Zn11Rh18B8 and Zn10MRh18B8 with M = Sc,Ti, V,Cr, Mn,Fe, Co,Ni, Cu,Al, Si,Ge, Sn – New Ternary and Quaternary Zinc Rhodium Borides

Zn₁₁Rh₁₈B₈ and Zn₁₀MRh₁₈B₈ with M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, Si, Ge and Sn are obtained by reaction of the elemental components in sealed tantalum tubes at 1500 K. They crystallize tetragonally with Z = 2 in the spacegroup P4/mbm with lattice constants a = 1771.2(2) pm, c = 286.40(4) pm for Zn₁₁Rh₁₈B₈ and in the range a = 1767.65(9) pm, c = 285.96(3) pm (Zn₁₀NiRh₁₈B₈) to a = 1774.04(9) pm, c = 286.79(2) pm (Zn₁₀SnRh₁₈B₈) for the quaternary compounds. According to powder photographs all compounds are isotypic. Struture determinations based on single crystal X-ray data were performed with Zn₁₁Rh₁₈B₈, Zn₁₀FeRh₁₈B₈ and Zn₁₀NiRh₁₈B₈. The structure of Zn₁₁Rh₁₈B₈ is related to the Ti₃Co₅B₂ type. Along the short axis planar nets of rhodium atoms composed of triangles, squares, pentagons and elongated hexagons alternate with layers containing the boron and zinc atoms. The rhodium atoms form trigonal prisms centered by boron atoms, two kinds of tetragonal and pentagonal prisms centered by zinc atoms and elongated hexagonal prisms containing pairs of zinc atoms. In the quaternary compounds Zn₁₀MRh₁₈B₈ the zinc atoms in one sort of tetragonal prisms are replaced by M atoms.     

Acetamidiniumhexafluorometallate von Aluminium,Gallium, Indium,Vanadium, Chrom,Mangan, Eisen und Cobalt

Acetamidiniumhexafluorometallates of Aluminium, Gallium, Indium, Vanadium, Chromium, Manganese, Iron and Cobalt The title compounds were crystallized from F-containing aqueous solutions of their hexafluoro-metallate acids by adding acetamidine. Their unit cells were determined and the thermal decomposition was investigated thermoanalytically. The crystal structure of [CH₃C(NH₂)₂]₃AlF₆ was determined: Space group P4₁2₁2/P4₃2₁2, a = 8,987(1), c = 17,894(3) Å, R = 0,054. The unit cell parameters: .     

Quaternäre Magnesium-Iridiumboride Mg2Xlr5B2 mit X = Be,Al, Si,P, Ti,V, Cr,Mn, Fe,Co, Ni,Cu, Zn,Ga, Ge,As – eine Besetzungsvariante des Ti3Co5B2-Typs

Quaternary Magnesium Iridium Borides Mg₂XIr₅B₂ with X = Be, Al, Si, P, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As – a Substitution Variant of the Ti₃Co₅B₂ Type of Structure The compounds Mg₂XIr₅B₂ with X = Be, Al, Si, P, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge and As crystallize tetragonally with Z = 2 in the space group P4/mbm. The lattice constants are in the range a = 9.199 Å, c = 2.880 Å for Mg₂BeIr₅B₂ und a = 9.406 Å, c = 2.953 Å for Mg₂TiIr₅B₂ (further lattice constants are given in Table 1). X-ray structure determinations carried out with single crystals of the Si-and the P-compounds showed that a substitution variant of the Ti₃Co₅B₂ type of structure is formed. According to X-ray powder photographs the other compounds are isotypic. In the compounds with X = P and As the X-siteset is only occupied at about 70% and 80% respectively.     

