The quality of diffraction data obtained using silver and molybdenum microsources has been compared for six model compounds with a wide range absorption factors. experiments were performed on two 30 W air-cooled Incoatec IµS microfocus sources multilayer optics mounted Bruker D8 goniometer SMART APEX II CCD detector. All analysed, processed refined standard software. results show that Ag

A trapped silicon atom: The compound (L:)2Si with low-valent was synthesized from its dichloride biradical precursor (L:)2SiCl2 by reduction KC8. Theoretical analysis suggest that there are two donor–acceptor σ bonds L:→Si←:L. There is one lone-pair orbital at Si and π which features significant π-back-donation L:←Si→:L giving short SiC bonds.

Packed in like sardines: Three BF4− ions are packed into the three cavities of an interpenetrated dimer a coordination cage (see scheme). While inner ion is tightly bound inside central position, loosely outer anions can be replaced with halide by allosteric binding mechanism and concerted structural change. In particular, Cl− great affinity.

The 35-residue subdomain of the villin headpiece (HP35) is a small ultrafast folding protein that being intensely studied by experiments, theory, and simulations. We have solved x-ray structures HP35 its fastest mutant [K24 norleucine (nL)] to atomic resolution compared their experimentally measured kinetics using laser temperature jump. structures, which are in different space groups, almost identical each other but differ significantly from previously NMR structures. Hence, differences...

Four examples of the refinement twinned structures are discussed. These illustrate three different types twins: twinning by merohedry, pseudo-merohedry and non-merohedral twins. How was detected, how were solved they refined shown in this paper. The difference between a as disordered model is illustrated. Sometimes twin law necessary to solve structure, while other first recognized during structures. Finally, list `characteristic warning signs' presented which indicative possible twinning.

This article reports the reduction of chloride [PhC(NtBu)2]GeCl with potassium in THF to afford reddish crystals [PhC(NtBu)2]2Ge2 (2). The molecule 2 contains a Ge−Ge bond. X-ray structure and DFT calculation indicate that bond possesses an unusual gauche-bent geometry. length is 2.570 Å, which very close single interaction (2.61 Å) but significantly longer than for typical digermenes, R2GeGeR2 (2.21−2.51 two structurally characterized digermynes (2.2850 Å 2.2060 Å), proves there no multiple...

The cyclic alkyl(amino) carbene (cAAC:)-stabilized acyclic germylones (Me2-cAAC:)2Ge (1) and (Cy2-cAAC:)2Ge (2) were prepared utilizing a one-pot synthesis of GeCl2(dioxane), cAAC:, KC8 in 1:2:2.1 molar ratio. Dark green crystals compounds 1 2 produced 75 70% yields, respectively. reported methods for the preparation corresponding silicon turned out to be not applicable case germanium. single-crystal X-ray structures feature C-Ge-C bent backbone, which possesses three-center two-electron...

The cyclic alkyl(amino) carbene stabilized Si2H2 has been isolated in the molecular form of composition (Me-cAAC:)2Si2H2 (1) and (Cy-cAAC:)2Si2H2 (2) at room temperature. Compounds 1 2 were synthesized from reduction HSiCl3 using 3 equiv KC8 presence Me-cAAC: Cy-cAAC:, respectively. These are first examples characterized by single crystal X-ray structural analysis. Moreover, electrospray ionization mass spectrometry 1H as well 29Si NMR data reported. Furthermore, structure compound...

Low-energy contamination caused by focusing multilayer optics has been known for a long time. So far, the only method to avoid this problem is attenuation interposition of low-density material foil into beam. However, lowers intensity, which might be crucial, especially charge density data collection, and course not possible already measured data. In article, an empirical correction proposed as alternative or addition. The low-energy mainly affects reflections with indices 3 h k l . program...

Abstract Solid‐state luminescent materials are essential for the development of optoelectronic devices like lasers, sensors, and organic light‐emitting diodes. Organic molecules reveal several benefits stability, costs, environmental compatibility compared to metal‐based materials. As common fluorophores often suffer from aggregation‐caused quenching, different strategies have been established overcome this which mainly based on intramolecular modifications. Controlling photophysical...

Enantioselective catalysis is one of the most prominent strategies in organic synthesis to access chiral bioactive compounds and advanced materials. Particularly development ligands has significantly efficiency selectivity transition metal-catalyzed enantioselective transformations. Over recent decades, numerous ligand classes with distinct geometrical electronic properties were established. Despite these advances, demand for novel, tunable, highly effective persist, driven by need...

Enantioselective electrocatalyzed C–H activations have emerged as a transformative platform for the assembly of value-added chiral organic molecules. Despite recent progress, construction multiple C(sp3)-stereogenic centers via C(sp3)–C(sp3) bond formation has thus far proven to be elusive. In contrast, we herein report an annulative activation strategy, generating Fsp3-rich molecules with high levels diastereo- and enantioselectivity. κ2-N,O-oxazoline preligands were effectively employed in...

