Zur Kenntnis der Dialkalimetalldichalkogenide β-Na2S2, K2S2, α-Rb2S2, β-Rb2S2, K2Se2, Rb2Se2, α-K2Te2, β-K2Te2 und Rb2Te2

On Dialkali Metal Dichalcogenides β-Na₂S₂, K₂S₂, α-Rb₂S₂, β-Rb₂S₂, K₂Se₂, Rb₂Se₂, α-K₂Te₂, β-K₂Te₂ and Rb₂Te₂ The first presentation of pure samples of α- and β-Rb₂S₂, α- and β-K₂Te₂, and Rb₂Te₂ is described. Using single crystals of K₂S₂ and K₂Se₂, received by ammonothermal synthesis, the structure of the Na₂O₂ type and by using single crystals of β-Na₂S₂ and β-K₂Te₂ the Li₂O₂ type structure will be refined. By combined investigations with temperature-dependent Guinier-, neutron diffraction-, thermal analysis, and Raman-spectroscopy the nature of the monotropic phase transition from the Na₂O₂ type to the Li₂O₂ type will be explained by means of the examples α-/β-Na₂S₂ and α-/β-K₂Te₂. A further case of dimorphic condition as well as the monotropic phase transition of α- and β-Rb₂S₂ is presented. The existing areas of the structure fields of the dialkali metal dichalcogenides are limited by the model of the polar covalence.     

Syntheses of 2-hydroperoxy-and 2-hydroxy-2H-imidazoles

Oxidation of fully substituted imidazoles 1 by singlet oxygen gives in good yield fully substituted 2-hydroperoxy-2H-imidazoles 2 . Reduction of 2 by triphenylphosphine leads to 2-hydroxy-2H-irnidazoles 3 . Limitations of the methods are reported.     

H_2O_2氧化N_2生成N_2O和H_2O机理的研究

采用量子化学计算方法研究了Ｈ２Ｏ２ 氧化Ｎ２ 生成Ｎ２Ｏ 和Ｈ２Ｏ 的机理．结果发现, Ｈ２Ｏ２ 氧化Ｎ２ 先通过１ 个四元环过渡态形成中间体Ｈ２Ｎ２Ｏ２ 分子,Ｈ２Ｎ２Ｏ２ 再通过一个五元环过渡态形成Ｎ２Ｏ和Ｈ２Ｏ．根据计算得到的每步反应的活化能,得知Ｈ２Ｏ２ 氧化Ｎ２ 生成中间体Ｈ２Ｎ２Ｏ２ 分子是整个反应的控制步骤．     

Efficient C2 functionalisation of 2H-2-imidazolines

Alkylation and oxidation of 2H-2-imidazolines, followed by regioselective deprotection, thionation and microwave-assisted Liebeskind-Srogl reaction, efficiently led to 2-aryl-2-imidazolines as new analogues of p53-hdm2 interaction inhibitors (Nutlins).     

Formal [(2+2)+2] and [(2+2)+(2+2)] nonconjugated dienediyne cascade cycloadditions

[reaction: see text] Fluoranthene 2 and heptacycle 3 are easily accessible from the reaction of diyne 1 and norbornadiene (NBD) in the presence of the rhodium catalyst. The unusual [(2+2)+(2+2)] adduct 3 was confirmed by the X-ray crystal structure analysis.     

Synthesis,Characterization and Crystal Structure of (PhCH2)2Sn(S2CENt2) and (PhCH2)2Sn(S2CNC4H8)2

Two new dibenzyltin bisditiocarbamates(PhCH2)2 Sn(S2CNEt2)2(1) and (PhCH2)2 Sn(S2CNC4H8)2(2) were synthesized by the reaction of dibenzyltin dichloride with dithiocarbamates and characterized by elemental analysis ,IR,^1H NMR and MS spectra.The crystal structures were determined by X-ray single crystal diffraction analysis.In both complexes,the tin atom is six-coordinated in a distorted octahedral configuration.In the crystals of 1,the molecular packing in unit cell reveals that the two adjacent molecules are symmetrically linked to each other in dimers by two Sn S interactions of 0.3816nm.In the crystals of 2,the molecules are packed in the unit cell in one-dimensional chain structure linked by weaker intermolecular S S conmtacts.     

