jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Elena Shersher | Armando D. Pardillo | Xuemin Wang
Source: Journal of Enzymes (article, 2024-11-01)
Field: Chemistry — Inorganic Chemistry

Disruption of Hydrogen Bonding Network Decreases Catalytic Diversity of Chloroperoxidase via Abolishing Both Chlorination and Dismutation Activities The perpendicular orientation of the proximal alpha helix to the heme plane in chloroperoxidase (CPO) maximizes the influence of its intrinsic helix dipole that has been shown to reduce the “push-effect”, thereby increasing the heme redox potential and fine-tuning the catalytic capabilities of CPO. We investigated the effects of a disruption of the hydrogen bonding network between R26-N37 and A27-N33, formed by the proximal alpha helix, on the CPO structural stability and catalytic profile using site-directed mutagenesis and spectroscopy. The mutant CPO (R26A, N33A, and R26A/N33A) exhibited significant tertiary structural changes and distinct heme coordination, likely, due to destabilization of the proximal helix as a result of the disruption of the proximal hydrogen bonding network. In line with these observations, biochemical characterizations showed that all mutants displayed dramatically different activity profiles relative to that of the WT CPO. Mutant epoxidation and peroxidation activities were markedly enhanced, especially in the R26A/N33A CPO mutant. Moreover, all mutant CPO enzymes exhibited broader pH profiles in both epoxidation and peroxidation activities, including a shift in the optimal peroxidation activity towards pH 3.5 as opposed to pH 2.75. Conversely, the dismutation activity (pH 3.0-5.5) was almost completely lost while chlorination activity (pH 2.75-5.0) was virtually non-existent in all CPO mutants. Our results demonstrate the important role the R26-N37 and A27-N33 hydrogen bond pairs play in the heme coordination and tertiary structure of CPO defining its catalytic capabilities, and also suggest the importance of the proximal helix stability and orientation. Catalysis ; Chemistry ; Diversity (politics) ; Hydrogen bond ; Organic chemistry ; Molecule ; Political science Vanadium and Halogenation Chemistry ; Heme Oxygenase-1 and Carbon Monoxide ; Metal-Catalyzed Oxygenation Mechanisms
Source:  (article, 2024-11-23)
Field: Materials Science — Surfaces, Coatings and Films

Tuning Fibrinogen Adsorption on Layer-by-Layer Built PAA/PAH Mul-tilayer Films: Effect of Deposition Conditions and Hydrophilicity This work investigates the relationship between adsorption of fibrinogen (FNG) on solid surfaces modified by polyelectrolyte multilayer films (PEM) and their surface properties. A pair of weak polyelectrolytes, polyacrylic acid and poly (allylamine hydrochloride), was used to prepare four different PEM films by assembly under different deposition conditions. The thickness of the films was examined by ellipsometry and surface wettability was analyzed by the contact angle method. The Bradford assay and ELISA method were used to quantify FNG adsorption and conformation onto different PEMs. The study contributes to understanding the impact of hydrophilicity and film structure on protein adsorption, and can be used to design biocompatible biomedical devices. Adsorption ; Contact angle ; Wetting ; Polyacrylic acid ; Polyelectrolyte ; Protein adsorption ; Deposition (geology) ; Ellipsometry Polymer Surface Interaction Studies ; Blood properties and coagulation ; Electrospun Nanofibers in Biomedical Applications
Authors: Finnian Rist | H. L. Nourse | B. J. Powell
Source: arXiv (Cornell University) (preprint, 2024-08-22)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Competing quantum effects in spin crossover chains: spin-orbit coupling, magnetic exchange, and elastic interactions We derive and study a model of square planar, d8 spin crossover materials that treats elastic, magnetic and spin-orbit interactions on an equal footing. For 1D chains density matrix renormalization group calculations show that the competition between these interactions leads to six different phases. For weak spin-orbit coupling (SOC) and large antiferromagnetic interactions we find a symmetry protected topological (SPT) Haldane phase. This is equivalent to the Haldane-large-D phase transition driven by single ion anisotropy(D) in the spin-one Heisenberg model. For strong SOC the Sz=+-1 HS states are high-energy excitations. Thus, the system can be understood as a transverse field Ising model with the SOC playing the role of the transverse field. Consistent with this, we find a quantum phase transition between the THS phase and a quantum disordered (QD) phase. However, if the magnetic coupling is non-zero or the HS and LS states of a single molecule are non-degenerate the Z2 (Ising) symmetry is broken and the phase transition becomes a crossover. Thus, the QD phase and the THS phases are adiabatically connected, as, equivalently, are the large-D phase of the spin-one Heisenberg model and the quantum disordered phase of the transverse field Ising model. We also find a ferroelastic LS phase, and antierroelastic phase, with alternating HS and LS complexes, and a dimer phase, which results from the competition between antiferromagnetic and antiferroelastic interactions. Condensed matter physics ; Coupling (piping) ; Crossover ; Spin–orbit interaction ; Spin crossover ; Spin (aerodynamics) ; Physics ; Quantum ; Quantum mechanics ; Materials science ; Computer science Magnetism in coordination complexes ; Quantum and electron transport phenomena ; Lanthanide and Transition Metal Complexes
Authors: Charbel D. Assaf | Xin Gui | Oleg G. Salnikov | Arne Brahms | Nikita V. Chukanov | Ivan V. Skovpin | Eduard Y. Chekmenev | Rainer Herges | Simon B. Duckett | Igor V. Koptyug | Kai Buckenmaier | Rainer Körber | Markus Plaumann | Alexander Aurer | Jan‐Bernd Hövener | Andrey N. Pravdivtsev
Source: Research Square (preprint, 2024-08-23)
Field: Chemistry — Spectroscopy

