Deciphering the mechanism of γ-cyclodextrin's hydrophobic cavity hydration: an integrated experimental and theoretical study.

Cyclodextrins (CDs) are host systems with inherent capability for inclusion complex formation with various molecular entities, mostly hydrophobic substances. Host CDs are highly accommodative to water molecules as well and usually contain water in the native state. There is still an ongoing discussion on both the total number of water molecules and their preferred binding position inside the cavities of the CDs.

Sequential Injection Analysis Method for the Determination of Glutathione in Pharmaceuticals.

A sequential injection analysis method for the determination of glutathione (GSH) in pharmaceuticals has been developed. It is based on the reduction of the Cu(II)-neocuproine complex by GSH and the formation of an orange-yellow colored Cu(I)-neocuproine complex with maximum absorbance at 458 nm. Under optimal conditions the method is characterized by a linear calibration range of 6.

TADF Blue Emitters with Balanced π-Conjugation─Design, Synthesis, Spectral Characterization, and a Model OLED with 8-(5-(-Butyl)-1,3,4-oxadiazol-2-yl)-,-bis(4-(-butyl)phenyl)dibenzo[,]furan-2-amine.

Blue organic light-emitting diodes (OLED) suffer from relatively short lifetimes and a comparatively low lighting efficiency. One of the approaches to improving their characteristics is the development of luminophores with the potential for thermally activated delayed fluorescence (TADF). Herein, a set of donor-spacer-acceptor compounds with potential for TADF are designed, synthesized, and computationally and spectroscopically characterized.

Easy and Effective Method for α-CD:NO Host-Guest Complex Formation.

α-CD:NO "host-guest" type complexes were formed by a simple solid-gas reaction (NO sorption into α-CD) under different gas pressures and temperatures. The new NO inclusion method applied in the present study was compared with the already known technique based on the crystallization of clathrates from a water solution of α-CD saturated with NO. A maximum storage capacity of 4.

Enhanced Solubility of Ibuprofen by Complexation with β-Cyclodextrin and Citric Acid.

The ability of β-CD to form inclusion complexes with ibuprofen (IBU) and at the same time to make a two-phase system with citric acid was explored in the present study for achieving improved solubility and dissolution rate of IBU. Mechanical milling as well as mechanical milling combined with thermal annealing of the powder mixtures were applied as synthetic methods. Solubility and dissolution kinetics of the complexes were studied in compliance with European Pharmacopoeia (ICH Q4B).

Luminescence of Binary-Doped Silica Aerogel Powders: A Two-Step Sol-Gel Approach.

In this study, we report a novel synthesis of hydrophobic silica aerogel powder composites, functionalized and binary-doped with [Tb(phen)](NO) and [Eu(phen)](NO) nanocrystals, employing a two-step sol-gel methodology. The investigation delves into the structural elucidation, optical properties and thermal conductivity of these functionalized Tb(III)-Eu(III) composites. Our analysis includes diffuse reflectance spectra and excitation and luminescence spectra, highlighting the quantum yields of composites with varying chemical compositions.

Determination of -Acetyl-L-cysteine Ethyl Ester (NACET) by Sequential Injection Analysis.

New sequential injection analysis (SIA) methods with optical sensing for the determination of -acetyl-L-cysteine ethyl ester (NACET) have been developed and optimized. NACET is a potential drug and antioxidant with advantageous pharmacokinetics. The methods involve the reduction of Cu(II) in its complexes with neocuproine (NCN), bicinchoninic acid (BCA), and bathocuproine disulfonic acid (BCS) to the corresponding chromophoric Cu(I) complexes by the analyte.

Silica Gels Doped with Gold Nanoparticles: Preparation, Structure and Optical Properties.

A novel, one-pot sol-gel preparation scheme leading to reproducible incorporation of 20-40 nm sized gold nanoparticles (AuNPs) in SiO gels is developed based on in situ reduction during gelation using chloroauric acid and ascorbic acid. Variation in the preparation conditions affects the chemical composition, optical properties and size distribution of the AuNPs incorporated in the silica gels. Different organic dopants, i.

