Evolution of Water State in the "Ionic Liquid EAN/Al(NO)/HO" System Depending on Temperature and Aluminum Salt Concentration.

Although lithium salts are the most successful materials for electrochemical devices so far, there is growing interest in electrolytes containing divalent and trivalent salts, which are characterized by a much higher energy density than lithium systems. For this purpose, the physical and chemical properties of solutions of aluminum nitrate in ethylammonium nitrate (EAN) were studied in a number of works. However, it was demonstrated by the H NMR method that solutions contain water (from aluminum crystallohydrates) in the first solvated shell of the Al cation even after usual drying procedures, and this solvated water cannot be directly detected by the standard Karl Fischer analysis.

Modulation of Albumin Esterase Activity by Warfarin and Diazepam.

Data are accumulating on the hydrolytic activity of serum albumin towards esters and organophosphates. Previously, with the help of the technology of proton nuclear magnetic resonance (H NMR) spectroscopy, we observed the yield of acetate in the solution of bovine serum albumin and -nitrophenyl acetate (NPA). Thus, we showed that albumin possesses true esterase activity towards NPA.

The State of Water in "Ionic Liquid [bmim]Cl/AlCl/HO" Systems.

The unique physical and chemical properties of ionic liquids (ILs) determine their numerous applications in "green" chemistry and material science. Recently, systems based on ILs have been considered to be promising for use in a new generation of electrochemical devices. The results of a nuclear magnetic resonance (NMR) study of the microstructure of 1-butyl-3-methylimidazolium chloride (IL)/water mixtures in the presence of Al cations are presented.

NMR Studies of Two Lysine Based Dendrimers with Insertion of Similar Histidine-Arginine and Arginine-Histidine Spacers Having Different Properties for Application in Drug Delivery.

In this paper we study two lysine-based peptide dendrimers with Lys-His-Arg and Lys-Arg-His repeating units and terminal lysine groups. Combination of His and Arg properties in a dendrimer could be important for biomedical applications, especially for prevention of dendrimer aggregation and for penetration of dendrimers through various cell membranes. We describe the synthesis of these dendrimers and the confirmation of their structure using 1D and 2D Nuclear Magnetic Resonance (NMR) spectroscopy.

Esterase Activity of Serum Albumin Studied by H NMR Spectroscopy and Molecular Modelling.

Serum albumin possesses esterase and pseudo-esterase activities towards a number of endogenous and exogenous substrates, but the mechanism of interaction of various esters and other compounds with albumin is still unclear. In the present study, proton nuclear magnetic resonance (H NMR) has been applied to the study of true esterase activity of albumin, using the example of bovine serum albumin (BSA) and -nitrophenyl acetate (NPA). The site of BSA esterase activity was then determined using molecular modelling methods.

Iodonium salts as efficient iodine(iii)-based noncovalent organocatalysts for Knorr-type reactions.

Hypervalent iodine(iii)-derivatives display higher catalytic activity than other aliphatic and aromatic iodine(i)- or bromine(i)-containing substrates for a Knorr-type reaction of -acetyl hydrazides with acetyl acetone to give -acyl pyrazoles. The highest activity was observed for dibenziodolium triflate, for which 10 mol% resulted in the generation of -acyl pyrazole from acyl hydrazide and acetyl acetone typically at 50 °C for 3.5-6 h with up to 99% isolated yields.

The Universal Soldier: Enzymatic and Non-Enzymatic Antioxidant Functions of Serum Albumin.

As a carrier of many biologically active compounds, blood is exposed to oxidants to a greater extent than the intracellular environment. Serum albumin plays a key role in antioxidant defence under both normal and oxidative stress conditions. This review evaluates data published in the literature and from our own research on the mechanisms of the enzymatic and non-enzymatic activities of albumin that determine its participation in redox modulation of plasma and intercellular fluid.

How Strong is Hydrogen Bonding to Amide Nitrogen?

The protonation of the carboxamide nitrogen atom is an essential part of in vivo and in vitro processes (cis-trans isomerization, amides hydrolysis etc). This phenomenon is well studied in geometrically strongly distorted amides, although there is little data concerning the protonation of undistorted amides. In the latter case, the participation of amide nitrogen in hydrogen bonding (which can be regarded as the incipient state of a proton transfer process) is less well-studied.

Local dynamics in LiCl-CsCl-DO water-in-salt solutions according to NMR relaxation.

The main purpose of this study was to investigate the local structure and dynamics in 'water-in-salt' solutions, namely the ternary concentrated LiCl-CsCl-D2O electrolytes. Water based electrolyte solutions are components of natural waters, they are very widespread and possess many practical abilities. NMR was applied as the main technique to study the local structure of the solutions as well as ion and solvent dynamics.

