Neutronenpulverdiffraktionsmessungen an [Zn(ND3)4]I2 bei 1,5 K, 10 K und 293 K: Wasserstoff-Brückenbindungen und Bewegungen von ND3-Molekülen

Neutron Powder Diffraction Measurements on [Zn(ND₃)₄]I₂ at 1.5 K, 10 K, and 293 K: Hydrogen Bonds and Dynamic of ND₃ Molecules Microcrystalline powder of [Zn(ND₃)₄]I₂ can be prepared by the reaction of gaseous NH₃ with dry ZnI₂ at room temperature within 8 h. Neutron powder diffraction measurements at 1.5 K, 10 K and 293 K were used to localize all hydrogen atoms. Isolated [Zn(ND₃)₄]²⁺ tetrahedra are three dimensionally linked with 2- and 3-centre (bent and bifurcated) N? D …? I^?-hydrogen bonds. Ammonia molecules are ordered at 1.5 K. Room temperature high thermal displacement parameters for D hint to the fact that NH₃-dynamics take place. Lattice parameters 300 K [10 K; 1,5 K]: a = 10.3783(8) Å [10.3407(4) Å; 10.3381(5)], b = 7.5239(6) Å [7.3960(2) Å; 7.3935(4) Å], c = 13.088(1) Å [12.9731(4) Å; 12.9695(6) Å], space group: Pnma.     

Salts of HCN‐Cyanide Aggregates: [CN(HCN)2]− and [CN(HCN)3]−

Although pure hydrogen cyanide can spontaneously polymerize or even explode, when initiated by small amounts of bases (e.g. CN^?), the reaction of liquid HCN with [WCC]CN (WCC=weakly coordinating cation=Ph₄P, Ph₃PNPPh₃=PNP) was investigated. Depending on the cation, it was possible to extract salts containing the formal dihydrogen tricyanide [CN(HCN)₂]^? and trihydrogen tetracyanide ions [CN(HCN)₃]^? from liquid HCN when a fast crystallization was carried out at low temperatures. X‐ray structure elucidation revealed hydrogen‐bridged linear [CN(HCN)₂]^? and Y‐shaped [CN(HCN)₃]^? molecular ions in the crystal. Both anions can be considered members of highly labile cyanide‐HCN solvates of the type [CN(HCN)_n]^? (n=1, 2, 3 …) as well as formal polypseudohalide ions.     

Die Struktur der Hydrate von Co3[Co(CN)6]2 und Cd3[Co(CN)6]2

The crystal structures of Co₃[Co(CN)₆]₂, 12 H₂O (a, = 10.210 ± 0.005 Å) and Cd₃[Co(CN)₆]₂, 12 H₂O (a = 10.590 ± 0.005 Å) have been determined by X-ray powder methods. According to the measured density the unit cell contains 1 1/3 formula units with 4 Co²⁺ (Cd²⁺) in 4a, 2 2/3 Co³⁺ in 4b, 16 C and 16 N in 24e, 8 H₂O_I near 24e, (96k) and 8 H₂O_II near 8 _c (192 l). Structure factor calculations based on the space group O_h⁵ - F m 3 m lead to the following final values of the reliability index R: 0.038 (Co₃[Co(CN)₆]₂, 12 H₂O) and 0.037 (Cd₃[Co(CN)₆]₂, 12 H₂O). The interatomic distances for the cobaltous compound (in parentheses for the cadmium compound) are: Co³⁺-C: 1.88 Å (1.89); C-N: 1.15 Å (1.17); Co²⁺-N: 2.08 Å (2.24); Co²⁺-O_I: 2.10 Å (2.27); shortest O_I-H-O_II-bonds: 2.89 Å (2.82). Co³⁺ is octahedrally coordinated by six carbon atoms, the divalent metal ion by four nitrogen atoms and two water molecules. The two different metal ions are connected by M²⁺-N-C-Co³-bonds to a threedimensional network. The infrared and electronic spectra are shown to be in agreement with the results of the structure analyses of these compounds. The observed positions of the OH-stretching vibrations lead to a hydrogenbond-length of 2.8–2.95 Å.     

