jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Grant J. Strachan | Magdalena Majewska | Damian Pociecha | John M. D. Storey | Corrie T. Imrie
Source: ChemPhysChem (article, 2022-11-30)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Using Lateral Substitution to Control Conformational Preference and Phase Behaviour of Benzanilide‐based Liquid Crystal Dimers The inclusion of secondary and tertiary benzanilide-based mesogenic groups into liquid crystal dimers is reported as a means to develop new materials. Furthermore, substitution at the nitrogen atom is shown to introduce an additional synthetic 'handle' to modify the molecular structure of the tertiary materials. The design of these materials has proved challenging due to the strong preferences of 3° benzanilides for the E amide conformation. In this work, lateral substitution is used to modify the conformational preferences of the amide linkage and promote liquid crystallinity for a series of N-methyl benzanilide dimers. As the proportion of the E conformer decreases, the nematic-isotropic transition temperatures increase, and enantiotropic nematic behaviour is observed. We also report the synthesis and characterisation of the analogous 2° benzanilide-based materials, which show nematic and twist-bend nematic behaviour. This approach highlights the effects that seemingly small structural modifications, such as the inclusion and position of a methyl group, can have on molecular shape and hence, liquid crystalline behaviour. Liquid crystal ; Mesogen ; Amide ; Crystallography ; Materials science ; Conformational isomerism ; Chemistry ; Molecule ; Stereochemistry ; Organic chemistry ; Liquid crystalline Liquid Crystal Research Advancements ; Photonic Crystals and Applications ; Synthesis and Properties of Aromatic Compounds
Authors: Ke Yan | Bin Chen | Mengen Hu | Ningning Zhou | Zhulin Huang | Guowen Meng
Source: Nanomaterials (article, 2022-03-31)
Field: Materials Science — Electronic, Optical and Magnetic Materials

In-Situ Monitoring the SERS Spectra of para-Aminothiophenol Adsorbed on Plasmon-Tunable Au@Ag Core–Shell Nanostars Plasmon-induced photocatalysis on noble metal surfaces has attracted broad attention due to its application in sunlight energy conversion, while the selectivity of plasmonic platforms remains unclear. Herein, we present the controlled plasmon-mediated oxidation of para-aminothiophenol (<i>p</i>-ATP) by employing Au@Ag core-shell nanostars with tunable tip plasmons in visible-near-infrared range as reactors. In-situ Raman measurements indicate that Au@Ag core-shell nanostars essentially promote the conversion of <i>p</i>-ATP to 4,4'-dimercaptoazobenzene (DMAB) due to hot carriers excited by localized surface plasmon resonance. Au@Ag nanostars with plasmon modes under resonant light excitation suggested higher catalytic efficiency, as evidenced by the larger intensity ratios between 1440 cm<sup>-1</sup> (N=N stretching of DMAB) and 1080 cm<sup>-1</sup> shifts (C-S stretching of <i>p</i>-ATP). Importantly, the time-dependent surface-enhanced Raman scattering spectra showed that the conversion efficiency of <i>p</i>-ATP was mainly dictated by the resonance condition between the tip plasmon mode of Au@Ag core-shell nanostars and the excitation light, as well as the choice of excitation wavelength. These results show that plasmon bands of metal nanostructures play an important role in the efficiency of plasmon-driven photocatalysis. Plasmon ; Surface plasmon resonance ; Materials science ; Raman scattering ; Photocatalysis ; Localized surface plasmon ; Surface plasmon ; Photochemistry ; Raman spectroscopy ; Excitation ; Noble metal ; Optoelectronics ; Nanotechnology ; Nanoparticle ; Metal ; Chemistry ; Optics ; Catalysis Gold and Silver Nanoparticles Synthesis and Applications ; Advanced Photocatalysis Techniques ; Copper-based nanomaterials and applications
Authors: Ester Sans-Panadés | Juan J. Vaquero | Manuel A. Fernández‐Rodríguez | Patricia García‐García
Source: Organic Letters (article, 2022-08-01)
Field: Chemistry — Organic Chemistry

