jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Nighat Yousuf | Yanping Ma | Qaiser Mahmood | Wenjuan Zhang | Yizhou Wang | Hassan Saeed | Wen‐Hua Sun
Source: Dalton Transactions (article, 2023-11-30)
Field: Chemistry — Organic Chemistry

Enhancing isoprene polymerization with high activity and adjustable monomer enchainment using cyclooctyl-fused iminopyridine iron precatalysts In this study, a series of structurally rigid cyclooctyl-fused iminopyridine iron complexes, [L<sub>2</sub>FeCl][FeCl<sub>4</sub>] and [2L<sub>3</sub>Fe][Cl][3FeCl<sub>4</sub>], was synthesized <i>via</i> a one-pot method and investigated as precatalysts in conjunction with methylaluminoxane for isoprene (Ip) polymerization. Combined characterization through FTIR analysis, elemental analysis and single crystal XRD analysis fully verified the structure of these complexes. The most active iron complex, FeH, exhibited a trisligated nature, with its cation adopting an octahedral geometry around the metal center. In contrast, all the other iron complexes (Fe2Me, Fe2Et, Fe2iPr, Fe3Me, Fe2Et,Me) displayed bisligated configurations, with distorted trigonal bipyramidal geometry of cations. During isoprene polymerization, the extent of steric hindrance of the ligand framework exerted a significant impact on catalytic performance. The FeH precatalyst with less steric hindrance demonstrated excellent performance, producing high molecular weight polyisoprenes with conversions exceeding 99% for 4000 equiv. of monomer. Even at very low catalyst loadings, as low as 0.0025 mol% (Fe/Ip), the polymerization of isoprene could proceed smoothly with an exceptionally high activity of 4.0 × 10<sup>6</sup> g<sub>PI</sub> (mol<sub>Fe</sub>, h)<sup>-1</sup>. Moreover, this precatalyst exhibited good thermal stability, maintaining high activity levels (typically 10<sup>5</sup> g<sub>PI</sub> (mol<sub>Fe</sub>, h)<sup>-1</sup>) across a broad temperature range from -20 °C to 100 °C. Additionally, by adjusting steric substituents and the reaction temperature, the 1,4/3,4 regioselectivity could be modulated from 9/91 to 69/31 while maintaining a high stereoselectivity of <i>cis</i>-1,4 structures (<i>cis</i>/<i>trans</i>: >99/1). Isoprene ; Steric effects ; Chemistry ; Polymerization ; Trigonal bipyramidal molecular geometry ; Monomer ; Ligand (biochemistry) ; Catalysis ; Polymer chemistry ; Octahedral molecular geometry ; Thermal stability ; Crystal structure ; Crystallography ; Stereochemistry ; Organic chemistry ; Copolymer ; Polymer Organometallic Complex Synthesis and Catalysis ; Synthetic Organic Chemistry Methods ; Carbon dioxide utilization in catalysis
Authors: Adrián Saura-Sanmartín | Laura Andreu-Ardil
Source: International Journal of Molecular Sciences (review, 2023-02-28)
Field: Chemistry — Organic Chemistry

Recent Advances in the Preparation of Delivery Systems for the Controlled Release of Scents Scents are volatile compounds highly employed in a wide range of manufactured items, such as fine perfumery, household products, and functional foods. One of the main directions of the research in this area aims to enhance the longevity of scents by designing efficient delivery systems to control the release rate of these volatile molecules and also increase their stability. Several approaches to release scents in a controlled manner have been developed in recent years. Thus, different controlled release systems have been prepared, including polymers, metal-organic frameworks and mechanically interlocked systems, among others. This review is focused on the preparation of different scaffolds to accomplish a slow release of scents, by pointing out examples reported in the last five years. In addition to discuss selected examples, a critical perspective on the state of the art of this research field is provided, comparing the different types of scent delivery systems. Delivery system ; Nanotechnology ; Controlled release ; Computer science ; Biochemical engineering ; Materials science ; Engineering ; Biomedical engineering Advanced Polymer Synthesis and Characterization ; Pickering emulsions and particle stabilization ; biodegradable polymer synthesis and properties
Authors: Fabrizio Medici | Simonetta Resta | Stefano Andolina | Maurizio Benaglia
Source: Catalysts (article, 2023-05-28)
Field: Chemistry — Organic Chemistry

