The origin of the high directionality halogen bonding was investigated quantum chemically by a detailed comparison typical adducts in two different orientations: linear (most stable) and perpendicular. Energy decomposition analyses revealed that synergy between charge-transfer interactions Pauli repulsion are driving forces for directionality, while electrostatic contributions more favourable less-stable, perpendicular orientation.

Unexpected trends in the strengths of halogen-bond based adducts CY(3)I (Y = F, Cl, Br, I) with two typical Lewis bases (chloride and trimethylamine) show that donor strength (Lewis acidity) a compound R-X is not necessarily increased higher electronegativity (carbon-based) group R.

Building materials from the atom up is pinnacle of fabrication. Until recently only platform that offered single-atom manipulation was scanning tunneling microscopy. Here controlled and assembly a few structures are demonstrated by bringing together single atoms using transmission electron microscope. An atomically focused beam used to introduce Si substitutional defects defect clusters in graphene with spatial control nanometers enable motion atoms. The then further manipulated form dimers,...

When small clusters are studied in chemical physics or physical chemistry, one perhaps thinks of the fundamental aspects cluster electronic structure, precision spectroscopy ultracold molecular beams. However, also interest catalysis, where cold ground state an isolated may not even be right starting point. Instead, big question is: What happens to cluster-based catalysts under real conditions such as high temperature and coverage with reagents? Myriads metastable states become accessible,...

Immobilized Pt clusters are interesting catalysts for dehydrogenation of alkanes. However, surface-deposited deactivate rapidly via sintering and coke deposition. The results reported here suggest that adding boron to oxide-supported could be a "magic bullet" against both means deactivation. model systems studied herein pure B-doped deposited on MgO(100). nonstoichiometric boride cluster obtained such alloying is found anchor the support covalent B–O bond, cluster-surface binding much...

Partially oxidized surfaces of hexagonal boron nitride (hBN) and several metal borides are unexpectedly excellent catalysts for oxidative dehydrogenation alkanes to olefins, but the nature active site(s) on these B-containing interfaces remains elusive. We characterize surface partially B-rich hBN under reaction conditions from first principles. The interface has thermal access multiple different stoichiometries structures each stoichiometry. size ensemble is composition-dependent. phase...

Two-dimensional (2D) phases of boron are rare and unique. Here we report a new 2D all-boron phase (named the π phase) that can be grown on W(110) surface. The phase, composed four-membered rings six-membered filled with an additional B atom, is predicted to most stable this support. It characterized by outstanding stability upon exfoliation off W surface, unusual electronic properties. chemical bonding analysis reveals metallic nature material, which attributed multicentered π-bonds....

Nanoalloying MgO-deposited Pt clusters with eight main-group elements was computationally screened for potential selectivity toward partial dehydrogenation of small alkanes. Si revealed as a promising dopant across two cluster sizes, it appears to favor stopping alkanes at alkenes. Pure on MgO(100) tend strongly adsorb ethane and activate one the C–H bonds but then bind ethylene in an activated di-σ fashion even spontaneously dehydrogenate it. They also C atoms, first step deactivation by...

Borides have been recently identified to be a class of earth-abundant and low-cost materials that are surprisingly active toward oxidative dehydrogenation hydrogen evolution reaction (HER) catalysis. Here, we explain from first-principles calculations the HER activity WB, an industrial material known for its superior physical properties chemical inertness. We find that, compared bulk termination, major surface reconstruction takes place, leading off-stoichiometric B-rich termination contains...

The adsorption of glycine on the Ca-rich and P-rich HA(010) nonstoichiometric surfaces has been studied at B3LYP level using a polarized triple-ζ basis set within periodic boundary conditions. Although exhibit different terminations, giving rise to electrostatic features in regions, preferentially adsorbs as zwitterion both surfaces. When adsorbed canonical form, proton COOH group is always transferred surface except for one case, which, turn, also least stable one. Glycine by favorable...

We use simple acid-base chemistry to control the valency in self-assembled monolayers of two different carboranedithiol isomers on Au{111}. Monolayer formation proceeds via Au-S bonding, where manipulation pH prior or during deposition enables assembly dithiolate species, monothiol/monothiolate combination. Scanning tunneling microscopy (STM) images identify distinct binding modes each unmodified monolayer, simultaneous spectroscopic imaging confirms dipole offsets for mode. Density...