Desymmetrized Leaning Pillar[6]arene

In this work, a novel version of macrocyclic arenes, namely leaning pillar[6]arenes, was discovered and it can be considered as a tilted version of a pillar[6]arene with two hydroxy/alkoxy functionalities removed. Through a facile two‐step synthetic approaches, in conjunction with a diversity of post‐modification possibilities, a series of leaning pillar[6]arenes, with good cavity adaptability and enhanced guest‐binding capability, was synthesized, and their self‐assembly in single‐crystal states is presented. DFT calculations demonstrated that the lower rotational barrier of unsubstituted phenylene rings, the uneven electron density centered at the leaning phenyl rings, and the polarization effect along the edge generated by the hydrogen‐bond‐induced orientation of hydroxy groups greatly affected the host‐guest properties, and meanwhile provided an intuitive explanation for the pillar‐like and rigid structure of traditional pillar[6]arenes. Significantly, the crystal structure of cyclo‐oligomeric quinone was obtained by direct oxidation of leaning pillar[6]arenes.     

Zero Thermal Expansion in K0.46Co1.27[Fe(CN)6]·5.5H2O

Thermal expansion of materials is a comparatively easy‐understood physical property. Prussian blue analogues are of particular interest in engineering as new zero thermal expansion materials. We investigated the thermal expansion in K_0.46Co_1.27[Fe(CN)₆] · 5.5H₂O by x‐ray powder diffraction. This compound is a good example of a zero thermal expansion material. The origin of zero thermal expansion is considered to be the low frequency transverse vibrational motion of the cyano bridges.     

The Synthesis and Characterization of a New Cobalt Dimethylphenylpiperazinium Cyclotetraphosphate Hexahydrate,Co[C12 H19 N2]2 P4 O12.6 H2 O

Cobalt dimethylphenylpiperazinium cyclotetraphosphate hexahydrate, Co[C₁₂H₁₉N₂]₂P₄O₁₂.6H₂O, was synthesized by a reaction between cyclotetraphosphoric acid H₄P₄O₁₂, cobalt carbonate, and 1-(2,4-dimethylphenylpiperazine). It crystallizes in the triclinic system, space group P, with the following unit cell parameters: a = 7.336(1), b = 8.413(1), c = 14.926(2) Å, α = 87.46(1), β = 83.13(1), γ = 82.98(1)°, V = 907.3(2) ų, and Z = 1. The atomic arrangement can be described as layers containing P₄O₁₂ rings a and Co(H₂O)₆ octahedra spreading in the (001) planes between which are located the dimethylphenylpiperazinium groups via H-bonds. The synthesis and characterization by X-ray diffraction, IR absorption, and thermal analysis are described.     

Structural and Electronic Flexibility in Hydrides of Zintl Phases with Tetrel–Hydrogen and Tetrel–Tetrel Bonds

The hydrogenation of Zintl phases enables the formation of new structural entities with main‐group‐element–hydrogen bonds in the solid state. The hydrogenation of SrSi, BaSi, and BaGe yields the hydrides SrSiH_{5/3−x ,} BaSiH_5/3−x and BaGeH_5/3−x . The crystal structures show a sixfold superstructure compared to the parent Zintl phase and were solved by a combination of X‐ray, neutron, and electron diffraction and the aid of DFT calculations. Layers of connected HSr₄ (HBa₄) tetrahedra containing hydride ions alternate with layers of infinite single‐ and double‐chain polyanions, in which hydrogen atoms are covalently bound to silicon and germanium. The idealized formulae AeTt H_5/3 (Ae =alkaline earth, Tt =tetrel) can be rationalized with the Zintl–Klemm concept according to (Ae ²⁺)₃(Tt H⁻)(Tt ₂H²⁻)(H⁻)₃, where all Tt atoms are three‐binding. The non‐stoichiometry (SrSiH_5/3−x , x =0.17(2); BaGeH_5/3−x , x =0.10(3)) can be explained by additional π‐bonding of the Tt chains.     

An unusually strong intramolecular C-H...N hydrogen bond in 3-(α-hydroperfluoroisobutyryl)-2-(α-hydroperfluoroisobutyryl)imino-1,3-thiazolidine

An unusually strong intramolecular C-H...N hydrogen bond with the shortest known H...N distance of 2.00(3) » has been found by X-ray diffraction analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1593–1595, August, 1995.     

Synthesis,Crystal Structure,and NMR Spectroscopy of a New P-Phenylenediamonium Diphosphate [p-NH3C6H4NH3]H2P2O7

Crystal growth and characterization by X-ray diffraction and NMR spectroscopy of a new p-phenylenediamonium diphosphate [p-NH₃ C ₆ H ₄ NH ₃]H ₂ P ₂ O ₇ are reported. This compound crystallizes in a triclinic unit cell P1 with the parameters a = 7.130(3), b = 9.047(3), c = 9.350(2) Å, α = 133.44(2)°, β = 95.02(2)°, γ = 107.11(4)°, Z = 2, V = 514.3(15) ų, and D _x = 1.848 g.cm^{? 3}. The crystal structure has been solved and refined to R = 0.0273, using 3678 independent reflections. The atomic arrangement is build up by infinite ribbons of [H₂ P ₂ O ₇] ^2? anions, extending along the a-direction at y = 1/2. Between these ribbons are located the p-phenylenediammonium entities, which form hydrogen bonds N─H…O with some external oxygen atoms of phosphoric groups. Crystallographic results are correlated with that of the solid state ¹³C and ³¹P MAS NMR spectroscopy.     

