jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Grzegorz Romanowski | Justyna Budka | Iwona Inkielewicz‐Stępniak
Source: Molecules (article, 2023-11-03)
Field: Chemistry — Inorganic Chemistry

Synthesis, Spectroscopic Characterization, Catalytic and Biological Activity of Oxidovanadium(V) Complexes with Chiral Tetradentate Schiff Bases New oxidovanadium(V) complexes, <b>VOL<sup>1</sup></b>-<b>VOL<sup>10</sup></b>, with chiral tetradentate Schiff bases obtained by monocondensation reaction of salicylaldehyde derivatives with 1<i>S</i>,2<i>S</i>-(+)-2-amino-1-(4-nitrophenyl)-1,3-propanediol. All complexes have been characterized using different spectroscopic methods, viz. IR, UV-Vis, circular dichroism, one- (<sup>1</sup>H, <sup>51</sup>V) and two-dimensional (COSY, NOESY) NMR spectroscopy, and elemental analysis. Furthermore, the catalytic ability of all compounds in the epoxidation of styrene, cyclohexene, and its naturally occurring monoterpene derivatives, i.e., <i>S</i>(-)-limonene and (-)-α-pinene has also been studied, using two different oxidants, i.e., aqueous 30% H<sub>2</sub>O<sub>2</sub> or <i>tert</i>-butyl hydroperoxide (TBHP). In addition, the biological properties of these chiral oxidovanadium(V) compounds, but also <i>cis</i>-dioxidomolybdenum(VI) complexes with the same chiral Schiff bases, were studied. Their cytotoxic and cytoprotective activity studies with the HT-22 hippocampal neuronal cells revealed a concentration-dependent effect in the range of 10-100 μM. Moreover, vanadium(V) complexes, in contrast to <i>cis</i>-dioxidomolybdenum(VI) compounds, demonstrated higher cytotoxicity and lack of cytoprotective ability against H<sub>2</sub>O<sub>2</sub>-induced cytotoxicity. Chemistry ; Salicylaldehyde ; Catalysis ; Schiff base ; Circular dichroism ; Cyclohexene ; Cytotoxicity ; Stereochemistry ; Chirality (physics) ; Styrene ; Vanadium ; Nuclear magnetic resonance spectroscopy ; Medicinal chemistry ; Organic chemistry ; In vitro Vanadium and Halogenation Chemistry ; Polyoxometalates: Synthesis and Applications ; Metal-Catalyzed Oxygenation Mechanisms
Authors: Mahmoud A.S. Sakr | Mohamed A. Saad | Hazem Abdelsalam | Nahed H. Teleb | Qinfang Zhang
Source: Scientific Reports (article, 2023-09-19)
Field: Materials Science — Materials Chemistry

Electronic and optical properties of chemically modified 2D GaAs nanoribbons We employed density functional theory calculations to investigate the electronic and optical characteristics of finite GaAs nanoribbons (NRs). Our study encompasses chemical alterations including doping, functionalization, and complete passivation, aimed at tailoring NR properties. The structural stability of these NRs was affirmed by detecting real vibrational frequencies in infrared spectra, indicating dynamical stability. Positive binding energies further corroborated the robust formation of NRs. Analysis of doped GaAs nanoribbons revealed a diverse range of energy gaps (approximately 2.672 to 5.132 eV). The introduction of F atoms through passivation extended the gap to 5.132 eV, while Cu atoms introduced via edge doping reduced it to 2.672 eV. A density of states analysis indicated that As atom orbitals primarily contributed to occupied molecular orbitals, while Ga atom orbitals significantly influenced unoccupied states. This suggested As atoms as electron donors and Ga atoms as electron acceptors in potential interactions. We investigated excited-state electron-hole interactions through various indices, including electron-hole overlap and charge-transfer length. These insights enriched our understanding of these interactions. Notably, UV-Vis absorption spectra exhibited intriguing phenomena. Doping with Te, Cu, W, and Mo induced redshifts, while functionalization induced red/blue shifts in GaAs-34NR spectra. Passivation, functionalization, and doping collectively enhanced electrical conductivity, highlighting the potential for improving material properties. Among the compounds studied, GaAs-34NR-edg-Cu demonstrated the highest electrical conductivity, while GaAs-34NR displayed the lowest. In summary, our comprehensive investigation offers valuable insights into customizing GaAs nanoribbon characteristics, with promising implications for nanoelectronics and optoelectronics applications. Passivation ; Doping ; Density functional theory ; Materials science ; Band gap ; Atomic orbital ; Atom (system on chip) ; Semiconductor ; Electronic structure ; Chemical physics ; Molecular physics ; Electron ; Atomic physics ; Optoelectronics ; Nanotechnology ; Computational chemistry ; Chemistry ; Physics 2D Materials and Applications ; Quantum Dots Synthesis And Properties ; Nanowire Synthesis and Applications
Authors: Edwin Shigwenya Madivoli | Justine V. Schwarte | Patrick Gachoki Kareru | Anthony Gachanja | Katharina M. Fromm
Source: Preprints.org (preprint, 2023-01-25)
Field: Chemistry — Organic Chemistry

