锰(Ⅲ)离子与羧酸或α-羟基羧酸体系引发丙烯酰胺聚合

 锰(Ⅲ)离子可以引发烯类单体自由基聚合。羧酸,α-羟基羧酸对丙烯酰胺聚合有促进作用,其活性顺序为羟基多元羧酸(柠檬酸)>羟基羧酸(乳酸)>羧酸(正丁酸)。测定了在较高酸性([H⁺]=3.0M)的硫酸水溶液中,单独Mn³⁺,Nn³⁺-乙醇酸,Mn³⁺-乳酸引发丙烯酰胺聚合的活化能与动力学方程。     

溶胶插入法制备高比表面TiO2柱层状铌酸

采用溶胶插入法合成了氧化钛柱层状铌酸，并用XRD、IR、BET和TEM等技术进行了表征。所得层柱材料是多孔性的，包含大量的中孔，其BET比表面积高达131.3m²·g^-1(450℃)。另外，材料具有较好的热稳定性，经450℃焙烧后其层间距为1.26nm，经550℃焙烧2h后其层柱结构仍然保持。     

氧化硅柱层状镧钛酸盐的制备和表征

本文报道通过先用正己胺盐酸盐水溶液与K₂La₂Ti₃O₁₀发生离子交换得到正己铵离子柱撑的层状镧钛酸盐，然后再与氨基丙基三乙氧基硅烷的正八面体多聚体作用，最后将层间的有机物焙烧分解掉后可得新型氧化硅柱层状镧钛酸盐。采用X射线衍射(XRD)、红外光谱(IR)、差热--热重分析(TG/DTA)、透射电子显微镜(TEM)和比表面测定等方法对该新材料进行了表征。结果表明，所得氧化硅柱层状镧钛酸盐具有很高的热稳定性(>800℃)     

金属离子对联吡啶钌电致化学发光影响的研究

在玻碳电极上, 联吡啶钌[Ru(bpy)₃^2＋]于＋1.50 V (vs. Ag/AgCl)左右被氧化为Ru(bpy)₃^3＋, 该氧化态离子与碱性水溶液中(pH 8.2)的OH•反应生成激发态的[Ru(bpy)₃^2＋*]而发光. 研究比较了15种金属离子对Ru(bpy)₃^2＋碱性水溶液电致化学发光的影响, 并对这些影响进行了初步的解释.     

二(过碘酸根)合铜(Ⅲ)酸根离子氧化二乙醇胺的反应动力学及机理

在25～40℃区间用分光光度法在碱性介质中研究了二(过碘酸根)合铜(Ⅲ)酸根配离子(DPC)氧化二乙醇胺(DEA)的反应动力学。结果表明,反应对DPC为一级,对二乙醇胺是1.7～1.9级。准一级速率常数k_obs随［OH^-］增大而增大,随［IO^-₄］ex(外加的IO^-₄离子浓度)的增加而减小,也随［KNO₃］增大而减小,有负盐效应。在氮气保护下,反应体系能引发丙烯腈聚合。提出了含有自由基过程的反应机理。经此导出的速率方程圆满地解释了全部实验事实,并计算出速控步骤的速率常数及相应的活化参数。     

介孔磷酸铌一锅法高效催化木糖制备糠醛

木糖转化到糠醛一般包括两步: 首先在酶、碱或路易斯(L)酸的催化作用下异构化木糖到木酮糖, 接下来木酮糖在酸的作用下脱水得到糠醛. 针对木糖水相脱水一步制备糠醛, 利用十六烷基三甲基溴化铵(CTAB)为模板剂, 借助软模板合作策略制备了一种抗水的新型固体酸催化剂, 介孔磷酸铌, 并利用X射线衍射(XRD)、N₂吸脱附、透射电镜(TEM)、氨气程序升温脱附(NH₃-TPD)和吡啶吸附傅里叶变换红外(Py-FTIR)光谱对材料的结构和酸性质进行了表征. 研究发现介孔磷酸铌不仅具有很高的比表面积(>200 m²·g^-1), 比较窄的孔径分布(3.5nm), 同时还具有很强的L酸性和布朗斯特(B)酸性. 通过L酸催化的木糖异构化为木酮糖/来苏糖和B酸催化的木酮糖/来苏糖进一步脱水得到糠醛, 实现了一步由木糖到糠醛的高效转化. 为了优化反应条件, 考察了水溶液中反应温度、投料质量比及反应时间对木糖转化率和糠醛收率的影响, 在最佳的反应条件下, 木糖的转化率为96.5%, 糠醛的收率达49.8%. 进一步地, 为了提高收率且易于分离, 利用4-甲基-2-戊酮(MIBK)/NaCl水溶液(体积比为7:3)作为反应混合溶剂, 使糠醛收率提高到68.4%.     