Synthesis of BN-Polyarenes by a Mild Borylative Cyclization Cascade Reaction of BCl<sub>3</sub> with suitably substituted <i>o</i>-alkynylanilines promotes a cascade reaction in which BN-polycyclic compounds are obtained via the formation of two new cycles and three new bonds in a single operational step. The reaction is highly efficient and takes place at room temperature, providing a very mild and straightforward strategy for the preparation of BN-aromatic compounds, which can be further transformed into a variety of BN-PAHs with different polycyclic cores and substituents. Chemistry ; Cascade ; Reaction conditions ; Combinatorial chemistry ; Cascade reaction ; Computational chemistry ; Organic chemistry ; Catalysis Organoboron and organosilicon chemistry ; Catalytic Cross-Coupling Reactions ; Chemical Synthesis and Analysis
Authors: Egor V. Gorshkov | Денис В. Корчагин | E. A. Yur’eva | G.V. Shilov | Mikhail V. Zhidkov | A. I. Dmitriev | Nikolay N. Efimov | Andrew Palii | С. М. Алдошин
Source: Magnetochemistry (article, 2022-11-07)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Effect of Ligand Substitution on Zero-Field Slow Magnetic Relaxation in Mononuclear Dy(III) β-Diketonate Complexes with Phenanthroline-Based Ligands Herein, we report the synthesis, structure and magnetic properties of two mononuclear complexes of general formula [Dy(acac)3(L)], where L = 2,2-dimethyl-1,3-dioxolo[4,5-f][1,10] phenanthroline (1) or 1,10-phenanthroline-5,6-dione (2), and acac− = acetylacetonate anion. A distorted square-antiprismatic N2O6 environment around the central Dy(III) ion is formed by three acetylacetonate anions and a phenanthroline-type ligand. Both complexes display a single-molecule magnet (SMM) behavior at zero applied magnetic field. Modification of the peripheral part of ligands L provide substantial effects both on the magnetic relaxation barrier Ueff and on the quantum tunneling of magnetization (QTM). Ab initio quantum-chemical calculations are used to analyze the electronic structure and magnetic properties. Phenanthroline ; Chemistry ; Magnetization ; Ligand (biochemistry) ; Relaxation (psychology) ; Crystallography ; Quantum tunnelling ; Ion ; Ab initio ; Ab initio quantum chemistry methods ; Magnetic field ; Molecule ; Computational chemistry ; Condensed matter physics ; Physics ; Organic chemistry ; Receptor Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Electron Spin Resonance Studies
Authors: Margarita A. Sadovnikova | Fadis F. Murzakhanov | G. V. Mamin | Marat Gafurov
Source: Energies (article, 2022-08-26)
Field: Chemistry — Analytical Chemistry

HYSCORE Spectroscopy to Resolve Electron–Nuclear Structure of Vanadyl Porphyrins in Asphaltenes from the Athabasca Oil Sands In Situ Conditions The purpose of this work is to analyze the electron–nuclear interactions of the vanadyl-porphyrin (VP) complexes in oil asphaltenes. Asphaltenes from the Athabasca oil sands were studied by HYperfine Sublevel CORrelation Spectroscopy (HYSCORE) electron paramagnetic resonance (EPR). It makes it possible to resolve and interpret complex hyperfine spectra of intrinsic VP with strong and weak hyperfine interactions between the electron magnetic moment and various nuclear spins (1H, 14N, 51V). The main parameters of spin-Hamiltonian for the VP spin system are determined. The axially symmetric structure of the VP complexes is revealed, and the local nuclear environment of the paramagnetic center is investigated. The results can be used for the study of asphaltene electron–nuclear structure and asphaltene aggregates with the aim of elucidating asphaltenes’ transformation(s) under the influence of external treatment. Asphaltene ; Hyperfine structure ; Electron paramagnetic resonance ; Chemistry ; Oil sands ; Spins ; Paramagnetism ; Spectroscopy ; Porphyrin ; Nuclear magnetic resonance ; Atomic physics ; Materials science ; Condensed matter physics ; Photochemistry ; Organic chemistry ; Physics Petroleum Processing and Analysis ; Porphyrin and Phthalocyanine Chemistry ; NMR spectroscopy and applications
Authors: Renata Cerruti da Costa | Ana Paula Ineichen | Cristiano da Silva Teixeira | Ismael C. Bellettini | Larissa N. Carli
Source: Polímeros (article, 2022-01-01)
Field: Materials Science — Biomaterials

