Efficient and Reversible Separation of Chloroform from Chlorinated Hydrocarbons and Water Utilizing a Two-Dimensional Coordination Network.

Chloroform is a volatile organic solvent and a contaminant that is slightly soluble in water, making the reversible separation of chloroform from water a critical and challenging task within the chemical and environmental industries. In this study, we present a newly developed coordination framework, [Zn(4-pmntd)(opa)] [4-pmntd, N,N'-bis(4-pyridylmethyl)naphthalene diimide; opa, o-phthalic acid], which demonstrates a high adsorption capacity for chloroform (2.5 mmol/g) and an excellent ability to separate chloroform from water. The effectiveness of chloroform extraction by Zn(4-pmntd)(opa) was confirmed through vapor sorption, grand canonical Monte Carlo simulation, and 1H nuclear magnetic resonance spectroscopy. The porous framework was also utilized to create a filtration film using natural rubber, which successfully separated chloroform from water with a minimum test concentration of approximately 1 × 10-6 mol/L and a chloroform purity of 99.2%. [Zn(4-pmntd)(opa)] therefore has significant potential for low-energy separation and recycling of chloroform from water under ambient conditions.

Cyclic Shear Behavior of Frozen Cement-Treated Sand-Concrete Interface.

The cyclic shear behavior of frozen cement-treated soil-concrete interfaces is critical for analyzing soil-structure interfaces and foundation design in cold regions and artificially frozen ground. The cyclic shear behavior of the interface between frozen cement-treated sand and structure is investigated in this paper at various normal stresses and temperatures. Experimental results include the variation of the peak shear stress, peak normal displacement, shear stiffness with the number of cycles, and the relationship between peak shear stress and smoothness under certain conditions. Peak shear stresses of warm frozen cement-treated sand and cold frozen cement-treated sand varied with cycle number. Additionally, the former is significantly larger than the latter in the stable phase. The peak normal displacement showed the same results, indicating that the ice crystals formed on the surface and the strength of the frozen cement-treated sand have significant differences at various temperatures. The study's findings aid in understanding the complexities of the cyclic shear behavior of frozen cement-treated sand and structure interfaces and provide references on frozen cement-treated sand zones in practical engineering.

Cucumber (Cucumis sativus L.) Leaf Extract as a Green Corrosion Inhibitor for Carbon Steel in Acidic Solution: Electrochemical, Functional and Molecular Analysis.

An extract of cucumber leaves (ECSL) was prepared as a green corrosion inhibitor for carbon steel. Its carbon steel corrosion inhibition performance against 0.5 mol L-1 H2SO4 was investigated using electrochemical methods and scanning electron microscopy (SEM). Its composition was analyzed by gas chromatography and mass spectroscopy (GC-MS). Quantum chemical calculations and molecular dynamics simulations (MDS) were conducted to elucidate the adsorption mechanism of the inhibitor molecules on the carbon steel surface. The results indicated that the inhibition efficiency increases with its increasing concentration. The extract acted as a mixed type corrosion inhibitor, and its inhibition properties were ascribed to the geometric coverage effect induced by its adsorption on the metal surface in accordance with Langmuir's law. The active components in the extract were identified as mainly organic compounds with functional groups such as aromatic moieties and heteroatoms. The inhibition activities of ECSL are delivered through the ability of the active components to adsorb on the metal surface through their functional groups to form a protective layer which hinders the contact of aggressive substances with carbon steel and thus suppresses its corrosion. This research provides an important reference for the design of green corrosion inhibitors based on plant waste materials.

Anions effect construction of 1D naphthalene diimide supramolecular chains by π interactions and fluorescence detect iodide anion.

Five diverse 1D supramolecular chains, {[4-pmntd]}n(1), {H2[4-pmntd]•2Br-}n(2), {H2[4-pmntd]•2NO3-}n(3), {H2[4-pmntd]•2ClO4-}n(4), {H2[4-pmntd]•2BF4-}n(5), (where 4-pmntd was N,N'-bis (4-pyridylmethyl)naphthalene diimide) were synthesized and characterized by X-ray single-crystal structure analysis, IR spectroscopy, elemental analyses, thermogravimetric analyses, fluorescence detection. The anions effect construction of their 1D chain structural diversity through different π interactions. Compound 1 through the adjacent pyridine rings parallel π∙∙∙π interactions formed 1D linear chain structure. Compound 2 through Br- anion∙∙∙π interactions and halogenbond interactions formed 1D zigzag chain structure. Compound 3 through lone pair∙∙∙π interactions of naphthalene diimide and the adjacent carboxyl group formed 1D stairway chain structure. Compound 4 through ClO4- anion∙∙∙π interactions formed 1D ribbon chain structure. Compound 5 through parallel π∙∙∙π interactions of the adjacent naphthalene diimide planes and pyridine rings formed 1D ladder chain structure. The five compounds' fluorescence properties and thermal stabilities were investigated. The compound 2 solution could fluorescence detection for iodide anion via fluorescence quenching.

Diverse 1D chains supramolecular structures of N,N'-bis(3-pyridylmethyl)pyromellitic diimide and fluorescence iodide sensing.