锰(Ⅲ)离子与羧酸或α-羟基羧酸体系引发丙烯酰胺聚合

锰(Ⅲ)离子可以引发烯类单体自由基聚合。羧酸,α-羟基羧酸对丙烯酰胺聚合有促进作用,其活性顺序为羟基多元羧酸(柠檬酸)>羟基羧酸(乳酸)>羧酸(正丁酸)。测定了在较高酸性([H~+]=3.0M)的硫酸水溶液中,单独Mn~(3+),Nn~(3+)-乙醇酸,Mn~(3+)-乳酸引发丙烯酰胺聚合的活化能与动力学方程。     

LiNi1/3Co1/3Mn1/3O2的Si/F复合掺杂及电化学性能

以共沉淀法合成的(Ni_1/3Co_1/3Mn_1/3)(OH)₂为前驱体，在氧气氛中合成了层状正极材料LiNi_1/3Co_1/3Mn_1/3O₂，用F、Si离子复合掺杂的方法对其进行改性。X射线粉末衍射(XRD)分析表明，复合掺杂没有改变晶体的六方单相层状结构。扫描电镜(SEM)观察到产物呈类球形且颗粒均匀，平均粒径在0.1～0.2 μm。循环伏安(CV)性能显示，复合掺杂提高了该材料中Li⁺离子脱-嵌过程的可逆性。电化学阻抗谱(EIS)测试结果表明，复合掺杂降低了该材料的电化学极化，抑制其在循环过程中电化学反应阻抗的增加。复合掺杂后的层状材料首次放电容量为172.8 mAh·g^-1 (0.2C)，20次循环后仍有166.4 mAh·g^-1。     

碱性介质中二(碲酸根)合铜(Ⅲ)酸根氧化乙二醇一乙醚的反应动力学及机理

在碱性介质中用分光光度法研究了二过碲酸合铜(Ⅲ)配离子(DTC)氧化乙二醇一乙醚(EGE)的反应动力学及机理。反应速率表明:反应对DTC为准一级,对EGE为分数级;在保持准一级条件([EGE]》[DTC])下,表观速率常数随着OH^-浓度的增加而增大,随着TeO₄^2-浓度的增加而减小;有负的盐效应。据此提出了包括配离子和EGE形成络合物的前期平衡的反应机理,由假设反应机理推出的速率方程能很好的解释全部实验现象,进一步求得速控步的速率常数和活化     

［Eu2(BA)6(bipy)2］的晶体结构和荧光光谱

标题配合物晶体属单斜晶系，P2₁/n空间群，晶胞参数a=1.4162(3) nm，b=1.5377(5) (nm), c=2.6017(5) nm, β=103.56(3°)， Z=4。标题配合物是双核分子，4个苯甲酸的羧基桥联两个中心Eu(Ⅲ)离子。它们又分别与1个苯甲酸的羧基的两个氧原子和一个联吡啶分子的两个氮原子螯合配位，形成4，4′-双帽三角棱柱体。两个Eu(Ⅲ)离子的Eu-O和Eu-N平均键长不等。两个Eu(Ⅲ)离子的化学环境略有不同。在配合物的 ⁷F₀→ ⁵D₀激发光谱里，580.17和580.31 nm处呈现两个锐峰，可以认为配合物具有两种Eu(Ⅲ)格位，选择激发配合物的 ⁵D₀能级，得到的 ⁵D₀→ ⁷F_1,2发光光谱表明配合物中Eu(Ⅲ)离子有不同的化学环境，这与晶体结构分析结果一致。     