Recent Advances in Enantioselective Catalytic Electrochemical Organic Transformations Different approaches can be undertaken to realise a stereoselective electrochemical synthesis. Significant contributions to enantioselective electrochemical organic synthesis have been reported and largely reviewed in recent years. However, the development of general strategies for the electrochemical enantiocontrol of a transformation still presents considerable challenges; in particular, relatively few contributions of highly enantioselective catalytic electrochemical reactions have been reported to date. In this review article, the most recent examples of asymmetric electrochemical catalysis are discussed. The article is organised by the three types of enantioselective catalysis: metal-based catalysis, organocatalysis and biocatalysis; in each section, the most significant and recent advances are presented and discussed. Enantioselective synthesis ; Organocatalysis ; Catalysis ; Electrochemistry ; Organic synthesis ; Combinatorial chemistry ; Biocatalysis ; Chemistry ; Biochemical engineering ; Nanotechnology ; Organic chemistry ; Materials science ; Reaction mechanism ; Electrode ; Engineering Radical Photochemical Reactions ; Asymmetric Hydrogenation and Catalysis ; Asymmetric Synthesis and Catalysis
Authors: Jiaqi Liang | Shuai Lu | Yang Yang | Yun‐Jia Shen | Jin-Ku Bai | Xin Sun | Xu‐Lang Chen | Jie Cui | Aijiao Guan | Junfeng Xiang | Xiaopeng Li | Heng Wang | Yu‐Dong Yang | Han‐Yuan Gong
Source: Nature Communications (article, 2023-12-09)
Field: Chemistry — Organic Chemistry

Thermally-induced atropisomerism promotes metal-organic cage construction Molecular folding regulation with environmental stimuli is critical in living and artificial molecular machine systems. Herein, we described a macrocycle, cyclo[4] (1,3-(4,6-dimethyl)benzene)[4](1,3-(4,6-dimethyl)benzene)(4-pyridine). Under 298 K, it has three stable stiff atropisomers with names as 1 (C<sub>s</sub> symmetry), 2 (C<sub>s</sub> symmetry), and 3 (C<sub>4v</sub> symmetry). At 393 K, 1 can reversibly transform into 2, but at 473 K, it can irrevocably transform into 3. At 338 K, 3 and (PhCN)<sub>2</sub>PdCl<sub>2</sub> complex to produce the metal-organic cage 4. Only at 338 K does the combination of 1 or 2 and (PhCN)<sub>2</sub>PdCl<sub>2</sub> create a gel-like structure. Heating both gels to 473 K transforms them into 4. In addition to offering a thermally accelerated method for modifying self-assembled systems using macrocyclic building blocks, this study also has the potential to develop the nanoscale transformation material with a thermal response. Atropisomer ; Benzene ; Pyridine ; Metal ; Biphenyl ; Chemistry ; Cage ; Folding (DSP implementation) ; Symmetry (geometry) ; Molecular machine ; Materials science ; Crystallography ; Nanotechnology ; Stereochemistry ; Organic chemistry ; Mathematics ; Geometry ; Mechanical engineering Supramolecular Chemistry and Complexes ; Supramolecular Self-Assembly in Materials ; Dendrimers and Hyperbranched Polymers
Authors: Shubhanth Jain | V. Vedavyas | R. V. Prajwal | Malavika Shaji | Vishnu G Nath | S. Angappane | A. Govindaraj
Source: Frontiers in Chemistry (review, 2023-03-20)
Field: Materials Science — Biomaterials