Reduction of LAlI(2) (1) (L = HC[(CMe)(NAr)](2), Ar 2,6-i-Pr(2)C(6)H(3)) with potassium in the presence alkynes C(2)(SiMe(3))(2), C(2)Ph(2), and C(2)Ph(SiMe(3)) yielded first neutral cyclopropene analogues aluminum LAl[eta(2)-C(2)(SiMe(3))(2)] (3), LAl(eta(2)-C(2)Ph(2)) (4), LAl[eta(2)-C(2)Ph(SiMe(3))] (5), respectively, whereas reduction 1 Ph(2)CO gave an pinacolate LAl[O(2)(CPh(2))(2)] (6), irrespective amount employed. The unsaturated molecules CO(2), Ph(2)CO, PhCN inserted into one Al-C...

In a simple one-pot reaction the host-guest compounds 1 (white spheres FeIII; black = FeII; gray NH; angled rods 2: R Me, Et) are accessible in gram quantities by self-assembly. They only fully characterized redox isomers whose cyclic voltammograms display four quasi-reversible waves and mixed-valent character has been established Mössbauer spectra. The endohedral complexation of one NH ion confirmed X-ray crystallography.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural characterization of two modifications tris(tetrahydrofuran)(tris(trimethylsilyl)silyl)lithium: a compound with silicon-29-lithium-7 NMR couplingAndreas Heine, Regine Herbst-Irmer, George M. Sheldrick, and Dietmar StalkeCite this: Inorg. Chem. 1993, 32, 12, 2694–2698Publication Date (Print):June 1, 1993Publication History Published online1 May 2002Published inissue 1 June...

Silicon(II) bis(trimethylsilyl)amide (LSiN(SiMe(3))(2), L= PhC(NtBu)(2)) (2) has been synthesized by the reaction of LSiHCl(2) with KN(SiMe(3))(2) in 1:2 molar ratio high yield where 1 equiv latter functions as a dehydrochlorinating agent. 2 exhibits stability up to 154 °C and can be handled open air for short period time without any appreciable decomposition. An amazing five-membered cyclic silene (3) results from cleavage one Si-Me bond an adamantyl phosphaalkyne. 3 is first example heavy...

Wie die Ölsardinen quetschen sich BF4−-Ionen in drei Kavitäten eines Dimers aus interpenetrierenden Koordinationskäfigen. Während ein BF4−-Ion fest der zentralen Kavität gebunden ist, können schwach gebundenen äußeren Anionen durch Halogenidionen nach einem allosterischen Bindungsmechanismus Verbindung mit einer konzertierten Strukturänderung ersetzt werden. Besonders Chlorid wird enorm hohen Affinität gebunden. Detailed facts of importance to specialist readers are published as "Supporting...

Two different synthetic methodologies of silicon dihalide bridged biradicals the general formula (Ln•)2SiX2 (n = 1, 2) have been developed. First, metathesis reaction between NHC:SiX2 and Ln: (Ln: cyclic akyl(amino) carbene in a 1:3 molar ratio leads to products 2 X Cl), 4 2, 6 Br), 7 Br). These reactions also produce coupled NHCs (3, 5) under C–C bond formation. The formation (Lm alkyl(amino) substituted N-heterocyclic carbene; m 3, n 1 (3) 4, =2 (5)) is faster during NHC:SiBr2 when...

The neutral radical (Me2 -cAAC)2 AlCl2 (2) is stabilized by cyclic (alkyl)(amino)carbenes (cAACs). Complex 2 was synthesized reduction of the Me2 -cAAC:→AlCl3 (1) adduct with KC8 in presence another equivalent -cAAC. crystal structure shows that Al-C bond lengths two carbenes bound to Al center are considerably different, which likely result intermolecular interactions. Quantum-chemical calculations from gas phase give an equilibrium identical lengths. Compound exhibits monoradical...

Grignard reagents that are at the simplest level described as "RMgX" (where R is an organic substituent and X a halide) one of most widely utilized classes synthetic reagents. Lately, especially with amido ligands type R1R2NMgX, so-called Hauser bases, their Turbo analogue R1R2NMgX·LiCl play outranging role in modern chemistry. However, because complex solution behavior, where Schlenk-type equilibria involved, very little known about structure solution. Especially impact LiCl on...

Blocking the C2 position of an imidazole-derived classical N-heterocyclic carbene (NHC) with aryl group is essential strategy to establish a route mesoionic carbenes (MICs), which coordinate metal via C4 (or C5) carbon atom. An efficient catalytic MIC precursors by direct arylation NHC reported. Treatment 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) iodide (RC6H4I) in presence 0.5 mol % [Pd2(dba)3] (dba = dibenzylideneacetone) precatalyst affords C2-arylated imidazolium salts...

Isolation of two-coordinate compounds heavier Group 15 elements in low oxidation state is challenging due to the preferential formation dimers or oligomers. Herein, we report first examples donor-stabilized Sb(I) and Bi(I) ions. The reduction antimony bismuth trihalides with KC8 presence cyclic alkyl(amino) carbene (cAAC) afforded cations form triflate salts [(cAAC)2Sb][OTf] (1) [(cAAC)2Bi][OTf] (2). Compounds 1 2 belong a new class acyclic eight valence electrons are isoelectronic analogues...