jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Yihui Xie | Danni Luo | Jesse Wiener | Alexander B. Koval | Conrad T. Pfeiffer | Christian E. Schafmeister
Source: Angewandte Chemie International Edition (article, 2023-04-19)
Field: Chemistry — Inorganic Chemistry

Spiroligomer‐Based Macrocycles for Atomically Precise Membranes Abstract Here, we report a new class of peptidomimetic macrocycles with well‐defined three‐dimensional structures and low conformational flexibility. They are assembled from fused‐ring spiro‐ladder oligomers (spiroligomers) by modular solid‐phase synthesis. Two‐dimensional nuclear magnetic resonance confirms their shape persistency. Triangular macrocycles of tunable sizes assemble into membranes with atomically precise pores, which exhibit size and shape‐dependent molecular sieving towards a series of structurally similar compounds. The exceptional structural diversity and stability of spiroligomer‐based macrocycles will be explored for more applications. Membrane ; Modular design ; Flexibility (engineering) ; Peptidomimetic ; Materials science ; Ring (chemistry) ; Crystallography ; Nanotechnology ; Chemical physics ; Chemistry ; Computer science ; Peptide ; Mathematics ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Supramolecular Chemistry and Complexes ; Supramolecular Self-Assembly in Materials
Authors: Y. Bagherzadeh | M.H. Golmakani | Ebrahim Zohourvahid Karimi
Source: Journal of Mining and Metallurgy Section B Metallurgy (article, 2023-01-01)
Field: Materials Science — Biomaterials

Straight synthesis of α and γ alumina from kaolin by HCl acid leaching In this work the preparation of alumina from kaolinite by leaching with hydrochloric acid is studied. Crude kaolin was calcined at 850?C and then leached with 6 M hydrochloric acid at 90?C. Aluminum hydroxide was precipitated by adding 6 M HCl solution to the leaching water. Finally, the precipitated aluminum hydroxide was heated at 1100?C and converted to aluminum oxide. The materials were identified by XRF, XRD and SEM-EDX techniques. The percentage of alumina recovery was determined at different kaolin particle sizes (?200 to ?400 standard Tyler sieve), different times (1, 2, 3 and 4 h), different leaching temperatures (80, 90, 100 and 104?C) and different concentrations of hydrochloric acid (20, 25, 30 and 37%). The phase changes of alumina were also investigated at two calcination temperatures (1100 and 1200?C). The purity of aluminum oxide obtained by this method is about 97% and the percentage of recovery is about 98%. It was observed that the kaolin granulation with dimensions smaller than 75 ?m had no significant effect on the percentage of alumina recovery. It was also found that the percentage of alumina recovery increased with increasing leaching temperature. Hydrochloric acid ; Leaching (pedology) ; Calcination ; Hydroxide ; Materials science ; Nuclear chemistry ; Gibbsite ; Kaolinite ; Sodium hydroxide ; Particle size ; Aluminium ; Chemistry ; Inorganic chemistry ; Metallurgy ; Catalysis Clay minerals and soil interactions
Authors: Arif Hassan Dar | Anas Ahmad | Ajay Kumar | Vijayendran Gowri | Chandrashekhar Jori | Shaifali Sartaliya | K M Neethu | Rehan Khan | Govindasamy Jayamurugan
Source: ChemRxiv (preprint, 2023-06-14)
Field: Materials Science — Materials Chemistry

