Reactivity of liquid ammonia solutions of the Zintl phase K12Sn17 towards mesitylcopper(I) and phosphinegold(I) chloride.

To gain more insight into the reactivity of intermetalloid clusters, the reactivity of the Zintl phase K12 Sn17 , which contains [Sn4 ](4-) and [Sn9 ](4-) cluster anions, was investigated. The reaction of K12 Sn17 with gold(I) phosphine chloride yielded K7 [(η(2) -Sn4 )Au(η(2) -Sn4 )](NH3 )16 (1) and K17 [(η(2) -Sn4 )Au(η(2) -Sn4 )]2 (NH2 )3 (NH3 )52 (2), which both contain the anion [(Sn4 )Au(Sn4 )](7-) (1 a) that consists of two [Sn4 ](4-) tetrahedra linked through a central gold atom. Anion 1 a represents the first binary AuSn polyanion. From this reaction, the solvate structure [K([2.2.2]crypt)]3 K[Sn9 ](NH3 )18 (3; [2.2.2]crypt=4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) was also obtained. In the analogous reaction of mesitylcopper with K12 Sn17 in the presence of [18]crown-6 in liquid ammonia, crystals of the composition [K([18]crown-6)]2 [K([18]crown-6)(MesH)(NH3 )][Cu@Sn9 ](thf) (4) were isolated ([18]crown-6=1,4,7,10,13,16-hexaoxacyclooctadiene, MesH=mesitylene, thf=tetrahydrofuran) and featured a [Cu@Sn9 ](3-) cluster. A similar reaction with [2.2.2]crypt as a sequestering agent led to the formation of crystals of [K[2.2.2]crypt][MesCuMes] (5). The cocrystallization of mesitylene in 4 and the presence of [MesCuMes](-) (5 a) in 5 provides strong evidence that the migration of a bare Cu atom into an Sn9 anion takes place through the release of a Mes(-) anion from mesitylcopper, which either migrates to another mesitylcopper to form 5 a or is subsequently protonated to give MesH.

Bi-Zn bond formation in liquid ammonia solution: [Bi-Zn-Bi]4-, a linear polyanion that is iso(valence)-electronic to CO2.

Reactions of the zinc(I) complex [Zn2(Mesnacnac)2] (Mesnacnac = [(2,4,6-Me3C6H2)NC(Me)]2CH) with solid K3Bi2 dissolved in liquid ammonia yield crystals of the compound K4[ZnBi2]⋅(NH3)12 (1), which contains the molecular, linear heteroatomic [Bi-Zn-Bi](4-) polyanion (1 a). This anion represents the first example of a three-atomic molecular ion of metal atoms being iso(valence)-electronic to CO2 and being synthesized in solution. The analogy of the discrete [Bi-Zn-Bi](4-) anion and the polymeric ∞(1)[(ZnBi4/2)(4-)] unit to monomeric CO2 and polymeric SiS2 is rationalized.

Synthesis and Lewis acid properties of (ReO3F)∞ and the X-ray crystal structures of (HF)2ReO3F·HF and [N(CH3)4]2-[{ReO3(µ-F)}3(µ3-O)]·CH3CN.

A high-yield, high-purity synthesis of (ReO3F)∞ has been achieved by solvolysis of Re2O7 in anhydrous HF (aHF) followed by reaction of the water formed with dissolved F2 at room temperature. The improved synthesis has allowed the Lewis acid and fluoride ion acceptor properties of (ReO3F)∞ to be further investigated. The complex, (HF)2ReO3F·HF, was obtained by dissolution of (ReO3F)∞ in aHF at room temperature and was characterized by vibrational spectroscopy and single-crystal X-ray diffraction at -173 °C. The HF molecules are F-coordinated to rhenium, representing the only known example of a HF complex with rhenium. The trirhenium dianion, [{ReO3(µ-F)}3(µ3-O)](2-), was obtained as the [N(CH3)4](+) salt by the reaction of stoichiometric amounts of (ReO3F)∞ and [N(CH3)4]F in CH3CN solvent at -40 to -20 °C. The anion was structurally characterized in CH3CN solution by (19)F NMR spectroscopy and in the solid state by Raman spectroscopy and a single-crystal X-ray structure determination of [N(CH3)4]2[{ReO3(µ-F)}3(µ3-O)]·CH3CN at -173 °C. The structural parameters and vibrational frequencies of the [{MO3(µ-F)}3(µ3-O)](2-) and [{MO3(µ-F)}3(µ3-F)](-) anions (M = Re, Tc) were calculated using density functional theory. The calculated geometries of [{ReO3(µ-F)}3(µ3-O)](2-) and [{TcO3(µ-F)}3(µ3-F)](-), are in very good agreement with their experimental geometries. Calculated vibrational frequencies and Raman intensities have been used to assign the Raman spectra of (HF)2ReO3F·HF and [N(CH3)4]2[{ReO3(µ-F)}3(µ3-O)]·CH3CN. The X-ray crystal structures of the byproducts, [N(CH3)4][ReO4] and KF·4HF, were also determined in the course of this work.

[P9]+ [Al(OR(F))4)]-, the salt of a homopolyatomic phosphorus cation.

Positive at last: The first condensed-phase homopolyatomic phosphorus cation [P(9)](+) was prepared using a combination of the oxidant [NO](+) and weakly coordinating anion, [Al{OC(CF(3))(3)}(4)](-). [P(9)](+) consists of two P(5) cages linked by a phosphonium atom to give a D(2d)-symmetric Zintl cluster. NMR (see picture), Raman, and IR spectroscopy, mass spectrometry, and quantum-chemical calculations confirmed the structure.

