• Denton Silver posted an update 2 days, 5 hours ago

    AgF2 is a layered material and a correlated charge transfer insulator with an electronic structure very similar to the parent compounds of cuprate high-TC superconductors. It is also interesting as it is a powerful oxidizer. Here we present a first principles computation of its electronic properties in a slab geometry including its work function for the (010) surface (7.76 eV) which appears to be the highest among known materials with non-dipolar surfaces, and surpassing even that of fluorinated diamond (7.24 eV). We demonstrate that AgF2 will show a “broken-gap” type alignment becoming electron doped and promoting injection of holes in many wide band gap insulators if chemical reaction can be avoided. Novel junction devices involving p type and n type superconductors have been proposed. The issue of chemical reaction is discussed in connection with the possibility to create flat AgF2 monolayers achieving high-TC superconductivity. As a first step in this direction, we studied the stability and properties of an isolated AgF2 monolayer.A set of alkynyl-tris(2-pyridyl)phosphine Au(i) complexes was synthesized and characterized. Free coordination functions on the ligand environment periphery, namely ‘scorpionate’ PPy3 and the C[triple bond, length as m-dash]C bond, allowed these ditopic metalloligands to be selectively linked to 1D coordination polymers by reaction with Cu(i), which used both Cu-(N-PPy3) and Cu-(η2-C[triple bond, length as m-dash]C) coordination modes. Single-crystal and powder XRD, NMR, and XPS techniques were used to characterize the coordination polymers obtained. Heterobimetallic Au(i)-Cu(i) coordination polymers demonstrate triplet photoluminescence which was studied by spectroscopic and computational methods to understand the pathway of energy transfer inside the chain of linked chromophore centres. The intriguing feature of the electronic structure of heterobimetallic supramolecular assemblies is the ‘long-distance’ electronic transition involving PhC2 and PPy3 ligands located at a distance of more than 1 nm from each other. Thus, the assembly of a heterobimetallic coordination polymer from relatively simple ‘building blocks’ retains the block-wise nature of the electronic structure, but the photophysical properties of the polymer are fundamentally different from the properties of discrete organometallic components.Lanthanide-doped silicon clusters have been extensively studied in the fields of optoelectronics, magnetism and nanomaterials during the last decade. Herein, systematic structure searches for typical neutral clusters of lanthanide-doped silicon clusters LnSin (n = 5, 10; Ln = Sm, Eu, Yb) have been performed by means of density functional theory coupled with the “stochastic kicking” global search technique. It is found that the Ln atom in LnSin prefers to locate on the surface of Sin to form an exohedral structure, and this exohedral configuration may dominate the nascent structure of LnSin. CP-673451 order The spin density and Mulliken population analyses indicate that LnSin clusters possess remarkable magnetic moments (except for YbSin), which are mainly supplied by the Ln 4f electrons (except for Yb). Density of states visually shows the significant spin polarization for open-shell structures of SmSin and EuSin. As for the YbSin (n = 5, 10) system, it has a closed-shell electronic structure with a large HOMO-LUMO gap of 2.72 eV. Bonding analysis, including localized orbital locator and electron density difference, shows that the Si-Si covalent interaction and Sm-Si electrostatic interaction are important for the structural stability of LnSin.One of the fundamental goals of chemistry is to determine how molecular structure influences interactions and leads to different reaction products. Studies of isomer-selected and resolved chemical reactions can shed light directly on how form leads to function. In the following, we present the results of gas-phase reactions between acetylene cations (C2D2+) with two different isomers of C3H4 propyne (DC3D3) and allene (H2C3H2). Our highly controlled, trapped-ion environment allows for precise determination of reaction products and kinetics. From these results, we can infer details of the underlying reaction dynamics of C2H2+ + C3H4. Through the synergy of experimental results and high-level quantum chemical potential energy surface calculations, we are able to identify distinct reaction mechanisms for the two isomers. We find long-range charge exchange with no complex formation is favored for allene, whereas charge exchange leads to an intermediate reaction complex for propyne and thus, different products. Therefore, this reaction displays a pronounced isomer-selective bi-molecular reactive process.We report surface force balance measurements of the normal surface force and friction between two mica surfaces separated by a nanofilm of the deep eutectic solvent ethaline. Ethaline, a 1  2 mixture of choline chloride and ethylene glycol, was studied under dry conditions, under ambient conditions and with added water, revealing surface structural layers and quantised frictional response highly sensitive to water content, including regions of super-lubric behaviour under dry conditions and with added water. We also report exceptionally long-ranged electrostatic repulsion far in excess of that predicted by Debye-Hückel theory for a system with such high electrolyte content, consistent with previously reported observations of “underscreening” in ionic liquid and concentrated aqueous electrolyte systems [Smith et al., J. Phys. Chem. Lett., 2016, 7(12), 2157].Molecular spin qubits with long spin coherence time as well as non-invasive operation methods on such qubits are in high demand. It was shown that both molecular electronic and nuclear spin levels can be used as qubits. In solid state systems with dopants, an electric field was shown to effectively change the spacing between the nuclear spin qubit levels when the electron spin density is high at the nucleus of the dopant. Inspired by such solid-state systems, we propose that divalent lanthanide (Ln) complexes with an unusual electronic configuration of Ln2+ have a strong interaction between the Ln nuclear spin and the electronic degrees of freedom, which renders electrical tuning of the interaction. As an example, we study electronic structure and hyperfine interaction of the 159Tb nucleus in a neutral Tb(ii)(CpiPr5)2 single-molecule magnet (SMM), which exhibits unusually long magnetization relaxation time, using the complete active space self-consistent field (CASSCF) method with spin-orbit interaction included within the restricted active space state interaction (RASSI).