新型层状磷酸铝[Al6P8O32][(C2H5)2NHCH2CH2NH3]2·[C2H5NH2CH2CH2NH2C2H5] 的合成、表征及其共模板作用

在溶剂热体系中,以N,N-二乙基乙二胺为结构导向剂,合成了Al/P为3/4的层状磷酸铝[Al6P8O32][(C2H5)2NHCH2CH2NH3]2·[C2H5NH2CH2CH2NH2C2H5]单晶,并通过X射线单晶衍射结构分析.XRD,ICP,元素分析,差热-热重分析等手段进行了表征.该化合物属单斜晶系,P2(1)/c空间群,晶胞参数:a=0.90945(2)nm,b=1.46424(4)nm,c=1.87572(5)nm,β=102.672(2)°,Z=4.其阴离子层由AlO4四面体和PO3(=O)四面体单元交替连接构成,形成四、六、八元环拓扑结构,无机层以ABAB方式堆积,两种质子化的有机胺分子N,N-二乙基乙二胺及其重排产物N,N′-二乙基乙二胺填充在层间.用分子动力学模拟方法,考察了标题化合物中有机胺与无机层间的相互作用,讨论了这两种有机胺的共模板作用.     

配合物[RE2(H2L)2(HL)2(2,6-H2PDA)(H2O)2]•2H2O的合成、 晶体结构及其与DNA作用方式初探

以N-(2-异丙酸)-邻羟基苯甲酰腙(C10H10N2O4, H3L)、2,6-吡啶二甲酸(2,6-H2PDA)与RE(NO3)3•nH2O (RE＝Pr, Eu)在室温下反应, 合成了配合物1 [Pr2(H2L)2(HL)2(2,6-H2PDA)(H2O)2]•2H2O和配合物2 [Eu2(H2L)2(HL)2(2,6-H2PDA)- (H2O)2]•2H2O, 对其进行了元素分析、红外光谱、紫外光谱等表征, 测定了两种配合物的晶体结构. 通过紫外吸收光谱、荧光发射光谱和稳态荧光猝灭方法及其与溴化乙锭(EB)的竞争实验研究了两种配合物与小牛胸腺DNA的作用情况. 结果表明, 两种配合物与小牛胸腺DNA均是以插入方式结合的.     

The alkali hypophosphites KH2PO2, RbH2PO2 and CsH2PO2

The structures of the hypophosphites KH₂PO₂ (potassium hypophosphite), RbH₂PO₂ (rubidium hypophosphite) and CsH₂PO₂ (caesium hypophosphite) have been determined by single‐crystal X‐ray diffraction. The structures consist of layers of alkali cations and hypophosphite anions, with the latter bridging four cations within the same layer. The Rb and Cs hypophosphites are isomorphous.     

CeO2及Pt/CeO2催化剂上H2、O2的作用特性

采用TPD、TPR、FT-IR和TPEC等方法研究了CeO_2及Pt/CeO_2上H_2、O_2作用特性。结果表明, Pt促进CeO_2还原, 并形成高活动性氢物种。Pt的存在使吸H_2和放氢温度下阵达300 ℃。部分还原的CeO_2常温下吸附氧形成分子离子氧物种(O_2~-, O_2~(2-)), Pt的存在改变氧化铈催化剂在常温下氧吸附物种的形态, 以解离态存在。氧化铈上吸附的氧物种在升温时可部分脱附, 高于170 ℃时则转化为晶格氧。     

Zur Kristallstruktur von Rb2C2 und Cs2C2

On the Crystal Structure of Rb₂C₂ and Cs₂C₂ By reaction of rubidium or caesium solved in liquid ammonia with acetylene AC₂H with A = Rb, Cs was obtained, which was subsequently converted into the binary acetylide A₂C₂ in vacuum at temperatures of 520 K (Rb₂C₂) and 470 K (Cs₂C₂) using a surplus of the respective alkali metal. The crystal structures of the very air sensitive compounds were solved and refined by a combination of both neutron and X‐ray powder diffraction data. Rb₂C₂ as well as Cs₂C₂ coexist in two modifications. The hexagonal modification (P 6 2m, Z = 3) crystallises in the known Na₂O₂ structure type with two crystallographic independent sites for the C₂^2– dumbbells. For the orthorhombic modification (Pnma, Z = 4) a new structure type was found, which is related to the PbCl₂ structure type with ordered C₂^2– dumbbells occupying the Pb sites. Temperature dependent investigations between 4 K and the decomposition temperature by the means of neutron and X‐ray powder diffraction resulted in a very complex dynamic disorder of the C₂ dumbbells, which is still not completely understood. The frequencies of the C–C stretching vibration determined by the help of Raman spectroscopy fit nicely to the results obtained for other alkali metal acetylides and alkali metal hydrogen acetylides. These results seem to indicate that the electronegativity of the alkali metal has a strong influence on the frequency of the C–C stretching vibration.     