Beiträge zur Chemie des Phosphors. 152. Funktionalisierte Cyclotriphosphane des Typs (t-BuP)2PX (X = K,SiMe3, SnMe3, Cl,Br, PCl2, P(t-Bu)Cl,P(t-Bu)I)

Contributions to the Chemistry of Phosphorus. 152. Functionalized Cyclotriphosphanes of the Type (t-BuP)₂PX (X = K, SiMe₃, SnMe₃, Cl, Br, PCl₂, P(t-Bu)Cl, P(t-Bu)I) Functionalized cyclotriphosphanes of the type (t-BuP)₂PX with electropositive or electronegative substituents X have been prepared on various synthetic routes: KP(t-BuP)₂ ( 1 ) can be obtained in 50–55 per cent purity by reacting (t-BuP)₄ or (t-BuP)₃ with potassium. Reaction of 1 with Me₃SiCl or Me₃SnCl leads to the cyclotriphosphanes (t-BuP)₂PSiMe₃ ( 2 ) and (t-BuP)₂PSnMe₃ ( 3 ), respectively; the cyclocondensation of Cl(t-Bu)P? P(t-Bu)Cl with P(SnMe₃)₃, however, is more convenient for the preparation of 3 . In a similar way the halogenated compounds (t-BuP)₂PCl ( 4 ) and (t-BuP)₂PBr ( 5 ) can be obtained from Me₃Sn(t-Bu)P? P(t-Bu)SnMe₃ ( 6 ) and PX₃ (X = Cl, Br). The phosphino-substituted cyclotriphosphanes (t-BuP)₂P? PCl₂ ( 7 ), (t-BuP)₂P? P(t-Bu)Cl ( 8 ), and (t-BuP)₂P? P(t-Bu)I ( 9 ) are accessible by the reaction of 3 with PCl₃ and t-BuPX₂ (X = Cl, I), respectively. 2–9 could be obtained free from phosphorus-containing by-products and were ³¹P-NMR spectroscopically characterized as compounds with a cyclic P₃ skeleton.     

Strukturelle Abwandlungen am Vitamin D3. 3. Mitteilung [1]. Synthese und eigenschaften von SO2-addukten des (5Z)- und (5E)-vitamins D3

Structural Modifications of Vitamin D₃. Synthesis and Properties of the SO₂-Adducts with (5 Z )- and (5 E )-Vitamin D₃ Treatment of (5Z)- and (5E)-vitamin D₃ ( 4 ) with sulfur dioxide yields each quantitatively the cyclic sulfones 1a and 1b . Thermally induced elimination of sulfur dioxide leads to either isotachysterol₃ ( 3 ) alone or mixtures of isotachysterol₃ ( 3 ) and isovitamin D₃ ( 2 ). On the other hand the extrusion of SO₂ can be brought about by means of KOH/CH₃OH or on an alumina surface affording (5E)-vitamin D₃ ( 4 ). On treatment with CD₃UD/tBuOK/D₂O 1a and 1b are transformed (5E)-6, 19, 19′-trideuteriovitamin D₃ ( 4a ).     

Beiträge zur Chemie des Phosphors. 134. Über die Triphosphane H(t-BuP)3H,Li(t-BuP)3Li und Me3Si(t-BuP)3SiMe3

Contributions to the Chemistry of Phosphorus. 134. On the Triphosphanes H(t-BuP)₃H' Li(t-BuP)₃Li, and Me₃Si(t-BuP)₃SiMe₃ The reaction of 1,3-diiodo-1,2,3-tri-tert-butyltriphosphane, I(t-BuP)₃I, with lithium aluminium hydride leads to 1,2,3-tri-tert-butyltriphosphane, H(t-BuP)₃H ( 1 ). 1 reacts with n-butyllithium to 1,3-dilithium-1,2,3-tri-tert-butyltriphosphide, Li(t-BuP)₃Li ( 2 ), which reacts further with trimethylchlorosilane yielding 1,3-bis(trimethylsilyl)-1,2,3-tri-tert-butyltriphosphane, Me₃Si(t-BuP)₃SiMe₃ ( 3 ). The triphosphanes 1, 2 and 3 could be isolated in a pure state. In solution 1 forms the threo, threo and the threo,erythro configurated diastereomers 1a and 1b in a ratio of about 2:1. 3 predominantly exists in form of the threo,erythro configurated diastereomer 3b by steric reasons.     