Release of oregano essential oil from PHBV films in simulated food conditionsa Poly(hydroxybutyrate-co-hydroxyvalerate) – PHBV plays an important role in sustainability and food safety. In this work, active packaging with antimicrobial properties was analyzed for the controlled release of active compound in three environments (acidic aqueous foods, fresh foods, and fatty foods). The compositions were produced with the addition of sepiolite nanoparticles (Sep) and oregano essential oil (OEO). The GC-MS analysis detected the presence of 3-methyl-4-isopropyl phenol as the primary constituent of the OEO (71.7%). The characterization of the films by FTIR and SEM confirmed the presence of additives, and the quantification of OEO and thermal stability of the nanocomposites was verified by TGA. Four kinetic models were used to analyze the release profile. Our findings indicate that it is possible to adjust the kinetic release of the OEO by varying the composition of the films, which is a promising alternative for producing an antibacterial biomaterial for application in food packaging. Food packaging ; Chemistry ; Thermal stability ; Food science ; Aqueous solution ; Active packaging ; Fourier transform infrared spectroscopy ; Chemical engineering ; Nanocomposite ; Phenol ; Nuclear chemistry ; Materials science ; Organic chemistry ; Nanotechnology Nanocomposite Films for Food Packaging ; biodegradable polymer synthesis and properties ; Agricultural and Food Sciences
Authors: Lady Johana Cárdenas | Liliana Giraldo | Juan Carlos Moreno‐Piraján
Source: Processes (article, 2022-01-18)
Field: Materials Science — Materials Chemistry

Physicochemical Characterization of Santa Barbara Amorphous-15 (SBA-15) and Its Functionalization with Polyaniline for Phenol Adsorption The chemical surface of Santa Barbara Amorphous-15 (SBA-15) was functionalized with polyaniline (SBA-15/PA) and was prepared using aniline and ammonium persulfate as the modifying agent and oxidant. The samples were characterized by N2 physical adsorption at 77 K. SBA-15’s surface area was 654.5 m2 g−1, changing to 254.6 m2 g−1. The total acidity and basicity were determined using a modified Boehm’s method, and the point of zero charge pH (pHpzc) was determined. Immersion calorimetry in water, benzene, and NaOH, HCl, and phenol (100 mg L−1) solutions was performed, producing values ranging from −15.1 to −174.1 J g−1 related to the chemical surface, pHpzc, and acid and base group values. Finally, the phenol adsorption capacity was found to be higher for the modified polyaniline silica, at 138 mg g−1. Point of zero charge ; Polyaniline ; Adsorption ; Aniline ; Phenol ; Ammonium persulfate ; Surface modification ; Nuclear chemistry ; Amorphous solid ; Chemistry ; Polyaniline nanofibers ; Inorganic chemistry ; Organic chemistry ; Polymer Mesoporous Materials and Catalysis ; Conducting polymers and applications ; Electrochemical sensors and biosensors
Authors: Alessia Arrigoni | Luigi Brambilla | Chiara Castiglioni | Chiara Bertarelli
Source: Nanomaterials (article, 2022-12-04)
Field: Materials Science — Polymers and Plastics

