Ca6GaN5 und Ca6FeN5. Verbindungen mit [CO3]2−-isosteren Anionen [GaN3]c− und [FeN3]6−

Ca₆GaN₅ and Ca₆FeN₅: Compounds Containing [CO₃]^2?-isosteric Anions [GaN₃]^6? and [FeN₃]^6? The isotypic phases Ca₆GaN₅ and Ca₆FeN₅ (hexagonal, P6₃/mem; a = 627.7(3)/ 623,7(1) pm, c = 1219.8(3)/1233.2(6) pm; Z = 2) are prepared by reaction of Ca/Ga mixtures (molar ratio 6:1) and Fe/Ca₃N₂/Ca mixtures (molar ratios from 3:1:13 to 5:2:15) with nitrogen at temperatures of 850°C and 950°C to 1100°C, respectively. The structures contain trigonal-planar anions [MN₃]^6? which are isosteric to carbonate ions (Ga? N: 195,1(28) pm; Fe? N: 177,0(15) pm). The structures are closely related to those compounds of the hydrotalcite group.     

Pertechnetyl Fluorosulfate, [TcO3]+[SO3F]−

A one step synthesis of [TcO₃]⁺[SO₃F]^? is reported. The compound is volatile at room temperature and has according to calculations a tetrahedral coordination around Tc and a monodentate SO₃F group. In the solid state the [SO₃F]^? anion bridges three [TcO₃]⁺ cations, and vice versa. Space group P2₁/c, Z = 4, lattice dimensions at 173 K: a = 695.4(11), b = 808.6(12), c = 893.3(14) pm, β = 97.36(8)°.     

Pseudochalkogen-Verbindungen. XVI. IR-spektroskopische Untersuchungen an Cyanamidomonophosphaten, [PO4−n (NCN)n]3−

Pseudochalkogen Compounds. XVI. Infrared-spectroscopic Investigations of Cyanamidomonophosphates, [PO_4?n(NCN)_n]^3? Infrared spectroscopic investigations of trisodium cyanamidomonophosphates of the general type Na₃[PO_4?n(NCN)_n] · aq (n: 1, 2, 3) are reported. The vibrational spectra of the compounds are confirming very clearly the special position of cyanamidophosphates within the group of substituted phosphates: Cyanamidophosphates are characterized by a full participation of pseudochalkogen groups representing NCN substituents into the mesomeric system of the anions and an only slight shortening of the P? O distances in comparision to [PO₄]^3?. Characteristic frequencies between 970 and 1150 cm^?1 are attributed to v(PO_4?nN_n)-stretching frequencies. A partial ¹⁵N labelling of the monocyanamidophosphate anion, [PO₃NCN]^3? leads to some splitting or shifting of frequencies being connected with vibrations of the NCN group; isolated v(P? N) stretching frequencies cannot be found.     

Formation of [Bi11]3−, A Homoatomic,Polycyclic Bismuth Polyanion,by Pyridine‐Assisted Decomposition of [GaBi3]2−

Until now, polycyclic bismuth polyanions have not been known—thus discriminating bismuth from its lighter congeners. However, the synthesis of [K([2.2.2]crypt)]₃(Bi₁₁)?2 py?tol, allows us to present the first structurally characterized homoatomic, polycyclic bismuth polyanion, which exhibits the [P₁₁]^3? “ufosan” structure. It was obtained upon treatment of [K([2.2.2]crypt)]₂(GaBi₃)?en with the solvent pyridine. The binary Zintl anion [GaBi₃]^2? decomposes under oxidative coupling of pyridine molecules and release of H₂ to form the title compound. The unprecedented reaction, its products and by‐products were investigated by means of spectroscopy, spectrometry, and DFT studies. All findings reveal the specific reaction conditions to be crucial for the formation of the [Bi₁₁]^3? ion—and indicate the possibility of the generation and isolation of further, large bismuth polyanions.     

Sind die ‚Lehrbuch-Anionen’︁ O2−, [CO3]2− und [SO4]2− Fiktionen?

