Untersuchungen zu Bismutseltenerdoxidhalogeniden der Zusammensetzung Bi2SEO4X (X = Cl,Br, I)

Investigations on the Bismuth Rare‐Earth Oxyhalides Bi₂REO₄X (X = Cl, Br, I) Compounds of the composition of Bi₂REO₄X (RE = Y, La–Lu; X = Cl, Br, I) have been prepared by solid state reaction of stoichiometric mixtures of BiOX, Bi₂O₃, and RE₂O₃. They were characterized by X‐ray powder diffraction, IR spectroscopy, mass spectrometry and DTA/TG measurements as well. The crystal structure (tetragonal, P4/mmm, a ≈ 3.9 Å, c ≈ 9 Å) was determined by the Rietveld method. In the structure [M₃O₄]⁺ layers are interleaved by single halogen layers. Rare‐earth and bismuth atoms in Bi₂REO₄X are 8‐coordinated. The structure can be derived from the LiBi₃O₄Cl₂ type structure. The enthalpies of formation are derived from heats of solution. The standard entropies were calculated from low‐temperature measurements of the specific heat capacities.     

[μ‐(Me3SiCH2Sb)5–Sb1,Sb3–{W(CO)5}2] und [{(Me3Si)2CHSb}3Fe(CO)4] – zwei cyclische Komplexe mit Antimon‐Liganden

Syntheses and Crystal Structures of [μ‐(Me₃SiCH₂Sb)₅–Sb¹,Sb³–{W(CO)₅}₂] and [{(Me₃Si)₂CHSb}₃Fe(CO)₄] – Two Cyclic Complexes with Antimony Ligands cyclo‐(Me₃SiCH₂Sb)₅ reacts with [(THF)W(CO)₅] (THF = tetrahydrofuran) to form cyclo‐[μ‐(Me₃SiCH₂Sb)₅–Sb¹,Sb³–{W(CO)₅}₂] ( 1 ). The heterocycle cyclo‐ [{(Me₃Si)₂CHSb}₃Fe(CO)₄] ( 2 ) is formed by an insertion reaction of cyclo‐[(Me₃Si)₂CHSb]₃ and [Fe₂(CO)₉]. The crystal structures of 1 and 2 are reported.     

Tl4Pd3Cl10 – eine Verbindung mit neuartiger [(PdCl2Cl2/2)4]4–‐Baugruppe

Tl₄Pd₃Cl₁₀ – A Compound with a New [(PdCl₂Cl_2/2)₄]^4– Group Single crystals of Tl₄Pd₃Cl₁₀ can be obtained by hydrothermal synthesis. They show tetragonal symmetry with lattice parameters a = 15.956(1) Å and c = 14.146(1) Å, Z = 8 and space group I42d (No. 122). The atomic arrangement of Tl₄Pd₃Cl₁₀ is explored by X‐ray crystal structure analysis. Tl₄Pd₃Cl₁₀ is the first example of a new structural type with a hitherto not isolated tetramer [(PdCl₂Cl_2/2)₄]^4– group.     

cis‐trans‐Isomerie bei (Me4Sb)2[Ph2Sb2I6]

cis‐trans‐Isomerism in (Me₄Sb)₂[Ph₂Sb₂I₆] Crystals of cis‐(Me₄Sb)₂[Ph₂Sb₂I₆] ( 1 a ) are formed by reaction of PhSbI₂ and Me₄SbI in ethanol/petroleum ether at –7 °C. In ethanol/acetone crystals of trans‐(Me₄Sb)₂[Ph₂Sb₂I₆] · acetone ( 1 b ) form. The X‐ray crystal structure analyses reveal that both isomers consist of tetrahedral cations and of dimeric anions with the geometry of two edge sharing tetragonal pyramids. The phenyl groups possess apical cis ( 1 a ) or trans ( 1 b ) positions relative to the I₂SbI₂SbI₂ plane. The acetone molecules in 1 b are non coordinating.     