Enhancing Photophysical and Photosensitizing Properties of Nanoaggregates of Weakly Emissive Non-Planar Push-Pull Chromophore The development of luminescent dye based on 1,1,4,4-tetracyanobuta-1,3-dienes (TCBDs) is an active research area, to date, only a few examples of designer TCBDs molecules displaying emission properties with quantum yields of 7.8 and 8.5% due to fluorophore conjugation and aggregation have been reported, both in organic, non-polar solvents. Our novel method radically refines weakly emissive 2,3-disubstituted TCBD (phenyl-TCBD 1) (ΦF = 2.3% in CH3CN) into a water-soluble, biocompatible nano-formulation as highly emissive aggregates 1NPsPF-127 with ΦF = 7.9% in H2O and without fluorophore conjugation. Spectroscopic studies including FT-IR revealed that aggregated phenyl-TCBD particles were encapsulated in a non-luminescent tri-block copolymer (PF-127) based nano-micelle. With increasing water fraction, the Phenyl-TCBD nano-aggregates exhibit a 3-fold higher quantum yield, greater lifetime, and redshift (155 nm). Singlet oxygen generation capability was tested to explore future studies as a bio-probe for bio-imaging applications and in photodynamic therapy to selectively target cancer cell lines with singlet oxygen generation (Φ= 0.25) capability. This study has significant implications for developing non-planar push-pull chromophores-based dyes as biosensors and their potential applications beyond bioimaging. Chromophore ; Singlet oxygen ; Fluorophore ; Photochemistry ; Luminescence ; Quantum yield ; Photodynamic therapy ; Fluorescence ; Chemistry ; Molecule ; Materials science ; Nanotechnology ; Optoelectronics ; Oxygen ; Organic chemistry ; Optics Luminescence and Fluorescent Materials ; Advanced Polymer Synthesis and Characterization ; Photochromic and Fluorescence Chemistry
Authors: Xiaodong Li | Ailing Feng | Yanqing Zu | Peitao Liu | Fengbo Han
Source: Molecules (article, 2023-04-13)
Field: Materials Science — Materials Chemistry

Experimental and Theoretical Study on Crown Ether-Appended-Fe(III) Porphyrin Complexes and Catalytic Oxidation Cyclohexene with O2 Modifying non-precious metal porphyrins at the <i>meso</i>-position is sufficient to further improve the ability to activate O<sub>2</sub> and the selectivity of the corresponding redox products. In this study, a crown ether-appended Fe(III) porphyrin complex (FeTC<sub>4</sub>PCl) was formed by replacing Fe(III) porphyrin (FeTPPCl) at the <i>meso</i>-position. The reactions of FeTPPCl and FeTC<sub>4</sub>PCl catalysed by O<sub>2</sub> oxidation of cyclohexene under different conditions were studied, and three main products, 2-cyclohexen-1-ol (<b>1</b>), 2-cyclohexen-1-one (<b>2</b>), and 7-oxabicyclo[4.1.0]heptane (<b>3</b>), were obtained. The effects of reaction temperature, reaction time, and the addition of axial coordination compounds on the reactions were investigated. The conversion of cyclohexene reached 94% at 70 °C after 12 h, and the selectivity toward product <b>1</b> was 73%. The geometrical structure optimization, molecular orbital energy level analysis, atomic charge, spin density, and density of orbital states analysis of FeTPPCl, FeTC<sub>4</sub>PCl, as well as the oxygenated complexes (Fe-O<sub>2</sub>)TCPPCl and (Fe-O<sub>2</sub>)TC<sub>4</sub>PCl formed after adsorption of O<sub>2,</sub> were carried out using the DFT method. The results of thermodynamic quantity variation with reaction temperature and Gibbs free energy variation were also analysed. Finally, based on experimental and theoretical analysis, the mechanism of the cyclohexene oxidation reaction with FeTC<sub>4</sub>PCl as a catalyst and O<sub>2</sub> as an oxidant was deduced, and the reaction mechanism was obtained as a free radical chain reaction process. Chemistry ; Cyclohexene ; Catalysis ; Porphyrin ; Gibbs free energy ; Selectivity ; Reaction mechanism ; Redox ; Photochemistry ; Density functional theory ; Crown ether ; Ether ; Physical chemistry ; Computational chemistry ; Inorganic chemistry ; Organic chemistry ; Thermodynamics ; Ion Porphyrin and Phthalocyanine Chemistry ; Metal-Catalyzed Oxygenation Mechanisms ; Free Radicals and Antioxidants
Authors: Toshikazu Kitagawa | Narimi Hanai | Takashi Kawano | Ayaka Tono | Hiroki Tabata | Tae Kobayashi | Katsuyuki Hirai | Takao Okazaki
Source: Journal of Physical Organic Chemistry (article, 2023-01-25)
Field: Chemistry — Spectroscopy

