Synthese und Kristallstruktur der Spiro-Verbindung [(i-Pr)2P(S)NSiMe3]2SnCl2

Synthesis and Crystal Structure of the Spirocycle [(i-Pr)₂P(S)NSiMe₃]₂SnCl₂ The reaction of (i-Pr)₂P(S)N(SiMe₃)₂ ( 1 ) with SnCl₄ in 2:1 ratio yields under elimination of ClSiMe₃ the four-membered spirocycle [(i-Pr)₂P(S)NSiMe₃]₂SnCl₂ ( 2 ). The molecular structure of 2 was investigated by an X-ray structure analysis. Compound 2 crystallises in the monoclinic space group P2₁, Z = 2, a = 938.1(1), b = 1 424.1(2), c = 1 207.2(1) pm, β = 110.59(1)°, R = 2.05% for 4 102 reflexions. Compound 2 is a spirocycle with two Sn? N? P? S-rings joined at tin. The two rings are in cis-position.     

Neue phosphidoverbrückte Mehrkernkomplexe des Ag und Zn. Die Kristallstrukturen von [Ag3(PPh2)3(PnBu2tBu)3], [Ag4(PPh2)4(PR3)4] (PR3 = PMenPr2, PnPr3), [Ag4(PPh2)4(PEt3)4]n, [Zn4(PPh2)4Cl4(PRR2)2] (PRR′2 = PMenPr2, PnBu3, PEt2Ph), [Zn4(PhPSiMe3)4Cl4(C4H8O)2] und [Zn4(PtBu2)4Cl4]

New Phosphido-bridged Multinuclear Complexes of Ag and Zn. The Crystal Structures of [Ag₃(PPh₂)₃(PⁿBu₂^tBu)₃], [Ag₄(PPh₂)₄(PR₃)₄] (PR₃ = PMeⁿPr₂, PⁿPr₃), [Ag₄(PPh₂)₄(PEt₃)₄]_n, [Zn₄(PPh₂)₄Cl₄(PRR′₂)₂] (PRR′₂ = PMeⁿPr₂, PⁿBu₃, PEt₂Ph), [Zn₄(PhPSiMe₃)₄Cl₄(C₄H₈O)₂] and [Zn₄(P^tBu₂)₄Cl₄] AgCl reacts with Ph₂PSiMe₃ in the presence of tertiary Phosphines (PⁿBu₂^tBu, PMeⁿPr₂, PⁿPr₃ and PEt₃) to form the multinuclear complexes [Ag₃(PPh₂)₃(PⁿBu₂^tBu)₃] 1 , [Ag₄(PPh₂)₄(PR₃)₄] (PR₃ = PMeⁿPr₂ 2 , PⁿPr₃ 3 ) and [Ag₄(PPh₂)₄(PEt₃)₄]_n 4 . In analogy to that ZnCl₂ reacts with Ph₂PSiMe₃ and PRR′₂ to form the multinuclear complexes [Zn₄(PPh₂)₄Cl₄(PRR′₂)₂] (PRR′₂ = PMeⁿPr₂ 5 , PⁿBu₃ 6 , PEt₂Ph 7 ). Further it was possible to obtain the compounds [Zn₄(PhPSiMe₃)₄Cl₄(C₄H₈O)₂] 8 and [Zn₄(P^tBu₂)₄Cl₄] 9 by reaction of ZnCl₂ with PhP(SiMe₃)₂ and ^tBu₂PSiMe₃, respectively. The structures were characterized by X-ray single crystal structure analysis. Crystallographic data see “Inhaltsübersicht”.     