SnAl2OCl6, ein quaternäres Oxidchlorid mit kantenverknüpften [Al4O2Cl10]‐Tetrameren und [(SnCl2/2Cl5)2]‐Dimeren

SnAl₂OCl₆, a Quaternary Oxide‐Chloride with Edge‐Sharing [Al₄O₂Cl₁₀] Tetramers and [(SnCl_2/2Cl₅)₂] Dimers Single crystals of SnAl₂OCl₆ were obtained from the educts SnCl₂ and AlCl₃ (obviously containing an oxidic impurity) in silica ampoules with the aid of the Bridgman technique. According to single‐crystal structure analysis, SnAl₂OCl₆ crystallizes with the monoclinic system (P2₁/n, Z = 4, a = 942.3(2), b = 1225.8(2), c = 948.4(3) pm, β = 96.42(2)°). Characteristic structural features are centrosymmetric tetramers [Al₄O₂Cl₁₀] and [(SnCl_2/2Cl₅)₂] dimers which are connected via common edges, finally building up a three‐dimensional structure.     

Darstellung und Struktur von U2Ta6O19, einer neuen Verbindung mit „Jahnberg‐Struktur”︁, sowie Anmerkungen zu den ersten Oxidchloriden in den Systemen Th/Nb/O/Cl und Th/Zr(Hf)/Nb/O/Cl

Synthesis and Crystal Structure of U₂Ta₆O₁₉, a New Compound with “Jahnberg‐Structure” and a Note to the First Oxide Chlorides in the Systems Th/Nb/O/Cl and Th/Zr(Hf)/Nb/O/Cl Black crystals of U₂Ta₆O₁₉ with hexagonal shape were obtained (at T₁) by chemical transport using HCl (p (HCl, 298 K) = 1 atm; silica tube) as transport agent in a temperature gradient (T₂ → T₁; 1000 °C → 950 °C) and using a mixture of UO₂, Ta₂O₅, and HfO₂ (or ZrO₂) (1 : 2 : 2) as starting materials (at T₂). For the structure determination the best result was achieved in space group P6₃/mcm (No. 193, a = 6.26(2) Å, c = 19.86(6) Å). U₂Ta₆O₁₉ is isotypical to Th₂Ta₆O₁₉. In the crystal structure each uranium atom is surrounded by oxygen atoms like a bi‐capped trigonal antiprism and tantalum atoms like a pentagonal bipyramid (CN = 7). Like the “Jahnberg Structures” both coordination polyhedra arrange themselves in separate layers (U–O‐polyhedra, in o‐, Ta–O‐polyhedra in p‐layers) so that in the direction of the c‐axis the sequence of layers is p‐p‐o. Using chemical transport it was possible to prepare the compounds Th₁₂Nb₁₆O₆₃Cl₂ and Th₈M₄Nb₁₆O₆₃Cl₂ (M = Zr, Hf), which are the first quaternary and quinquinary examples in these systems. They crystallize isotypically.     

Ca3Cl2CBN,eine Verbindung mit dem neuen Anion CBN4−

Ca₃Cl₂CBN, a Compound with the New CBN^4? Unit The new compound Ca₃Cl₂CBN was obtained from the reaction of Ca and CaCl₂ with CaCN₂, B and C or with BN and C, in sealed tantalum containers at 900°C. The crystal structure is related with the structure of Ca₃Cl₂C₃ whereas the C₃^4? units (C_2v symmetry) are substituted by isoelectronic CBN^4? anions (C_s symmetry): Ca₃Cl₂CBN, Pnma, a = 1 386.7(9) pm, b = 384.7(3) pm, c = 1 124.7(6) pm, Z = 4; R = 0.055, R_w = 0.036 for 380 independent intensities. The CBN^4? units are located between layers of Ca²⁺ that are interconnected by Cl^?. The bond angle (C? B? N) is 176° and bond distances are d_{C? B} = 144 pm and d_{B? N} = 138 pm, respectively.     