Metal‐ion sensor composed of self‐assembled monolayer of amine ligand formed by the use of molecular tripod Abstract The electrochemical ion‐sensor performance of the self‐assembled monolayer (SAM) of 3 H ‐imidazo[4,5‐ b ]pyridine, which is known as a metal ionophore, was examined using a triad composed of ferrocene, an ionophore, and a tripodal trithiol with adamantane core. The voltammetry of the SAM‐modified Au electrode showed a large positive change (280 mV) in the ferrocene oxidation potential via the addition of Pb 2+ , with a detection limit of 10 –6 M. A Langmuir adsorption‐type analysis of the ion binding equilibrium suggested that as much as 70% of the imidazopyridine ligand was actually functioning as a Pb 2+ ionophore on the SAM, whereas the rest of the ligand was uncomplexed because of the crowding of the molecules in the SAM. Control experiments using an analogous triad of monothiol revealed a strong advantage in using trithiol; thus, tripod‐shaped anchor is requisite for the ionophore to function well as a sensor. Chemistry ; Ionophore ; Monolayer ; Self-assembled monolayer ; Ligand (biochemistry) ; Molecule ; Crystallography ; Electrochemistry ; Ferrocene ; Tripod (photography) ; Cyclic voltammetry ; Inorganic chemistry ; Stereochemistry ; Physical chemistry ; Electrode ; Organic chemistry ; Calcium Molecular Sensors and Ion Detection ; Electrochemical Analysis and Applications ; Analytical Chemistry and Sensors
Authors: Л. Л. Гладков | D. V. Klenitsky | M. M. Kruk
Source: Organics (article, 2023-10-09)
Field: Materials Science — Materials Chemistry

Absorption Spectra of Protonated Corroles: Two Distinct Patterns Due to Peripheral Substitution Architecture The origin of individual features in the ground state absorption spectra of two protonated corroles differing in the architecture of peripheral substitution (either Cm-aryl or Cb-alkyl) have been studied in detail with the ground state absorption spectroscopy and density functional theory calculations. The geometry optimization, molecular orbitals and absorption spectra calculation have been carried out. It was found that protonation leads to the saddle type macrocycle conformation in contrast with the wave type conformation known for the parent-free base corroles. The mean plane deviation parameter Δ23 for the macrocycle, pyrrole tilting angles and the degree of pyramidalization λ2 of all four pyrrole nitrogens was found to depend on the peripheral substitution architecture. Macrocycle conformation of the protonated forms has distinct asymmetrical features which are reflected by the sets of values of the tilting angles and values of pyramidalization degree. The pair of pyrroles B and C has smaller tilting angles and higher pyramidalization degree values, whereas the opposite trend was found for the pair of pyrroles A and D. Electronic effects and structural differences induced by substitution lead to the pronounced shifts of the molecular orbitals. In the Cb-alkylated corrole, almost-degenerated HOMO and HOMO-1 molecular orbitals lead to enhancement of the configuration interaction. As a result, the Qx transition oscillator strength goes down, becoming comparable to that of the Qy one. A large HOMO-HUMO-1gap in the Cm-aryl corrole minimizes the configuration interaction, giving rise to Qx band domination in the visible range spectrum. Corrole ; Protonation ; Chemistry ; Absorption spectroscopy ; Density functional theory ; Crystallography ; Pyrrole ; Molecular orbital ; Computational chemistry ; Photochemistry ; Molecule ; Physics ; Organic chemistry Porphyrin and Phthalocyanine Chemistry ; Photochemistry and Electron Transfer Studies ; Spectroscopy and Quantum Chemical Studies
Authors: Shuo Wang | Xianrui Chen | Shuangsheng Xiong | Xiaoting Zhang | Li Hou | Qian Zhang | Yatao Wang | Faming Gao
Source: Catalysts (article, 2023-12-29)
Field: Chemistry — Organic Chemistry