Electrochemical Reduction of Pentafluorophenylxenonium, -diazonium, -iodonium, -bromonium,and -phosphonium Salts

Cyclic voltammetry measurements on pentafluorophenylonium compounds of [C₆F₅X]⁺ Y^– type with X = Xe, N₂, C₆F₅Br, C₆F₅I, and (C₆F₅)₃P were carried out. In these series [C₆F₅Xe]⁺ shows the lowest and [(C₆F₅)₄P]⁺ the highest reduction potential. One electron reduction of [C₆F₅Xe]⁺ and [C₆F₅N₂]⁺ followed by the loss of Xe or N₂, respectively, leads to the generation of the [C₆F₅] ^· radical. Favoured following reactions of the [C₆F₅] ^· radical are the abstraction of hydrogen from MeCN or dimerisation. After the first reduction step the other onium cations split off the pentafluorophenyl element molecule such as (C₆F₅)₃P, C₆F₅Br, or C₆F₅I, respectively. These molecules undergo further reductions. The low reduction potential of [C₆F₅Xe]⁺ is in contrast to former measurements on partially fluorinated or chlorinated phenylxenonium cations. A plausible explaination for the different behaviour of these Xe–C compounds in electrochemical reduction processes is given.     

Neues über Hexafluoromanganate(IV). MIIMnF6 mit M=Mg,Ca, Zn,Cd, Hg,Ni, Cu,Ag

Newly obtained are NiMnF₆ (ochre-yellow) and ZnMnF₆ (orangeyellow), both VF₃-type [a = 4.91₀, c = 13.16₉ Å (Ni); a = 4.96₆, c = 13.29₃ Å (Zn)], as well as CdMnF₆ (yellow) and HgMnF₆ (orange), both of LiSbF₆ type [a = 5.08₇, c = 14.00₇ Å (Cd); a = 5.08₄, c = 14.12₅ Å (Hg)]. CuMnF₆ (copper-red) and AgMnF₆ (blackbrown) show complicated powder diagrams. MgMnF₆ and CaMnF₆ belong to the LiAbF₆ type, too [Guinier-photographs].     

Zur Kenntnis der RbNiCrF6Typs. III. Neue Fluoride des Typs CsZnMF6 mit M = Al,Ga, In,Tl, Sc,Ti, V,Mn, Cu,Rh

On the RbNiCrF₆ Type. III. New Fluorides of the Type CsZnMF₆ (M = Al, Ga, In, Tl, Sc, Ti, V, Mn, Cu, Rh) Cubic compounds are CsZnGaF₆ [3] (colourless, a = 10.29 Å); CsZnInF₆ (colourless, a = 10.58 Å); CsZnTlF₆ (colourless, a = 10.62 Å); CsZnScF₆ (colourless, a = 10.58 Å); CsZnTiF₆ (lightblue, a = 10.50 Å); CsZnVF₆ (lightgreen, a = 10.43 Å); CsZnMnF₆ (redbrown, a = 10.40 Å); CsZnCuF₆ (light brown, a = 10.24 Å); CsZnRhF₆ (redbrown, a = 10.41 Å), all RbNiCrF₆ type of structure, in addition non cubic: CsZnAlF₆ (colourless). The Madelung part of lattice energy, MAPLE, is calculated and discussed.     

Structure and Polymorphism of M(thd)3 (M = Al,Cr, Mn,Fe, Co,Ga, and In)

Formation, crystal structure, polymorphism, and transition between polymorphs are reported for M(thd)₃, (M = Al, Cr, Mn, Fe, Co, Ga, and In) [(thd)^– = anion of H(thd) = C₁₁H₂₀O₂ = 2, 2, 6, 6‐tetramethylheptane‐3, 5‐dione]. Fresh crystal‐structure data are provided for monoclinic polymorphs of Al(thd)₃, Ga(thd)₃, and In(thd)₃. Apart from adjustment of the M–O_k bond length, the structural characteristics of M(thd)₃ complexes remain essentially unaffected by change of M. Analysis of the M–O_k, O_k–C_k, and C_k–C_k distances support the notion that the M–O_k–C_k–C_k–C_k–O_k– ring forms a heterocyclic unit with σ and π contributions to the bonds. Tentative assessments according to the bond‐valence or bond‐order scheme suggest that the strengths of the σ bonds are approximately equal for the M–O_k, O_k–C_k, and C_k–C_k bonds, whereas the π component of the M–O_k bonds is small compared with those for the O_k–C_k, and C_k–C_k bonds. The contours of a pattern for the occurrence of M(thd)₃ polymorphs suggest that polymorphs with structures of orthorhombic or higher symmetry are favored on crystallization from the vapor phase (viz. sublimation). Monoclinic polymorphs prefer crystallization from solution at temperatures closer to ambient. Each of the M(thd)₃ complexes subject to this study exhibits three or more polymorphs (further variants are likely to emerge consequent on systematic exploration of the crystallization conditions). High‐temperature powder X‐ray diffraction shows that the monoclinic polymorphs convert irreversibly to the corresponding rotational disordered orthorhombic variant above some 100–150 °C (depending on M). The orthorhombic variant is in turn transformed into polymorphs of tetragonal and cubic symmetry before entering the molten state. These findings are discussed in light of the current conceptions of rotational disorder in molecular crystals.     