Conducting Electrospun Nanofibres: Monitoring of Iodine Doping of P3HT through Infrared (IRAV) and Raman (RaAV) Polaron Spectroscopic Features Aligned polymer nanofibres are prepared by means of the electrospinning of a chlorobenzene solution containing regioregular poly(3-hexyltiophene-2,5-diyl), P3HT, and poly(ethylene oxide), PEO. The PEO scaffold is easily dissolved with acetonitrile, leaving pure P3HT fibres, which do not show structural modification. Polymer fibres, either with or without the PEO supporting polymer, are effectively doped by exposure to iodine vapours. Doping is monitored following the changes in the doping-induced vibrational bands (IRAVs) observed in the infrared spectra and by means of Raman spectroscopy. Molecular orientation inside the fibres has been assessed by means of IR experiments in polarised light, clearly demonstrating that electrospinning induces the orientation of the polymer chains along the fibre axis as well as of the defects introduced by doping. This work illustrates a case study that contributes to the fundamental knowledge of the vibrational properties of the doping-induced defects-charged polarons-of P3HT. Moreover, it provides experimental protocols for a thorough spectroscopic characterisation of the P3HT nanofibres, and of doped conjugated polymers in general, opening the way for the control of the material structure when the doped polymer is confined in a one-dimensional architecture. Materials science ; Polymer ; Raman spectroscopy ; Doping ; Electrospinning ; Polaron ; Conductive polymer ; Conjugated system ; Infrared spectroscopy ; Chemical engineering ; Ethylene oxide ; Infrared ; Polymer chemistry ; Nanotechnology ; Composite material ; Optoelectronics ; Organic chemistry ; Chemistry ; Optics ; Copolymer Conducting polymers and applications ; Electrospun Nanofibers in Biomedical Applications ; Advanced Sensor and Energy Harvesting Materials
Authors: Cristina V. Manzano | Olga Caballero‐Calero | Aída Serrano | Pedro M. Resende | Marisol Martín‐González
Source: Nanomaterials (article, 2022-12-12)
Field: Materials Science — Polymers and Plastics

The Thermoelectric Properties of Spongy PEDOT Films and 3D-Nanonetworks by Electropolymerization Recently, polymers have been attracted great attention because of their thermoelectric materials' excellent mechanical properties, specifically their cost-effectiveness and scalability at the industrial level. In this study, the electropolymerization conditions (applied potential and deposition time) of PEDOT films were investigated to improve their thermoelectric properties. The morphology and Raman spectroscopy of the PEDOT films were analyzed according to their applied potential and deposition time. The best thermoelectric properties were found in films grown at 1.3 V for 10 min, with an electrical conductivity of 158 ± 8 S/cm, a Seebeck coefficient of 33 ± 1 µV/K, and a power factor of 17 ± 2 µW/K·m<sup>2</sup>. This power factor value is three times higher than the value reported in the literature for electropolymerized PEDOT films in acetonitrile using lithium perchlorate as a counter-ion. The thermal conductivity was found to be (1.3 ± 0.3) × 10<sup>-1</sup> W/m·K. The highest figure of merit obtained at room temperature was (3.9 ± 1.0) × 10<sup>-2</sup> using lithium perchlorate as a counter-ion. In addition, three-dimensional (3D) PEDOT nanonetworks were electropolymerized inside 3D anodic aluminum oxide (3D AAO), obtaining lower values in their thermoelectric properties. Seebeck coefficient ; Materials science ; PEDOT:PSS ; Thermoelectric effect ; Raman spectroscopy ; Anode ; Lithium (medication) ; Electrical resistivity and conductivity ; Conductive polymer ; Poly(3,4-ethylenedioxythiophene) ; Lithium perchlorate ; Chemical engineering ; Nanotechnology ; Analytical Chemistry (journal) ; Thermal conductivity ; Composite material ; Polymer ; Electrochemistry ; Electrode ; Chemistry ; Physical chemistry ; Organic chemistry ; Electrical engineering ; Optics ; Layer (electronics) Conducting polymers and applications ; Advanced Sensor and Energy Harvesting Materials ; Advanced Thermoelectric Materials and Devices
Authors: Gorazd Koderman Podboršek | Špela Zupančič | Rok Kaufman | Angelja Kjara Šurca | Aleš Marsel | Andraž Pavlišič | Nejc Hodnik | Goran Dražić | Marjan Bele
Source: Nanomaterials (article, 2022-06-24)
Field: Materials Science — Materials Chemistry