Facilitated Synthesis of MgNi Based Composites with Attractive Hydrogen Sorption Properties.

Composites based on MgNi with 5% activated carbon from apricot stones (ACAP) have been prepared by ball milling and subsequent annealing in hydrogen atmosphere. The purpose of the primary metal (Mg, Ni, and V) milling was to reduce the particle size and achieve a good contact between them, without forming intermetallic compounds. During hydriding/dehydriding at 300 °C the amount of the MgNi phase progressively increased, and after 10 cycles about 50% Mg(Ni,V) was achieved.

Hydrogen Gas Phase and Electrochemical Hydriding of LaNiM (M = Sn, Co, Al) Alloys.

Hydriding/dehydriding properties of a series of LaNi based alloys were compared by applying both hydrogen gas phase and electrochemical hydrogen charge/discharge methods. The highest hydrogen absorption capacity of 1.4 wt.

Localization of mercury and gold in cassava (Manihot esculenta Crantz).

The potential of cassava (Manihot esculenta Crantz.) for simultaneous Hg and Au phytoextraction was explored by investigating Hg and Au localization in cassava roots through Micro-Proton Induced X-Ray Emission, High-Resolution Transmission Electron Microscopy (HR-TEM) and X-Ray Diffractometry (XRD). The effect of Hg and Au in the cyanogenic glucoside linamarin distribution was also investigated using Matrix Assisted Laser Desorption Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (MALDI-FT-ICR-MS) imaging.

The Influence of Preparation Conditions on the Hydrogen Sorption of Mg-Nb₂O-CNT Produced by Ball Milling and Subsequent High-Pressure Torsion.

High energy ball milling and subsequent high-pressure torsion method was carried out on nanocrystalline Mg powders catalyzed by 5 wt.% Nb₂O and 5 wt.% carbon nanotubes.

Water inside β-cyclodextrin cavity: amount, stability and mechanism of binding.

Cyclodextrins (CDs) are native host systems with inherent ability to form inclusion complexes with various molecular entities, mostly hydrophobic substances. Host cyclodextrins are accommodative to water molecules as well and contain water in the native state. For β-cyclodextrin (β-CD), there is no consensus regarding the number of bound water molecules and the location of their coordination.

α-Cyclodextrin: How Effectively Can Its Hydrophobic Cavity Be Hydrated?

Cyclodextrins (CDs) are among the most widely used native host systems with ability to form inclusion complexes with various molecular objects. This ability is so strong that the "hydrophobic" CD cavity never remains empty, even in the guest-free state it is filled with water molecules. However, no consensus has been reached concerning both the total number of hydrating water molecules and their preferred binding location in the CDs.

Microstructural investigations of carbon foams derived from modified coal-tar pitch.

This work reports the microstructural evaluation of carbon foams derived from coal-tar pitch precursors treated with H2SO4 and HNO3 and finally annealed at 1000°C and 2000°C. Our experimental investigations combine scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) imaging, X-ray photoelectron spectroscopy (XPS) and micro-spot near-edge X-ray absorption fine structure (μ-NEXAFS) spectroscopy. This set of complementary techniques provides detailed structural and chemical information of the surface and the bulk of the carbon foams.

Cyclodextrin-Based Solid-Gas Clathrates.

"Cyclodextrin-gas" clathrates were obtained by crystallization from water solution of α-, β-, and γ-cyclodextrins (CDs) under pressure of the gas to be entrapped into the CD molecules. When the pressure is released, these clathrates are stable at ambient conditions and dissociate at elevated temperature, which makes them interesting for various applications as foam boosters in food and other industries. It was found that under these conditions α-CD forms clathrates with all of the gases used in this study (N2, N2O, CO2, Ar), whereas β- and γ-CDs can form clathrates only with N2.