Dipyrromethane-Based PGeP Pincer Germyl Rhodium Complexes

A family of germyl rhodium complexes derived from the PGeP germylene 2,2’-bis(di-isopropylphosphanylmethyl)-5,5’-dimethyldipyrromethane-1,1’-diylgermanium(II), Ge(pyrmPⁱPr₂)₂CMe₂ ( 1 ), has been prepared. Germylene 1 reacted readily with [RhCl(PPh₃)₃] and [RhCl(cod)(PPh₃)] (cod=1,5-cyclooctadiene) to give, in both cases, the PGeP-pincer chloridogermyl rhodium(I) derivative [Rh{κ³P,Ge,P-GeCl(pyrmPⁱPr₂)₂CMe₂}(PPh₃)] ( 2 ). Similarly, the reaction of 1 with [RhCl(cod)(MeCN)] afforded [Rh{κ³P,Ge,P-GeCl(pyrmPⁱPr₂)₂CMe₂}(MeCN)] ( 3 ). The methoxidogermyl and methylgermyl rhodium(I) complexes [Rh{κ³P,Ge,P-GeR(pyrmPⁱPr₂)₂CMe₂}(PPh₃)] (R=OMe, 4 ; Me, 5 ) were prepared by treating complex 2 with LiOMe and LiMe, respectively. Complex 5 readily reacted with CO to give the carbonyl rhodium(I) derivative [Rh{κ³P,Ge,P-GeR(pyrmPⁱPr₂)₂CMe₂}(CO)] ( 6 ), with HCl, HSnPh₃ and Ph₂S₂ rendering the pentacoordinate methylgermyl rhodium(III) complexes [RhHX{κ³P,Ge,P-GeMe(pyrmPⁱPr₂)₂CMe₂}] (X=Cl, 7 ; SnPh₃, 8 ) and [Rh(SPh)₂{κ³P,Ge,P-GeMe(pyrmPⁱPr₂)₂CMe₂}] ( 9 ), respectively, and with H₂ to give the hexacoordinate derivative [RhH₂{κ³P,Ge,P-GeMe(pyrmPⁱPr₂)₂CMe₂}(PPh₃)] ( 10 ). Complexes 3 and 5 are catalyst precursors for the hydroboration of styrene, 4-vinyltoluene and 4-vinylfluorobenzene with catecholborane under mild conditions.     

Nitrides with Inverse K2[NiF4] Structure: (R1–xCa3+xN1–x/3)Bi2 with R = Rare‐Earth Metal

The novel nitrides (R_1–xCa_3+xN_1–x/3)Bi₂ (with R = La, Ce, Pr) crystallize in the K₂[NiF₄] structure type (I4/mmm, No. 139, Z = 2). Samples (La_1–xCa_3+xN_1–x/3)Bi₂ with x = 0.10, 0.05, 0.00, (Ce_1–xCa_3+xN_1–x/3)Bi₂ with x = 0.30, and (PrCa₃N)Bi₂ were obtained as single phase microcrystalline powders according to X‐ray diffraction and the crystal structure details were derived from Rietveld refinements based on X‐ray and neutron diffraction powder patterns. A partial order of R³⁺/Ca²⁺ on two crystallographic sites is governed by different ionic radii and charges. (La_1–xCa_3+xN_1–x/3)Bi₂ and (Ce_1–xCa_3+xN_1–x/3)Bi₂ exhibit small homogeneity ranges and typically a nitrogen deficiency. In contrast, for (PrCa₃N)Bi₂ no indications for a significant homogeneity range or deficiency of nitrogen was observed. (La_1–xCa_3+xN_1–x/3)Bi₂ with x = 0.05 is a diamagnet. X‐ray absorption spectroscopy at the CeL₃‐edge as well as magnetic susceptibility measurements evidence that (Ce_1–xCa_3+xN_1–x/3)Bi₂ with x = 0.30 contains Ce³⁺ in the 4f¹ configuration. According to electrical resistivity data, samples from all three systems are heavily doped semiconductors.     