Ru-Loaded Biphasic TiO2 Nanosheet-Tubes Enriched with Ti3+ Defects and Directionally Deficient Electrons as Highly Efficient Catalysts in Benzene Selective Hydrogenation Crystalline phase engineering is a prominent strategy for synergistically optimizing the surface–body phases of a catalyst. In this work, TiO2 nanosheets assembled into nanotubes (TNSTs) with two phases, anatase and rutile, were firstly synthesized via crystal engineering by simple thermal annealing. These were subsequently loaded with Ru nanoparticles, with a mean size of 5.0 nm, to create the efficient benzene hydrogenation catalyst Ru/TNSTs. The well-designed nanosheet-tube structure boasts a large specific surface area and excellent transmission channels, which effectively prevents the agglomeration and deactivation of loaded Ru nanoparticles, as well as promoting the internal diffusion in the reaction process of benzene hydrogenation to cyclohexene. Furthermore, titanium dioxide nanosheet-tubes contain numerous Ti3+ defects, which not only improves the overall conversion rate of cyclohexene but also enhances the suppression of cyclohexene adsorption. Most importantly, the titanium dioxide with its two-phase composition of 75 wt% anatase and 25 wt% rutile increases the ratio of electron deficiencies of Ru and promotes cyclohexene desorption. These synergistic properties enhance the selectivity and efficiency of the Ru/TNSTs catalysts, resulting in excellent performance in the hydrogenation of benzene to cyclohexene. In particular, the Ru/TNSTs-4 catalyst (annealed for 4 h), under the specific conditions of 140 °C temperature and 5 MPa hydrogen pressure for the hydrogenation process, achieves a 95% initial selectivity and 51% yield of cyclohexene in the reaction, outperforming most supported Ru-based catalysts. This work may provide new perspectives for designing efficient benzene hydrogenation catalysts via crystalline phase engineering. Nanosheet ; Cyclohexene ; Materials science ; Catalysis ; Chemical engineering ; Rutile ; Anatase ; Benzene ; Titanium dioxide ; Selectivity ; Inorganic chemistry ; Nanotechnology ; Chemistry ; Photocatalysis ; Organic chemistry ; Composite material Nanomaterials for catalytic reactions ; Caching and Content Delivery ; Catalysis and Hydrodesulfurization Studies
Authors: Ana M. Gómez | Lourdes Infantes | J. Ticona-Chambi | Eduardo Duque-Redondo | Leire Gartzia‐Rivero | Clara Uriel | Jorge Bañuelos | Inmaculada García‐Moreno | J. Cristobal López
Source: Journal of Molecular Liquids (article, 2023-12-09)
Field: Materials Science — Materials Chemistry

Naturally J-aggregated F-BODIPYs: Self-assembly organization driven by substitution pattern The development of self-assembled dyes able to display J-aggregation-induced emission has gained a renewed interest as an appealing and distinctive approach for the design of smart photoactive materials. F-BODIPY dyes have been exploited to this aim since J-type supramolecular organization has been effectively photoinduced under specific surrounding conditions (hydrophilic or constrained media) although, up to date, it has never been observed in pure organic media. Herein, we report the first systematic study of the self-assembly properties of F-BODIPYs in pure organic solvents and analyze in depth the control exerted by the substitution pattern of its carbon skeleton into the formation of emissive J-aggregates. Spontaneous J-aggregation in F-BODIPYs is evidenced by their lasing properties and supported by the analysis of their solid-state photophysics and X-ray crystalline packing as well as by molecular dynamics in solvent cages. These studies point out the key role of the stereoelectronic properties of the substituents orthogonally grafted at the dipyrrin core (meso and C-2 and C-6 positions) as the main driving force to control the molecular stacking arrangement of F-BODIPYs in common organic solvents. The understanding of the interplay between the molecular structure and the properties of the resulting aggregates sheds light on the workability of BODIPY-based self-assembly as a tool for advanced luminescent materials. Stacking ; BODIPY ; Aggregation-induced emission ; Supramolecular chemistry ; Chemistry ; Luminescence ; Lasing threshold ; Self-assembly ; Solvent ; J-aggregate ; Photochemistry ; Nanotechnology ; Molecule ; Materials science ; Organic chemistry ; Fluorescence Luminescence and Fluorescent Materials ; Porphyrin and Phthalocyanine Chemistry ; Supramolecular Chemistry and Complexes
Authors: Masatoshi Maeki | Niko Kimura | Yuto Okada | Kazuki Shimizu | Kana Shibata | Yusuke Miyazaki | Akihiko Ishida | Kento Yonezawa | Nobutaka Shimizu | Wataru Shinoda | Manabu Tokeshi
Source: ChemRxiv (preprint, 2023-06-09)
Field: Materials Science — Biomaterials