Abstract Ethylene is a key molecule in the chemical industry and it can be obtained through catalytic dehydrogenation of ethane. Pt‐based catalysts show high performance toward alkane dehydrogenation, but suffer from coke formation sintering that deactivate catalyst. Ge was recently discovered to promising alloying element suppresses deactivation Pt while preserving its activity dehydrogenation. This work explores effect content supported PtGe cluster alloys, on ethane selectivity against...

Low lying electronic states of Al

The global minima of the cluster anions with generic chemical formula (XAl₁₂)²⁻, where X = Be, Mg, Ca, Sr, Ba, and Zn, are determined by an extensive search their potential energy surfaces using Gradient Embedded Genetic Algorithm (GEGA). All characterized have icosahedral-like structure, resembling that Al₁₃⁻ cluster. These cages comprise closed-shell electronic configurations 40 electrons, therefore, in accordance to jellium model, they predicted be highly stable amenable experimental...

Abstract Control of CO emissions raises serious environmental concerns in the current chemical industry, as well nascent technologies based on hydrogen such electrolyzers and fuel cells. As for now, Pt remains one state‐of‐the‐art catalysts oxidation reaction, but unfortunately, it suffers from self‐poisoning. Recently, Pt−Ge alloys were proposed to be an excellent alternative reduce poisoning. This work investigates impact Ge content kinetics 4 n subnanoclusters supported MgO. A...

We have studied the electronic structure of F-centers in bulk and on (100) surface MgO crystal. Chemical bonding analysis was performed using natural bond orbital (NBO) with periodic boundary conditions solid state adaptive density partitioning (SSAdNDP) method. The pristine found to be very ionic, i.e., there are four lone pairs (s-, px-, py-, pz-type) every oxygen atom occupation numbers (ONs) range 1.76–1.86 |e|. Within O vacancy (Ov) located we a pair electrons place missing that is...

The top monolayers of surface carbides and nitrides Co Ni are predicted to yield new stable 2D materials upon exfoliation. These phases p4g clock reconstructed, contain planar tetracoordinated C or N. stability these flat is high, ab initio molecular dynamics at a simulation temperature 1800 K suggest that the thermally elevated temperatures. owe their local triple aromaticity (π, σ-radial, σ-peripheral) associated with binding main group element metal. All conductors, two alloys also...

Hollow CdS nanoclusters were predicted to trap alkali metals and halogen atoms inside their cavity. Furthermore, electron affinities (EA) of endohedrally doped clusters ionization potentials (IE) be very similar. This makes them suitable build cluster-assembled materials, in the same vein as do related ZnO, ZnS MgO nanoclusters, which yield porous solid materials. With this aim mind, we have focused on assembly bare CdiSi endohedral K@CdiSi–X@CdiSi (i = 12, 16, X Cl, Br) order obtain solids...

The high catalytic activity of Pt is accompanied by a affinity for CO, making it extremely susceptible to poisoning. Such CO poisoning limits the use proton exchange membrane fuel cells. In this work, using global minima search techniques and exhaustive electronic structure characterization, dopant concentration pinpointed as crucial factor improve tolerance catalysts. By investigating PtGe nanoclusters different sizes compositions, we found that, those clusters with roughly same amount Ge,...

Endohedral (X@CdiSi)q=0,±1 structures have been characterized by means of the density functional theory with X being alkali metals such as Na and K or halogens Cl Br i = 4, 9, 12, 15, 16. These nanoclusters chosen because their high sphericity, which is known to be one parameters determining stability endohedral nanoclusters, along charge size guest atom. In these structures, atoms are trapped inside previously spheroid hollow positively charged Cd negatively S atoms. Moreover, although...

Subnanometer metal clusters offer catalytic properties not possible on bulk or nanoparticle metals.

Abstract The vulnerability towards CO poisoning is a major drawback affecting the efficiency and long‐term performance of platinum catalysts in fuel cells. In present work, by combination density functional theory calculations mass spectrometry experiments, we test explain promotional effect Ge on Pt with higher resistance to deactivation via poisoning. A thorough exploration configurational space gas‐phase n + GePt −1 ( =5–9) clusters using global minima search techniques subsequent...