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.     

Polychloride Monoanions from [Cl3]− to [Cl9]−: A Raman Spectroscopic and Quantum Chemical Investigation

Polychloride monoanions stabilized by quaternary ammonium salts are investigated using Raman spectroscopy and state‐of‐the‐art quantum‐chemical calculations. A regular V‐shaped pentachloride is characterized for the [N(Me)₄][Cl₅] salt, whereas a hockey‐stick‐like structure is tentatively assigned for [N(Et)₄][Cl₂???Cl₃^?]. Increasing the size of the cation to the quaternary ammonium salts [NPr₄]⁺ and [NBu₄]⁺ leads to the formation of the [Cl₃]^? anion. The latter is found to be a pale yellow liquid at about 40 °C, whereas all the other compounds exist as powders. Further to these observations, the novel [Cl₉]^? anion is characterized by low‐temperature Raman spectroscopy in conjunction with 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.     

Über die Darstellung der Dichlormethylen-halogensulfenium-Salze Cl2CSCl+ AsF6− und Cl2CSBr+ AsF6− [1]

The Synthesis of the Dichloromethylene-halogenosulfenium Salts Cl₂CSCl⁺ AsF₆^? and Cl₂CSBr⁺ AsF₆^? The sulfenium salts Cl₂CSCl⁺ AsF₆^? and Cl₂CSBr⁺ AsF₆^? are synthesized by oxidative halogenation of thiophosgene, Cl₂CS with X₂/AsF₅ (X = Cl, Br) at 195 K and are characterized by vibrational as well as NMR spectroscopy.     

Cs[Cl3F10]: A Propeller‐Shaped [Cl3F10]− Anion in a Peculiar A[5]B[5] Structure Type

Reaction of CsF with ClF₃ leads to Cs[Cl₃F₁₀]. It contains a molecular, propeller‐shaped [Cl₃F₁₀]^? anion with a central μ₃‐F atom and three T‐shaped ClF₃ molecules coordinated to it. This anion represents the first example of a heteropolyhalide anion of higher ClF₃ content than [ClF₄]^? and is the first Cl‐containing interhalogen species with a μ‐bridging F atom. The chemical bonds to the central μ₃‐F atom are highly ionic and quite weak as the bond lengths within the coordinating XF₃ units (X = Cl, and also calculated for Br, I) are almost unchanged in comparison to free XF₃ molecules. Cs[Cl₃F₁₀] crystallizes in a very rarely observed A^[5]B^[5] structure type, where cations and anions are each pseudohexagonally close packed, and reside, each with coordination number five, in the trigonal bipyramidal voids of the other.     

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.     

Pr10[Si10−xAlxO9+xN17−x]Cl with x ≈ 1 – an Oxonitridoaluminosilicate Chloride

The oxonitridoaluminosilicate chloride Pr₁₀[Si_10?xAl_xO_9+xN_17?x]Cl was obtained by the reaction of praseodymium metal, the respective chloride, AlN and Al(OH)₃ with “Si(NH)₂” in a radiofrequency furnace at temperatures around 1900 °C. The crystal structure was determined by single‐crystal X‐ray diffraction (Pbam, no. 55, Z = 2,a = 10.5973(8) Å, b = 11.1687(6) Å, c = 11.6179(7) Å, R1 = 0.0337). The sialon crystallizes isotypically to the oxonitridosilicate halides Ce₁₀[Si₁₀O₉N₁₇]Br, Nd₁₀[Si₁₀O₉N₁₇]Br and Nd₁₀[Si₁₀O₉N₁₇]Cl, which represent a new layered structure type. The structure refinement was performed utilizing an O/N‐distribution model according to Paulings rules, i.e. nitrogen was positioned on all bridging sites and mixed O/Noccupation was assumed on the terminal sites resulting in charge neutrality of the compounds. The Si and Al atoms were refined equally distributed on their three crystallographic sites, due to their poor distinguishability by X‐ray analysis. The tetrahedra layers of the structure consist of condensed [(Si,Al)N₂(O,N)₂] and [(Si,Al)N₃(O,N)] tetrahedra of Q² and Q³ type. The chemical composition of the compound was derived from electron probe micro analyses (EPMA).     

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.     

A structural study of Si6‐ring‐containing [Si6Cl14]2− chlorosilicates

The crystal structures of four substituted‐ammonium dichloride dodecachlorohexasilanes are presented. Each is crystallized with a different cation and one of the structures contains a benzene solvent molecule: bis(tetraethylammonium) dichloride dodecachlorohexasilane, 2C₈H₂₀N⁺·2Cl⁻·Cl₁₂Si₆, (I), tetrabutylammonium tributylmethylammonium dichloride dodecachlorohexasilane, C₁₆H₃₆N⁺·C₁₃H₃₀N⁺·2Cl⁻·Cl₁₂Si₆, (II), bis(tetrabutylammonium) dichloride dodecachlorohexasilane benzene disolvate, 2C₁₆H₃₆N⁺·2Cl⁻·Cl₁₂Si₆·2C₆H₆, (III), and bis(benzyltriphenylphosphonium) dichloride dodecachlorohexasilane, 2C₂₅H₂₂P⁺·2Cl⁻·Cl₁₂Si₆, (IV). In all four structures, the dodecachlorohexasilane ring is located on a crystallographic centre of inversion. The geometry of the dichloride dodecachlorohexasilanes in the different structures is almost the same, irrespective of the cocrystallized cation and solvent. However, the crystal structure of the parent dodecachlorohexasilane molecule shows that this molecule adopts a chair conformation. In (IV), the P atom and the benzyl group of the cation are disordered over two sites, with a site‐occupation factor of 0.560 (5) for the major‐occupied site.     

Metallocages for Metal Anions: Highly Charged [Co@Ge9]5− and [Ru@Sn9]6− Clusters Featuring Spherically Encapsulated Co1− and Ru2− Anions

Endohedral clusters count as molecular models for intermetallic compounds—a class of compounds in which bonding principles are scarcely understood. Herein we report soluble cluster anions with the highest charges on a single cluster to date. The clusters reflect the close analogy between intermetalloid clusters and corresponding coordination polyhedra in intermetallic compounds. We now establish Raman spectroscopy as a reliable probe to assign for the first time the presence of discrete, endohedrally filled clusters in intermetallic phases. The ternary precursor alloys with nominal compositions “K₅Co_1.2Ge₉” and “K₄Ru₃Sn₇” exhibit characteristic bonding modes originating from metal atoms in the center of polyhedral clusters, thus revealing that filled clusters are present in these alloys. We report also on the structural characterization of [Co@Ge₉]^5? ( 1a ) and [Ru@Sn₉]^6? ( 2a ) obtained from solutions of the respective alloys.