Understanding the effects of ethanol on structural changes in liposomes using microfluidic-based time-resolved small-angle X-ray scattering and MD simulations Lipid nanoparticles (LNPs) are essential carrier particles in drug delivery systems, particularly in ribonucleic acid delivery. In preparing lipid-based nanoparticles, microfluidic-based ethanol injection may produce precisely size-controlled nanoparticles. Ethanol is critical in LNP formation and post-treatment processes and affects liposome size, structure, lamellarity, and drug-loading efficiency. However, the effects of time-dependent changes in the ethanol concentration on the structural dynamics of liposomes are not clearly understood. Herein, we investigated ethanol-induced structural changes in liposomes on a time scale from microseconds to tens of seconds using a microfluidic-based small-angle X-ray scattering (SAXS) measurement system coupled with molecular dynamics (MD) simulations. The time-resolved SAXS measurement system revealed that single unilamellar liposomes converted to multilamellar liposomes within 0.8 s of contact with ethanol, and the d-spacing was decreased from 6.1 (w/o ethanol) to 4.4 nm (80% ethanol) with increasing ethanol concentration. We conducted 1 µs MD simulations to understand the molecular-level structural changes in the liposomes. The MD simulations revealed that the changes in the lamellar structure caused by ethanol at the molecular level could explain the structural changes in the liposomes observed via time-resolved SAXS. Therefore, the post-treatment process to remove residual ethanol is critical in liposome formation. Small-angle X-ray scattering ; Liposome ; Molecular dynamics ; Microfluidics ; Ethanol ; Lamellar structure ; Dynamic light scattering ; Nanoparticle ; Chemistry ; Drug delivery ; Materials science ; Pulmonary surfactant ; Scattering ; Chemical physics ; Chemical engineering ; Nanotechnology ; Biophysics ; Chromatography ; Crystallography ; Organic chemistry ; Optics ; Biochemistry ; Computational chemistry Nanoparticle-Based Drug Delivery ; Characterization and Applications of Magnetic Nanoparticles ; HIV-related health complications and treatments
Authors: Michael Arkas | Theofanis Bompotis | Κωνσταντίνος Γιαννακόπουλος | Evangelos P. Favvas | Marina Arvanitopoulou | Konstantinos Arvanitopoulos | Labros Arvanitopoulos | Georgia Kythreoti | M. Vardavoulias | Dimitrios A. Giannakoudakis | Laura Castellsagués | Sara M. Soto
Source: Preprints.org (preprint, 2023-07-25)
Field: Materials Science — Biomaterials

