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.     

Collision-induced dissociation of negative ions in the gas phase: [Aryl S]−, [aryl SO]− and [aryl SO2]−

Collision-induced dissociation of the ions [ArS]^?, [ArSO]^? and [ArSO₂]^? has uncovered a rich and varied ion chemistry. The major fragmentations of [ArS]^? are complex and occur without prior ring hydrogen scrambling: for example, [C₆H₅S]^?→[C₂HS]^? and [HS]^?; [p-CD₃C₆H₄S]^?→[C₆H₄S]^?˙, [CD₃C₄S]^? and [C₂HS]^?. In contrast, all decompositions of [C₆H₅CH₂S]^? are preceded by specific benzylic and phenyl hydrogen interchange reactions. [ArSO₂]^? and [ArSO₂]^? ions undergo rearrangement, e.g. [C₆H₅SO]^?→[C₆H₅O]^? and [C₆H₅S]^?; [C₆H₅SO₂]^?→[C₆H₅O] ^?. The ion [C₆H₅CH₂SO]^? eliminates water, this decomposition is preceded by benzylic and phenyl hydrogen exchange.     

Pseudoelementverbindungen. IV. Modifizierung der Ionen Sulfit [SOY2]2−, Sulfat [SO4−nYn]2− und Sulfonat [RSO2Y]− durch Einführung der Pseudochalkogengruppen NCN und C(CN)2

Pseudoelement Compounds. IV. Modification of the Ions Sulfite [SO₂Y]^2?, Sulfate [SO_4?nY_n]^2?, and Sulfonate [RSO₂Y]^? by Introducing Pseudochalcogen Groups NCN and C(CN)₂ . Described is the synthesis of pseudochalcogen modified sulfites M₂[SOY₂], sulfates M₂[SO_4?nY_n] (Y = NCN), and arylsulfonates M[RSO₂Y] (Y = NCN, C(CN)₂). The ¹³C-NMR and IR spectra of the new compounds are discussed.     

Darstellung und spektroskopische Charakterisierung der Monofluorohydro-closo-Borate [B6H5F]2− und [B12H11F]2−

Preparation and Spectroscopic Characterization of the Monofluorohydro-closo-borates [B₆H₅F]^2? and [B₁₂H₁₁F]^2? By treatment of [B₆H₆]^2? with 1-(chloromethyl)-4-fluoro-1,4-diazabicyclo[2.2.2]octane-bis(tetrafluoroborate)in acetonitrile monofluorohydro-closo-hexaborate [B₆H₅F]^2? ( 1 ) is formed in good yields. [B₁₂H₁₂]^2? reacts with unhydrous HF yielding the monofluorododecaborate [B₁₂H₁₁F]^2? ( 2 ). These compounds are separated by ion exchange chromatography on diethylaminoethyl(DEAE) cellulose from by-products. The ¹¹B nmr spectra exhibit the characteristic patterns (1 : 4 : 1) of a monosubstituted B₆ octahedron and (1 : 5 : 5 : 1) of a monosubstituted B₁₂ icosahedron with strong downfield shifts of the ipso-B nuclei at +9.3 ppm ( 1 ) and at +9.0 ppm ( 2 ). The ¹⁹F nmr spectra reveal quartets at ?212 ppm ( 1 ) and ?209 ppm ( 2 ) proving a B? F bonding. In the i.r. spectra, for ( 1 ) in the Raman spectrum too, cage vibrations depending on the F substituent at 1195 ( 1 ) and at 1182/1154 cm^?1 ( 2 ) are observed. The Raman spectra show the B₆F stretching mode at 535 cm^?1 and the B₁₂F stretching vibration at 445 cm^?1.     

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.     

Elektronenstruktur von strukturell offenen Derivaten des [Mo6X14]2−-Clusters: [Mo5Cl13]2− und [Mo4I11]2−

Electronic Structure of Structural Open Derivatives of the [Mo₆X₁₄]^2?-Cluster: [Mo₅Cl₁₃]^2? and [Mo₄I₁₁]^2? The electronic structure of structural open derivatives of the [Mo₆X₁₄]^2?-cluster [Mo₅Cl₁₃]^2? and [Mo₄I₁₁]^2? has been studied by the EHMO method. In [Mo₅Cl₁₃]^2? 9 occupied MO's with dominant Mo4d character are responsible for the formation of the 8 metal-metal bonds. In [Mo₄I₁₁]^2? the stronger covalent character of the Mo? I bonds affects the localization and the energy of molecular orbitals and also the charge distribution. The metal-metal bonds are formed by 8 MO's containing considerable participation of halogen AO's contrary to the chloride cluster. There is no bonding between the Mo atoms at the wing tips of the Mo₄ butterfly and the reason for decreasing the dihedral angle between the Mo₃ planes in [Mo₄I₁₁]^2? compared with the octahedral angle is apparently the stabilization of the whole system (Mo? Mo and Mo? I bonds). The unpaired electron occupies in both clusters a slightly antibonding (with regard to the Mo? Mo bonds) orbital.     

Dinuclear Manganese(II) Complexes with Bridging Selenidodiarsenate Anions [As2Se4]4−, [As2Se5]4− and [As2Se6]2−

Solvothermal reaction of [MnCl₂(amine)] (amine = terpy and tren) with elemental As and Se at a 1:1:2 molar ratio in H₂O/tren (10:1) affords the dimanganese(II) complexes [{Mn(terpy)}₂(μ‐As₂Se₄)] ( 1 ) and [{Mn(tren)}₂(μ‐As₂Se₅)] ( 2 ) respectively. The tetradentate [As₂Se₄]^4? bridging ligands in 1 contain a central As–As bond and exhibit approximately C_2h symmetry. Pairs of gauche sited Se atoms participate in five‐membered As₂Se₂Mn chelate rings. In contrast, two AsSe₃ pyramids share a common corner in the [As₂Se₅]^4? ligands of 2 and each coordinates an [Mn(tren)]²⁺ fragment through a single terminal Se atom. Such dinuclear complexes are linked into tetranuclear moieties through weak Se···Mn interactions of length 3.026(3) Å involving one of these terminal Se atoms. At a 1:3:6 molar ratio, solvothermal reaction of [MnCl₂(tren)] with As and Se leads to formation of a second dinuclear complex [{Mn(tren)}₂(μ‐As₂Se₆)₂] ( 3 ), which contains two bridging bidentate [As₂Se₆]^2? ligands. These are cyclic with an As₂Se₄ ring and can be regarded as being derived from [As₂Se₅]^4? anions by formation of two Se‐Se bonds to an additional Se atom.     

NaAg3S2, ein Thioargentat mit dem Clusteranion [Ag6S4]2−

NaAg₃S₂, a Thioargentate Containing the Anionic Cluster [Ag₆S₄]^2? . Dark-red octahedrally shaped crystals of NaAg₃S₂ could be obtained by the reaction of NaAg(CN)₂ and NaCN in a stream of hydrogen sulfide at 630 K. NaAg₃S₂ crystallizes cubic, a=12.358(1) Å, space group Fd3 m, Z=16. The structure was determined from four-circle diffractometer data. NaAg₃S₂ contains the anionic cluster [Ag₆S₄]^2?. The structure can be traced back to the spinel structure typ. An extended Hückel calculation for the cluster anion, which is considered to be isolated, shows weak bonding silver-silver interactions. NaAg₃S₂ is diamagnetic at room temperature.