The present work demonstrates the structure variation of hexarhenium anionic cluster units {Re6S8}(CN)(6-n)(OH)n4- (n = 0, 2, 4) as the strategy to develop Mn2+-containing nanoparticles (NPs) ...exhibiting pH-dependent leaching. The dicyanotetrahydroxo complex {Re6S8}(CN)2(OH)44- is the optimal for the synthesis of the Mn2+-based NPs with a lamellar shape exhibiting the pH-dependent aggregation and magnetic relaxation behavior. The pH-dependent behavior of the NPs derives from the easy protonation of the apical hydroxo ligands of {Re6S8}(CN)2(OH)44- cluster, which triggers partial leaching of Mn2+ ions and aggregation of the NPs driven by the surface neutralization. The in vivo MRI scanning of the mice intravenously injected with the NPs indicates the preferable accumulation of the lamellar NPs within mouse intestine over liver and kidneys. This differs from the spherical NPs constructed from {Re6Se8}(CN)64- units, which provide the preferable brightening of mouse liver over kidneys and intestine.
The catalytic activity of the nickel complexes of thiophosphorylated calix4resorcinols for oxygen reduction in a polymer electrolyte membrane fuel cell (PEMFC) has been studied. The conformation of ...the macrocyclic ligand determines the morphology and catalytic properties of the resulting organometallic species.
•Water soluble complexes of pectin with Ca, Mg, Co, Cu, Fe, Mn, Zn are synthesized.•Complexation is established by NMR, IR, ESR and AFM methods.•Antianemic activity of Na,Fe and Na,Ca,Fe pectin ...complexes is studied in rats.•The complexes prevent erythropoiesis disorders in rats after the loss of blood.
New water–soluble pectin complexes with Ca2+, Mg2+, Co2+, Cu2+, Fe2+, Mn2+, Zn2+ on the basis of pectin biopolymer have been synthesized and successfully tested on white rats. For a starting, we have obtained a sodium pectate to enhance solubility of target complexes as a whole. Shortly afterwards, running the reaction of ligand exchange of Nа+ ions with corresponding s-, d- metal cations we were able to synthesize new pectin complexes. The ranges of s-, d-metals salts concentrations were detected experimentally, in which the selective formation of water-soluble complexes occurred. Antianemic effect of new pectin complexes with Na, Fe and Na, Ca, Fe was investigated on white rats with posthemorrhagic anemia. Under the effect of complexes, the improvement of animals and prevention of erythropoiesis disorders were observed. Antianemic effect of the complexes manifested itself in the doses equivalent to 25% or 50% of the iron daily rate, recommended in the treatment of iron-deficiency anemia with the drugs based on iron sulphate.
Abstract
This study is part of the work on the creation of a transparent conductive coating based on oriented nanonetwork and submicron nickel fibres. It is devoted to finding the optimal values of ...electrical conductivity and optical transparency of the developed coating. In this work, we study the transmission spectra of oriented nickel networks on a glass substrate in the UV, visible and near-IR regions at different amounts of deposited metal. An exciting feature of the coating was discovered: in the range of 950 nm and above, there is a "bend" of the transmission spectrum downward. This bend (increased absorption of radiation in the near-IR region) is observed only in the presence of nickel nanonetwork and is not typical for a pure submicron network.
Abstract
The paper investigates the optical transparency dependence of a coating based on an oriented network of platinum nanowires on the amount of metal used. Oriented platinum nanowires on a glass ...surface are produced by chemical deposition from an aqueous hexachloroplatinic acid solution. The topography of the deposited metal layer on glass is visualized using atomic force microscopy. Optical transparency was investigated with a spectrophotometer. In almost the entire region of optical radiation, the transparency is approximately 98%. The absorption spectrum shows that the absorption coefficient increases sharply in the near UV region.
