The [U2F12]2− Anion of Sr[U2F12]

The D_2h‐symmetric dinuclear complex anion [U₂F₁₂]^2? of pastel green Sr[U₂F₁₂] shows a hitherto unknown structural feature: The coordination polyhedra around the U atoms are edge‐linked monocapped trigonal prisms, the U^V atoms are therefore seven‐coordinated. This leads to a U–U distance of 3.8913(6) Å. A weak U^V–U^V interaction is observed for the dinuclear [U₂F₁₂]^2? complex and described by the antiferromagnetic exchange J_exp of circa ?29.9 cm^?1. The crystalline compound can be easily prepared from SrF₂ and β‐UF₅ in anhydrous hydrogen fluoride (aHF) at room temperature. It was studied by means of single crystal X‐ray diffraction, IR, Raman and UV/VIS spectroscopy, magnetic measurements, and by molecular as well as by solid‐state quantum chemical calculations.     

Strukturelle Untersuchungen an Cs2[B12H12]

Structural Investigations on Cs₂[B₁₂H₁₂] The crystal structure of Cs₂[B₁₂H₁₂] has been determined from X‐ray single‐crystal data collected at room temperature. Dicesium dodecahydro‐closo‐dodecaborate crystallizes as colourless, face‐rich crystals (cubic, Fm 3; a = 1128.12(7) pm; Z = 4). Its synthesis is based on the reaction of Na[BH₄] with BF₃(O(C₂H₅)₂) via the decomposition of Na[B₃H₈] in boiling diglyme, followed by subsequent separations, precipitations (with aqueous CsOH solution) and recrystallizations. The crystal structure is best described as anti‐CaF₂‐type arrangement with the Cs⁺ cations in all tetrahedral interstices of the cubic closest‐packed host lattice of the icosahedral [B₁₂H₁₂]^2–‐cluster dianions. The intramolecular bond lengths are in the range usually found in closo‐hydroborates: 178 pm for the B–B and 112 pm for the B–H distance. Twelve hydrogen atoms belonging to four [B₁₂H₁₂]^2– icosahedra provide an almost perfect cuboctahedral coordination sphere to the Cs⁺ cations, and their distance of 313 pm (12 ×) attests for the salt‐like character of Cs₂[B₁₂H₁₂] according to {(Cs⁺)₂([B₁₂H₁₂]^2–)}. The ¹¹B{¹H}‐NMR data in aqueous (D₂O) solution are δ = –12,70 ppm (¹J_B–H = 125 Hz), and δ = –15,7 ppm (linewidth: δν_1/2 = 295 Hz) for the solid state ¹¹B‐MAS‐NMR.     

Drei Wege zur Oxydation von [Ta6Cl12]2+ ([Ta6Br12]2+ und [Nb6Cl12]2+)

Three Oxidation Paths of [Ta₆Cl₁₂]²⁺ ([Ta₆Br₁₂]²⁺ and [Nb₆Cl₁₂]²⁺) [Ta₆Cl₁₂]²⁺ is oxidized autocatalytically to [Ta₆Cl₁₂]⁴⁺ by HNO₃. The titration of [Ta₆Cl₁₂]²⁺ with KBrO₃ (in HBr-containing solutions) or with Ce⁴⁺ or K₂Cr₂O₇ (in HNO₃-containing solutions) leads to a clear [Ta₆Cl₁₂]³⁺ step. The further titration leads beside [Ta₆Cl₁₂]⁴⁺ to the formation of Ta₂O₅(· xH₂O). [Ta₆Cl₁₂]²⁺ behaves with KBrO₃(+ HBr) equally, but the formation of [Ta₂O₅](· xH₂O) is only small. [Nb₆Cl₁₂]²⁺ (22°C) titrated with Ce(ClO₄)₄ in 2n HClO₄ gives the first potential step nearby exact ([Nb₆Cl₁₂]³⁺) and at a very slow titration in a second step a precipitation of Nb₂O₅(· xH₂O) occurs, which adsorbed Ce⁴⁺ additionally. At ?15°C with Ce(ClO₄)₄ the first potential step was exactly at [Nb₆Cl₁₂]^2+→3+, while the second step needs a distinct additional consumption of titer. (Formation of [Nb₆Cl₁₂]⁴⁺ and beside it [Nb₂O₅](· xH₂O)). From the titration curves and sections of its normal progress in all cases we get the normal potentials 2+/3+ and 3+/4+ with an accuracy of ± 0.01 volt. In alkaline solution the complexes are oxidized with air-oxygen to [M₆X₁₂](OH)₆^2?, while the Br-containing complexes suffer hydrolysis afterwards.     

