Closed-surface hexameric metal-organic nanocapsules derived from cavitand ligands

Assembly of cavitand ligands, (4-), and Zn2+ ions yields a one-dimensional polymer comprised of hexameric, closed-surface, metal-organic nanocapsules.     

Thermal properties of sulfonic acid group functionalized Brönsted acidic ionic liquids

Thermal decomposition onset temperatures have been measured for a total of 24 methylimidazolium, triethanolammonium, and pyridinium type sulfonic acid groups functionalized Brönsted acidic ionic liquids with Cl^?, Br^?, SO₄ ^2?, PO₄ ^3?, BF₄ ^? _, CH₃CO₂ ^?, and CH₃SO₃ ^? anions, using thermogravimetric analysis. Thermal stabilities of these sulfonic acid group functionalized ionic liquids decreases in the order, methylimidazolium > triethanolammonium > pyridinium. The methylimidazolium, pyridinium, and triethanolammonium ionic liquids investigated showed decomposition onset temperatures (air) in the 213–353, 167–240, and 230–307 °C ranges, respectively. Additionally, the decomposition temperatures of these ionic liquids are highly dependent on the nature of the anion.     

Synthesis of functionalized polysiloxane 4-acylpyrazolone Schiff base ligand system and its applications in the adsorption of lanthanide ions from aqueous solutions

A novel functionalized polysiloxane material with covalently bonded 4-acylpyrazolone Schiff base ligand was prepared by polycondensation of 4-[1-(3-triethoxysilyl-propylamino)-ethylidene]-5-methyl-2-phenyl-2,4-dihydro-pyrazol-3-one with four equivalents of tetraethoxysilane under basic conditions. This polysiloxane material was characterized using elemental analysis, solid-state CP MAS ¹³C, ²⁹Si NMR, TG-DTA and FT-IR spectroscopy. Lanthanide ion adsorption properties of this polysiloxane material were studied for seven trivalent lanthanide ions and are shown to be selective in the adsorption of Yb³⁺ ions from dilute aqueous solutions, in which 99% adsorption was observed from a 1.00 × 10⁻⁵ M aq. solution of pH 6.7, after 24 h at room temperature. Six other lanthanides studied, Gd³⁺, Tb³⁺, Eu³⁺, La³⁺, Nd³⁺ and Sm³⁺ showed moderate to weaker adsorptions of 36, 36, 28, 17, 14, and 11% respectively under identical conditions.     

An achiral form of the hexameric resorcin[4]arene capsule sustained by hydrogen bonding with alcohols

The well-known hexameric capsules sustained by self-assembly of resorcin[4]arenes 1 with water molecules (1(6).(H2O)8) are shown to assemble similarly with (+/-)-2-ethylhexanol (2EH) as an achiral 1(6).(2EH)6.(H2O)2 species which further encapsulates 2EH.     

Photochromic property of ternary transition metal oxide nanocomposite prepared with co-solvated deep eutectic mixtures

Research on Chemical Intermediates - The application of deep eutectic solvents (DES) in the synthesis of photochromic transition metal oxide (TMO)-based nanocomposites is gaining attention in...     

A new distortion energy-based equivalent stress for multiaxial fatigue life prediction

A new equivalent stress amplitude expression has been developed for the assessment of fatigue life in components under multiaxial loading. The expression was generated by incorporating non-linear/plastic stress–strain relation into a mechanical energy calculation, and then applying the calculation to the distortion energy theory for a cyclic loading case. Therefore, the new uniaxial equivalent stress expression determines an appropriate stress amplitude value for multiaxial cyclic loading. The purpose of the equivalent stress value is to determine multiaxial fatigue failure using an energy-based fatigue life prediction criterion. The governing understanding behind the criterion states that the physical damage quantity for failure is equal to the accumulated strain energy in a monotonic fracture, which is also equal to the accumulated strain energy during fatigue failure. Using the new equivalent stress amplitude expression and the energy-based life prediction method, a comparison is made between prediction results and multiaxial empirical data. The multiaxial data was acquired by a vibration-based biaxial bending fatigue test and a torsion fatigue test with an assumed axial misalignment. The results of the comparison provide encouragement regarding the capability of the newly developed equivalent stress amplitude expression for fatigue life prediction.     

A selective and efficient chemosensor for the rapid detection of arsenic ions in aqueous medium

Research on Chemical Intermediates - The development of selective, efficient, and economical sensors for the rapid determination of arsenic in an aqueous medium is of paramount importance, due to...