3-Dialkylamino-1,2,4-triazoles via Zn-Catalyzed Acyl Hydrazide-Dialkylcyanamide Coupling.

Zinc(II)-catalyzed (10 mol % ZnCl) coupling of acyl hydrazides and dialkylcyanamides in ethanol leads to 3-dialkylamino-1,2,4-triazoles (76-99%; 17 examples). This reaction represents a novel, straightforward, and high-yielding approach to practically important 3-NR-1,2,4-triazoles, which utilizes commercially available and/or easily generated substrates. Seventeen new 3-NR-1,2,4-triazoles were characterized by HRESI-MS and IR, H, and C{H} NMR spectroscopies and five species additionally by single-crystal X-ray diffraction (XRD).

Stable Deuterium Labeling of Histidine-Rich Lysine-Based Dendrimers.

Peptide dendrimers, due to their biocompatibility and low toxicity, are highly promising candidates as nanocarriers for drugs and genes. The development of this kind of delivery system requires reliable monitoring of their metabolic and biological pathways. In this respect, hydrogen isotope labeling has tremendous importance, being a safe tool for detection of the labeled nanocarriers.

Lysine-based dendrimer with double arginine residues.

Due to their well-defined structure, multivalency, biocompatibility, and low toxicity, lysine dendrimers can be used as safe and efficient nanocarriers for drug and gene delivery. One useful strategy for improving the gene delivery properties of dendrimers is modification with arginine amino acid (Arg) residues. Incorporation of Arg residues could be favorable for the enhancement in transfection efficiency of lysine based dendrimers.

Complexation of κ-carrageenan with gelatin in the aqueous phase analysed by H NMR kinetics and relaxation.

The H NMR spectroscopy is used to study the kinetics of gelation in the aqueous mixtures of κ-carrageenan with gelatin. The time dependence of NMR signals intensities shows that the kinetics of gel formation consists of classical 'fast' (rate constant k≈6h) and 'slow' (k≈1h) periods, corresponding to a coil→helix transition and subsequent aggregation of helices. Upon increase of the κ-carrageenan/gelatin (w/w) ratio Z the rate of the fast process slows down by a factor of 1.

Formation of κ-carrageenan-gelatin polyelectrolyte complexes studied by (1)H NMR, UV spectroscopy and kinematic viscosity measurements.

The intermolecular interactions between an anionic polysaccharide from the red algae κ-carrageenan and a gelatin polypeptide, forming stoichiometric polysaccharide-polypeptide (bio)polyelectrolyte complexes in the aqueous phase, were examined. The major method of investigation was high-resolution (1)H NMR spectroscopy. Additional data were obtained by UV absorption spectroscopy, light scattering dispersion and capillary viscometry.

Ring lithiation of 1,8-bis(dimethylamino)naphthalene: another side of the 'proton sponge coin'.

It has been found that 1,8-bis(dimethylamino)naphthalene (DMAN), unlike N,N-dimethylaniline, undergoes ring metallation in the n-BuLi-TMEDA-Et2O system with a low selectivity and in poor total yields. The situation is significantly improved in the t-BuLi-TMEDA-n-hexane system when 3- and 4-lithium derivatives become the only reaction products obtained in good yields. The formation of 3-Li-DMAN is especially desired since no method of direct meta-functionalization of DMAN is known to date.

"Hydration Shells" of CH2 Groups of ω-Amino Acids as Studied by Deuteron NMR Relaxation.

Hydration phenomena play a very important role in various processes, in particular in biological systems. Water molecules in aqueous solutions of organic compounds can be distributed among the following substructures: (i) hydration shells of hydrophilic functional groups of molecules, (ii) water in the environment of nonpolar moieties, and (iii) bulk water. Up to now, the values of hydration parameters suggested for the description of various solutions of organic compounds were not thoroughly analyzed in the aspect of the consideration of the total molecular composition.

Conformational state of β-hydroxynaphthylamides: Barriers for the rotation of the amide group around CN bond and dynamics of the morpholine ring.

Three β-hydroxynaphthylamides (morpholine, pyrrolidine and dimethylamine derivatives) have been synthesized and their conformational state was analyzed by NMR, X-ray and DFT calculations. In aprotic solution the molecules contain intramolecular OHO hydrogen bonds, which change into intermolecular ones in solid state. The energy barriers for the amide group rotation around the CN bond were estimated from the line shape analysis of (1)H and (13)C NMR signals.