Synthesis and Thermal Behavior of the Hydrogen Praseodymium Diphosphate (HPrP2O7·3H2O)

The preparation of a new acid lanthanide diphosphate is reported. The acid praseodymium diphosphate, obtained as a trihydrate salt, is investigated by chemical analysis, X-ray powder diffraction and IR spectroscopy. The study of the thermal behavior of HPrP₂O₇·3H₂O shows that its dehydration begins at 367 K. A scheme of its decomposition is proposed.This revised version was published online in November 2005 with corrections to the Cover Date.     

Single-Crystal Neutron Structure Analysis of (NH4)21[H3Mo57V6(NO)6O183(H2O)18]·53 H2O

The crystal structure of (NH₄)₂₁[H₃Mo₅₇V₆(NO)₆O₁₈₃ (H₂O)₁₈]·53 H₂O a supramolecular heteropoly cluster compound (space group P6₃/mmcZ=2 final R1=0.1302 (I>2σ(I)) for 1745 unique reflections) was redetermined by single-crystal neutron diffraction studies at 20 K. The X-ray diffraction results reported in 1994 by Müller et al. (Z. Anorg. Allg. Chem. 620 599) are confirmed. Additionally we could localize many hydrogen positions not found so far and establish a phase transition near 240 K. Many of the ammonium ions the ligand and hydrate H₂O molecules and the hydroxy group are orientationally disordered even at 20 K. The central cavity of the structure is built up by two twelve-membered rings consisting of six O-H·sdot;·O hydrogen bonds each. These strong hydrogen bonds are obviously decisive for the stability of the cluster. The hydrate H₂O molecules are stronger-hydrogen-bond acceptor groups than the oxoligands of the cluster.     

Strukturchemische Untersuchungen von Monammin-Kupfer(I)-Komplexen: [CuNH3]2[Pt(CN)6], [CuNH3]2[Pt(CN)4] und Cu3[Co(CN)6]-2 NH3

Structurally Chemical Investigation of Monoammin Copper (I) Complexes : [CuNH₃]₂[Pt(CN)₆], [CuNH₃]₂[Pt(CN)₄] and Cu₃[Co(CN)₆] · 2NH₃ The preparation and the properties of [CuNH₃]₂[Pt(CN)₆], [CuNH₃]₂[Pt(CN)₄] and Cu₃[Co(CN)₆] · 2NH₃ are described. I.R. and Raman spectra have been recorded and assigned. According to X-ray powder diagrams, [CuNH₃]₂[Pt(CN)₆] crystallizes in the trigonal space group D–P3 ml, a = 7.771, c = 5.988 Å, Z = 1. According to the spectroscopic and crystallographic data, it is concluded that the Cu_I ion is coordinated with one NH₃ group and with the N atoms of the cyanometallate anions. The coordination number of the Cu⁺ is 4 in [CuNH₃]₂[Pt(CN)₆] and 3 in [CuNH₃]₂[Pt(CN)₄]. In the Cu₃[Co(CN)₆] · 2 NH₃ complex two Cu atoms have the coordination number 2, the third Cu atom 4.     

Activity and Osmotic Coefficients from the Emf of Liquid Membrane Cells. VIII. K.3[Co(CN)6], Mg3[Co(CN)6]2, and Ca3[Co(CN)6]2

The activity coefficients of K₃[Co(CN)₆], Mg₃[Co(CN)₆]₂, and Ca₃[Co(CN)₆]₂,are examined. The results highlight close similarity with the correspondinghexacyanoferrate (III) salts. On dilution, K₃[Co(CN)₆], like K₃[Fe(CN)₆], approachesthe limiting law from the upper side, while Mg₃[Co(CN)₆]₂ and Ca₃[Co(CN)₆]₂tend to the limiting law from the opposite side, like Mg₃[Fe(CN)₆]₂,Ca₃[Fe(CN)₆]₂, Sr₃[Fe(CN)₆]₂, and Ba₃[Fe(CN)₆]₂. Both kinds of behavior agreewith theory for a model of hard spheres bearing electric charges +1 and –3 or+2 and –3, respectively. The paramater values of the Pitzer equation for activityand osmotic coefficients are reported.     