Stimuli Responsive and Antimicrobial Cellulose-Chitosan Hydrogels Containing Polydiacetylene Nanosheets Herein, we report a stimuli responsive hydrogel with inhibitory activity against Escherichia coli prepared by chemical crosslinking of carboxymethyl chitosan (CMCs) and hydroxyethyl cellulose (HEC). The hydrogels were prepared by esterification of chitosan (Cs) with monochloroacetic acid to produce CMCs which was then chemically crosslinked to HEC using citric acid as the crosslinking agent. To impart a stimuli responsiveness property to the hydrogels, polydiacetylene-zinc oxide (PDA-ZnO) nanosheets were synthesized in-situ during the crosslinking reaction followed by photopolymerization of the resultant composite. To achieve this, ZnO was anchored on carboxylic groups in 10,12-pentacosadiynoic acid (PCDA) layers to restrict movement of alkyl portion of PCDA during crosslinking CMCs and HEC hydrogels. This was followed by irradiating the composite with UV radiation to photopolymerize the PCDA to PDA within the hydrogel matrix so as to impart thermal and pH responsiveness to the hydrogel. From the results obtained, the prepared hydrogel had a pH dependant swelling capacity as it absorbed more water in acidic media as compared to basic media. Incorporation of PDA-ZnO resulted in a thermochromic composite responsive to pH evidenced by a visible colour transition from pale purple to pale pink. Upon swelling, PDA-ZnO-CMCs-HEC hydrogels had inhibitory activity against E. coli attributed to the slow release of the ZnO nanoparticles as compared to CMCs-HEC hydrogels. Self-healing hydrogels ; Chitosan ; Swelling ; Carboxymethyl cellulose ; Polymer chemistry ; Materials science ; Photopolymer ; Chemistry ; Chemical engineering ; Composite number ; Cellulose ; Organic chemistry ; Polymer ; Monomer ; Composite material ; Sodium Polydiacetylene-based materials and applications ; Ocular Surface and Contact Lens ; Supramolecular Self-Assembly in Materials
Authors: Giacomo Biagiotti | Gianluca Toniolo | Martin Albino | Mirko Severi | Patrizia Andreozzi | Marcello Marelli | Hana Kokot | Giancarlo Tria | Annalisa Guerri | Claudio Sangregorio | Javier Rojo | Debora Berti | Marco Marradi | Stefano Cicchi | Iztok Urbančič | Yvette van Kooyk | Fabrizio Chiodo | Barbara Richichi
Source: Nanoscale Horizons (article, 2023-01-01)
Field: Materials Science — Biomaterials

Simple engineering of hybrid cellulose nanocrystal–gold nanoparticles results in a functional glyconanomaterial with biomolecular recognition properties Cellulose nanocrystal and gold nanoparticles are assembled, in a unique way, to yield a novel modular glyconanomaterial whose surface is then easily engineered with one or two different headgroups, by exploiting a robust click chemistry route. We demonstrate the potential of this approach by conjugating monosaccharide headgroups to the glyconanomaterial and show that the sugars retain their binding capability to C-type lectin receptors, as also directly visualized by cryo-TEM. Nanocrystal ; Colloidal gold ; Nanotechnology ; Materials science ; Cellulose ; Nanoparticle ; Transmission electron microscopy ; Chemistry ; Organic chemistry Advanced Cellulose Research Studies ; Glycosylation and Glycoproteins Research ; Polysaccharides and Plant Cell Walls
Authors: Ying Kuang | Puming Liu | Yichen Yang | Xiaosa Wang | Menglong Liu | Wei Wang | Tianlin Guo | Man Xiao | Kai Chen | Fatang Jiang | Cao Li
Source: Molecules (article, 2023-02-10)
Field: Chemistry — Spectroscopy

