Optical activation of patterned Si nanowires grown from sol-gel prepared gold/Er-doped aluminous film

Optical activation of patterned Si nanowires grown from sol-gel prepared gold/Er-doped aluminous film is investigated. The growth of patterned Si nanowires (SiNWs), the doping of Er ions and the sintered process are completed by one step. Si nanowires were grown from a sol-gel solution containing both Au catalysts and Er ions by the vapor-liquid-solid method. Such Er-activated Si nanowires achieve both high carrier-mediated excitation efficiency and high Er luminescence efficiency while at the same time providing high areal density of Er and easy current injection, indicating the possibility of activated patterned Si nanowires grown from sol-gel film as a material platform for Si-based photonics.     

Heterogeneous photoredox catalysis using fluorescein polymer brush functionalized glass beads

Photocatalysis is a valuable and versatile method to perform a variety of chemical transformations under ambient temperatures and pressures using mild visible light. This work showcases an example of fluorescein-functionalized polymers grafted to micro-scale glass beads as heterogeneous photoredox catalysts. X-ray photoelectron spectroscopy and thermogravimetric analysis were used to analyze the resulting functional glass beads. Model reactions that are demonstrated include a cyclic condensation and a radical dehalogenation that can both be performed to high yields. Successful recyclability of the fluorescein polymer brush beads is demonstrated with detailed characterization confirming that photocatalytic polymer brushes remain tethered to the surface. As such, this allows for purification and reuse of the heterogeneous photocatalyst beads after simple filtration.     

Focusing in Liquid Thermal Adsorption Systems

Focusing can be obtained in liquid thermal cycling zone adsorption by significantly increasing the temperature of the hot feed. To prevent boiling column pressure is raised. This method for concentrating dilute fluids was studied using the simulation package ADSIM. The systems studied were ethanol-water on silicalite and toluene-n-heptane on silica gel. Substantial concentration of dilute feeds while producing a pure solvent product were obtained. This research highlights the need for equilibrium data for liquid adsorption systems at elevated temperatures and pressures.     

A polydiacetylene-based fluorescent sensor chip

Self-assembled diacetylene vesicles were spotted and immobilized on aldehyde-modified glass substrates using conventional microarray technology. Irradiation of the immobilized diacetylenes allowed generation of nonfluorescent "blue-phase" polydiacetylene (PDA) arrays. Specific interaction of the PDA vesicle arrays with carbohydrates or poly(acrylic acid) solutions afforded fluorescent profiles.     

Molecular properties and potential energy surfaces of the cyanides of the groups 1 and 11 metal atoms

Ab initio calculations on the metal (groups 1 and 11) cyanide complexes show two stable configurations for the ground state geometry, a linear cyanide (MCN) and a triangular (MNC) form with an obtuse M-N-C angle. Lithium complex may exist in a linear isocyanide (MNC) form, but it cannot be differentiated from the triangular configuration because of the flatness of the potential energy surface connecting the two isomers. The metal atom and cyano radical are bonded through a strongly ionic configuration (M+CN-) in both geometrical forms. The MNC triangular form is a very floppy structure having one low frequency for the bending mode, whereas the MCN linear form is more rigid. The CN complexes of the alkali atoms have a triangular geometry as the lowest energy conformer, while the noble metal atoms prefer the linear cyanide one. The relative stability of the two isomers, dipole moments, and effective charges are reported in this paper. The essential aspects of the potential energy surfaces for the ground and the first excited states exhibiting a closely avoided crossing are also explained.     

Ion-selective electrodes based on molecular tweezer-type neutral carriers

Potentiometric properties of cholic and deoxycholic acid derivatives substituted with various ion-recognizing moieties, such as dithiocarbamate, bipyridyl, glycolic and malonic diamides, urea and thiourea, and trifluoroacetophenons (TFAP), have been studied using solvent polymeric membranes. The dithiocarbamate and bipyridyl group containing ionophores exhibit high silver ion selectivity. The cholic acid derivatized with glycolic diamides exhibited high calcium selectivity, but its complex formulation constant was 10⁵ times smaller than that of ETH 1001. The reduced calcium binding ability of the glycolic diamide-substituted ionophore was advantageous for eliminating anionic interference. The bi- or tripodal malonic diamide-substituted ionophores exhibited substantially increased magnesium selectivity. Anion-selective ionophores have been designed by substituting urea and thiourea group containing chains to the hydroxyl linkers of chenodeoxycholic acid frames; their selectivity closely followed the sequence of Hoffmeister series, except the unusually large response of the thiourea-substituted ionophore to sulfate. The most successful examples of cholic or deoxycholic acid frame-based ionophores are those functionalized with two carbonate-selective TFAP groups: bipodal TFAP groups behaves like a tweezers for the incoming carbonate, and exhibit analytically interference free and quantitative responses to the carbonate in serum and seawater samples.     

Large electron correlation effect leading to BeBe bond

The bonding of the beryllium diatomic molecule (Be₂) in the ground state is exclusively made from the electron correlation effect. Unlike the ordinary van der Waals bond, where the electron correlation of the dispersion type makes weak bond energy (D_e) at large bond distance (R_e), the BeBe bond is surprisingly strong with D_e = 830 cm^?1 and R_e = 245 pm. This paper presents in an analytical way the different electron correlation effects with the corresponding spectroscopic data.     

Theoretical investigation of RbCs via two-component spin-orbit pseudopotentials: spectroscopic constants and permanent dipole moment functions

Potential energy curves for the 28 lowest LambdaSigma states and 49 Omega states of RbCs are obtained from large-scale multireference configuration interaction calculations using both spin-averaged and two-component spin-orbit energy-consistent effective core potentials. Spectroscopic properties of all states are compared across available data in literature to date. Variations of the permanent dipole moments on the internuclear separation (R) for the (1)Sigma(+), (3)Sigma(+), (1)Pi, and (3)Pi states are evaluated over a wide range of R. The most important effects of the spin-orbit interaction on the dipole moment distribution are discussed.     

Palladium-catalyzed decarboxylative aminocarbonylation with alkynoic acid and tertiary amine for the synthesis of alkynyl amide

We developed a method for the synthesis of alkynyl amides via the carbonylation of alkynoic acids and C-N activation of tertiary amines. The reaction of alkynoic acid and tertiary amine with carbon monoxide using a palladium catalyst in the presence of oxygen, KI, and K₃PO₄, gave the desired alkynyl amides in good yields.