Darstellung und Kristallstruktur der Pnictidoxide Na2Ti2As2O und Na2Ti2Sb2O

Preparation and Crystal Structure of the Pnictide Oxides Na₂Ti₂As₂O and Na₂Ti₂Sb₂O Na₂Ti₂As₂O and Na₂Ti₂Sb₂O were synthesized in form of very easily hydrolysed metallic-grey powders by reaction of Na₂O and TiAs resp. TiSb in sealed tantalum tubes under argon. The tetrahedral bodycentered crystallizing compounds from a modified anti-K₂NiF₄ structure type [1] (also called Eu₄As₂O-type [2,3]), space group I4/mmm (no. 139), with the lattice constants for Na₂Ti₂As₂O: a = 407.0(2) pm, c = 1528.8(4) pm and for Na₂Ti₂Sb₂O: a = 414.4(0) pm, c = 1656.1(1) pm. Magnetic measurements of powder samples of Na₂Ti₂Sb₂O show antiferromagnetic interaction within the Ti—O-layers. Superconductivity was not found by ac-shielding method down to 4 K.     

Solid-supported [2+2+2] cyclotrimerizations

The transition-metal-catalyzed [2+2+2] cyclotrimerization of a diyne and an alkyne provides a convergent route to highly-substituted aromatic rings. This reaction possesses distinct drawbacks, especially low chemo- and regioselectivities, which hamper its application in combinatorial synthesis. These problems have been solved by the development of solid-supported [2+2+2]-cycloaddition reactions. If conducted on a solid-support, this reaction enables rapid combinatorial access to diverse sets of carbo- and heterocyclic small-molecule arrays. The scope of this methodology has been investigated by examining different immobilization strategies, different diyne precursors, and a variety of functionalized alkyne reaction partners. Overall, isoindoline, phthalan, and indan libraries were assembled in good to excellent yields and with high purities.     

Cl_2 2HI=2HCl I_2反应机理的理论研究

分别在MP2/3-21G!!、CCSD(T)/3-21G!!//MP2/3-21G!!和B3LYP/3-21G!!3种水平上,计算研究了气相反应Cl2 2HI=2HCl I2的机理,求得一系列四中心和三中心的过渡态.通过比较六种反应通道的活化能大小,得到了相同的结论:双分子基元反应Cl2 HI"HCl ICl和ICl HI"I2 HCl的最小活化能小于Cl2、HI和ICl的解离能,从理论上证明了反应Cl2 2HI=2HCl I2将优先以分子与分子作用形式分两步完成.用内禀反应坐标(IRC)验证了MP2/3-21G!!方法计算得到的过渡态.     

Quenching of I(2P1/2) by NO2, N2O4, and N2O

Quenching of excited iodine atoms (I(5p5, 2P1/2)) by nitrogen oxides are processes of relevance to discharge-driven oxygen iodine lasers. Rate constants at ambient and elevated temperatures (293-380 K) for quenching of I(2P1/2) atoms by NO2, N2O4, and N2O have been measured using time-resolved I(2P1/2) --> I(2P3/2) 1315 nm emission. The excited atoms were generated by pulsed laser photodissociation of CF3I at 248 nm. The rate constants for I(2P1/2) quenching by NO2 and N2O were found to be independent of temperature over the range examined with average values of (2.9 +/- 0.3) x 10(-15) and (1.4 +/- 0.1) x 10(-15) cm3 s(-1), respectively. The rate constant for quenching of I(2P1/2) by N2O4 was found to be (3.5 +/- 0.5) x 10(-13) cm3 s(-1) at ambient temperature.     

Fe2P2O7(H2O)2

The compound diiron diphosphate dihydrate, Fe₂P₂O₇(H₂O)₂, was synthesized hydro­thermally and crystallizes in the monoclinic space group P2₁/n. The compound has a somewhat open framework made up of edge‐sharing iron(II) octahedra that form chains connected by five bridging diphosphates. The remaining octahedral site of each iron is occupied by coordinated water. The H atoms of the water molecules all point into a common channel.     

