The labile tautomerism of -unsubstituted 5-acyl-4-pyridones, which exist in the form of 4-pyridone or 4-hydroxypyridine depending on the solvent, has been demonstrated. This equilibrium determines the reactivity of pyridones and their ability to undergo substitution reactions of the OH group. A regioselective and convenient method for the construction of functionalized pyrazolo[4,3-]pyridines (30-93%) based on the intramolecular amination reaction of 4-pyridones with hydrazines has been developed.
View Article and Find Full Text PDFThe widespread use of the oral poliovaccine from Sabin strains (tOPV) radically reduced poliomyelitis incidence worldwide. However, OPV became a source of neurovirulent vaccine-derived polioviruses (VDPVs). Currently, circulating type 2 VDPVs (cVDPV2) are the leading cause of poliomyelitis.
View Article and Find Full Text PDFThe present work explores the specificity of supramolecular assemblies comprising dialkylaminostyrylhetarene dye molecules incorporated into phosphatidylcholine (PC) or phosphatidylserine (PS) aggregates. In PS-based assemblies, the dyes demonstrate a concentration-dependent fluorescent response, distinguishing anionic proteins such as bovine serum albumin (BSA) and pepsin from lysozyme (LYZ) in aqueous solutions. Conversely, no significant response is observed when the dyes are incorporated into the well-organized bilayers of neutral PC.
View Article and Find Full Text PDFTo date, researchers in chase of economic cost-efficiency are faced with the problem of developing effective catalysts for water splitting without the use of platinoids. Herein, catalytic properties of hexanuclear rhenium cluster complexes are investigated in application to the hydrogen evolution reaction (HER). A paste composite electrode containing the cluster complexes was obtained, producing a current density of 10 mA cm at an extraordinarily low overpotential of 90 mV (RHE).
View Article and Find Full Text PDFThe unique properties of superparamagnetic iron oxide nanoparticles (SPIONs) enable their use as magnetic biosensors, targeted drug delivery, magnetothermia, magnetic resonance imaging, etc. Today, SPIONs are the only type of metal oxide nanoparticles approved for biomedical application. In this work, we analyzed the cellular response to the previously reported luminescent silica coated SPIONs of the two cell types: M-HeLa cells and primary motor neuron culture.
View Article and Find Full Text PDFDevelopment of nanoparticles (NPs) serving as contrast enhancing agents in MRI requires a combination of high contrasting effect with the biosafety and hemocompatibility. This work demonstrates that bovine serum albumin (BSA) molecules bound to paramagnetic Mn ions are promising building blocks of such NPs. The desolvation-induced denaturation of BSA bound with Mn ions followed by the glutaraldehyde-facilitated cross-linking provides the uniform in size 102.
View Article and Find Full Text PDFThe present work demonstrates the structure variation of hexarhenium anionic cluster units [{ReS}(CN)(OH)] (n = 0, 2, 4) as the strategy to develop Mn-containing nanoparticles (NPs) exhibiting pH-dependent leaching. The dicyanotetrahydroxo complex [{ReS}(CN)(OH)] is the optimal for the synthesis of the Mn-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 [{ReS}(CN)(OH)] cluster, which triggers partial leaching of Mn ions and aggregation of the NPs driven by the surface neutralization.
View Article and Find Full Text PDFGold(I) complexes of LAuCl composition based on PN ligands, namely 1,5-diaza-3,7-diphosphacyclooctanes, containing ethylpyridyl substituents at the phosphorus atoms and sp- or sp-hybridized endocyclic nitrogen atoms were synthesized. The SCXRD analysis indicated the strong impact of the geometry of the nitrogen atom on the structure and conformational flexibility of the complexes. The -aryl substituted ligand with the planar endocyclic nitrogen atom provides higher flexibility of the complex and an ability to bind the solvent molecules in the "host-guest" mode, whereas that kind of behavior is forbidden for the complex with an -alkyl substituted ligand with a pyramidal nitrogen atom.
View Article and Find Full Text PDFThe work presents core-shell nanoparticles (NPs) built from the novel Cu(I) complexes with cyclic PN-ligands (1,5-diaza-3,7-diphosphacyclooctanes) that can visualize their entry into cancer and normal cells using a luminescent signal and treat cells by self-enhancing generation of reactive oxygen species (ROS). Variation of P- and N-substituents in the series of PN-ligands allows structure optimization of the Cu(I) complexes for the formation of the luminescent NPs with high chemical stability. The non-covalent modification of the NPs with triblock copolymer F-127 provides their high colloidal stability, followed by efficient cell internalization of the NPs visualized by their blue (⁓450 nm) luminescence.