Three diverse supramolecular compounds, {[3-pmpmd]}n(1), {H2[3-pmpmd]·2NO3-}n(2), {H2[3-pmpmd]·2tbb}n(3), (where 3-pmpmd was N,N'-bis(3-pyridylmethyl)pyromellitic diimide; tbb was tertiary butyl benzoic acid) were synthesized and characterized by elemental analyses, IR spectroscopy, thermogravimetric analyses, and X-ray single-crystal structure analysis. The co-crystal anions affect their structural diversity. Compound 1 is a 1D stairway chain structure by perpendicular π⋯π interactions of pyromellitic diimide and the neighboring pyridine rings. Compound 2 is a typical 1D ladder chain structure by hydrogen bond of nitrate arranged in a parallel array. Compound 3 is a 1D zigzag chain structure of one 3-pmpmd and two tbb by parallel π⋯π interactions and hydrogen bond interactions. Thermal stabilities and fluorescence properties of all compounds were investigated. The solution of compound 2 in DMF can fluorescence sense for iodide ions by remarkably quenching fluorescence intensity.

Synthesis, crystal structure, fluorescence properties of 1D chain Manganese (II) and Cadmium (II) complexes.

Two complexes, {[Mn(3-pmpmd)2(Cl)2]·2H2O}n(1), {[Cd(3-pmpmd) (I)2]·CHCl3·H2O}n(2), (3-pmpmd, N,N'-bis(3-pyridylmethyl)pyromellitic diimide) were synthesized and characterized by elemental analyses, IR spectroscopy, thermogravimetric analyses, and X-ray single-crystal structure analysis. The conformations of 3-pmpmd ligand affect their structural diversity. Complex 1 is a 1D double chain structure in edge-to-edge arrangement by π⋯π interactions. Complex 2 is a typical 1D zigzag chain structure arranged in a parallel array containing 1D channel to accommodate the chloroform and water guest molecules. Thermal stabilities and fluorescence properties of both complexes were investigated. The solution of complex 2 in DMF can sense for I- anion by quenching fluorescence intensity, whereas other anions increasing fluorescence intensity.

Luminescence properties of Ce3+ in orthosilicate oxyapatite NaY9 (SiO4 )6 O2.

Ce3+ -doped orthosilicate oxyapatite NaY9 (SiO4 )6 O2 phosphors NaY9-x (SiO4 )6 O2 :xCe3+ were prepared by a conventional high-temperature solid-state reaction method, and their spectroscopic characteristics were systematically investigated. The occupancies of Ce3+ ions at two different sites (Wyckoff 6 h and 4f sites) in NaY9 (SiO4 )6 O2 were determined. The influence of doping concentration on the emission intensity of Ce3+ was investigated and the critical distance Rc was estimated in terms of the concentration quenching data.

Optical properties of Eu2+ /Eu3+ mixed valence phosphor Ca2 SiO2 F2 :Eu2+ /Eu3.

The Eu2+ /Eu3+ mixed valence phosphor Ca2 SiO2 F2 :Eu2+ /Eu3+ was prepared using a solid-state reaction synthesis method in a CO atmosphere, and the optical properties were investigated. The spectroscopic properties revealed that Ca2+ ions were occupied by both Eu2+ and Eu3+ ions in Ca2 SiO2 F2 , and both ions were able to generate their characteristic emissions. A broad 5d â†’ 4f Eu2+ band at ~470 nm and narrow 4f â†’ 4f Eu3+ peaks upon excitation with n-UV light were observed. The ratio between Eu2+ and Eu3+ emissions changed regularly, and the relative intensity of the red component from Eu3+ became systematically stronger with increasing overall Eu content. As a result, the emission color of these phosphors can be tunable from blue to pink under n-UV light excitation.

The synthesis and luminescence of europium (III) complex based on deprotonated 1-(4-ethyl-4H-thieno[3,2-b]indol-6-yl)-4,4,4-trifluorobutane-1,3-dionate and 1,10-phenanthroline.

A new ß-diketone ligand, 1-(4-ethyl-4H-thieno[3,2-b]indol-6-yl)-4,4,4-trifluoro-butane-1,3-dione(HL) was synthesized by four steps reaction (Suzuki-Miyaura cross-coupling, Cadogan cyclization, N-ethylation and Claisen condensation reaction) from 1-(4-bromo-3-nitrophenyl)ethanone and thiophen-2-ylboronic acid. Deprotonated ligand (L(-1)) and 1,10-phenanthroline (phen) coordinated to Eu(3+) to obtain a new europium (III) complex, EuL(3)(phen). The complex was characterized by elementary analysis, IR, (1)H NMR, UV-Visible absorption spectroscopy, thermogravimetric analysis (TGA) and photoluminescence (PL) measurements in detail. TGA shows that the decomposition temperature of the complex is up to 320 °C. PL measurement results indicate that the Eu(III) complex exhibit intense red-emission with the characteristic of europium ion. Red LED device was successfully fabricated by employing the complex onto 380 nm-emitting InGaN chip, which shows that the complex can act as red phosphor in combination with 380 nm-emitting chips.