Bromination of silatranyl-, germatranyl-, silyl-, and germyl-phenylacetylenes

Reactions of element-substituted alkynes R₃MCCPh (R₃M = Me₃Si, Et₃Si, Ph₃Si, Et₃Ge, n-Bu₃Sn, N(CH₂CH₂O)₃Si, N(CH₂CH₂O)₃Ge, N(CH₂-CHMeO)₃Ge, and N(CH₂CH₂O)₂(CH₂CHPhO)Ge) with bromine, tetra-n-butylammonium tribromide (TBAT), and N-bromosuccinimide (NBS)/DMSO were investigated. The Z,E-ratio of isomeric dibromoalkenes formed in bromination reaction with Br₂ and TBAT are discussed. The crystal structures of N(CH₂CH₂O)₃SiCCPh and N(CH₂CHMeO)₃GeX (X = C CPh, C(Br)C(Br)Ph, C(Br₂)C(O)Ph), and Ph₃SiC(Br)C(Br)Ph are reported. © 2003 Wiley Periodicals, Inc. 15:43–56, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.hc10211     

Organoborane Chemistry : by Thomas ONak,Academic Press,New York and London, 1975, x + 360 pages, $38, £18.25.

Methyl iodide reacts with Pt₂(μ-SMe)₂Ph₂(PMe₂Ph)₂ to give PtIPh(SMe₂)(PMe₂Ph) and with Pt₂(μ-SMe)₂Me₂(PMe₂Ph)₂ to give PtI₂Me₂(SMe₂)(PMe₂Ph) via an isolable intermediate Pt₂I₂(μ-SMe)₂Me₄(PMe₂Ph)₂. The mechanisms of the reactions are discussed.     

Synthesis,Characterization, and Crystal Structures of Cu,Ag, and Pd Dinitramide Salts

The literature known, but not fully characterized, silver dinitramide transfer reagents AgN(NO₂)₂ ( 1 ), [Ag(NCCH₃)][N(NO₂)₂] ( 2 ), and [Ag(py)₂][N(NO₂)₂] ( 3 ) have been investigated by ¹⁰⁹Ag, ¹⁴N NMR and vibrational spectroscopy (IR, Raman). In addition, the poorly understood [Cu(NH₃)₄][N(NO₂)₂)]₂ ( 4 ) and [Pd(NH₃)₄][N(NO₂)₂]₂, ( 5 ) have also been prepared and characterized by ¹⁴N NMR and vibrational spectroscopy (IR, Raman). The structures of 2 — 5 have also been determined by X‐ray diffraction.     