Silk and its composites for humidity and gas sensing applications Silk fibroin (SF) is a natural protein largely used in the textile industry with applications in bio-medicine, catalysis as well as in sensing materials. SF is a fiber material which is bio-compatible, biodegradable, and possesses high tensile strength. The incorporation of nanosized particles into SF allows the development of a variety of composites with tailored properties and functions. Silk and its composites are being explored for a wide range of sensing applications like strain, proximity, humidity, glucose, pH and hazardous/toxic gases. Most studies aim at improving the mechanical strength of SF by preparing hybrids with metal-based nanoparticles, polymers and 2D materials. Studies have been conducted by introducing semiconducting metal oxides into SF to tailor its properties like conductivity for use as a gas sensing material, where SF acts as a conductive path as well as a substrate for the incorporated nanoparticles. We have reviewed gas and humidity sensing properties of silk, silk with 0D (i.e., metal oxide), 2D (e.g., graphene, MXenes) composites. The nanostructured metal oxides are generally used in sensing applications, which use its semiconducting properties to show variation in the measured properties (e.g., resistivity, impedance) due to analyte gas adsorption on its surface. For example, vanadium oxides (i.e., V<sub>2</sub>O<sub>5</sub>) have been shown as candidates for sensing nitrogen containing gases and doped vanadium oxides for sensing CO gas. In this review article we provide latest and important results in the gas and humidity sensing of SF and its composites. Materials science ; SILK ; Composite material ; MXenes ; Fibroin ; Graphene ; Nanocomposite ; Nanoparticle ; Oxide ; Ultimate tensile strength ; Chemiresistor ; Nanotechnology ; Metallurgy Silk-based biomaterials and applications ; Advanced Sensor and Energy Harvesting Materials ; ZnO doping and properties
Authors: Dmitry E. Shybanov | Maxim E. Kukushkin | Yanislav S. Hrytseniuk | Yuri K. Grishin | Vitaly A. Roznyatovsky | В. А. Тафеенко | Dmitry A. Skvortsov | N. V. Zyk | Елена К. Белоглазкина
Source: International Journal of Molecular Sciences (article, 2023-03-06)
Field: Chemistry — Organic Chemistry

[4+2]-Cycloaddition to 5-Methylidene-Hydantoins and 5-Methylidene-2-Thiohydantoins in the Synthesis of Spiro-2-Chalcogenimidazolones Novel hydantion and thiohydantoin-based spiro-compounds were prepared via theDiels-Alder reactions between 5-methylidene-hydantoins or 5-methylidene-2-thiohydantoins and 1,3-dienes (cyclopentadiene, cyclohexadiene, 2,3-dimethylbutadiene, isoprene). It was shown that the cycloaddition reactions proceed regioselectively and stereoselectively with the formation of exo-isomers in the reactions with cyclic dienes andthe less sterically hindered products in the reactions with isoprene. Reactions of methylideneimidazolones with cyclopentadiene proceed viaco-heating the reactants; reactions with cyclohexadiene, 2,3-dimethylbutadiene, and isoprene require catalysis by Lewis acids. It was demonstrated that ZnI<sub>2</sub> is an effective catalyst in the Diels-Alder reactions of methylidenethiohydantoins with non-activated dienes. The possibility of alkylation and acylation of the obtained spiro-hydantoinsat the N(1)nitrogen atoms with PhCH<sub>2</sub>Cl or Boc<sub>2</sub>O and the alkylation of the spiro-thiohydantoinsat the S atoms with MeI or PhCH<sub>2</sub>Cl in high yields have been demonstrated. The preparativetransformation of spiro-thiohydantoins into corresponding spiro-hydantoinsin mild conditions by treating with 35% aqueous H<sub>2</sub>O<sub>2</sub> or nitrile oxide has been carried out. The obtained compounds show moderate cytotoxicity in the MTT test on MCF7, A549, HEK293T, and VA13 cell lines. Some of the tested compounds demonstrated some antibacterial effect against <i>Escherichia coli</i> (<i>E. coli</i>) BW25113 DTC-pDualrep2 but were almost inactive against <i>E. coli</i> BW25113 LPTD-pDualrep2. Cycloaddition ; Chemistry ; Combinatorial chemistry ; Stereochemistry ; Organic chemistry ; Catalysis Synthesis and Characterization of Heterocyclic Compounds ; Synthesis and biological activity ; Synthesis of heterocyclic compounds
Authors: Subhendu Dhibar | Baishakhi Pal | Kripasindhu Karmakar | Sanϳay Roy | Sk Abdul Hafiz | Arpita Roy | Subham Bhattacharjee | Soumya Jyoti Ray | Partha Pratim Ray | Bidyut Saha
Source: Nanoscale Advances (article, 2023-01-01)
Field: Materials Science — Biomaterials

