Mendeleev Communications最新文献

In this work, a new cathode material for lithium–sulfur (Li–S) batteries was developed. Microporous carbon (with predominant pore size £1.2 nm) served as both a matrix for sulfur retention and conductive additive. Microporous carbon was shown to be capable of adsorbing lithium polysulfides thereby suppressing their migration toward lithium anode. The discharge capacity of the S/C composite at the 1st and 20th cycles in Li–S battery operation was 513 and 421 mAh g–1 at a scan rate of 0.1 mV s–1.

The experimental results of luminescence measurements in Ca₃Al₂O₆ : Tb showed single excitation wavelengths at 246 and 278 nm in the UV region. For the 278 nm excitation, six distinct emission peaks were found at 378, 419, 437, 447, 487 and 544 nm. Some spectroscopic parameters were calculated using CIE coordinates showing emission in the near-blue region, which may be useful for various display devices.

Transition metal complexes of copper subgroup metals are actively studied objects for temperature sensors. Their luminescence arising from the ³ILCT, ³MLCT or ³CC excited states is characterized by emission in all ranges of visible spectra and high quantum yields. Due to the ability of the complexes to emit in a dual band mode, these complexes are attractive for the temperature sensing in the ratiometric mode. Dual emission of complexes is usually susceptible of the irregular changes in intensity of two emission bands during the temperature changes. This is an important and necessary property for the utilization of phosphors as ratiometric thermometers. The structures and emission properties of gold(i) and copper(i) complexes are considered with the aim to demonstrate the possibility to apply such complexes as ratiometric molecular luminescent thermometers for the remote control of the object’s temperature.

Well-defined silica-supported Ti imido complex (SiO)Ti(NBu^t)(Me₂Pyr)(Py)₂ (Me₂Pyr = 2,5-dimethyl- pyrrolyl) catalyzes condensation of N-sulfinylanilines into sulfurdiimines via the oxo/imido heterometathesis providing a convenient synthetic route to functionalized sulfurdiimines.

Methyl dihydrojasmonate and methyl (5-methylidene-4-oxocyclopent-2-en-1-yl)acetate were synthesized from 4-hydroxy-2-(hydroxymethyl)cyclopentenone, which, in turn, was obtained from D-glucose. The conditions for the key step, the Johnson–Claisen rearrangement, were optimized to get the maximum yield of the intermediate methyl 2-[2-methylene-3-oxo-5-(triisopropylsilyloxy)-cyclopentyl]acetate.

The azido-Ugi reaction of methyl maleopimarate N-(2- aminoethyl) imide with isocyanides, paraformaldehyde and trimethylsilyl azide in one step leads to 1,5-disubstituted diterpene bis-tetrazoles. The compounds demonstrate selective cytotoxicity against NCI-60 cancer cell panel.

The copper-catalyzed azide–alkyne cycloaddition of BODIPY acetylene derivative and ferrocene azides in supercritical CO₂ at 80 °C and 81 bar affords the corresponding triazole-containing BODIPY–ferrocene conjugates in high yields. The fluorescent and electrochemical properties of the compounds thus obtained were explored.

Catalysts of 1% Pd/TiO₂ type were prepared via the deposition–precipitation of Pd polyhydroxo complexes followed by reduction with hydrogen at 23 °C. These catalysts were found to be active for the selective hydrogenation of m-dinitrobenzene into m-phenylenediamine at 25–50 °C and 0.5 MPa H₂ in a batch reactor.

The enhancing effect of natural flavonoids, quercetin and dihydroquercetin, on the catalytic activity of galactonolactone oxidase from Trypanosoma cruzi has been established.

A 100% atom-efficient thia-Michael addition process between thiols and α,β -unsaturated carbonyl compounds in a Brønsted acidic deep eutectic solvent at room temperature has been developed. The medium, choline chloride/p-toluene- sulfonic acid, not only showed good catalytic activity, but also could be readily recovered and reused with slight decrease in its activity after successive five runs.