In situ oxidation study of Pt(110) and its interaction with CO

Many interesting structures have been observed for O(2)-exposed Pt(110). These structures, along with their stability and reactivity toward CO, provide insights into catalytic processes on open Pt surfaces, which have similarities to Pt nanoparticle catalysts. In this study, we present results from ambient-pressure X-ray photoelectron spectroscopy, high-pressure scanning tunneling microscopy, and density functional theory calculations. At low oxygen pressure, only chemisorbed oxygen is observed on the Pt(110) surface. At higher pressure (0.5 Torr of O(2)), nanometer-sized islands of multilayered α-PtO(2)-like surface oxide form along with chemisorbed oxygen. Both chemisorbed oxygen and the surface oxide are removed in the presence of CO, and the rate of disappearance of the surface oxide is close to that of the chemisorbed oxygen at 270 K. The spectroscopic features of the surface oxide are similar to the oxide observed on Pt nanoparticles of a similar size, which provides us an extra incentive to revisit some single-crystal model catalyst surfaces under elevated pressure using in situ tools.     

Activation of Spruce Wood Surfaces by Plasma Treatment After Long Terms of Natural Surface Inactivation

Surface inactivation is a phenomenon that causes poor adhesion. A wood surface exposed to contaminants such as dust or atmospheric grime can experience surface inactivation. Inactivation mechanisms can reduce the attractive forces on the wood surface and lead to a decrease in wettability. Plasma treatment has been applied to recover inactivated wood surfaces for better adhesion and bonding. Plasma treatment technology is very simple and the cost is rather low. In addition, this treatment produces no environmental pollution. In this study, low pressure plasma treatment was applied to reactivate the surfaces of spruce wood for glue bonding and to increase wettability after a 9-year period of natural surface inactivation. Changes in contact angles, surface energy, surface colour and bonding strength of inactivated and oxygen plasma treated wood surfaces were studied. Wettability, bonding and other mechanical strength properties of plywood panels increased with the oxygen plasma treatment.     

N-ferrocenoyl benzotriazole: A convenient tool for the synthesis of ferrocenoyl esters

A new synthesis methodology has been presented for the preparation of the ferrocenoyl esters. Ferrocene carboxylic acid was derivatized using direct 1H-benzotriazole/SOCl₂ methodology to prepare N-ferrocenoyl benzotriazole as a convenient tool for the functionalization of ferrocene ring. N-ferrocenoyl benzotriazole was reacted with alcohols in mild conditions to prepare ferrocenoyl esters in high purity and in good yield. The solid state structure of benzyl-1-ferrocenoate, 2f, has also been determined by X-ray crystallography. In the crystal structure, intermolecular C-H···O hydrogen bonds link the molecules into a two-dimensional network. The π···π contacts between the cyclopentadiene rings and cyclopentadiene and phenyl rings, [centroid-centroid distances = 3.296(1) and 3.750(1) Å] may further stabilize the structure. Two weak C-H···π interactions are also found.     

Stabilities of Scandium(III)- and Yttrium(III)-Tiron Chelates and their hydrolytic behavior

The interactions of Sc³⁺ and Y³⁺ ions with disodium 1,2-dihydroxybenzene-3,5-disulfonate (Na₂H₂L, where H₂L_2- = Tiron) were investigated in aqueous solution by means of potentiometric and spectroscopic methods. The coordination of Tiron to Sc³⁺ and Y³⁺ takes place through two phenolic oxygen atoms of catecholate ion in different stoichiometries. Thus, the binding of Tiron to Sc³⁺ occurs either in 1 : 1 or 1 : 2 molar ratios; they have resulted by the formation of [ScL]^- and [ScL₂]^5- type complexes, respectively. On the other hand, Y³⁺ ion behaves like Th⁴⁺ and Ln³⁺ ions toward Tiron. It forms [YL]^-type complex in 1 : 1 molar ratio; but in 1 : 2 or in higher molar ratios, only unique [Y₂L₃]^6- type complex formation takes place. The formation constants of [ScL]^-, [ScL₂]^5-, [YL]^-, and [Y₂L₃]^6- complexes were determined by analysis of the potentiometric data in ionic medium of 0.1 M KNO₃ or NaClO₄ at 25°C. The hydrolytic reactions of Sc(III) and Y(III) complexes with Tiron were determined from potentiometric data and the formation constants of [ScL(OH)]^2- and [YL(OH)]^2- were also calculated.From Koordinatsionnaya Khimiya, Vol. 31, No. 1, 2005, pp. 62–68.Original English Text Copyright © 2005 by Aydin, Türkel, Özer.     

Erratum to: Simultaneous High-Performance Thin-Layer Chromatographic Determination of Indole Acetic Acid,Indole Butyric Acid,and Absisic Acid in in vitro Seedling of Watermelon Exposed to Heavy Metals

JPC – Journal of Planar Chromatography – Modern TLC - Simultaneous High-Performance Thin-Layer Chromatographic Determination of Indole Acetic Acid, Indole Butyric Acid, and Absisic Acid...     

Asymmetric Henry reactions catalyzed by metal complexes of chiral oxazoline based ligands

Chiral oxazolines have been synthesized from norephedrine and pyrrole nitrile or benzoyl chloride and applied to the catalytic asymmetric Henry reactions of p-nitro aldehydes with nitromethane to provide β-hydroxy nitroalkanols in high conversion (up to 92%). The reaction was then optimized in terms of the metal, solvent, temperature, and amount of chiral ligand. The corresponding catalyst with Cu(OTf)₂ and isopropanol as the solvent gave the best enantioselectivities (up to 84% ee) of the corresponding β-nitroalkanol for p-nitrobenzaldehyde.     

Synthesis of novel thiophene‐based chiral ligands and their application in asymmetric Henry reaction

Novel chiral thiolated amino alcohols were synthesized from norephedrine and thiophene carbaldehydes (methyl‐ or ethyl‐substituted) and applied to the catalytic asymmetric Henry reaction of various aldehydes with nitromethane to provide β‐hydroxy nitroalkanols in high conversion (92%). The reaction was optimized in terms of the metal, solvent, temperature and amount of chiral ligand. The corresponding catalyst with Cu(OTf)₂ and 2‐propanol as the solvent provided the best enantioselectivities (up to 96% ee) of the corresponding nitroalcohols for aliphatic aldehydes. Copyright © 2013 John Wiley & Sons, Ltd.