A 5-aminoisophthalic acid low molecular weight gelator based novel semiconducting supramolecular Zn(<scp>ii</scp>)-metallogel: unlocking an efficient Schottky barrier diode for microelectronics A novel method has been successfully developed for creating supramolecular metallogels using zinc(ii) ions and 5-aminoisophthalic acid as the gelator (low molecular weight gelator) in a dimethylformamide (DMF) solvent at room temperature. Comprehensive rheological investigations confirm the robust mechanical strength of the resulting zinc(ii)-metallogel. Microstructural analysis conducted through field-emission scanning electron microscopy (FESEM) unveils a unique flake-like morphology, with energy-dispersive X-ray (EDX) elemental mapping confirming the prevalence of zinc as the primary constituent of the metallogel. To understand the formation mechanism of this metallogel, Fourier-transform infrared (FT-IR) spectroscopy was employed. Notably, these supramolecular zinc(ii)-metallogel assemblies exhibit electrical conductivity reminiscent of metal-semiconductor (MS) junction electronic components. Surprisingly, the metallogel-based thin film device showcases an impressive electrical conductivity of 1.34 × 10<sup>-5</sup> S m<sup>-1</sup>. The semiconductor characteristics of the synthesized zinc(ii)-metallogel devices, including their Schottky barrier diode properties, have been extensively investigated. This multifaceted study opens up a promising avenue for designing functional materials tailored for electronic applications. It harnesses the synergistic properties of supramolecular metallogels and highlights their significant potential in the development of semiconductor devices. This work represents a novel approach to the creation of advanced materials with unique electronic properties, offering exciting prospects for future innovations in electronic and semiconductor technologies. Materials science ; Semiconductor ; Zinc ; Supramolecular chemistry ; Nanotechnology ; Schottky diode ; Nanoporous ; Microelectronics ; Schottky barrier ; Fourier transform infrared spectroscopy ; Conductivity ; Diode ; Chemical engineering ; Optoelectronics ; Chemistry ; Molecule ; Organic chemistry ; Metallurgy ; Physical chemistry Supramolecular Self-Assembly in Materials ; Peptidase Inhibition and Analysis ; Nonlinear Optical Materials Research
Authors: Petr Rozhin | Slavko Kralj | Brigitte Soula | Silvia Marchesan | Emmanuel Flahaut
Source: Nanomaterials (article, 2023-02-24)
Field: Materials Science — Biomaterials