Microstructure and Electrical Conductivity of Electrospun Titanium Oxynitride Carbon Composite Nanofibers Titanium oxynitride carbon composite nanofibers (TiON/C-CNFs) were synthesised with electrospinning and subsequent heat treatment in ammonia gas. In situ four-probe electrical conductivity measurements of individual TiON/C-CNFs were performed. Additionally, the TiON/C-CNFs were thoroughly analysed with various techniques, such as X-ray and electron diffractions, electron microscopies and spectroscopies, thermogravimetric analysis and chemical analysis to determine the crystal structure, morphology, chemical composition, and N/O at. ratio. It was found that nanofibers were composed of 2-5 nm sized titanium oxynitride (TiON) nanoparticles embedded in an amorphous carbon matrix with a small degree of porosity. The average electrical conductivity of a single TiON/C-CNF was 1.2 kS/m and the bulk electrical conductivity of the TiON/C-CNF fabric was 0.053 kS/m. From the available data, the mesh density of the TiON/C-CNF fabric was estimated to have a characteristic length of 1.0 µm and electrical conductivity of a single TiON/C-CNF was estimated to be from 0.45 kS/m to 19 kS/m. The electrical conductivity of the measured TiON/C-CNFs is better than that of amorphous carbon nanofibers and has ohmic behaviour, which indicates that it can effectively serve as a new type of support material for electrocatalysts, batteries, sensors or supercapacitors. Materials science ; Carbon nanofiber ; Electrospinning ; Electrical resistivity and conductivity ; Conductivity ; Microstructure ; Nanofiber ; Titanium ; Composite material ; Composite number ; Chemical engineering ; Amorphous solid ; Carbon fibers ; Carbon nanotube ; Metallurgy ; Polymer ; Chemistry ; Crystallography MXene and MAX Phase Materials ; Supercapacitor Materials and Fabrication ; Advancements in Battery Materials
Authors: Victoria J. Laye | Shahlo Solieva | Vincent A. Voelz | Shiladitya DasSarma
Source: International Journal of Molecular Sciences (article, 2022-12-09)
Field: Materials Science — Materials Chemistry

Effects of Salinity and Temperature on the Flexibility and Function of a Polyextremophilic Enzyme The polyextremophilic β-galactosidase enzyme of the haloarchaeon <i>Halorubrum lacusprofundi</i> functions in extremely cold and hypersaline conditions. To better understand the basis of polyextremophilic activity, the enzyme was studied using steady-state kinetics and molecular dynamics at temperatures ranging from 10 °C to 50 °C and salt concentrations from 1 M to 4 M KCl. Kinetic analysis showed that while catalytic efficiency (<i>k<sub>cat</sub></i>/<i>K</i><sub>m</sub>) improves with increasing temperature and salinity, <i>K</i><sub>m</sub> is reduced with decreasing temperatures and increasing salinity, consistent with improved substrate binding at low temperatures. In contrast, <i>k<sub>cat</sub></i> was similar from 2-4 M KCl across the temperature range, with the calculated enthalpic and entropic components indicating a threshold of 2 M KCl to lower the activation barrier for catalysis. With molecular dynamics simulations, the increase in per-residue root-mean-square fluctuation (RMSF) was observed with higher temperature and salinity, with trends like those seen with the catalytic efficiency, consistent with the enzyme's function being related to its flexibility. Domain A had the smallest change in flexibility across the conditions tested, suggesting the adaptation to extreme conditions occurs via regions distant to the active site and surface accessible residues. Increased flexibility was most apparent in the distal active sites, indicating their importance in conferring salinity and temperature-dependent effects. Salinity ; Enzyme ; Function (biology) ; Flexibility (engineering) ; Temperature salinity diagrams ; Chemistry ; Environmental science ; Biology ; Biochemistry ; Ecology ; Cell biology ; Mathematics ; Statistics Enzyme Structure and Function ; Biocrusts and Microbial Ecology ; Enzyme Production and Characterization
Authors: Alina Vozniak | Z. Bartczak
Source: Polymers (article, 2022-12-24)
Field: Materials Science — Polymers and Plastics