Periphere Anbindung von Quecksilber(II)-iodid an dreikernige Molybdän-Schwefel-Dithiophosphinatocluster: [Mo3S4(R2PS2)4HgI2] (R = Et,Pr)

Peripheral Bonding of Mercury(II) Iodide to Trinuclear Molybdenum-Sulfur-Dithiophosphinato Clusters: [Mo₃S₄(R₂PS₂)₄HgI₂] (R = Et, Pr) Reaction of Mo₃S₄(R₂PS₂)₄ 1 (a : R = Et, b : R = Pr) with HgI₂ in THF yields the diamagnetic title complexes [Mo₃S₄(R₂PS₂)₄HgI₂] 3 . The crystal structure of [ 3a (H₂O)] · 2 CH₂Cl₂ shows the complexes to consist of a triangular array of Mo atoms which are bridged by μ₂? S atoms and capped by a μ₃? S atom. Each of the Mo atoms is chelated by a dithiophosphinato ligand Et₂PS₂^? and in addition two Mo atoms are bridged by a Et₂PS₂^? ligand while the H₂O molecule is bonded weakly to the third Mo atom. Thus, all Mo atoms reveal a distorted octahedral coordination sphere. HgI₂ is ?peripherally”? bonded to the cluster via two S atoms, one of which belongs to a chelating ligand and the other one to the bridging ligand. Space group P1 , lattice constants a = 12.157(2), b = 15.284(3), c = 16.049(3) Å, α = 115.56(1), β = 107.35(1), and γ = 94.62(1)°; Z = 2, d_calc = 2.23 mg/mm³; 4 236 observed reflections, R = 0.068. In organic solvents complexes 3 are strong electrolytes. VT-³¹P NMR data suggest a stepwise dissociation of 3 with formation of [Mo₃S₄(R₂PS₂)₃] ⁺[(R₂PS₂)HgI₂]^? and elimination of the bridging ligand from the cluster.     

Synthese und Kristallstruktur eines μ-Methylen-μ-hydrido-dialanats [R2Al(μ-CH2)(μ-H)AlR2]− (R = CH(SiMe3)2)

Synthesis and Crystal Structure of a μ-Methylene-μ-hydrido-dialanate [R₂Al(μ-CH₂)(μ-H)AlR₂]^? (R = CH(SiMe₃)₂) tert-Butyl lithium reacts with the recently synthesized methylene bridged dialuminium compound [(Me₃Si)₂CH]₂Al? CH₂? Al[CH(SiMe₃)₂]₂ 2 in the presence of TMEDA under β-elimination; the thereby formed hydride anion is bound in a chelating manner by both unsaturated aluminium atoms forming a 3c–2e–Al? H? Al bond. The crystal structure of the product shows two independent molecules differing only slightly in bond lengths and angles, but significantly in conformation. While one of the Al₂CH heterocycles deviates little from planarity with a rough C₂ symmetry for the whole anion, the other one is folded with an angle of 21.1° and the arrangement of the substituents is best described by C_s symmetry.     

Synthesis,Crystal Structure and Properties of [Mn(hdpa)2(N(CN)2)2] and [Co(hdpa)2(N(CN)2)2] (hdpa = 2, 2'‐Dipyridylamine)

Two new transition metal(II) complexes [M(hdpa)₂(N(CN)₂)₂] (M = Mn ( 1 ), Co ( 2 ); hdpa = 2, 2'‐dipyridylamine) have been prepared and characterized structurally and magnetically. Both compounds crystallize in the monoclinic space group C2/c. 1 and 2 are isotypic with the unit cell parameters a = 8.634(9), b = 13.541(14), c = 21.99(2) Å, β = 94.806(18)°, and V = 2562(5) ų for 1 , a = 8.617(3) Å, b = 13.629(5)Å, c = 21.598(8)Å, β = 94.593(6)°, and V = 2528.4(15)ų for 2 , and Z = 4 for both. According to X‐ray crystallographic studies, each metal(II) ion was six‐coordinated with four nitrogen atoms from two bidentate hdpa ligand and two nitrogen atoms from two N(CN)^— anions to form slightly distorted octahedrons. Adjacent complex molecules are connected by hydrogen bonds or π···π interactions to form three‐dimensional network. The IR and UV spectroscopy were measured and the magnetic behaviors were investigated.     