First-principles Density Functional Theory Elucidation of the Hydrogen Evolution Reaction on TM-promoted TiC2 (TM=Fe,Co, Ni,Cu, Ru,Rh, Pd,Ag, Os,Ir, Pt,and Au)

Single-atom-catalyst-based systems have been attractive by virtue of their desirable catalytic performance. Herein, the possibility of the 15 transition-metal (TM)-promoted (TM=Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, Cd, Os, Ir, Pt, Au, and Hg) and their hydrogen evolution reaction (HER) performance were investigated on two-dimensional titanium carbides (TiC₂). It is found that the adsorption strength of TMs on TiC₂ is stronger than that of TMs on γ-graphyne and weaker than that of TMs on Ti₃C₂. Among the fifteen investigated catalysts, Ru−TiC₂, Ag−TiC₂, Ir−TiC₂, Au−TiC₂, and Fe−TiC₂ exhibits overpotential of −0.18, −0.15, −0.18, −0.17, and −0.04 V, respectively. In addition, the Volmer-Tafel step was preferred to the Volmer-Heyrovsky step on Fe−TiC₂. This work suggests that Fe−TiC₂ is possibly a superior HER electrocatalyst.     

New pentafluorothiophenoxo derivatives of tin,lead, antimony,bismuth, gold and platinum

Summary Salts of the anions [SnX₅]^–, [SnX₄Cl, [SnX₃Cl₂]^–, [SnX₃]^–, [PbX₃]^–, [SbX₄]^–, [SbX₃Cl]^–, [SbX₂Cl₂]^–, [BiX₄]^–, [AuCl₂]^–, [AuX₂]^–, [AuXCl]^–, [AuX₄]^–, [Au₂X₆]^2– and [PtX₄]^2–, where X^– = C₆F₅S^–, have been isolated and characterised. The neutral SbX₃ and BiX₃ species, have also been isolated and shown to be pyramidal monomers (¹⁹F.n.m.r., i.r., and Raman spectral evidence). Various physical properties of the complexes prepared, as well as their stereochemistries (where these could be ascertained), are similar to those of the known corresponding halogeno compounds of these elements. These results further demonstrate the pseudo-halide nature of the pentafluorothiophenoxide ion.Author to whom all correspondence should be directed at: Laboratoire de Chimie de Coordination, Uniyersité Louis Pasteur, 67008 Strasbourg, France.     

Synthesis, characterization, and reactivity of half-sandwich Ru(II) complexes containing phosphine, arsine, stibine, and bismutine ligands

The synthesis and some reactions of the Ru(II) and Ru(IV) half-sandwich complexes [RuCp(EPh₃)(CH₃CN)₂]⁺ (E=P, As, Sb, Bi) and [RuCp(EPh₃)(η³-C₃H₅)Br]⁺ have been investigated. The chemistry of this class of compounds is characterized by a competitive coordination of EPh₃ either via a RuE or a η⁶-arene bond, where the latter is favored when the former is weaker, that is in going down the series. Thus in the case of Bi, the starting material [RuCp(CH₃CN)₃]⁺ does not react with BiPh₃ to give [RuCp(BiPh₃)(CH₃CN)₂]⁺ but instead gives only the η⁶-arene species [RuCp(η⁶-PhBiPh₂)]⁺ and [(RuCp)₂(μ-η⁶,η⁶-Ph₂BiPh)]²⁺. Similarly, the EPh₃ ligand can be replaced by an aromatic solvent or an arene substrate. Thus, the catalytic performance of [RuCp(EPh₃)(CH₃CN)₂]⁺ for the isomerization of allyl-phenyl ethers to the corresponding 1-propenyl ethers is best with E=P, while the conversion drops significantly using the As and Sb derivatives. By the same token, only [RuCp(PPh₃)(CH₃CN)₂]⁺ is stable in a non-aromatic solvent, whereas both [RuCp(AsPh₃)(CH₃CN)₂]⁺ and [RuCp(SbPh₃)(CH₃CN)₂]⁺ rearrange upon warming to [RuCp(η⁶-PhEPh₂)]⁺ and related compounds. In addition, the potential of [RuCp(EPh₃)(CH₃CN)₂]⁺ as precatalysts for the transfer hydrogenation of acetophenone and cyclohexanone has been investigated. Again aromatic substrates are clearly less suited than non-aromatic ones due to facile η⁶-arene coordination leading to catalyst's deactivation.     

