〈７．４０时,三种化合物的出峰顺序为：三氯水杨酸、５－氯代水杨酸、水杨酸;当ｐＨ〉７．４０时,三种化合物的出峰顺序为：５－氯代水杨酸、水杨酸、三氯水杨酸。水杨酸、５－氯代水杨酸、三氯水杨酸的检出限分别为０．１     

锂离子电池阻燃剂磷酸三(β-氯乙基)酯

将磷酸三(β-氯乙基)酯(TCEP)作为锂离子电池阻燃剂以提高电池的安全性。本文采用循环伏安、差热分析(DTA)和电子扫描电镜(SEM)研究了电解液1mol/L LiPF6 EC DMC(质量比1/1)中添加7.5(wt)%TCEP时TCEP的分解电位、分解温度和电池100次循环后的负极表面形貌,用高温测试和电化学测试手段考察了电解液中添加3(wt)%和7.5(wt)%TCEP对电池安全性和电化学性能的影响。结果表明,当TCEP含量为7.5(wt)%时,电解液的分解电压为4.7V,电解液差热分析(DTA)曲线分别在250、280和320℃出现TCEP的三个分解吸热峰,电池循环100次后表面形貌良好。在150℃环境温度下对电池进行的耐高温测试表明,电池温度在147~155℃上下波动,且TCEP对电池循环性能的影响极小,是一种较为理想的阻燃剂。     

三人博弈问题的模型和一种解法的修正

简要叙述了三个擂台赛博弈问题,指出解法[1]的错误所在,其一是将无限延伸的博弈树以有限的形式看待,其二是概率计算过程与结果错误,提出一种新的解法,并比较了结果的大小。     

二[三（2-甲基-2-苯基）丙基锡]二元羧酸酯的合成、结构、热稳定性及除草活性研究

氧化双[三（2-甲基-2-苯基）丙基]锡分别与酒石酸、乙二酸反应,合成了2个二[三（2-甲基-2-苯基）丙基锡]二元羧酸酯[CH（OH）COOSn（CH₂Me₂CPh）₃]₂（1）和[COOSn（CH₂Me₂CPh）₃]₂·2MeOH（1）。经元素分析、IR、¹H和¹³C-NMR以及X-射线单晶衍射表征结构。化合物中,锡原子均为畸变四面体构型,分子间通过O-H…O和C-H…O氢键作用,化合物1和2分别形成一维无限链结构和二维网状结构。在空气氛下化合物有较好的热稳定性;除草活性结果表明,化合物1和2对马齿苋、稗草、反枝苋、决明子、狗尾草和藜等农作物杂草显示出一定的生物活性,特别是对马齿苋、狗尾草和藜的茎和根的作用较明显,化合物2在25mg·L^-1的较低浓度下选择性、高效地抑制马齿苋的茎和根的生长,为马齿苋的除草剂研究提供了一种方法。     

Two Sterically Encumbered 1,3,2‐Dioxaphospholanes – Reactions,Comparison of Crystal Structures and Computational Explanations

3,4,5,6‐Tetrachlorobenzo‐3‐(2,4,6‐tri‐tert‐butylphenyl)‐1,3,2‐dioxaphospholane ( 2 ) and benzo‐3‐(2,4,6‐tri‐tert‐butylphenyl)‐1,3,2‐dioxaphospholane ( 4 ), in which the reactive P^III‐center lies close to the sterically demanding Mes* group (Mes* = 2,4,6‐tri‐tert‐butylphenyl), were prepared from Mes*–Br and the corresponding P‐chloro‐phospholane. Compounds 2 and 4 reacted with various oxidants, azides, MeSO₃CF₃ or [(tht)AuCl] (tht = tetrahydrothiophene) to give the expected products. All crystal structures of the products display a strongly distorted Mes* system with a boat conformation of the phenyl ring and appreciable out‐of‐plane deviations of phosphorus and the ortho‐tert‐butyl groups to opposite sides of the ring. Quantum chemical calculations at the DFT (density functional theory) level of theory were used in order to discriminate between intra‐ and intermolecular forces, which are responsible for these distortions.     

Possible key intermediates in arsenic biochemistry: Synthesis and identification by liquid chromatography electrospray ionization mass spectrometry and high resolution mass spectrometry