Phosphinophosphiniden-Phosphorane tBu2P?P = P(R)tBu2 aus Li(THF)2[η2-(tBu2P)2P] und Alkylhalogeniden

The Phosphinophosphinidene-phosphoranes ^tBu₂P? P = P(R)^tBu₂ from Li(THF)₂[η²-(^tBu₂P)₂P] and Alkyl Halides We report the formation of ^tBu₂P? P = P(R)^tBu₂ a and (^tBu₂)₂PR b (with R = Me, Et, ⁿPr, ⁱPr, ⁿBu, PhCH₂, H₂C = CH? CH₂ and CF₃) reactions of Li(THF)₂[η²-(^tBu₂P)₂P] 2 with MeCl, MeI, EtCl, EtBr, ⁿPrCl, ⁿPrBr, ⁱPrCl, ⁿBuBr, PhCH₂Cl, H₂C = CH? CH₂Cl or CF₃Br. In THF solutions the ylidic compounds a predominate, whereas in pentane the corresponding triphosphanes b are preferrably formed. With ClCH₂? CH = CH₂ only b is produced; CF₃Br however yields both ^tBu₂P? P = P(Br)^tBu₂ and ^tBu₂P? P = P(CF₃)^tBu₂, but no b . The ratio of a:b is influenced by the reaction temperature, too. The compounds ^tBu₂P? P = P(Et)^tBu₂ 4a and (^tBu₂P)₂PEt 4 b , e. g., are produced in a ratio of 4:3 at ?70°C in THF, and 1:1 at 20°C; whereas 1:1 is obtained at ?70°C in pentane, and 1:2 at 20°C. Neither ^tBuCl nor H₂C = CHCl react with 2 . The compounds a decompose thermally or under UV irradiation forming ^tBu₂PR and the cyclophosphanes (^tBu₂P)_nP_n.     

Building und Reaktionen des Phosphanyliden-Phosphorans (tBu)2P?P = PX(tBu)2 (X = Br,Cl)

Formation and Reaction of the Phosphanylidene-phosphorane (tBu)₂P? P = PX(tBu)₂ (X = Br, Cl) The formation of (tBu)₂P? P = P(Br)tBu₂ 1 from [(tBu)₂P]₂PLi and BrH₂C? CH₂Br begins with an exchange of Li against Br and is then determined by the migration of Br from the secondary P atom in [(tBu)₂P]₂PBr 6 to the primary P in 1 . Similarly, (tBu)₂P? P = PC1(tBu)₂ 2 is obtained starting from PCl₃ and LiP(tBu)₂. The formation of Phospanylidene—phosporane is not influenced by the choice o the halogene substituent, but the presence of the tBu groups is strongly required. (tBu)₂P? P(Li)? P(SiMe₃)₂ e. g., yields (tBu)₂P? P(br)? P(SiMe₃)₂ with BrH₂C? CH₂Br; however neither this nor (tBu)₂P? P(Cl)? P(SiMe₃)₂ do rearrange to a Phosphanylidene-phosphorane. The F₃C substituent could be neglected in this investigation as [(F₃C)₂P]₂P? SiMe₃ cannot be lithiated by means of BuLi. Compounds 1 and 2 display a charateristic temperature dependent behavior. While 1 at +20°C decomposes via the reactive intermediate (tBu)₂P? P to from the cyclophosphanes P₃[P(tBu)₂]₄, it gives crystals of [(tBu)₂P]₂P? p[P(tBu)₂]₂ at ?20°C (from a solution in toluene). Reacting 1 with tBuLi produces (tBu)₂P? P = P(H)tBu₂ 20 and (tBu)₂P? P(H)? P(tBu)₂ 14 . Initially, a transmetallation yield tBuBr and (tBu)₂ P? P=Pli(tBu)₂ 21 ,then LiBr and isobutene are eliminated and 20 is formed which can rearrange to produce 14 . Without the elimination of isobutene, 1 react with nBuLi to give 21 witch can be trapped with Me₃SiCl as (tBu)₂P? P(tBu)₂ 23 . The main product in in this reaction is however [(tBu)₂P]₂P? nBu 22 .     