Ternary metal borides [La,Ce,Pr,Nd,Sm] Os4B4 and [Y,La,Ce,Pr,Nd,Sm,Gd,Tb] Ir4B4 with NdCo4B4-type structure

New ternary metal borides with compositionR. E. T ₄B₄ (R. E.=rare earth metal,T=transition metal) have been synthesized within the systems [La,Ce,Pr,Nd,Sm]–Os–B and [Y, La, Ce, Pr, Nd, Sm, Gd, Tb]–Ir–B. All compounds were found to be crystallizing with NdCo₄B₄-type structure. Magnetic measurements (80–300 K,Curie-Weiss behaviour, _p ~ 16K and µ_eff=9.94µ_B for TbIr₄B₄) indicate Y andR. E. elements (except Ce) to be trivalent in these compounds. The crystal chemistry of the isotypic series [Y,R. E.] [Os,Ir]₄B₄ is discussed.

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Ternäre Metallboride. [La,Ce,Pr,Nd,Sm] Os₄B₄ und [Y,La,Ce,Pr,Nd,Sm,Gd,Tb] Ir₄B₄ mit NdCo₄B₄-Struktur

Zusammenfassung Es wurden neue Metallboride der ZusammensetzungR. E. T ₄B₄ (R. E.=Seltenerdmetall,T=Übergangsmetall) innerhalb der Systeme [La,Ce, Pr,Nd,Sm]–Os–B und [Y,La,Ce,Pr,Nd,Sm,Gd,Tb]–Ir–B hergestellt. Alle Verbindungen kristallisieren entsprechend dem NdCo₄B₄-Typ. Magnetische Messungen (80–300K,Curie-Weiss-Verhalten, _p ~ 16K und µ_eff=9.94µ_B für TbIr₄B₄) zeigen an daß Y und dieR. E.-Elemente (ausgenommen Ce) in diesen Verbindungen trivalent sind. Die Kristallchemie der isotypen [Y,R. E.][Os,Ir]₄B₄-Verbindungen wird diskutiert.

     

Fluoride mit zweiwertigem Silber. Zur Kenntnis der Verbindungen AgII[MF6] mit M = Ge,Sn, Pb,Ti, Zr,Hf, Rh,Pd, Pt.

Fluorides with divalent Silver. On the compounds Ag^II[MF₆] with M = Ge, Sn, Pb, Ti, Zr, Hf, Rh, Pd, Pt. For the first time AgTiF₆, AgGeF₆, AgSnF₆ AgPbF₆ (all light-blue), AgRhF₆ (black), AgPdF₆ (d.brown), AgPtF₆ (brownviolet) as well as AgZrF₆ and AgHfF₆ (both deeply blueviolet) are prepared. AgSnF₆, AgPbF₆ and AgPdF₆ obey the Curie-Weiss Law (m? = 2,0 m?_B, small θ-value). In the case of AgZrF₆ and AgHfF₆ there is a strong magnetic exchange between Ag²⁺ ions; this may be the cause for the unexpected deep colour.     

Polymorphism of the bivalent metal vanadates MeV2O6 (Me = Mg,Ca, Mn,Co, Ni,Cu, Zn,Cd)

Based on the literature data, our former findings and additional DTA and high-temperature X-ray studies performed for CdV₂O₆, MgV₂O₆, and MnV₂O₆, a consistent scheme of the phase transformations of the MeV₂O₆ (Me = Mg, Ca, Mn, Co, Ni, Cu, Zn, Cd) metavanadates is constructed at normal pressure between room temperature and melting points. Three types of structures exist for the considered compounds: brannerite type (B), pseudobrannerite type (P), and NiV₂O₆ type (N). The following phase transformations have been observed: Me = Mg, B → P at 535°C; Me = Mn, B → P at 540°C; Me = Co, N → B at 660°C; Me = Cu, B (with triclinic distortion) → B at 625°C (secondary order); and Me = Cd, B → P at 170°. CaV₂O₆P, NiV₂O₆N, and ZnV₂O₆B exist in unique form in the entire temperature range. P-form seems to be favored by Me of larger ionic radii. N-form seems to appear at a peculiar d-shell structure and small Me size. Preliminary explanation of the dependence of the structure type on Me size is offered. New X-ray data are given for CdV₂O₆B, CdV₂O₆P, MgV₂O₆B, MgV₂O₆P, and MnV₂O₆P.     