Effect of SiC/nano‐CeO2 on wear resistance and microstructures of Ti3Al/γ‐Ni matrix laser‐cladded composite coating on Ti–6Al–4V alloy

The Ti–6Al–4V alloy is an important aviation material, but has a poor resistance to slide wear. Laser cladding of the Al₃Ti + Ni/Cr/C + TiB₂/Al₂O₃ + SiC/nano‐CeO₂ preplaced powders on the Ti–6Al–4V alloy can form the Ti₃Al/γ‐Ni matrix composite coating, which improves the wear resistance of the substrate. In this study, the Al₃Ti + Ni/Cr/C + TiB₂/Al₂O₃ + SiC/nano‐CeO₂ laser‐cladded coating was researched by means of X‐ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. The experimental results indicate that under the action of SiC/nano‐CeO₂, this composite coating exhibited a fine microstructure. Furthermore, the proper content of nano‐CeO₂ decreased the crack tendency. The results above indicated that, it is feasible to improve the tribological property of the Al₃Ti + Ni/Cr/C + TiB₂/Al₂O₃ laser‐cladded coating by adding of SiC/nano‐CeO₂. Copyright © 2011 John Wiley & Sons, Ltd.     

Molecular Precursors for the Phase‐Change Material Germanium‐Antimony‐Telluride,Ge2Sb2Te5 (GST)

This review provides an overview of the precursor chemistry that has been developed around the phase‐change material germanium‐antimony‐telluride, Ge₂Sb₂Te₅ (GST). Thin films of GST can be deposited by employing either chemical vapor deposition (CVD) or atomic layer deposition (ALD) techniques. In both cases, the success of the layer deposition crucially depends on the proper choice of suitable molecular precursors. Previously reported processes mainly relied on simple alkoxides, alkyls, amides and halides of germanium, antimony, and tellurium. More sophisticated precursor design provided a number of promising new aziridinides and guanidinates.     

New Structure Type among Octahydrated Rare‐Earth Sulfates, β‐Ce2(SO4)3·8H2O,and a new Ce2(SO4)3·4H2O Polymorph

Syntheses, crystal structures and thermal behavior of two new hydrated cerium(III) sulfates are reported, Ce₂(SO₄)₃·4H₂O ( I ) and β‐Ce₂(SO₄)₃·8H₂O ( II ), both forming three‐dimensional networks. Compound I crystallizes in the space group P2₁/n. There are two non‐equivalent cerium atoms in the structure of I , one nine‐ and one ten‐fold coordinated to oxygen atoms. The cerium polyhedra are edge sharing, forming helically propagating chains, held together by sulfate groups. The structure is compact, all the sulfate groups are edge‐sharing with cerium polyhedra and one third of the oxygen atoms, belonging to sulfate groups, are in the S–Oμ₃–Ce₂ bonding mode. Compound II constitutes a new structure type among the octahydrated rare‐earth sulfates which belongs to the space group Pn. Each cerium atom is in contact with nine oxygen atoms, these belong to four water molecules, three corner sharing and one edge sharing sulfate groups. The crystal structure is built up by layers of [Ce(H₂O)₄(SO₄)]_nⁿ⁺ held together by doubly edge sharing sulfate groups. The dehydration of II is a three step process, forming Ce₂(SO₄)₃·5H₂O, Ce₂(SO₄)₃·4H₂O and Ce₂(SO₄)₃, respectively. During the oxidative decomposition of the anhydrous form, Ce₂(SO₄)₃, into the final product CeO₂, small amount of CeO(SO₄) as an intermediate species was detected.     