NO2在Ag/Pt(110)双金属表面上的吸附和分解

利用俄歇电子能谱(AES)和程序升温脱附谱(TDS)研究了NO₂在Ag/Pt(110)双金属表面的吸附和分解.室温下NO₂ 在Ag/Pt(110)双金属表面发生解离吸附, 生成NO(ads)和O(ads)表面吸附物种. 在升温过程中NO(ads)物种发生脱附或者进一步分解. 500 K时NO₂在Ag/Pt(110)双金属表面发生解离吸附生成O(ads)表面吸附物种. Pt 向Ag传递电子, 从而削弱Pt－O键的强度, 降低O(ads)从Pt 表面的并合脱附温度. 发现能够形成具有稳定组成的Ag/Pt(110)合金结构, 其表现出与Pt(110)-(1×2)相似的解离吸附NO₂能力, 但与O(ads)的结合明显弱于Pt(110)-(1×2). 该AgPt(110)合金结构是可能的低温催化直接分解氮氧化物活性结构.     

Bildung von NH4[Hg3(NH)2](NO3)3 und Umwandlung in [Hg2N](NO3)

Formation of NH₄[Hg₃(NH)₂](NO₃)₃ and Transformation to [Hg₂N](NO₃) NH₄[Hg₃(NH)₂](NO₃)₃ ( 1 ) and [Hg₂N](NO₃) ( 2 ) are obtained from conc. aqueous ammonia solutions of Hg(NO₃)₂ at ambient temperature and under hydrothermal conditions at 180 °C, respectively, as colourless and dark yellow to light brown single crystals. The crystal structures {NH₄[Hg₃(NH)₂](NO₃)₃: cubic, P4₁32, a = 1030.4(2) pm, Z = 4, R_all = 0.028; [Hg₂N](NO₃): tetra gonal, P4₃2₁2, a = 1540.4(1), c = 909.8(1) pm, Z = 4, R_all = 0.054} have been determined from single crystal data. Both exhibit network type structures in which [HNHg₃] and [NHg₄] tetrahedra of the partial structures of 1 and 2 are connected via three and four vertices, respectively. 1 transforms at about 270 °C in a straightforward reaction to 2 whereby the decomposition products of NH₄NO₃ are set free. 2 decomposes at about 380 °C forming yellow HgO. Most certainly, 1 is identical with a mineral previously analyzed as “Hg(NH₂)(NO₃)” with the same Hg:N:O ratio.     

Die Kristallstruktur des Tetrakis(di-tert.-butylphosphino)diphosphans. [(tBu)2P]2P?P[P(tBu)2]2

The Crystal Structure of Tetrakis(di-tert.-butylphosphino)diphosphane [(tBu)₂P]₂P? P[P(tBu)₂]₂ [(tBu)₂P]₂P? P[P(tBu)₂]₂ 1 obtained at ?20°C from a solution of (tBu)₂P? P=P(Br)tBu₂ forms yellow crystals (regular hexagons). 1 crystallizes monoclinic in the space group C2/c with a = 2145.6pm, b = 1137pm, c = 1696.1pm, β = 110.075° and Z = 4 formula units in the elementary cell. Due to high steric load the bond angles at the tertiary P atoms with δ = 115.7° are significantly larger than those at the primary P atoms with δ = 108.6°.     

具有分级多孔结构和光催化性质的核-壳纳米球(HP-Fe2O3@TiO2)

通过溶剂热和溶胶-凝胶涂层法, 设计并制备了具有分级多孔结构和光催化性质的核-壳纳米球(HP-Fe₂O₃@TiO₂). 透射电子显微镜(TEM)照片证明所得HP-Fe₂O₃@TiO₂样品具备分级多孔结构, 这是因为HP-Fe₂O₃@TiO₂的内核-Fe₂O₃具有大孔空隙, 同时外壳-TiO₂具有介孔空隙. 此外, 通过X射线衍射(XRD)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、X射线光电子能谱(XPS)以及氮气吸附-脱附曲线深入研究了HP-Fe₂O₃@TiO₂的结构及其性质. 分别在可见及紫外光照下, 研究了样品在H₂O₂体系下的光催化降解亚甲基蓝(MB)的性质. 所观察到的HP-Fe₂O₃@TiO₂纳米球的光催化性能, 可归因于核-壳结构的协同作用, 这进一步表明, TiO₂外壳对α-Fe₂O₃的光催化活性有重要影响作用. 在可见光照射下, HP-Fe₂O₃@TiO₂ (1 mL Ti(OC₄H₉)₄ (TBT))具有较优异的光催化活性. 同时, HP-Fe₂O₃@TiO₂ (4mL TBT)具备优异的单分散形貌, 并在紫外光照射下, 表现出最优的光催化活性.     