Polyfluoride anions, a matrix-isolation and quantum-chemical investigation.

Laser-ablation experiments with metals provide a source of electrons for capture processes, which are codeposited with solid argon and neon containing molecular fluorine. New argon and neon matrix absorptions at 510.6 and 524.7 cm(-1), respectively, are photosensitive upon irradiation at >290 nm, which is consistent with their assignment to an isolated anion. These bands are below the [M](+)[F(3)](-) antisymmetric trifluoride stretching frequency of 550 cm(-1) in an argon matrix, which is the typical relationship for cation-anion complexes and matrix-isolated anions. Thus, we report the isolated [F(3)](-) anion in solid argon and neon environments. Moreover, we have carried out quantum-chemical calculations up to and including the CCSD(T) method to investigate the stabilities of polyfluoride anions higher than the [F(3)](-) anion.

In silico predictions of the temperature-dependent viscosities and electrical conductivities of functionalized and nonfunctionalized ionic liquids.

The viscosity (η) and electrical conductivity (κ) of ionic liquids are, next to the melting point, the two key properties of general interest. The knowledge of temperature-dependent η and κ data before their first synthesis would permit a much more target-oriented development of ionic liquids. We present in this work a novel approach to predict the viscosity and electrical conductivity of an ionic liquid without further input of experimental data. For the viscosity, only some basic physical observables like the Gibbs solvation energy (ΔG(solv)(*,∞)), which was calculated at the affordable DFT-level (RI-)BP86/TZVP/COSMO, the molecular radius, calculated from the molecular volume V(m) of the ion volumes, and the symmetry number (σ), according to group theory, are necessary as input. The temperature dependency (253-373 K) of the viscosity (4-19000 mPa s) was modeled by an Arrhenius approach. An alternative way, which avoids the deficits of the Arrhenius relation by a series expansion in the exponential term, is also presented. On the basis of their close connection, the same set of parameters is suitable to describe the electrical conductivity as well (238-468 K, 0.003-193 mS/cm). Nevertheless, more elegant alternatives like the usage of the Stokes-Einstein/Nernst-Einstein relation or the Walden rule are highlighted in this work. During this investigation, we additionally found an approach to predict the dielectric constant ε* of an ionic liquid at 298 K by using V(m) and ΔG(solv)(*,∞) between ε* = 9 and 43.

Metastable Se6 as a ligand for Ag+: from isolated molecular to polymeric 1D and 2D structures.

Attempts to prepare the hitherto unknown Se(6)(2+) cation by the reaction of elemental selenium and Ag[A] ([A](-) = [Sb(OTeF(5))(6)](-), [Al(OC(CF(3))(3))(4)](-)) in SO(2) led to the formation of [(OSO)Ag(Se(6))Ag(OSO)][Sb(OTeF(5))(6)](2)1 and [(OSO)(2)Ag(Se(6))Ag(OSO)(2)][Al(OC(CF(3))(3))(4)](2)2a. 1 could only be prepared by using bromine as co-oxidant, however, bulk 2b (2a with loss of SO(2)) was accessible from Ag[Al(OC(CF(3))(3))(4)] and grey Se in SO(2) (chem. analysis). The reactions of Ag[MF(6)] (M = As, Sb) and elemental selenium led to crystals of 1/∞{[Ag(Se(6))](∞)[Ag(2)(SbF(6))(3)](∞)} 3 and {1/∞[Ag(Se(6))Ag](∞)}[AsF(6)](2)4. Pure bulk 4 was best prepared by the reaction of Se(4)[AsF(6)](2), silver metal and elemental selenium. Attempts to prepare bulk 1 and 3 were unsuccessful. 1-4 were characterized by single-crystal X-ray structure determinations, 2b and 4 additionally by chemical analysis and 4 also by X-ray powder diffraction, FT-Raman and FT-IR spectroscopy. Application of the PRESTO III sequence allowed for the first time (109)Ag MAS NMR investigations of 4 as well as AgF, AgF(2), AgMF(6) and {1/∞[Ag(I(2))](∞)}[MF(6)] (M = As, Sb). Compounds 1 and 2a/b, with the very large counter ions, contain isolated [Ag(Se(6))Ag](2+) heterocubane units consisting of a Se(6) molecule bicapped by two silver cations (local D(3d) sym). 3 and 4, with the smaller anions, contain close packed stacked arrays of Se(6) rings with Ag(+) residing in octahedral holes. Each Ag(+) ion coordinates to three selenium atoms of each adjacent Se(6) ring. 4 contains [Ag(Se(6))(+)](∞) stacks additionally linked by Ag(2)(+) into a two dimensional network. 3 features a remarkable 3-dimensional [Ag(2)(SbF(6))(3)](-) anion held together by strong Sb-FAg contacts between the component Ag(+) and [SbF(6)](-) ions. The hexagonal channels formed by the [Ag(2)(SbF(6))(3)](-) anions are filled by stacks of [Ag(Se(6))(+)](∞) cations. Overall 1-4 are new members of the rare class of metal complexes of neutral main group elemental clusters, in which the main group element is positively polarized due to coordination to a metal ion. Notably, 1 to 4 include the commonly metastable Se(6) molecule as a ligand. The structure, bonding and thermodynamics of 1 to 4 were investigated with the help of quantum chemical calculations (PBE0/TZVPP and (RI-)MP2/TZVPP, in part including COSMO solvation) and Born-Fajans-Haber-cycle calculations. From an analysis of all the available data it appears that the formation of the usually metastable Se(6) molecule from grey selenium is thermodynamically driven by the coordination to the Ag(+) ions.