Syntheses,Crystal Structures,and Properties of the Isotypic Pair [Cr(H2O)6]2[B12H12]3·15H2O and [In(H2O)6]2[B12H12]3·15H2O

Single crystals of [Cr(H₂O)₆]₂[B₁₂H₁₂]₃ · 15H₂O and [In(H₂O)₆]₂[B₁₂H₁₂]₃ · 15H₂O were obtained by reactions of aqueous solutions of the acid (H₃O)₂[B₁₂H₁₂] with chromium(III) hydroxide and indium metal shot, respectively. The title compounds crystallize isotypically in the trigonal system with space group R$\bar{3}$ c (a = 1157.62(3), c = 6730.48(9) pm for the chromium, a = 1171.71(3), c = 6740.04(9) pm for the indium compound, Z = 6). The arrangement of the quasi‐icosahedral [B₁₂H₁₂]^2– dianions can be considered as stacking of two times nine layers with the sequence …ABCCABBCA… and the metal trications arrange in a cubic closest packed …abc… stacking sequence. The metal trications are octahedrally coordinated by six water molecules of hydration, while another fifteen H₂O molecules fill up the structures as zeolitic crystal water or second‐sphere hydrating species. Between these free and the metal‐bonded water molecules, bridging hydrogen bonds are found. Furthermore, there is also evidence of hydrogen bonding between the anionic [B₁₂H₁₂]^2– clusters and the free zeolitic water molecules according to B–H^δ– ··· ^δ+H–O interactions. Vibrational spectroscopy studies prove the presence of these hydrogen bonds and also show slight distortions of the dodecahydro‐closo‐dodecaborate anions from their ideal icosahedral symmetry (I_h). Thermal decomposition studies for the example of [Cr(H₂O)₆]₂[B₁₂H₁₂]₃ · 15H₂O gave no hints for just a simple multi‐stepwise dehydration process.     

双电荷离子[C12H12N2O]2+和[C12H12N2S]2+的气相单分子分解反应研究

The unimolecular dissociation reactions of doubly charged ions were reported,which resulted from a tandem mass spectrometer and a reversed geometry double focusing mass spectrometer by electron impact.Mass analyzed ion kinetic energy spectrometry(MIKES) was used to obtain the kinetic energy releases in charge separation reactions of doubly charged ions.The intercharge distances between the two charges at transition states can be calculated from the kinetic energy releases.Transition structures of unimolecular dissociation reactions were infered from MIKES and MS/MS.     

Synthesis,Characterization, and Crystal Structures of [N(CH3)4]2[B12H12] and [N(CH3)4]2[B12H12] · CH3CN

Bis(tetramethylammonium) dodecahydrododecaborate, [(CH₃)₄N]₂[B₁₂H₁₂], and bis(tetramethylammonium) dodecahydrododecaborate acetonitrile, [(CH₃)₄N]₂[B₁₂H₁₂] · CH₃CN, were synthesized and characterized via Infrared, ¹H and ¹¹B NMR spectroscopy. [(CH₃)₄N]₂[B₁₂H₁₂] crystallizes isopunctual to the alkali metal dodecaborates. The crystal structure of [(CH₃)₄N]₂[B₁₂H₁₂] · CH₃CN was determined from single crystal data and refined in the orthorhombic crystal system (Pcmn, no. 62, a = 898.68(8), b = 1312.85(9) c = 1994.5(1) pm, R(|F| , 4σ) = 5.9%, wR(F²) = 18.3%). Here, the geometry of the dodecaborate anion is that of an almost ideal icosahedron, less distorted than most other dodecaborates known. By low‐temperature Guinier‐Simon diffractometry phase transitions were detected for [(CH₃)₄N]₂[B₁₂H₁₂] and [(CH₃)₄N]₂[B₁₂H₁₂] · CH₃CN at –70 and –15 °C, respectively.     