Efficient h/d exchange reactions of alkyl-substituted benzene derivatives by means of the Pd/C-H(2)-D(2)O system

A method for efficient and extensive H/D exchange of substituted benzene derivatives which is catalyzed by heterogeneous Pd/C in D(2)O as a deuterium source under hydrogen atmosphere is described. Multi-deuterium incorporation into unactivated linear or branched alkyl chains that bear a carboxyl, hydroxyl, ether, ester, or amide moiety and are connected with a benzene ring was achieved by using the Pd/C-H(2)-D(2)O system. The present method does not require expensive deuterium gas or any special equipment.     

Zur Bildung und Struktur der Phosphinophosphiniden-phosphorane tBu2P?PP(Me)tBu2 1, tBu(Me3Si)P?PP(Me)tBu2 2 und tBu2P?PP(Br)tBu2 3

Synthesis and Structure of Phosphinophosphinidene-phosphoranes tBu₂P? P?P(Me)tBu₂ 1, tBu(Me₃Si)P? P?P(Me)tBu₂ 2, and tBu₂P? P?P(Br)tBu₂ 3 A new method for the synthesis of 1 and 2 (Formulae see ?Inhaltsübersicht”?) is reported based on the reaction of 5 with substitution reagents (Me₂SO₄ or CH₃Cl). The results of the X-ray structure determination of 1 and 2 are given and compared with those of 3 . While in 3 one P? P distance corresponds to a double bond and the other P? P distance to a single bond (difference 12.5 pm) the differences of the P? P distances in 1 and 2 are much smaller: 5.28 pm in 1 , 4.68 pm in 2 . Both 1 and 2 crystallize monoclinic in the space group P2₁/n (Z = 4). 2 additionally contains two disordered molecules of the solvent pentane in the unit cell. Parameters of 1 : a = 884.32(8) pm, b = 1 924.67(25) pm, c = 1 277.07(13) pm, β = 100.816(8)°, and of 2 : a = 1 101.93(12) pm, b = 1 712.46(18) pm, c = 1 395.81(12) pm, β = 111.159(7)°, all data collected at 143 K. The skeleton of the three P atoms is bent (PPP angle 100.95° for 1 , 100.29° for 2 and 105.77° for 3 ). Ab initio SCF calculations are used to discuss the bonding situation in the molecular skeleton of the three P atoms of 1 and 3 . The results show a significant contribution of the ionic structure R₂P? P(^?)? P(⁺)(X)R₂. The structure with (partially) charged P atoms is stabilized by bulky polarizable groups R (as tBu) as compared to the fully covalent structure R₂P? P(X)? PR₂.     

MgH2+20%(w)MgTiO3复合材料的吸/放氢性能

为了降低MgH₂的吸放氢温度, 提高其吸放氢动力学性能, 本文通过球磨方法制备了MgH₂+20%(w)MgTiO₃复合储氢材料, 并研究了其储氢性能. X射线衍射(XRD)结果表明, MgTiO₃在与MgH₂球磨过程中生成Mg₂TiO₄和TiO₂, 并且Mg₂TiO₄和TiO₂在体系的吸放氢过程中保持稳定, 能够对MgH₂的吸放氢过程产生催化作用. 程序升温脱附和吸/放氢动力学测试结果表明, 添加MgTiO₃后MgH₂的初始放氢温度从389 ℃降至249 ℃.150 ℃下的吸氢量从0.977%(w)提高到2.902%(w), 350 ℃下的放氢量从2.319%(w)提高到3.653%(w). 同时, MgH₂放氢反应的活化能从116 kJ·mol^-1降至95.7 kJ·mol^-1. 与MgH₂相比, MgH₂+20%(w) MgTiO₃复合材料的热力学与动力学性能均有显著提高, 这主要是由于球磨和放氢过程中原位生成的TiO₂和Mg₂TiO₄具有良好的催化活性.