Are the ‘Textbook Anions’ O^2?, [CO₃]^2?, and [SO₄]^2? Fictitious? Experimental second electron affinities are still unknown for the title anions. It will be shown by means of quantum chemical ab initio calculations that these dianions are unstable with respect to spontaneous ionization. They all must be designated as non-existent.     

Structure and Bonding in [Sb@In8Sb12]3− and [Sb@In8Sb12]5−

We report the characterization of the compound [K([2.2.2]crypt)]₄[In₈Sb₁₃], which proves to contain a 1:1 mixture of [Sb@In₈Sb₁₂]^3? and [Sb@In₈Sb₁₂]^5?. The tri‐anion displays perfect T_h symmetry, the first completely inorganic molecule to do so, and contains eight equivalent In³⁺ centers in a cube. The gas‐phase potential energy surface of the penta‐anion has eight equivalent minima where the extra pair of electrons is localized on one In⁺ center, and these minima are linked by low‐lying transition states where the electron pair is delocalized over two adjacent centers. The best fit to the electron density is obtained from a model where the structure of the 5? cluster lies close to the gas‐phase transition state.     

Darstellung und Schwingungsspektren der Komplexe [MBr6]−, [Br5MN3]− und [Br5MNPPh3]− von Niob und Tantal Die Kristallstruktur von PPh4[NbBr6]

Preparation and vibrational spectra of the complexes [MBr₆]^?, [Br₅MN₃]^? and [Br₅MNPPh₃]^? of niobium and tantalum. Cyrstal structure of PPh₄[NbBr₆] The compounds PPh₄[MBr₆] and PPh₄[MBr₅N₃] are obtained by reaction of MBr₅ with PPh₄Br or PPh₄N₃, respectively, in CH₂Cl₂ solution (M ? Nb, Ta). The azido complexes PPh₄[MBr₅N₃] can also be obtained by reactions of the hexabromo complexes with iodine azide. According to its i.r. spectrum the symmetry of the [MBr₆]^? ion is lower than O_h in the solide state. This is corfirmed for PPh₄[NbBr₆] by a crystal structure analysis; it crystallizes in the monoclinic space group B2/b with four formula units in the unit cell and with the lattice constants a = 2301, b = 1777, c = 686 pm and γ = 96,6°. The structure was determined with X-ray diffraction data and was refined to a residual index of R = 0.055. The [NbBr₆]^? ion has the symmetry C_i, the deviations from O_h being small. In the azido complexes [MBr₅N₃]^? the azido groups are covalently linked with the metal. From [NbBr₅N₃]^? and PPh₃ the complex [Br₅Nb?N?PPh₃]^?, is obtained; for the analogous formation of the corresponding Ta complex photochemical activation is necessary. In this way the complex [Cl₅Nb?N?AsPh₃]^? can also be obtained. I.r. spectra of all the compounds are reported and assigned.     

Investigation of Large Polychloride Anions: [Cl11]−, [Cl12]2−, and [Cl13]−

For decades the chemistry of polyhalides was dominated by polyiodides and more recently also by an increasing number of polybromides. However, apart from a few structures containing trichloride anions and a single report on an octachloride dianion, [Cl₈]^2?, polychlorine compounds such as polychloride anions are unknown. Herein, we report on the synthesis and investigation of large polychloride monoanions such as [Cl₁₁]^? found in [AsPh₄][Cl₁₁], [PPh₄][Cl₁₁], and [PNP][Cl₁₁]?Cl₂, and [Cl₁₃]^? obtained in [PNP][Cl₁₃]. The polychloride dianion [Cl₁₂]^2? has been obtained in [NMe₃Ph]₂[Cl₁₂]. The novel compounds have been thoroughly characterized by NMR spectroscopy, single‐crystal Raman spectroscopy, and single‐crystal X‐ray diffraction. The assignment of their spectra is supported by molecular and periodic solid‐state quantum‐chemical calculations.