Hybrid Silica Xerogel and Titania/Silica Xerogel Dispersions Reinforcing Hydrophilicity and Antimicrobial Resistance of Leathers Four leather substrates from different animals were treated by dispersions containing hydrophilic composite silica-hyperbranched poly(ethylene imine) xerogels. Antimicrobial activity was introduced by incorporating silver nanoparticles and /or benzalkonium chloride. The gel precursor solutions were also infused before gelation to titanium oxide powders typically employed for induction of self-cleaning properties. The dispersions from these biomimetically premade xerogels integrate environmentally friendly materials with short coating times. Scanning electron microscopy (SEM) provided information on the powder distribution onto the leathers. Substrate and coating composition were estimated by infrared spectroscopy (IR) and ener-gy-dispersive X-ray spectroscopy (EDS). Surface hydrophilicity and water permeability were assessed by water-contact angle experiments. The diffusion of the leather&amp;#039;s initial components and xerogel additives into the water were measured by Ultraviolet-Visible (UV-Vis) spectroscopy. Protection against GRAM- bacteria was tested for Escherichia coli, Pseudomonas aeruginosa, and Klebsiella Pneumoniae against GRAM+ bacteria for Staphylococcus aureus, and Enterococcus faecalis and against fungi for Candida albicans. Antibiofilm capacity experiments were performed against Staphylococcus aureus, Klebsiella Pneumoniae, Enterococcus faecalis, and Candida albicans. The application of xerogel dispersions proved an adequate and economically feasible alternative to the direct gel formation into the substrate’s pores for the preparation of leathers intended for medical uses Enterococcus faecalis ; Materials science ; Chemical engineering ; Coating ; Scanning electron microscope ; Nuclear chemistry ; Chemistry ; Nanotechnology ; Composite material ; Escherichia coli Collagen: Extraction and Characterization ; Polymer Surface Interaction Studies ; biodegradable polymer synthesis and properties
Authors: Semyon V. Tsybulin | Ekaterina A. Filatova | А. Ф. Пожарский | Valery A. Ozeryanskii | Anna V. Gulevskaya
Source: Beilstein Journal of Organic Chemistry (article, 2023-05-15)
Field: Chemistry — Organic Chemistry

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene A set of novel 1,4-diaryl-1,3-butadiynes terminated by two 7-(arylethynyl)-1,8-bis(dimethylamino)naphthalene fragments was prepared via the Glaser–Hay oxidative dimerization of 2-ethynyl-7-(arylethynyl)-1,8-bis(dimethylamino)naphthalenes. The oligomers synthesized in this way are cross-conjugated systems, in which two conjugation pathways are possible: π-conjugation of 1,8-bis(dimethylamino)naphthalene (DMAN) fragments through a butadiyne linker and a donor–acceptor aryl–C≡C–DMAN conjugation path. The conjugation path can be “switched” simply by protonation of DMAN fragments. X-ray diffraction, UV–vis spectroscopy and cyclic voltammetry are applied to analyze the extent of π-conjugation and the efficiency of particular donor–acceptor conjugation path in these new compounds. X-ray structures and absorption spectra of doubly protonated tetrafluoroborate salts of the oligomers are also discussed. Chemistry ; Conjugated system ; Naphthalene ; Protonation ; Linker ; Tetrafluoroborate ; Cyclic voltammetry ; Aryl ; Acceptor ; Photochemistry ; Medicinal chemistry ; Stereochemistry ; Organic chemistry ; Alkyl ; Electrochemistry ; Polymer ; Ion Synthesis and Properties of Aromatic Compounds ; Organic Electronics and Photovoltaics ; Synthesis of Indole Derivatives
Authors: Ru Feng | Zuoxu Chen | Yue Wang | Jianming Pan | Soji Shimizu
Source: Molecules (article, 2023-12-05)
Field: Materials Science — Materials Chemistry

Facile Synthesis of Asymmetric aza-Boron Dipyrromethene Analogues Bearing Quinoxaline Moiety An asymmetric aza-BODIPY analogue bearing quinoxaline moiety was synthesized via a titanium tetrachloride-mediated Schiff-base-forming reaction of 6,7-dimethyl-1,4-dihydroquinoxaline-2,3-dione and benzo[<i>d</i>]thiazol-2-amine. This novel aza-BODIPY analogue forms a complementary hydrogen-bonded dimer due to the quinoxaline moiety in the crystal structure. It also shows intense absorption and fluorescence, with fluorescence quantum yields close to unity. The electrochemical measurements and the DFT calculations revealed the presence of the low-lying HOMO, which benefits their potential applications as an electron-transporting material. Quinoxaline ; Moiety ; Chemistry ; BODIPY ; Fluorescence ; Photochemistry ; Schiff base ; Dimer ; Stereochemistry ; Combinatorial chemistry ; Organic chemistry Luminescence and Fluorescent Materials ; Molecular Sensors and Ion Detection ; Advanced biosensing and bioanalysis techniques