Synthesis and characterization of diiron(I) 1,2-dimethylethanedithiolate complexes with bridging or chelating 1,2-bis(diphenylphosphino)ethylene

The reaction of complex [μ-SCH(CH₃)CH(CH₃)S-μ]Fe₂(CO)₆ (1) with trans-1,2-bis(diphenylphosphino)ethylene (trans-dppv) in the presence of Me₃NO?2H₂O in CH₂Cl₂/CH₃CN afforded complex {[μ-SCH(CH₃)CH(CH₃)S-μ]Fe₂(CO)₅}₂(trans-dppv) (2) with a bridging dppv. Complex [μ-SCH(CH₃)CH(CH₃)S-μ]Fe₂(CO)₄(cis-dppv) (3) was prepared by the reaction of 1 with cis-dppv and Me₃NO?2H₂O. The new complexes 2 and 3 were characterized by elemental analysis, spectroscopy, and X-ray diffraction analysis.     

Preparation and Reactivity of Mixed‐Ligands Hydride Complexes [RuHCl(CO)(PPh3)2{P(OR)3}]

Mixed‐ligands hydride complexes [RuHCl(CO)(PPh₃)₂{P(OR)₃}] ( 2 ) (R = Me, Et) were prepared by allowing [RuHCl(CO)(PPh₃)₃] ( 1 ) to react with an excess of phosphites P(OR)₃ in refluxing benzene. Treatment of hydrides 2 first with triflic acid and next with an excess of hydrazine afforded hydrazine complexes [RuCl(CO)(κ¹‐NH₂NHR1)(PPh₃)₂{P(OR)₃}]BPh₄ ( 3 , 4 ) (R1 = H, CH₃). Diethylcyanamide derivatives [RuCl(CO)(N≡CNEt₂)(PPh₃)₂{P(OR)₃}]BPh₄ ( 5 ) were also prepared by reacting 2 first with HOTf and then with N≡CNEt₂. The complexes were characterized spectroscopically and by X‐ray crystal structure determination of [RuHCl(CO)(PPh₃)₂{P(OEt)₃}] ( 2b ).     

Bandgap engineering of SrTiO3/NaTaO3 heterojunction for visible light photocatalysis

Hybrid density functional of HSE06 has been adopted to investigate the geometry and electronic properties of SrTiO₃/NaTaO₃ heterostructures in contrast with the cubic SrTiO₃ and cubic NaTaO₃. The SrTiO₃/NaTaO₃ heterostructures with varied monolayers of SrTiO₃ and NaTaO₃ units are constructed, and all the heterojunction systems have the smaller bandgaps as compared with those of pure SrTiO₃ and NaTaO₃. For the (SrTiO₃)_m/(NaTaO₃)_n (m + n = 10) systems, the bandgap decreases in the order of m = 1, 2, 3, 4, 5, while the bandgap increases in the order of m = 5, 6, 7, 8, 9. We also investigate the (SrTiO₃)_m/(NaTaO₃)_m systems (m = 1, 2, 3, 4, 5, 6, 7), and the calculated results suggest that the (SrTiO₃)₆/(NaTaO₃)₆ system has the smallest bandgap of 2.58 eV in our considered systems. This study indicates the development of SrTiO₃/NaTaO₃ heterojunction is a promising way to improve the photocatalytic activities of SrTiO₃ and NaTaO₃.     