Neue [{Cp(CO)2Mo}2ESbCl]‐Cluster mit tetraedrischem Mo2SbE‐Gerüst (E = S,Se)

Reaction of [{Cp(CO)₃Mo}₂SbCl] with S₈ or Se₈ leads to the formation of cluster compounds [{Cp(CO)₂Mo}₂ESbCl] (E = S, Se). [{Cp(CO)₂Mo}₂SSbCl] crystallizes monoclinic, space group P2₁/n with a = 812.28(3), b = 855.65(4), c = 2441.01(9) pm and β = 90.149(3)°; [{Cp(CO)₂Mo}₂SeSbCl] · CH₂Cl₂ crystallizes triclinic, space group P$\bar{1}$ with a = 828.82(9), b = 1002.8(1), c = 1340.0(2) and α = 109.24(1), β = 100.87(1), γ = 96.81(1)°. For both compounds X‐ray crystal structure analysis reveals tetrahedral Mo₂SbE cluster cores with Sb–E bond lengths of 256.8(1) pm (E = S) and 265.3(1) (E = Se). According to the 18 electron rule the [{Cp(CO)₂Mo}₂ESbCl] clusters can be regarded as complexes of the 4 electron donator ESbCl that is coordinated “side‐on” to a {Cp(CO)₂Mo}₂ fragment.     

Nd3NCl6 und Nd4NS3Cl3: Zwei Neodymnitrid‐Derivate mit diskreten Einheiten kantenverknüpfter ([N2Nd6]12+) bzw. isolierter [NNd4]9+‐Tetraeder

Nd₃NCl₆ and Nd₄NS₃Cl₃: Two Derivatives of Neodymium Nitride with Discrete Units of Edge‐Shared ([N₂Nd₆]¹²⁺) and Isolated [NNd₄]⁹⁺ Tetrahedra, respectively For the preparation of Nd₃NCl₆ (orthorhombic, Pbca; a = 1049.71(8), b = 1106.83(8), c = 1621.1(1) pm; Z = 8) and Nd₄NS₃Cl₃ (hexagonal, P6₃mc; a = 922.78(6), c = 683.06(4) pm; Z = 2) elemental neodymium is reacted with sodium azide (NaN₃), neodymium trichloride (NdCl₃) and in the case of Nd₄NS₃Cl₃ additionally with sulfur in evacuated silica tubes at 750 °C (Nd₃NCl₆) and 850 °C (Nd₄NS₃Cl₃), respectively. Thereby the hydrolysis‐sensitive nitride chloride forms coarse, brick‐shaped single crystals, while those of the insensitive nitride sulfide chloride emerge hexagonally and pillar‐shaped. The pale violet compounds each exhibit [NNd₄] tetrahedra as characteristic structural features, which are connected via a common edge to form discrete pairs of tetrahedra ([N₂Nd₆]¹²⁺) in Nd₃NCl₆ and are present in Nd₄NS₃Cl₃ even as isolated [NNd₄]⁹⁺ units. Their three‐dimensional cross‐linkage as well as the charge‐balance regulation proceed solely through Cl^– anions in the nitride chloride, but through equimolar amounts of S^2– and Cl^– anions in the nitride sulfide chloride. The crystal structure of Nd₃NCl₆ shows three crystallographically independent Nd³⁺ cations, each of which is eightfold coordinated by anions (Nd1: 2 N^3– + 6 Cl^–; Nd2 and Nd3: 1 N^3– + 7 Cl^–). Only two different kinds of Nd³⁺ underlie the structure of Nd₄NS₃Cl₃: Nd1 is surrounded by one N^3–, six S^2– and three Cl^– with CN = 10, whereas one N^3–, four S^2– and three Cl^– only are coordinating Nd2 with CN = 8.     