Hydrogels from a Self-Assembling Tripeptide and Carbon Nanotubes (CNTs): Comparison between Single-Walled and Double-Walled CNTs Supramolecular hydrogels obtained from the self-organization of simple peptides, such as tripeptides, are attractive soft materials. Their viscoelastic properties can be enhanced through the inclusion of carbon nanomaterials (CNMs), although their presence can also hinder self-assembly, thus requiring investigation of the compatibility of CNMs with peptide supramolecular organization. In this work, we compared single-walled carbon nanotubes (SWCNTs) and double-walled carbon nanotubes (DWCNTs) as nanostructured additives for a tripeptide hydrogel, revealing superior performance by the latter. Several spectroscopic techniques, as well as thermogravimetric analyses, microscopy, and rheology data, provide details to elucidate the structure and behavior of nanocomposite hydrogels of this kind. Carbon nanotube ; Self-healing hydrogels ; Tripeptide ; Materials science ; Nanomaterials ; Nanocomposite ; Nanotechnology ; Supramolecular chemistry ; Carbon nanobud ; Rheology ; Thermogravimetric analysis ; Chemical engineering ; Composite material ; Polymer chemistry ; Nanotube ; Optical properties of carbon nanotubes ; Organic chemistry ; Chemistry ; Peptide ; Molecule Supramolecular Self-Assembly in Materials ; Polydiacetylene-based materials and applications ; Luminescence and Fluorescent Materials
Authors: Telma Costa | Mariana Peixoto | Marta Piñeiro | J. Sérgio Seixas de Melo
Source: Langmuir (article, 2023-04-12)
Field: Materials Science — Materials Chemistry

Solvent-Driven Self-Organization of <i>Meso</i>-Substituted Porphyrins: Morphological Analysis from Fluorescence Lifetime Imaging Microscopy A morphological analysis of different thin films of <i>meso</i>-tetra-<i>p</i>-(di-<i>p</i>-phenylamino)phenylporphyrin, <b>H</b><sub><b>2</b></sub><b>T(TPA)</b><sub><b>4</b></sub><b>P</b>, was made by fluorescence lifetime imaging microscopy (FLIM) and scanning electron microscopy (SEM). A comprehensive study of <b>H</b><sub><b>2</b></sub><b>T(TPA)</b><sub><b>4</b></sub><b>P</b> was undertaken through UV/vis absorption and fluorescence techniques in different solvents, solvent mixtures and in thin films. In solution, occurrence of intramolecular energy transfer from the triphenylamine (TPA) moieties to the porphyrin core, with quenching efficiencies in the order of 94-97%, is observed. The energy transfer rate constants are determined assuming Förster's dipole-dipole and Dexter's electron exchange mechanisms. In drop-cast-prepared thin films, from samples with different solvent mixtures, the photoluminescence (PL) quantum yield (Φ<sub>PL</sub>) decreases ∼1 order of magnitude compared to the solution behavior. FLIM and SEM experiments showed the self-organization and morphology of <b>H</b><sub><b>2</b></sub><b>T(TPA)</b><sub><b>4</b></sub><b>P</b> in thin films to be highly dependent on the solvent mixture used to prepare the film. In chloroform, the solvent's evaporation results in the formation of elongated and overlapped microrod structures. Introduction of a cosolvent, namely, a polar cosolvent, promotes changes in the morphology of the self-assembled structures, with the formation of three-dimensional spherical structures and hollow spheres. <b>H</b><sub><b>2</b></sub><b>T(TPA)</b><sub><b>4</b></sub><b>P</b> dispersed in a polymer matrix shows enhanced Φ<sub>PL</sub> values when compared to the drop-cast films. FLIM images showed coexistence of three different states or domains: aggregated, interface, and nonaggregated or less-aggregated states. This work highlights the importance of FLIM in the morphological characterization of heterogeneous films, together with the photophysical characterization of nano- and microdomains. Photoluminescence ; Materials science ; Solvent ; Fluorescence ; Scanning electron microscope ; Analytical Chemistry (journal) ; Chemical engineering ; Chemistry ; Organic chemistry ; Optics Porphyrin and Phthalocyanine Chemistry ; Photochemistry and Electron Transfer Studies ; Photodynamic Therapy Research Studies
Authors: Craig Hardy | Martin E. Levere | Gabriele Kociok‐Köhn | Antoine Buchard
Source: ACS Macro Letters (article, 2023-10-12)
Field: Materials Science — Biomaterials