Crystal Structures of [Bu2Sn(O2PPh2)2], [Ph2Sn(O2PPh2)2], and [PhClSn(O2PPh2)OMe]2. Raman Spectra of [Ph2Sn(O2PPh2)2] and [PhClSn(O2PPh2)OMe]2

[(n‐Bu)₂Sn(O₂PPh₂)₂] ( 1 ), and [Ph₂Sn(O₂PPh₂)₂] ( 2 ) have been synthesized by the reactions of R₂SnCl₂ (R=n‐Bu, Ph) with HO₂PPh₂ in Methanol. From the reaction of Ph₂SnCl₂ with diphenylphosphinic acid a third product [PhClSn(O₂PPh₂)OMe]₂ ( 3 ) could be isolated. X‐ray diffraction studies show 1 to crystallize in the monoclinic space group P2₁/c with a = 1303.7(1) pm, b = 2286.9(2) pm, c = 1063.1(1) pm, β = 94.383(6)°, and Z = 4. 2 crystallizes triclinic in the space group , the cell parameters being a = 1293.2(2) pm, b = 1478.5(4) pm, c = 1507.2(3) pm, α = 98.86(3)°, β = 109.63(2)°, γ = 114.88(2)°, and Z = 2. Both compounds form arrays of eight‐membered rings (SnOPO)₂ linked at the tin atoms to form chains of infinite length. The dimer 3 consists of a like ring, in which the tin atoms are bridged by methoxo groups. It crystallizes triclinic in space group with a = 946.4(1) pm, b = 963.7(1) pm, c = 1174.2(1) pm, α = 82.495(6)°, β = 66.451(6)°, γ = 74.922(6)°, and Z = 1 for the dimer. The Raman spectra of 2 and 3 are given and discussed.     

Synthesis and Crystal Structure of[Ni(C5H2N2O4)(2, 2'-bipy)(H2O)2]·2H2O

The crystal structure of [Ni(C5H2N2O4)(2, 2?-bipy)(H2O)2]·2H2O 1 has been determined by X-ray diffraction. Crystal data: triclinic system, space group P ī with a = 7.9424(3), b = 9.9417(3), c = 12.1867(3) (A。）, α = 84.771(1), β = 77.375(2), γ = 68.993(2)°, C15H18N4O8Ni, Mr = 440.7, V = 876.16(5) (A。）3, Z = 2, Dc = 1.672 g/cm3, F(000) = 456, ((MoK() = 1.162 mm-1, the final R = 0.0464 and wR = 0.1055 for 3026 observed reflections with I > 2((I). In the title compound, the nickel ion is coordinated by a nitrogen atom and an oxygen atom from the orotate ligand, two nitrogen atoms from 2, 2'-bipy and two oxygen atoms from the coordinated water molecules in a distorted octahedral geometry. The presence of intermolecular hydrogen bonding and (-( stacking interaction of aromatic rings from 2, 2'-bipy results in a 3D structure.     

Sc2MgGa2 and Y2MgGa2

Scandium magnesium gallide, Sc₂MgGa₂, and yttrium magnesium gallide, Y₂MgGa₂, were synthesized from the corresponding elements by heating under an argon atmosphere in an induction furnace. These intermetallic compounds crystallize in the tetragonal Mo₂FeB₂‐type structure. All three crystallographically unique atoms occupy special positions and the site symmetries of (Sc/Y, Ga) and Mg are m2m and 4/m, respectively. The coordinations around Sc/Y, Mg and Ga are pentagonal (Sc/Y), tetragonal (Mg) and triangular (Ga) prisms, with four (Mg) or three (Ga) additional capping atoms leading to the coordination numbers [10], [8+4] and [6+3], respectively. The crystal structure of Sc₂MgGa₂ was determined from single‐crystal diffraction intensities and the isostructural Y₂MgGa₂ was identified from powder diffraction data.     

The bivalent metal hypophosphites Sr(H2PO2)2, Pb(H2PO2)2 and Ba(H2PO2)2

The structures of isomorphous monoclinic strontium and lead bis­(di­hydrogenphosphate), Sr(H₂PO₂)₂ and Pb(H₂PO₂)₂, and orthorhombic barium bis­(di­hydrogen­phos­phate), Ba(H₂PO₂)₂, consist of layers of hypophosphite anions and metal cations exhibiting square antiprismatic coordination by O atoms. The Sr and Pb atoms are located on sites with point symmetry 2, and the Ba atoms are on sites with point symmetry 222. Within the layers, each anion bridges four metal cations.