View Article and Find Full Text PDFHighly accurate visualization of the points of transcranial magnetic stimulation (TMS) application on the brain cortical surface could provide anatomy-specific analysis of TMS effects. TMS is widely used to activate cortical areas with high spatial resolution, and neuronavigation enables site-specific TMS of particular gyrus sites. Precise control of TMS application points is crucial in determining the stimulation effects.
View Article and Find Full Text PDFMagnetic nanoparticles (MNPs) have recently begun to be actively used in biomedicine applications, for example, for targeted drug delivery, in tissue engineering, and in magnetic resonance imaging. The study of the magnetic field effect on MNPs internalized into living cells is of particular importance since it allows a non-invasive influence on cellular activity. There is data stating the possibility to manipulate and control individual MNPs utilizing the local magnetic field gradient created by electromagnetic needles (EN).
View Article and Find Full Text PDFObjective: This study examined the impact of family size and type on maternal rejection and its relationship with emotional-behavioral difficulties in children with ADHD compared to those typically developing.
Method: The participants were mothers of 7- to 12-year-old children with ADHD ( = 102) and mothers of typically developing children ( = 102) in Kazakhstan. In this cross-sectional study, multiple linear regression analysis was performed to explore the relationship between variables.
The silica nanoparticles (SNs) co-doped with paramagnetic ([Mn(HL)],) and luminescent ([Ru(dipy)]) complexes are represented. The specific distribution of [Mn(HL)] within the SNs allows to achieve about ten-fold enhancing in magnetic relaxivities in comparison with those of [Mn(HL)] in solutions. The leaching of [Mn(HL)] from the shell can be minimized through the co-doping of [Ru(dipy)] into the core of the SNs.
View Article and Find Full Text PDFThis work presents the synthesis of a new representative of hemicurcuminoids with a nonyloxy substituent () as a fluorescent amphiphilic structural element of vesicular aggregates based on phosphatidylcholine (PC), phosphatidylserine (PS), and 10,12-pentacosadiynoic acid (PCDA). Both X-ray diffraction analysis of the single crystal and H NMR spectra of in organic solvents indicate the predominance of the enol-tautomer of . DFT calculations show the predominance of the enol tautomer in supramolecular assemblies with PC, PS, and PCDA molecules.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2023
The present work demonstrates the optimization of the ligand structure in the series of bis(phosphine oxide) and β-ketophosphine oxide representatives for efficient coordination of Tb and Eu ions with the formation of the complexes exhibiting high Tb- and Eu-centered luminescence. The analysis of the stoichiometry and structure of the lanthanide complexes obtained using the XRD method reveals the great impact of the bridging group nature between two phosphine oxide moieties on the coordination mode of the ligands with Tb and Eu ions. The bridging imido-group facilitates the deprotonation of the imido- bis(phosphine oxide) ligand followed by the formation of tris-complexes.
View Article and Find Full Text PDFThe present work describes an efficient reaction of electrochemical phosphorylation of phenylacetylene controlled by the composition of catalytic nanoparticles based on non-noble-metals. The sought-after products are produced via the simple synthetic protocol based on room temperature, atom-economical reactions, and silica nanoparticles (SNs) loaded by one or two d-metal ions as nanocatalysts. The redox and catalytic properties of SNs can be tuned with a range of parameters, such as compositions of the bimetallic systems, their preparation method, and morphology.
View Article and Find Full Text PDFThe present work introduces the series of thiacalix[4]arenes (HL) bearing different upper-rim substituents (R = H, Br, NO) for rational design of ligands providing an antenna-effect on the NIR Yb-centered luminescence of their Yb complexes. The unusual inclusive self-assembly of HL (Br) through Brπ interactions is revealed through single-crystal XRD analysis. Thermodynamically favorable formation of dimeric complexes [2Yb:2HL] leads to efficient sensitizing of the Yb luminescence for HL (Br, NO), while poor sensitizing is observed for ligand HL (H).
