We have carried out a theoretical investigation of the methylalkalimetal monomers CH3M and tetramers (CH3M)4 with M = Li, Na, K, and Rb and, for comparison, the methyl halides CH3X with X = F, Cl, Br, and I, using density functional theory (DFT) at BP86/TZ2P. Our purpose is to determine how the structure and thermochemistry (e.g., C-M bond lengths and strengths, oligomerization energies) of org...

While ceramic-to-metal bonding has been used in many applications, the actual chemical and physical factors leading to optimum bond strength are not well understood. In this work, several variables affecting the bonding between dental porcelain and a palladium alloy (85% Pd, 10% Cu, and 5% Ga) were investigated: 1) precoating the metal by sputtering various oxides before porcelaining; 2) peroxi...

Supported Pd clusters catalyze methanol oxidation to methyl formate with high turnover rates and >90% selectivity at near ambient temperatures (313 K). Metal clusters are much more reactive than PdO clusters and rates are inhibited by the reactant O(2). These data suggest that ensembles of Pd metal atoms on surfaces nearly saturated with chemisorbed oxygen are required for kinetically-relevant ...

The feasibility of using transition metal fragments to stabilize B2H4 in planar configuration by donating 2 electrons to the boron moiety is investigated. Building upon the existing theoretical and experimental data and aided by the isolobal analogy, the model transition metal complexes Cr(CO)4B2H4 (6), Mn(CO)CpB2H4 (7), Fe(CO)3B2H4 (8) and CoCpB2H4 (9) are chosen to illustrate this unique bond...

Of late, Bader and Gatti [1] showed that the electron density ρ at any point r within a molecule may be viewed as consisting of contributions from a local source (LS) operating at all other points r' . When the LS is integrated over regions Ω satisfying the QTAIM definition of an atom in a molecule, ρ(r) may be equated to a sum of atomic contributions SF(r;Ω), each of which is termed as the sou...

Metal coating, metal materials are of two or more layers. The coating metals are widely used in industry. These sheets or saving performance and cost effective solution or both the user. Performance coating metals according to usage in structural applications, settings thermal expansion of the thermo-mechanical control (thermostat), electrical, magnetic, corrosion resistant, flowering and decor...

The activation of carbon-carbon (C-C) bonds is an effective strategy in building functional molecules. The C-C bond activation is typically accomplished via metal catalysis, with which high levels of enantioselectivity are difficult to achieve due to high reactivity of metal catalysts and the metal-bound intermediates. It remains largely unexplored to use organocatalysis for C-C bond activation...

Metal oxides play a very important role in many areas of chemistry, physical and materials science. Metal oxides are formed as a consequence of co-ordination tendency of metal ions so that oxide ions form co-ordination sphere around metal ions and give rise to close packed structure. The different physical, magnetic, optical and chemical properties of metal oxides are of great interest to chemi...

PURPOSE The aim of the present study was to record the metal-ceramic bond strength of a feldspathic dental porcelain and a Co-Cr alloy, using the Direct Metal Laser Sintering technique (DMLS) for the fabrication of metal substrates. MATERIALS AND METHODS Ten metal substrates were fabricated with powder of a dental Co-Cr alloy using DMLS technique (test group) in dimensions according to ISO 96...