Arsenic is a type 1 carcinogen and its toxicity is critically dependent on chemical speciation. However, after decades of research, the biogenesis of at least fifty naturally occurring arsenic species is still not well understood.Here, based on experimental work, it is proposed a set of pathways for the formation of multiple arsenic species that might help to clarify the present situation.These are focused on the thiol protein arsenic bond and on its interaction with reactive metabolites. In fact, arsenic bound to glutathione interacting with sulfur adenosyl methionine (SAM), MethylCB₁₂ and AdoCB₁₂, forms a number of complexes that might be key intermediates in arsenic biochemistry. These include dimethylarsino glutathione (DMAG) m/z 412 [M + H]⁺, synthesized non-enzymatically from glutathione and cacodylate. Trimethylarsonio glutathione (TMAG) m/z 426 [M]⁺ synthesized from DMA, GSH and SAM, apparently by a classical Challenger methylcarbonium attack. Tetramethyl arsonium ion m/z 135 [M]⁺ is formed in a third step, apparently by carbanion methylation. The presence of trimethylarsine oxide (TMAO) m/z 137 [M + H]⁺ is attributed to the hydrolysis of TMAG or TMA, or to carbanion methylation of dimethylarsinoyl glutathione (m/z 428 [M]⁺) formed from cacodylate and GSH. Cantoni type attacks of DMAG on SAM were unsuccessful, eventually due to competition of the trivalent S⁺ atom of SAM for the As^III atom attack. The presence of dimethylarsonio diglutathione (DMADG m/z 717 [M]⁺), is suggested to result from a GS^- attack on dimethylarsenoyl glutathione (m/z 428 [M + H]⁺). The presence of dimethylarsenoyladenosine (m/z 372 [M + H]⁺), trimethylarsenosugar adenine (m/z 370 [M]⁺), and dimethylthioarsenosugar adenine (m/z 388 [M + H]⁺), is explained by the synthesis of the pecursor dimethylarsonio-adenosine glutathione DMAAG (m/z 661 [M]⁺), a likely source of oxo-and trimethylated arsenosugars, as well as of thio-arsenosugars by the cleavage of its S-C bond. The results gathered suggest that cell vacuoles might play a major role in arsenic metabolism, and that the dominance of oxo-As sugars, in algae extracts, may be supported by a mechanism of synthesis independent of DMAAG (m/z 661).They also offer an explanation for the reason why arsenobetaine, and tetramethylarsonium are loosely bound to biotic tissues. Four arsenic species new to science, to the best of our knowledge, and a number of known arsenic compounds were synthesized in this work, identified by HPLC–ESI-MSⁿ and FTICR–ESI-MS, and suggestions regarding their mechanisms of synthesis were advanced. These results provide a framework for arsenic biochemistry which may explain the origin of a significant part of arsenic known metabolites.     

The First Dinuclear Nickel(II) Thiosulfate Obtained From Oxidation of Tri‐tert‐butoxysilanethiol. Contributions to the Chemistry of Silicon‐Sulfur Compounds No. 78[1]

The title complex, neutral {[Ni₂(μ‐S₂O₃)₂(C₇H₉N)₄H₂O]C₇H₈} ( 1 ), presents a dinuclear structure with the thiosulfate group acting as a (S, O) chelate and simultaneously as a (S) bridge. The molecular structure was determined by X‐ray crystallography. Complex 1 crystallizes as a hydrogen‐bonded dimer with molecule of toluene solvent in the unit cell. The environment of both central nickel atoms is octahedral with NiN₂O₂S₂ cores. This is the first metal thiosulfate complex isolated as a product of the oxidation of silanethiol. A mechanism of the reaction involving the formation of (RO)₃SiSSSi(OR)₃ intermediate is proposed with the subsequent cleavage of Si–S bond.     

Reactivity of the triruthenium ortho-metalated cluster [Ru3(CO)9{μ3-η,κ,κ-PhP(C6H4)CH2PPh}] with tri(2-thienyl)phosphine and tri(2-furyl)phosphine: Formation of 1,3-diphenyl-2,3-dihydro-1H-1,3-benzodiphosphine complexes via phosphorus-carbon bond formation

Reaction of [Ru₃(CO)₉{μ₃-η¹,κ¹,κ²-PhP(C₆H₄)CH₂PPh}] (1) with tri(2-thienyl)phosphine (PTh₃) in refluxing THF afforded [Ru₃(CO)₉(PTh₃)(μ-dpbm)] (3) {dpbm = PhP(C₆H₄)(CH₂)PPh} and [Ru₃(CO)₆(μ-CO)₂{μ-κ¹,η¹-PTh₂(C₄H₂S)}{μ₃-κ¹,κ²-Ph₂PCH₂PPh}] (5) in 18% and 12% yields, respectively, while a similar reaction with tri(2-furyl)phosphine (PFu₃) gave [Ru₃(CO)₉(PFu₃)(μ-dpbm)] (4) and [Ru₃(CO)₇(μ-η¹,η²-C₄H₃O)(μ-PFu₂){μ₃-η¹,κ¹,κ²-PhP(C₆H₄)CH₂PPh}] (6) in 24% and 27% yields, respectively. Compounds 2 and 4 are phosphine adducts of 1 in which the diphosphine ligand is transformed into 1,3-diphenyl-2,3-dihydro-1H-1,3-benzodiphosphine (dpbm) via phosphorus-carbon bond formation. Cluster 5 results from metalation of a thienyl ring, the cleaved proton being transferred to the diphosphine. Carbon-phosphorus bond cleavage of a PFu₃ ligand is observed in 6 to afford a phosphido-bridge and a furyl fragment, the latter bridging in a σ,π-vinyl fashion. The molecular structures of 3, 5 and 6 have been determined by X-ray diffraction studies.     

强萃取剂三(2-乙基己基)氧膦浸渍树脂分离测定矿石中金及其机理研究

本文在前文基础上,继续对萃取力极强的三(2-乙基己基)氧膦(TEHPO)能否作萃取色层分离金的固定相进行研究。实验证明,把我们提出的HAc辅助剂加到常用的金淋洗液硫脲-HCl中,仍然可行。试用于多种矿样中金的测定,均获得满意结果。用紫外和红外光谱法证明,TEHPO萃取金的机理是生成离子缔合物的机制。