Study on the Influence of the Preparation Method of Konjac Glucomannan-Silica Aerogels on the Microstructure, Thermal Insulation, and Flame-Retardant Properties Natural polysaccharides with high viscosity, good thermal stability, and biocompatibility can improve the mechanical properties of inorganic silica aerogels and enhance their application safety. However, the effects of the preparation methods of polysaccharide-silica aerogels on their microstructure and application properties have not been systematically studied. To better investigate the effect of the microstructure on the properties of aerogel materials, two aerogels with different structures were prepared using Konjac glucomannan (KGM) and tetraethoxysilane (TEOS) via physical blending (KTB) and co-precursor methods (KTC), respectively. The structural differences between the KTB and KTC aerogels were characterized, and the thermal insulation and fire-retardant properties were further investigated. The compressive strength of the KTC aerogels with a cross-linked interpenetrating network (IPN) structure was three times higher than that of the KTB aerogels, while their thermal conductivity was 1/3 of that of the KTB aerogels. The maximum limiting oxygen index (<i>LOI</i>) of the KTC aerogels was 1.4 times, the low peak heat release rate (PHRR) was reduced by 61.45%, and the lowest total heat release (THR) was reduced by 41.35% compared with the KTB aerogels. The results showed that the KTC aerogels with the IPN have better mechanical properties, thermal insulation, and fire-retardant properties than the simple physically blending KTB aerogels. This may be due to the stronger hydrogen-bonding interactions between KGM and silica molecules in the KTC aerogels under the unique forcing effect of the IPN, thus enhancing their structural stability and achieving complementary properties. This work will provide new ideas for the microstructure design of aerogels and the research of new thermal insulation and fire-retardant aerogels. Aerogel ; Materials science ; Microstructure ; Fire retardant ; Thermal insulation ; Thermal stability ; Composite material ; Compressive strength ; Biocompatibility ; Thermal conductivity ; Limiting oxygen index ; Chemical engineering ; Char Aerogels and thermal insulation ; Advanced Cellulose Research Studies ; Building materials and conservation
Authors: Fan Yin | Zhi Liu | Jian Yang | Li‐Peng Zhou | Chong‐Bin Tian | Qing‐Fu Sun
Source: ACS Omega (article, 2023-06-29)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Self-Assembly of Triple-Stranded Lanthanide Molecular Quasi-Lantern Containing 2,2′-Bipyridine Receptor: Luminescence Sensing and Magnetic Property Ln<sub>2</sub><b>L</b><sub>3</sub>-type supramolecular architectures have received significant attention recently due to their unique magnetism and optical properties. Herein, we report the triple-stranded Ln<sub>2</sub><b>L</b><sub>3</sub>-type lanthanide molecular quasi-lanterns, which are fabricated by the deprotonation self-assembly of a linear ligand featuring a β-diketone chelating claw and 2,2'-bipyridine (bpy) moiety with lanthanide ions (Ln = Eu<sup>3+</sup> and Dy<sup>3+</sup>). The crystal structure analysis indicates that Eu<sup>3+</sup> and Dy<sup>3+</sup> ions are all coordinated by eight oxygen donors but in different coordination geometries. The eight oxygen donors in Eu<sub>2</sub><b>L</b><sub>3</sub> and Dy<sub>2</sub><b>L</b><sub>3</sub> are arranged in a square antiprism and triangular dodecahedron geometry, respectively. Taking into account the fact that the bpy moiety has a strong coordination affinity for transition metal ions, luminescence sensing toward Cu<sup>2+</sup> ions has been demonstrated with Eu<sub>2</sub><b>L</b><sub>3</sub>, bearing a detection of limit as low as 2.84 ppb. The luminescence sensing behavior of Eu<sub>2</sub><b>L</b><sub>3</sub> is ascribed to the formation host-guest complex between Eu<sub>2</sub><b>L</b><sub>3</sub> and Cu<sup>2+</sup> ions with a 1:2 binding ratio. Dynamic AC susceptibility measurements for Dy<sub>2</sub><b>L</b><sub>3</sub> reveal the relaxation of magnetization in it. This work provides a potential way for design and fabrication of lanthanide-based molecular materials with functions endowed by the ligands. Lanthanide ; Luminescence ; Supramolecular chemistry ; Deprotonation ; Crystallography ; Moiety ; Square antiprism ; Bipyridine ; Ligand (biochemistry) ; Chemistry ; Ion ; Materials science ; Crystal structure ; Stereochemistry ; Organic chemistry Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Supramolecular Chemistry and Complexes
Authors: Alexey Gusev | Elena Braga | Alexandra Karmazina | Andrey Karmazin | O.V. Konnik | Mikhail A. Kiskin | Glib Baryshnikov | Wolfgang Linert
Source: Inorganica Chimica Acta (article, 2023-03-15)
Field: Chemistry — Spectroscopy

