Bis(μ‐phenyl 2‐pyridyl ketone N4,N4‐butane‐1,4‐diylthiosemicarbazonato)bis[chlorocopper(II)]

The title compound, [Cu₂(C₁₇H₁₇N₄S)₂Cl₂], exhibits a dimeric structure related by a centre of symmetry. The monomers are linked to each other by the longest Cu—S apical distance observed to date among Cu^II square‐pyramidal complexes of N⁴‐substituted thio­semicarbazones. Each Cu^II atom deviates from the coordination square plane, which contains the pyrid­yl and imine N atoms, the thiol­ate S atom and the Cl⁻ anion, towards the S atom of the adjacent monomer. The dimers pack in a zigzag manner through the crystal.     

Effect of metals on UV-excited plasmonic lithography for sub-50 nm periodic feature fabrication

This paper describes and compares the effect of metal films, such as aluminum (Al) and silver (Ag) on UV-excited two-beam surface plasmon interference nanolithography. A planar four-layer configuration has been employed to study the light intensity distribution on the recording medium. It is observed that high-density sub-50 nm periodic structures were achievable by employing the above-mentioned metal films when interrogated with p-polarized, 364 nm illumination wavelength source. It is found that the obtained periodic feature shows good exposure depth and high contrast when Al is used as a metal film. The initial experimental result of planar four-layer configuration is also presented.     

Carboxylic acid–pyridine supramolecular heterocatemer in a co-crystal

Robustness of carboxylic acid–pyridine supramolecular heterosynthon was examined in three 1:2 binary co-crystals of 4,4′-bipyridine with monocarboxylic acids, (4,4′-bipyridine)·(dl-hydroxyphenylacetic acid)₂, 1; (4,4′-bipyridine)_0.5·(4-bromonaphthalene-1-carboxylic acid), 2 and (4,4′-bipyridine)_0.5·(4-methylbenzoic acid), 3. All the three co-crystals form “two-component supermolecules” (consisting of one molecule of 4,4′-bipyridine and two molecules of the relevant carboxylic acid) stabilized through carboxylic acid–pyridine heterosynthons. Co-crystals 1 and 2 exhibits the expected carboxylic acid–pyridine dimer (heterodimer I) whereas co-crystal 3 forms a novel carboxylic acid–pyridine catemer (heterocatemer II).     

Synthetic approach toward the total synthesis of kempane diterpenes via transannular Diels-Alder strategy

Total syntheses of two new (+/-)-kempane derivatives 30 and 47 were achieved with transannular Diels-Alder reaction (TADA) serving as the key step for the stereoselective formation of tricyclic [6.6.5] system 3. This synthetic approach also reveals that the geometry of the C3 group of such a tricyclic system plays an important role for the formation of the seven-membered kempane skeleton.     

A tetracoordinated rhodium aminyl radical complex

A [16 + 1] valence electron configured rhodium aminyl radical complex could be synthesized and characterized in detail by pulse EPR spectroscopy and DFT calculations. The unpaired electron is delocalized over the metal center and two adjacent nitrogens. H-abstraction reactions from thiols and triethylsilane show that the spin density is predominantly localized on both nitrogens.     

High-throughput screening assay for the quantification of Cer d18:1/16:0, d18:1/24:0, d18:1/24:1, d18:1/18:0, d18:1/14:0, d18:1/20:0, and d18:1/22:0 in HepG2 cells using RapidFire mass spectrometry

Ceramides are known to be involved in various biological processes with their physiological levels elevated in various disease conditions such as diabetes, Alzheimer's, atherosclerosis. To facilitate the rapid screening of Cer d18:1/16:0, d18:1/24:0, d18:1/24:1, d18:1/18:0, d18:1/14:0, d18:1/20:0, and d18:1/22:0 inhibition in HepG2 cells, a RapidFire coupled to tandem mass spectrometry (RF–MS/MS) method has been developed. The RF platform provides an automated solid-phase extraction system that gave a throughput of 12.6 s per sample to an MS/MS system using electrospray ionization under the positive ion mode. Chromatographic separation of Cer d18:1/16:0, d18:1/24:0, d18:1/24:1, d18:1/18:0, d18:1/14:0, d18:1/20:0, and d18:1/22:0 was achieved using a ternary gradient on C₈ type E cartridge. The MS/MS ion transitions monitored were 538.2 → 264.2, 650.7 → 264.2, 648.6 → 264.2, 566.4 → 264.2, 510.4 → 264.2, 594.4 → 264.2, 622.5 → 264.2, and 552.3 → 250.2 for Cer d18:1/16:0, d18:1/24:0, d18:1/24:1, d18:1/18:0, d18:1/14:0, d18:1/20:0, d18:1/22:0, and the internal standard (Cer d17:1/18:0), respectively. The RF–MS/MS methodology showed an excellent performance with an average Z′ value of 0.5–0.7. This is the first report of an RF–MS/MS assay for screening of ceramides which is amenable for high-throughput screening.     

Pharmaceutical Formulation and Characterization of Dipeptide Nanotubes for Drug Delivery Applications

Peptide nanotubes are promising materials for a variety of biomedical applications with ultrashort (≤7 amino acids) forms providing particular promise for clinical translation. The manufacture of peptide nanotubes has, however, been associated with toxic organic solvents restricting clinical use. The purpose of this work is to formulate dipeptide nanotubes using mild techniques easily translated to industrial upscale and to characterize their physiochemical and biological properties. Phenylalanine‐phenylalanine variants can be successfully formulated using distilled water as demonstrated here. Formulations are homogenous in shape (tubular), with apparent size (50–260 nm) and a zeta potential of up to +30 mV. L‐(H₂N‐FF‐COOH), and D‐enantiomers (H₂N‐ff‐COOH) demonstrate no toxicity against glioblastoma cells and are explored for ability to deliver a model hydrophilic molecule, sodium fluorescein, at pH 5.5 (tumor) and 7.4 (physiological). Peptide nanotubes loaded with >85% sodium fluorescein, demonstrate burst release characteristics, fitting the Weibull model of drug release. This research provides important data contributing to the pharmaceutical formulation of peptide nanotubes as drug delivery platforms for hydrophilic drugs.     

Modeling the coupling of reaction kinetics and hydrodynamics in a collapsing cavity

We introduce a model of cavitation based on the multiphase Lattice Boltzmann method (LBM) that allows for coupling between the hydrodynamics of a collapsing cavity and supported solute chemical species. We demonstrate that this model can also be coupled to deterministic or stochastic chemical reactions. In a two-species model of chemical reactions (with a major and a minor species), the major difference observed between the deterministic and stochastic reactions takes the form of random fluctuations in concentration of the minor species. We demonstrate that advection associated with the hydrodynamics of a collapsing cavity leads to highly inhomogeneous concentration of solutes. In turn these inhomogeneities in concentration may lead to significant increase in concentration-dependent reaction rates and can result in a local enhancement in the production of minor species.