View Article and Find Full Text PDFObjectives: The detection of a vaccine-derived poliovirus (VDPV) requires an epidemiological assessment and response. Using repeated stool sampling from a child who is immunocompetent and was vaccinated against poliomyelitis with acute flaccid paralysis, a case of an extremely rapid evolution of Sabin-like poliovirus (PV) type 3 was traced in the child's body.
Methods: The case was independently identified in two countries-Tajikistan and Russia.
The present work introduces a simple, electrostatically driven approach to engineered nanomaterial built from the highly cytotoxic [AuL] complex (Au, L = 1,5-bis(p-tolyl)-3,7-bis(pyridine-2-yl)-1,5-diaza-3,7-diphosphacyclooctane (PNNP) ligand) and the pH-sensitive red-emitting [{ReQ}(OH)] (Re-Q, Q = S or Se) cluster units. The protonation/deprotonation of the Re-Q unit is a prerequisite for the pH-triggered assembly of Au and Re-Q into AuRe-Q colloids, exhibiting disassembly in acidic (pH = 4.5) conditions modeling a lysosomal environment.
View Article and Find Full Text PDFPharmaceutics
July 2022
The present work introduces rational design of nanoparticulate Mn(II)-based contrast agents through both variation of the μ (inner) ligands within a series of hexarhenium cluster complexes [{Re(μ-Q)}(CN)] (ReQ, Q = S, Se or Te) and interfacial decoration of the nanoparticles (NPs) KMnReQ ( = 1.3 - 1.8) by a series of pluronics (F-68, P-123, F-127).
View Article and Find Full Text PDFThe present work introduces self-assembled polystyrenesulfonate (PSS) molecules as soft nanocapsules for incorporation of Eu-Sm complexes by the solvent exchange procedure. The high levels of Eu- and Sm-luminescence of the complexes derives from the ligand-to-metal energy transfer, in turn, resulted from the complex formation of Euand Sm ions with the three recently synthesized cyclophanic 1,3-diketones. The structural features of the ligands are optimized for the high thermal sensitivity of Eu- luminescence in DMF solutions.
View Article and Find Full Text PDFА novel type of a complex neuro-glandular brain structure including both nervous and glandular elements and associated with sensory ones is detected in Pyramicocephalus phocarum plerocercoid (Cestoda: Diphyllobothriidea), parasite of Gadus morua from the White Sea. The brain has two lateral lobes connected by a long cellular median commissure. The brain is tightly surrounded by glandular cells, which receive numerous synapses from the brain neurons.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
March 2022
A series of dialkylaminostyrylhetarene dyes constructed from electron-rich and electron-deficient moieties of various structures connected via vinylene π-bridges are introduced as temperature-sensitive luminophores. The temperature dependent emission of the dyes in the acidified dichloromethane solutions derives from temperature-induced shift of the equilibrium between neutral and protonated forms of the dyes. The heating-induced blue shift and intensification of emission of neutral form of the dyes make them a promising basis for development of nanoparticles exhibiting temperature-sensitivity in aqueous solutions at pH typical of biological liquids.
View Article and Find Full Text PDFThe report introduces hybrid polyelectrolyte-stabilized colloids combining blue and green-emitting building blocks, which are citrate carbon dots (CDs) and [TbL] chelate complexes with 1,3-diketonate derivatives of calix[4]arene. The joint incorporation of green and blue-emitting blocks into the polysodium polystyrenesulfonate (PSS) aggregates is carried out through the solvent-exchange synthetic technique. The coordinative binding between Tb centers and CD surface groups in initial DMF solutions both facilitates joint incorporation of [TbL] complexes and the CDs into the PSS-based nanobeads and affects fluorescence properties of [TbL] complexes and CDs, as well as their ability for temperature sensing.
View Article and Find Full Text PDFElectrostatically driven self-assembly of [AuL] (L is cyclic PNNP ligand) with [{MoI}(L')] (L' = I, CHCOO) in aqueous solutions is introduced as facile route for combination of therapeutic and cellular contrasting functions within heterometallic colloids (Mo-Au). The nature of L' affects the size and aggregation behavior of crystalline Mo-Au aggregates, which in turn affect the luminescence of the cluster units incorporated into Mo-Au colloids. The spin trap facilitated electron spin resonance spectroscopy technique indicates that the level of ROS generated by Mo-Au colloids is also affected by their size.
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