The Synthesis of 12-Methyl-1, 2, 3, 4, 6, 7, 12, 12B-Octahydroindolo [2,3-A]Quinolizine (1), 1-Benzoyl-1, 2, 3, 4, 6, 7, 12, 12B-Octahydroindolo[2, 3-A]Quinolizine (2), and 1-Phenylcarbinol-1, 2, 3, 4, 6, 7, 12, 12B-Octahydroindolo[2, 3-A]Quinolizine (3)

12-Methyl-l, 2, 3, 4, 6, 7, 12, 12b-octahydroindolo[2, 3-a]quinolizine (1) is synthesized through a new route developed in our laboratory. The most important step in this synthesis is the condensation of I-methyltryptophyl bromide (4) with 2-piperidone (5) to give N -(2-(1-methylidol)-3-ylethyl)-2-piperidone (6) in good yield (70%). The synthesis of 1-benzoyl-1, 2, 3, 4, 6, 7, 12, 12b-octahydroindolo(2, 3-a]quinolizine (2) and 1-phenylcarbinol-1, 2, 3, 4, 6, 7, 12, 12b-octahydroindolo[2, 3-a]quinolizine (3) follow the method developed by Wenkert. But the yield of tetrahydropyridine 9 from partial hydrogenation of pyridinum bromide 8 with 10% palladium-charcoal is 84% which is much higher than the best yield (40%) in the literature, since the phenyl group contribute additional stability.     

Zur Kenntnis von Li2[CuO2] [1, 2]

On Li₂[CuO₂] At the first time single crystals of Li₂[CuO₂] are prepared by exchange reaction. The crystal structure (I mmm) with a = 365.4(0), b = 285.9(0), c = 937.4(0) pm, Z = 2, d_x = 3.73 g/cm³, d_pyk = 3.67 g/cm³ was refined (four-circle-diffractometer data PW 1100, 343 I_o(hkl), MoKα, R = 0.046, R_w = 0.041). The characteristic structure element is the planar chain \documentclass{article}\pagestyle{empty}\begin{document}$ {}_\infty ^1 \left[{{\rm CuO}_{4/2}} \right]^{2 -} $\end{document}. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, are calculated.     

Synthesen,Kristallstrukturen und Drillingsbildung der Cluster‐Trimere Bi2[PtBi6Br12]3 und Bi2[PtBi6I12]3

Syntheses, Crystal Structures, and Triple Twinning of the Cluster Trimers Bi₂[PtBi₆Br₁₂]₃ and Bi₂[PtBi₆I₁₂]₃ Melting reactions of Bi with Pt and BiX₃ (X = Br, I) yield shiny black, air insensitive crystals of the subhalides Bi₂[PtBi₆X₁₂]. Bi₂[PtBi₆Br₁₂]₃ crystallizes in the monoclinic space group C2/m with lattice parameters a = 1617.6(2) pm, b = 1488.5(1) pm, c = 1752.4(2) pm, and β = 110.85(4)°. Bi₂[PtBi₆I₁₂]₃ adopts the triclinic space group with pseudo‐monoclinic lattice parameters a = 1711.2(2) pm, b = 1585.1(1) pm, c = 1865.7(2) pm, and α = 90°, β = 111.15(4)°, γ = 90°. The two homoeotypic compounds consist of cuboctahedral [Pt^?IIBi^II₆X^?I₁₂]^2? clusters that are concatenated into linear trimers by Bi^III atoms. The ordered distribution of Bi^III atoms destroys the inherent threefold rotation axes in the packing of cluster anions. As a consequence of the pseudosymmetry the crystals are triple twinned along [201]. Due to different orientations of the cluster trimers there are two Bi^II···X inter‐cluster bridges per Bi^II atom in Bi₂[PtBi₆Br₁₂]₃ but only one bridge in Bi₂[PtBi₆I₁₂]₃. The structure of the iodine compound can be deduced from the NaCl structure type, leaving 37 of 96 atomic positions unoccupied. The arrangement of the cuboctahedral clusters follows the motif of a body‐centered cubic packing.     

穴醚[2, 2, 2]和穴醚[2, 2]对镉离子萃取行为的研究

本文研究了穴醚[2,2,2]和穴醚[2,2]在硝基甲烷中对镉的萃取行为。探讨了溶剂、穴醚浓度,碱浓度,无机酸浓度,盐效应及共存离子对镉萃取的影响。实验结果表明,硝基甲烷ε=35.6,μ=3.4德拜宜作为穴醚的溶剂。当穴醚[2,2,2]——硝基甲烷的浓度为2×10~(-3)M,Me_4NOH浓度为4×10~(-2)M时对镉的萃取最为有利。无机酸的引入使穴醚质子化程度加大,盐效应对镉的萃取无明显影响。十八种共存离子对镉萃取无干扰,因而选择性高。实验结果为用穴醚[2,2,2]萃取镉提供了依据。