In tyrosinium polyiodide hydrate, cations and anions aggregate in layers. The cation layers are stabilized by classical hydrogen bonds. The anionic part of the structure consists of parallel infinite polyiodide strands; the distance pattern along these chains suggests the presence of smaller subunits I 3 − , I 2 and I − . Comparative calculations for small fragments and longer chains in frozen geometries indicate that this unexpected arrangement is favoured by local stabilizing anion⋯anion interactions and partial charge transfer between the subunits. The topological analyses of the electron density ρ, its negative Laplacian L = −∇ 2 ρ and the electrostatic potential φ functions have been used to study the intrachain I-I and I⋯I interactions. Thorough analysis carried out with L indicates the successive arrangement of generalized charge concentration and charge depletion sites (for either L > 0 or L < 0 regions) along bond paths, and permits to distinguish iodides from iodine atoms even when they are involved in intermediate situations where interatomic distances and net charges are not conclusive.
Alkali metal triphenylsilyls [Li(12-crown-4)SiPh3]·(thf)0.5 (2), [Na(15-crown-5)SiPh3]·(thf)0.5 (3) and [K(18-crown-6)SiPh3(thf)] (4) were synthesized using 1,1,1-trimethyl-2,2,2-triphenyldisilane (Ph3SiSiMe3) and isolated in high yields. Solid state structures were determined by single crystal X-ray diffraction. These alkali metal silyls catalyzed the regioselective hydrosilylation of 1,1-diphenylethylene to give the anti-Markovnikov product. The presence of crown ethers enhanced the reactivity of the metal silyls in hydrosilylation catalysis.
Complete miscibility of the intermetallic phases (IPs) SrGa2 and BaGa2 forming the solid solution Sr(1-x)Ba(x)Ga2 is shown by means of X-ray diffraction, thermoanalytical and metallographic studies. Regarding the distances of Sr/Ba sites versus substitution degree, a model of isolated substitution centres (ISC) for up to 10% cation substitution is explored to study the influence on the Ga bonding situation. A combined application of NMR spectroscopy and quantum mechanical (QM) calculations proves the electric field gradient (EFG) to be a sensitive measure of different bonding situations. The experimental resolution is boosted by orientation-dependent NMR on magnetically aligned powder samples, revealing in first approximation two different Ga species in the ISC regimes. EFG calculations using superlattice structures within periodic boundary conditions are in fair agreement with the NMR spectroscopy data and are discussed in detail regarding their application on disordered IPs.
A multifunctional coupler with an ethylene carbonate- and a thiolactone ring was synthesized. As proof of principle the coupler was reacted with four low-molecular weight building blocks to form a multifunctional molecule. The reactivity/selectivity of the coupler towards amines, acrylates and acyl halides was evaluated.
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