Oxalate-2-ethanolamine complexes of some bivalent cations (Mn,Co, Ni,Cu, Zn and Cd)

On the refluxing ofM(II) oxalate (M=Mn, Co, Ni, Cu, Zn or Cd) and 2-ethanolamine in chloroform, the following complexes were obtained: MnC₂O₄·HOCH₂CH₂NH₂·H₂O, CoC₂O₄·2HOCH₂CH₂NH₂, Ni₂(C₂O₄)₂·5HOCH₂CH₂NH₂·3H₂O, Cu₂(C₂O₄)₂·5HOCH₂CH₂NH₂, Zn₂(C₂O₄)₂·5HOCH₂CH₂NH₂·2H₂O and Cd₂(C₂O₄)₂·HOCH₂CH₂NH₂·2H₂O. Following the reaction ofM(II) oxalate with 2-ethanolamine in the presence of ethanolammonium oxalate, a compound with the empirical formula ZnC₂O₄·HOCH₂CH₂NH₂·2H₂O¹ was isolated. The complexes were identified by using elemental analysis, X-ray powder diffraction patterns, IR spectra, and thermogravimetric and differential thermal analysis. The IR spectra and X-ray powder diffraction patterns showed that the complexes obtained were not isostructural. Their thermal decompositions, in the temperature interval between 20 and about 900°C, also take place in different ways, mainly through the formation of different amine complexes. The DTA curves exhibit a number of thermal effects.     

Synthesis, structures, physicochemical properties, and crystal-chemical systematics of M 2II AIIUO6 (MII = Pb, Ba, Sr; AII = Mg, Ca, Sr, Ba, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb) compounds

Pb₂A^IIUO₆ (A^II = Mg, Ca, Sr, Ni, Zn, Cd) compounds were synthesized by high-temperature reactions in the solid phase. For the Pb₂MgUO₆, Pb₂CaUO₆, and Pb₂CdUO₆ compounds, the crystal structures (space group P2₁/n) were refined by the Rietveld method. It was demonstrated that these structures belong to the perovskite structure type. Crystal-chemical systematics was performed for all synthesized perovskites. High-temperature X-ray diffraction and differential scanning calorimetry were used to study the thermal stability and phase transitions, determine the thermal expansion coefficients, and elucidate the effect of atoms located in octahedral and cuboctahedral positions on the heating behavior of the structure. The standard enthalpies of formation of the Pb₂A^IIUO₆ compounds were determined by reaction calorimetry.     

Electronic structure,geometry, and stability of organic cations,dications, and donor-acceptor complexes

Geometric, electronic, and energy characteristics of the complexes formed in the CF₄ ·nAIF₃ (n = I or 2) and CBr₄ ·nAIBr₃ (n = 1, 2, or 4) systems have been determined by the semiempirical AM I method. Besides the donor-acceptor complexes, the CBr₃ ⁺...AIBr₄ ^–, CBr₃ ⁺...Al₂Br₇ ^–, CBr2²⁺...(AlBr₄ ^–)₂, and CBr₂ ²⁺...(Al₂Br₇ ^–)₂ ionic complexes can be formed in the CBr₄ ·nAlBr₃ systems. In the cations and dications of polyhalomethanes (when Hal = Cl, Br, or l) in both the free and bound (included in ionic complexes) states, carbon atoms carry negative charges, the C-Hal bonds are substantially shortened, and the positive charges are located on one-coordinate halogen atoms. These cations and dications can be considered as halenium ions that differ from halenium salts with dicoordinate halogen atoms. In the cationic and dicationic complexes of the CBr₄ ·nAlBr₃ systems, the maximum positive charges on the Br atoms are 0.39 and 0.94, respectively. Fluorine-containing cations and dications have structures similar to those of carbenium ions, whereas in the CF₄ ·nAIF₃ systems (n = l or 2), only donor-acceptor complexes are formed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 3, pp. 554–560, March, 1996.