Alkalimolybdotellurate: Darstellung und Kristallstruktur von Rb6[TeMo6O24] · 10H2O und Rb6[TeMo6O24] · Te(OH)6 · 6H2O

Alkaline Molybdotellurates: Preparation and Crystal Structures of Rb₆[TeMo₆O₂₄] · 10H₂O and Rb₆[TeMo₆O₂₄] · Te(OH)₆ · 6H₂O Single crystals of Rb₆[TeMo₆O₂₄] · 10 H₂O and Rb₆[TeMo₆O₂₄] · Te(OH)₆ · 6 H₂O, respectively, were grown from aqueous solution. Rb₆[TeMo₆O₂₄] · 10 H₂O possesses the space group P1 . The lattice dimensions are a = 963.40(13), b = 972.56(12), c = 1 056.18(13) pm, α = 97.556(10), β = 113.445(9), γ = 102.075(10)°; Z = 1, 2 860 reflections, 215 parameters refined, R_g = 0.0257. The centrosymmetrical [TeMo₆O₂₄]^6? anions are stacked parallel to [010]. Rb(2) is coordinated with one exception by water molecules only. Folded chains consisting of [TeMo₆O₂₄]^6? anions and Rb(2) coordination polyhedra which are linked to pairs represent the prominent structural feature. Rb₆[TeMo₆O₂₄] · Te(OH)₆ · 6 H₂O crystallizes monoclinically in the space group C2/c with a = 1 886.4(3), b = 1 000.9(1), c = 2 126.5(3) pm, and β = 115.90(1)°; Z = 4, 3 206 reflections, 240 parameters refined, R_g = 0.0333. It is isostructural in high extent with (NH₄)₆[TeMo₆O₂₄] · Te(OH)₆ · 7 H₂O. Hydrogen bonds between Te(OH)₆ molecules and [TeMo₆O₂₄]^6? anions establish infinite strands. The [TeMo₆O₂₄]^6? anions gather around Te(OH)₆ providing channel-like voids extending parallel to [001].     

f-Element/crown ether complexes, 11. Preparation and structural characterization of [UO2(OH2)5] [ClO4]2·3(15-crown-5)·CH3CN and [UO2(OH2)5] [ClO4]2·2(18-crown-6)·2 CH3CN·H2O

The reaction of UO₂(ClO₄)·nH₂O with 15-crown-5 and 18-crown-6 in acetonitrile yielded the title complexes. [UO₂(OH₂)₅] [ClO₄]₂·3(15-crown-5)·CH₃CN crystallizes in the triclinic space groupPT with (at–150°C)a=8.288(6),b=12.874(7),c=24.678(7) Å, =82.62(4), =76.06(5), =81.06(5)°, andD _calc=1.67 g cm^–3 forZ=2 formula units. Least-squares refinement using 6248 independent observed reflections [F _o5(F _o)] led toR=0.111. [UO₂(OH₂)₅] [ClO₄]₂·2(18-crown-6)·2CH₃CN·H₂O is orthorhombicP2₁2₁2₁ with (at–150 °C)a=12.280(2),b=17.311(7),c=22.056(3) Å,D _calc=1.68 g cm^–3,Z=4, andR=0.032 (3777 observed reflections). In each complex the crown ether molecules are hydrogen bonded to the water molecules of the pentagonal bipyramidal [UO₂(OH₂)₅]²⁺ ions, each crown ether having exclusive use of two hydrogen atoms from one water molecule and one hydrogen from another water molecule. In the 15-crown-5 complex the remaining hydrogen bonding interaction is between one of the water molecules and one of the perchlorate anions. The solvent molecule has a close contact between the methyl group and a perchlorate anion suggesting a weak interaction. There are a total of three U-OH...OClO₃ hydrogen bonds to the two perchlorate anions in [UO₂(OH₂)₅] [ClO₄]₂·(18-crown-6)·2CH₃CN ·H₂O. The remaining coordinated water hydrogen bond is to the uncoordinated 2H₂O molecule, which in turn is hydrogen bonded to a perchlorate oxygen atom and an acetonitrile nitrogen atom. One solvent methyl group interacts with an anion, the other with one of the 18-crown-6 molecules. Unlike the 15-crown-5 structure, the hydrogen bonding in this complex results in a polymeric network with formula units joined by hydrogen bonds from one of the solvent molecules and the uncoordinated water molecule. Supplementary data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82051 (37 pages).For Part 10, see reference [1].