Structure-induced luminescence and bioactivities of Zinc(II) complexes with 2-(2,4-dichlorophenoxy)-N′-[pyridin-2-ylmethylene]acetohydrazide Chemistry ; Luminescence ; Supramolecular chemistry ; Zinc ; Ligand (biochemistry) ; Crystal structure ; Hydrazone ; Crystallography ; Single crystal ; Inorganic chemistry ; Stereochemistry ; Organic chemistry ; Receptor Molecular Sensors and Ion Detection ; Metal complexes synthesis and properties ; Crystal structures of chemical compounds
Authors: Tsukasa Abe | Naoki Sanada | Keisuke Takeuchi | Atsushi Okazawa | Shûichi Hiraoka
Source: ChemRxiv (preprint, 2023-05-03)
Field: Chemistry — Organic Chemistry

Assembly of six types of heteroleptic Pd2L4 cages under kinetic control Difficulty in multi-component self-assembly under thermodynamic control arises from increasing the number of possible isomers with similar thermodynamic stabilities. Past efforts on multi-component self-assembly of metal-organic cages have mainly focused on finding a suitable combination of building blocks to lead to a single multi-component self-assembly as the thermodynamically most stable product. Here, we present another approach to selectively produce multi-component Pd(II)-based self-assemblies under kinetic control based on the selective ligand exchanges of weak Pd–L coordination bonds retaining the original orientation of the metal centers in a kinetically stabilized cyclic structure and on local reversibility given in a certain area of the energy landscape in the presence of the assist molecule that facilitates error correction of coordination bonds. The kinetic approach enabled us to build all six types of Pd2L4 cages and heteroleptic tetranuclear cages composed of three kinds of ditopic ligands. Though the cage complexes thus obtained are metastable, they are stable for 1 month or more at room temperature. Metastability ; Kinetic energy ; Kinetic control ; Component (thermodynamics) ; Ligand (biochemistry) ; Molecule ; Metal ; Self-assembly ; Chemistry ; Energy landscape ; Chemical physics ; Materials science ; Crystallography ; Nanotechnology ; Thermodynamics ; Physics ; Catalysis ; Organic chemistry Supramolecular Chemistry and Complexes ; Supramolecular Self-Assembly in Materials ; Hemoglobin structure and function
Authors: Tăchiță Vlad‐Bubulac | Corneliu Hamciuc | Diana Serbezeanu | Dana Mihaela Suflet | Daniela Rusu | Gabriela Lisă | Ion Anghel | Dana-Maria Preda | Totka Todorova | C. Rîmbu
Source: Polymers (article, 2023-06-04)
Field: Materials Science — Polymers and Plastics

Organophosphorus Reinforced Poly(vinyl alcohol) Nanocomposites Doped with Silver-Loaded Zeolite L Nanoparticles as Sustainable Materials for Packaging Applications The sustainable development of innovative eco-friendly multifunctional nanocomposites, possessing superior characteristics, is a noteworthy topic. Novel semi-interpenetrated nanocomposite films based on poly(vinyl alcohol) covalently and thermally crosslinked with oxalic acid (OA), reinforced with a novel organophosphorus flame retardant (PFR-4) derived from co-polycondensation in solution reaction of equimolar amounts of co-monomers, namely, bis((6-oxido-6H-dibenz[c,e][1,2]oxaphosphorinyl)-(4-hydroxyaniline)-methylene)-1,4-phenylene, bisphenol S, and phenylphosphonic dichloride, in a molar ratio of 1:1:2, and additionally doped with silver-loaded zeolite L nanoparticles (ze-Ag), have been prepared by casting from solution technique. The morphology of the as prepared PVA-oxalic acid films and their semi-interpenetrated nanocomposites with PFR-4 and ze-Ag was investigated by scanning electron microscopy (SEM), while the homogeneous distribution of the organophosphorus compound and nanoparticles within the nanocomposite films has been introspected by means of energy dispersive X-ray spectroscopy (EDX). It was established that composites with a very low phosphorus content had noticeably improved flame retardancy. The peak of the heat release rate was reduced up to 55%, depending on the content of the flame-retardant additive and the doping ze-Ag nanoparticles introduced into the PVA/OA matrix. The ultimate tensile strength and elastic modulus increased significantly in the reinforced nanocomposites. Considerably increased antimicrobial activity was revealed in the case of the samples containing silver-loaded zeolite L nanoparticles. Vinyl alcohol ; Materials science ; Nanocomposite ; Oxalic acid ; Nanoparticle ; Polyvinyl alcohol ; Fire retardant ; Chemical engineering ; Polymer ; Polymer chemistry ; Nuclear chemistry ; Composite material ; Organic chemistry ; Chemistry ; Nanotechnology Flame retardant materials and properties ; Polymer Science and PVC ; biodegradable polymer synthesis and properties
Authors: Kevin Daus | Sorachat Tharamak | Wanchai Pluempanupat | Peter A. Galie | Maria A. Theodoraki | Emmanuel A. Theodorakis | Mary L. Alpaugh
Source: Scientific Reports (article, 2023-11-22)
Field: Chemistry — Spectroscopy