Syntheses of the Antimonides R2Sb− (R = Ph,Mes, tBu,tBu2Sb) and Sb73− by Reactions of Organoantimony Hydrides or cyclo‐(tBuSb)4 with Li,Na, K,or BuLi

Reactions of R₂SbH with BuLi at ?70 °C in tetrahydrofuran (thf) lead to [R₂SbLi(thf)₃] [R = Ph ( 1 ) or R = Mes ( 2 )]. The antimonides [tBu₂SbK(pmdeta)] ( 3 ) (pmdeta = pentamethyldiethylenetriamine), [Li(tmeda)₂][tBu₄Sb₃]·benzene ( 4 ) (tmeda = tetramethylethylenediamine), and [tBu₄Sb₃Na(tmeda, thf)] ( 5 ) result from the reduction of cyclo‐(tBuSb)₄ by Li, Na, or K with pmdeta or tmeda in thf. The primary stibanes RSbH₂ [R = Mes ( 6 ), 2‐(Me₂NCH₂)C₆H₂ ( 7 )] are synthesized by reactions of RSbCl₂ with LiAlH₄. PhSbH₂ reacts with BuLi, and tmeda in toluene to give [Sb₇Li₃(tmeda)₃]·toluene ( 8 ). [Sb₇Na₃(pmdeta)₃]·toluene ( 9 ) is obtained from PhSbH₂, Na in liqu. NH₃, pmdeta and toluene. Crystal structures are reported for 1 – 5 and 9 .     

Synthesis and Reaction Chemistry of Sb(ECH2CH2NMe2)3 (E = O,S)

The antimony aminoalkoxide and aminothiolates Sb(ECH₂CH₂NMe₂)₃ [E = O ( 1 ), S ( 2 )] were synthesized and their ability to form adducts with other metal moieties investigated. Compound 1 forms 1:1 adducts with NiI₂ ( 3 ) and M(acac)₂ [M = Cd ( 4 ), Ni ( 5 )], while 2 undergoes ligand exchange with AlMe₃ to afford Me₂AlSCH₂CH₂NMe₂ ( 6 ). The structures of 2 – 4 and 6 were determined. Compound 2 incorporates three S, N‐chelating ligands though the interaction with nitrogen is weaker than in analogous alkoxide complexes. Product 3 reveals one iodine has migrated from nickel to antimony, and all three alkoxide ligands bridge the two metals through μ₂‐O atoms. In contrast, in 4 , only one alkoxide links the antimony and cadmium. Compound 6 adopts the same structure, a chelating S,N ligand generating a tetrahedral center at aluminum, as known tBu₂AlSCH₂CH₂NR₂ species (R = Me, Et).     

稀土钬丙氨酸配合物的热力学性质

合成了稀土氯化钬丙氨酸配合物，[Ho2(Ala)4(H2O)8]Cl6，的晶体.用绝热量热法测定了其在78～363 K温区的热容.在214～255 K温区发现一固－固相变，相变峰温、相变焓和相变熵分别为235.09 K，3.017 kJ•mol－1和12.83 J•K－1•mol－1.用最小二乘法将实验热容值拟合成热容随温度变化的多项式方程,利用此方程式和热力学函数关系,计算出以298.15 K为参考温度的热力学函数值.在40～800 ℃温区，用热重分析和差示扫描量热法研究了该配合物的热稳定性，观察到[Ho2(Ala)4(H2O)8]Cl6分两步分解，第一步从80 ℃开始，179 ℃结束；第二步从242 ℃开始，479 ℃结束.从热分析结果推测出该配合物可能的热分解机理.     

Synthesis of 3,5‐Diarylcyclohex‐2‐enones by NH4Cl/HCl‐Catalyzed Cyclization and Deacetylation of 4‐Acetylhexane‐1,5‐diones

A new route for the synthesis of 3,5‐diarylcyclohex‐2‐enones is reported. The 4‐acetyl‐1,3‐diarylhexane‐1,5‐diones were obtained by the addition of pentane‐2,4‐dione to chalcones. The reaction of 4‐acetyl‐1,3‐diarylhexane‐1,5‐diones with NH₄Cl/HCl in EtOH under reflux conditions gave the 3,5‐diarylcyclohex‐2‐enones in good yields. All synthesized compounds were characterized by spectroscopic methods (¹H‐, ¹³C‐NMR, and IR), and elemental analyses.