Schrittweise Darstellung von verzweigten tripodalen Chlor‐Methyl‐Siloxanen der allgemeinen Formel tBuSi[{OSiMe2}yOSiMe3–xClx]3 [x = 0–3; y = 0–2] sowie Synthese der Silanole tBuSi[(OSiMe2)xOH]3 [x = 1, 2] und des bicyclischen Siloxans tBuSi(OSiMe2O)3SitBu

The branched tripodal chloro‐methyl‐siloxanes of the general formula tBuSi[{OSiMe₂}_yOSiMe_3–xCl_x]₃ [x = 0–3; y = 0–2] were synthesized, starting with tert‐Butyl‐trisilanol ( 1 ). The treatment of 1 with the chloro‐methyl‐silanes (Me_3–xSiCl_x+1) (x = 0–3) in the presence of triethylamine leads to the compounds tBuSi(OSiMe₂Cl)₃ ( 2 ), tBuSi(OSiMeCl₂)₃ ( 3 ) and tBuSi(OSiCl₃)₃ ( 4 ). The siloxanes 2 – 4 are colourless oily liquids, which can be purified by distillation. Their yields decrease with the number of chloro substituents. In the reaction of compound 2 with three equivalents of water the silantriol tBuSi(OSiMe₂OH)₃ ( 5 ) is generated which is used to create the branched tripodal chloro‐methyl‐siloxanes tBuSi(OSiMe₂OSiMe₃)₃ ( 6 ), tBuSi(OSiMe₂OSiMe₂Cl)₃ ( 7 ), tBuSi(OSiMe₂OSiMeCl₂)₃ ( 9 ) and tBuSi(OSiMe₂OSiCl₃)₃ ( 10 ). Compound ( 7 ) is only a side product with a yield of 25 %., The cyclic tBuSi[{(OSiMe₂)₂Cl}(OSiMe₂)₃O] ( 8 ) can be isolated and characterised. The transformation of the compound tBuSi(OSiMe₂OSiMe₂Cl)₃ ( 7 ) into the trisilanol tBuSi(OSiMe₂OSiMe₂OH)₃ ( 11 ) allows to prepare the tripodale siloxane tBuSi(OSiMe₂OSiMe₂OSiMe₃)₃ ( 12 ) in good yields., The reaction of tBuSi(OSiMe₂Cl)₃ ( 2 ) with tert‐butyl trisilanol 1 leads to the formation of bicyclic tBuSi(OSiMe₂O)₃SitBu ( 13 ). An X‐ray structure determination on 13 reveals a [3.3.3]‐bicycle with a C₃ axis, which crystallizes in the cubic crystal system in the space group Pa . The reported compounds 2 – 13 were characterised by NMR‐ and IR spectroscopy ( 5 , 11 ) and show correct elemental analyses. The ²⁹Si‐NMR‐data of the compounds show interesting trends with respect to the Si–O chain length and the chloro substistuents.     

Ba3P3I2 und Ba5P5I3: Stufenweise Oxidation von Bariumphosphid mit Iod

Ba₃P₃I₂ and Ba₅P₅I₃: Stepwise Oxidation of Barium Phosphide with Iodine The novel compounds Ba₃P₃I₂ and Ba₅P₅I₃ were obtained by the reaction of barium phosphide with iodine. The air and moisture sensitive compounds crystallize in new structure types: Ba₃P₃I₂ (oP32; Pnma; a = 1719.5(4) pm; b = 462.4(2) pm; c = 1427.2(4) pm; Z = 4; R(F)_N′ = 0.067 (N′(hkl) = 2667), Ba₅P₅I₃ (mC52; C2/m; a = 4266.4(13) pm; b = 456.3(2) pm; c = 943.1(3) pm; ß = 92.20(3)°; Z = 4; R(F)_N′ = 0.040 (N′(hkl) = 3909). Both can be described as double salts of a hypothetic Zintl Phase ('Ba₂P₃' or 'Ba₇P₁₀') and a halide (BaI₂). Characteristic structural features are P₃ and P₄ chains, corresponding to Ba₃[P₃]I₂ and Ba₁₀[P₃]₂[P₄]I₆, respectively. The bonding characteristics will be interpreted on the basis of the structure and the physical properties.