Radical Ring Opening Polymerization of Cyclic Ketene Acetals Derived From <scp>d</scp>-Glucal A cyclic ketene acetal (CKA) derived from d-glucal was synthesized, and its polymerization using free radicals has been investigated. NMR analysis of the resulting polymers revealed the formation of polyacetal-polyester copolymers, with up to 78% of ester linkages formed by radical ring-opening polymerization (rROP). Conversely, the polymerization of the monomer-saturated analogue only produced acetal linkages, demonstrating that the alkene functionality within the d-glucal pyranose ring is essential to promote ring-opening and ester formation, likely via the stabilization of an allyl radical. The thermal properties of the polymers were linked to the ratio of the ester and acetal linkages. Copolymerization with methyl methacrylate (MMA) afforded statistically PMMA-rich copolymers (66-98%) with linkages prone to hydrolytic degradation and decreased glass-transition temperatures. The retention of the pseudoglucal alkene function offers opportunities to functionalize further these bioderived (co)polymers. Ketene ; Acetal ; Polymer chemistry ; Polymerization ; Glucal ; Radical polymerization ; Copolymer ; Alkene ; Ring-opening polymerization ; Polymer ; Materials science ; Monomer ; Chemistry ; Organic chemistry ; Catalysis biodegradable polymer synthesis and properties ; Microplastics and Plastic Pollution ; Advanced Polymer Synthesis and Characterization
Authors: Enock Olugbenga Dare | Temilade F. Akinhanmi | Jimoh Ademola Aremu | Olayide R. Adetunji | J. T. Bamgbose | Victoria Vendrell‐Criado | M. Consuelo Jiménez | Raúl Pérez–Ruíz | Sebastián Bonardd | David Díaz Díaz
Source: Photochemical & Photobiological Sciences (article, 2023-03-16)
Field: Chemistry — Spectroscopy

Dual-mode colorimetric/fluorescent chemosensor for Cu2+/Zn2+ and fingerprint imaging based on rhodamine ethylenediamine bis(triazolyl silsesquioxane) A novel dual functional and visual rhodamine ethylenediamine bis(triazolyl silsesquioxane) (RBS) chemosensor was successfully synthesized using "click" chemistry. The results have unambiguously demonstrated that RBS can act in fluorescent and colorimetric sensing of Cu<sup>2+</sup> and Zn<sup>2+</sup> by their respective coordination with triazole structures and, more importantly, it has also been found that triazole-amide of RBS could turn on chelation-enhanced fluorescence (CHEF) of Cu<sup>2+</sup>. Remarkably, the addition of Cu<sup>2+</sup> triggered an enhanced fluorescent emission by 63.3-fold (ϕ<sub>F</sub> = 0.41), while Zn<sup>2+</sup> enhanced it 48.3-fold (ϕ<sub>F</sub> = 0.29) relative to the original RBS (ϕ<sub>F</sub> = 0.006) in acetonitrile (MeCN) solvent. The fluorescent limit of detection for Cu<sup>2+</sup> and Zn<sup>2+</sup> is similar and fall within 3.0 nM, while under colorimetric sensing the responses were 2.14 × 10<sup>-8</sup> and 4.0 × 10<sup>-8</sup> mol L<sup>-1</sup>, respectively. Moreover, the effective sensing profile of RBS and extended applications of RBS-Cu<sup>2+</sup> and RBS-Zn<sup>2+</sup> for fingerprinting detection and imaging were observed with adequate sensitivity, stability and legibility under the dual visual responses. Fluorescence ; Ethylenediamine ; Silsesquioxane ; Chemistry ; Chelation ; Rhodamine ; Triazole ; Detection limit ; Chromatography ; Polymer ; Inorganic chemistry ; Organic chemistry Molecular Sensors and Ion Detection ; Luminescence and Fluorescent Materials ; Silicone and Siloxane Chemistry