Here we represent the first example of the formation of mixed nanoscale associates, constructed from amphiphilic calixresorcinarenes and hydrophobic carboxylic acids including drugs. The ...amidoamino-calixresorcinarene self-associates effectively solubilize hydrophobic carboxylic acids - drugs such as naproxen, ibuprofen, ursodeoxycholic acid and aliphatic dodecanoic acid - with the formation of the mixed aggregates with the macrocycle/substrate stoichiometry from 1/1 to 1/7. The ionization of organic acids and the peripheral nitrogen atoms of the macrocycles with the subsequent inclusion of hydrophobic acids into the macrocycle self-associates is the driving force of solubilization. In some cases, this leads to the co-assembly of the macrocycle polydisperse associates into supramolecular monodisperse nanoparticles with the diameter of about 100 nm. The efficiency of drug loading into the nanoparticles is up to 45% and depends on the structure of organic acid. The dissociation of the mixed aggregates and release of organic acid are attained by decreasing pH.
This paper considers a method for determining the type of electrical conductivity of a previously developed composite transparent conductive coating based on oriented platinum networks embedded in ...the polymer matrix. Many researchers have recently been grappling with finding electrically conductive transparent coatings for smart devices with touch screens, particularly an alternative to the massively used indium tin oxide (ITO) having some disadvantages, the most serious of which is the lack of coating flexibility. The latter can be overcome by using various metal-polymer composites with high transparency in the optical range and low surface resistance. However, one should be aware that the type of conductivity depends on both the polymer matrix and the metal framework of a composite. This defines its electrical properties. Therefore, it is important to correctly identify and measure the electrical conductivity. The developed method is based on studying the temperature dependence of the surface resistance in the material.
Multitarget ligands (MTL) based on sterically hindered phenol and containing a quaternary ammonium moiety (SHP-n-Q) were synthesized. These compounds are inhibitors of cholinesterases with ...antioxidant properties. The inhibitory selectivity is 10-fold potent for BChE than for AChE. IC50 of SHP-n-Q for BChE is 20 μM. SHP-n-Q and their nanosystems exhibit more pronounced antioxidant properties than the synthetic antioxidant (hindered phenol, butylated hydroxytoluene). These compounds display a low hemolytic activity against human red blood cells. The nanotechnological approach was used to increase the bioavailability of SHP-n-Q derivatives. For water soluble SHP-n-Q derivative, the self-assembled structures have a size close to 100 nm at critical association concentration (0.01 M). Mixed cationic liposomes based on l-α-phosphatidylcholine and SHP-n-Q of 100 nm diameter were prepared. The stability, encapsulation efficacy and release from liposomes of a model drug, Rhodamine B, depend on the structure of SHP-n-Q. Cationic liposomes based on l-α-phosphatidylcholine and SHP-3-Q show a good stability in time (1year) and a sustained release (>65 h). They are promising templates for the development of anti-Alzheimer MT-drug delivery systems.
•Sterically hindered phenol containing quaternary ammonium moiety were synthesized.•The inhibitory selectivity is 10-fold higher for BuChE than for AChE.•Sterically hindered phenol self-assembled 100 nm structures were observed.•Sterically hindered phenol-loaded liposomes show a good stability and sustained release.•Sterically hindered phenols are promising templates for multitarget-drug delivery systems.
Searching for new ways of converting carbon dioxide into value-added products, such as fuels, is a relevant task of our time. Electrochemical reduction of carbon dioxide to carbon monoxide, ...hydrocarbons and alcohols is considered as one of the main approaches in this area. One of the most advanced approaches is the use of coordination polymers for homogeneous and heterogeneous catalysis of carbon dioxide reduction. We obtained coordination pectin biopolymers with different nickel ions contents (PG-NaNi). The structure and composition of the obtained biopolymers were characterized by such physicochemical methods as IR and ICP-AE spectroscopy. Morphology of PG-NaNi on a glassy carbon surface provides very high surface to volume ratio. Cyclic voltammetry on the modified glassy carbon working electrode in water solution saturated with carbon dioxide shows catalytic properties of PG-NaNi for CO2 reduction reaction.
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