Fluorescent molecular rotors as versatile in situ sensors for protein quantitation Accurate protein quantitation is essential for many cellular mechanistic studies. Existing technology relies on extrinsic sample evaluation that requires significant volumes of sample as well as addition of assay-specific reagents and importantly, is a terminal analysis. This study exploits the unique chemical features of a fluorescent molecular rotor that fluctuates between twisted-to-untwisted states, with a subsequent intensity increase in fluorescence depending on environmental conditions (e.g., viscosity). Here we report the development of a rapid, sensitive in situ protein quantitation method using ARCAM-1, a representative fluorescent molecular rotor that can be employed in both non-terminal and terminal assays. Fluorescence ; In situ ; Reagent ; Fluorescent protein ; Chemistry ; Chromatography ; Rotor (electric) ; Biophysics ; Green fluorescent protein ; Biological system ; Biochemistry ; Biology ; Organic chemistry ; Gene Molecular Sensors and Ion Detection ; Luminescence and Fluorescent Materials ; Analytical Chemistry and Sensors
Authors: Enrico Podda | Massimiliano Arca | Anna Pintus | Vito Lippolis | Claudia Caltagirone | Simon J. Coles | James B. Orton | Guido Ennas | Giacomo Picci | Robert P. Davies | M. Carla Aragoni
Source: CrystEngComm (article, 2023-01-01)
Field: Materials Science — Materials Chemistry

On the role of torsional dynamics in the solid-state fluorescent properties of a new bifluorene–tetracarboxylic acid and its supramolecular assemblies: a structural and TD-DFT investigation The solid-state emission properties of bifluorene–tetracarboxylic acid were reported and rationalised on the basis of fluorene torsional dynamics by SC-XRD and DFT calculations. Fluorescence ; Supramolecular chemistry ; Solid-state ; Dynamics (music) ; Materials science ; Crystallography ; Chemical physics ; Chemistry ; Physical chemistry ; Crystal structure ; Physics ; Optics Luminescence and Fluorescent Materials ; Crystallography and molecular interactions ; Advanced Chemical Physics Studies
Authors: Julian Vogel | Yu‐Sheng Chen | Rachel E. Fadler | Amar H. Flood | Max von Delius
Source: Chemistry - A European Journal (article, 2023-05-08)
Field: Chemistry — Organic Chemistry

Steric Control over the Threading of Pyrophosphonates with One or Two Cyanostar Macrocycles during Pseudorotaxane Formation The supramolecular recognition of anions is increasingly harnessed to achieve the self-assembly of supramolecular architectures, ranging from cages and polymers to (pseudo)rotaxanes. The cyanostar (CS) macrocycle has previously been shown to form 2 : 1 complexes with organophosphate anions that can be turned into [3]rotaxanes by stoppering. Here we achieved steric control over the assembly of pseudorotaxanes comprising the cyanostar macrocycle and a thread that is based, for the first time, on organo-pyrophosphonates. Subtle differences in steric bulk on the threads allowed formation of either [3]pseudorotaxanes or [2]pseudorotaxanes. We demonstrate that the threading kinetics are governed by the steric demand of the organo-pyrophosphonates and in one case, slows down to the timescale of minutes. Calculations show that the dianions are sterically offset inside the macrocycles. Our findings broaden the scope of cyanostar-anion assemblies and may have relevance for the design of molecular machines whose directionality is a result of relatively slow slipping. Steric effects ; Supramolecular chemistry ; Threading (protein sequence) ; Chemistry ; Rotaxane ; Molecular machine ; Intermolecular force ; Supramolecular assembly ; Crystallography ; Nanotechnology ; Stereochemistry ; Molecule ; Materials science ; Crystal structure ; Organic chemistry ; Protein structure Supramolecular Chemistry and Complexes ; Molecular Sensors and Ion Detection ; Supramolecular Self-Assembly in Materials