Plastic Deformation of High Density Polyethylene with Extended-Chain Crystal Morphology Samples of polyethylene with extended-chain crystal morphology, obtained by crystallization under high pressure, were subjected to uniaxial compression to various strains. Accompanying structural changes were analyzed using scanning electron microscopy. At the true strain of e = 0.2−0.3 the microbuckling instability was observed in longitudinally loaded lamellae, resulting in the formation of angular kinks. This induced a rapid reorientation of the lamellae, facilitating their further deformation by crystallographic slip. Microbuckling instability was found to occur earlier than in samples with folded-chain crystal morphology (e = 0.3−0.4) due to a smaller ratio of the amorphous to crystalline layer thickness. SEM observations demonstrated that the microbuckling instability begins with small undulation in long lamellae. Sharp angular lamellar kinks develop from the initial undulation through intense plastic deformation by crystallographic slip along the chain direction. The same slip system was found to operate throughout the kink, including the tip region as well as both limbs. In contrast to thin folded-chain lamellae that often undergo fragmentation during deformation, the thick extended-chain lamellae deform stably by chain slip and retain their continuity up to high strains, e > 1.6. This stability of deformation is related to the large thickness of extended-chain lamellae. Materials science ; Lamellar structure ; Slip (aerodynamics) ; Composite material ; Instability ; Deformation (meteorology) ; Crystal (programming language) ; Polyethylene ; Crystallization ; Amorphous solid ; Scanning electron microscope ; Crystallography ; Mechanics ; Chemistry Polymer crystallization and properties ; Mechanical Behavior of Composites ; Carbon Nanotubes in Composites
Authors: Hao Guo | Yu‐Fei Ao | De‐Xian Wang | Qi‐Qiang Wang
Source: Beilstein Journal of Organic Chemistry (article, 2022-05-02)
Field: Chemistry — Organic Chemistry

Bioinspired tetraamino-bisthiourea chiral macrocycles in catalyzing decarboxylative Mannich reactions A series of tetraamino-bisthiourea chiral macrocycles containing two diarylthiourea and two chiral diamine units were synthesized by a fragment-coupling approach in high yields. Different chiral diamine units, including cyclohexanediamines and diphenylethanediamines were readily incorporated by both homo and hetero [1 + 1] macrocyclic condensation of bisamine and bisisothiocyanate fragments. With the easy synthesis, gram-scale of macrocycle products can be readily obtained. These chiral macrocycles were applied in catalyzing bioinspired decarboxylative Mannich reactions. Only 5 mol % of the optimal macrocycle catalyst efficiently catalyzed the decarboxylative addition of a broad scope of malonic acid half thioesters to isatin-derived ketimines with excellent yields and good enantioselectivity. The rigid macrocyclic framework and the cooperation between the thiourea and tertiary amine sites were found to be crucial for achieving efficient activation and stereocontrol. As shown in control experiments, catalysis with the acyclic analogues having the same structural motifs were non-selective. Chemistry ; Thiourea ; Catalysis ; Combinatorial chemistry ; Isatin ; Diamine ; Enantioselective synthesis ; Amine gas treating ; Mannich reaction ; Stereochemistry ; Organic chemistry Synthesis and Catalytic Reactions ; Asymmetric Synthesis and Catalysis ; Chemical Synthesis and Analysis