Analysis of Chemical Exchange in Iridium N-Heterocyclic Carbene Complexes Using Heteronuclear Parahydrogen-Enhanced NMR Heteronuclear molecule ; Iridium ; Carbene ; Spin isomers of hydrogen ; Chemistry ; Nuclear magnetic resonance spectroscopy ; Organic chemistry ; Catalysis ; Hydrogen Advanced NMR Techniques and Applications ; Hydrogen Storage and Materials ; Muon and positron interactions and applications
Authors: Yan Wu | Chaofan Song | Guanwen Huang | K. H. Wu | Yinghong Zhao | An Ning | Wenhua Du | Jia Jia
Source: Separations (article, 2024-11-18)
Field: Materials Science — Materials Chemistry

In Situ Synthesis of Hypercrosslinked Polymer as Stationary Phase for Capillary Gas Chromatography Hypercrosslinked polymers (HCPs) constructed by the Friedel–Crafts alkylation reaction of aromatic compounds have emerged as a new class of porous materials with unique merit. Herein, a HCP named HCP-TPB was coated onto a capillary column through in situ synthesis. The prepared column exhibited a nonpolar nature, and the column efficiency for n-dodecane was 3003 plates m−1. Moreover, the relative standard deviations of retention time and peak area for six replicate injections of the C3–C6 were lower than 0.1% and 1.5%, respectively. The results of this study showed that it is very promising to utilize HCPs as stationary phases for the separation of C3–C6. In situ ; Gas chromatography ; Capillary action ; Polymer ; Capillary gas chromatography ; Chromatography ; Chemistry ; Stationary phase ; Materials science ; Organic chemistry Covalent Organic Framework Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Membrane Separation and Gas Transport
Authors: Juan Carlos Pérez‐Sánchez | Raquel P. Herrera | M. Concepción Gimeno
Source: Advanced Synthesis & Catalysis (article, 2024-07-04)
Field: Chemistry — Organic Chemistry

Exploring Ferrocenyl Imine‐Phosphane Complexes in Gold(I) Redox Switchable Catalysis and the Role of the “Magic Blue” Oxidant Abstract Another class of gold(I) redox‐switchable catalysts, incorporating ferrocenyl phosphane‐imines, enriches the existing library of gold(I) complexes. Our catalyst proves efficacy in gold(I)‐catalyzed cyclizations of furans and benzamides, exhibiting reversible “on‐off” switching. Furthermore, we explored the unconventional role of “Magic Blue”, commonly used as an oxidizing agent in various organic transformations, as a potential activator of the Au−Cl bond, initiating conventional gold(I) catalysis. Chemistry ; Redox ; Imine ; Ferrocene ; Combinatorial chemistry ; Catalysis ; Photochemistry ; Organic chemistry ; Electrochemistry ; Electrode Catalytic Alkyne Reactions ; Asymmetric Hydrogenation and Catalysis ; Oxidative Organic Chemistry Reactions
Authors: Ayman S. Al-Hussaini
Source: International Journal of Environmental Science and Technology (article, 2024-09-11)
Field: Materials Science — Polymers and Plastics

Development of functional materials based on new high content electron withdrawing groups terpolymer composites for potential applications Abstract Novel polymer composites with unique characteristics as new materials are essentially needed to meet future demands. Terpoly(anthranilic acid, m- aminobenzoic acid, and o- nitroaniline) emeraldine base (EB)/macro-microcomposites were generated from equimolar ratios of the corresponding molecules and different ratios of bentonite via in situ oxidative terpolymerization. Their spectral properties upon joining the m -aminobenzoic acid and the o -nitroaniline moieties in the skeleton of polyanthranilic acid were inspected. The spectral analyses were utilized to emphasize the results of both terpoly( o , m -aminobenzoic acid, and o -nitroaniline) (EB) and poly( o , m -aminobenzoic acid, and o -nitroaniline)/bentonite composites. The TGA analyses of the purified terpolymer with and without bentonite in the N 2 atmosphere were investigated. Furthermore, the terpolymer composite morphology was investigated by the SEM technique with the micro-macrometric particle sizes 0.470–2.780 μm at different magnifications. Graphical Abstract Materials science ; Composite material ; Copolymer ; Electron ; Physics ; Polymer ; Nuclear physics Polymer Nanocomposites and Properties ; Polymer Nanocomposite Synthesis and Irradiation ; Synthesis and properties of polymers
Authors: Caleb J. Setzler | Jeffrey T. Petty
Source: Nanoscale (article, 2024-01-01)
Field: Materials Science — Materials Chemistry

Click catalysis and DNA conjugation using a nanoscale DNA/silver cluster pair DNA-bound silver clusters are most readily recognized by their strong fluorescence that spans the visible and near-infrared regions. From this suite of chromophores, we chose a green-emitting Ag<sub>10</sub><sup>6+</sup> bound to C<sub>4</sub>AC<sub>4</sub>TC<sub>3</sub>GT<sub>4</sub> and describe how this DNA/cluster pair is also a catalyst. A DNA-tethered alkyne conjugates with an azide <i>via</i> cycloaddition, an inherently slow reaction that is facilitated through the joint efforts of the cluster and DNA. The Ag<sub>10</sub><sup>6+</sup> structure is the catalytic core in this complex, and it has three distinguishing characteristics. It facilitates cycloaddition while preserving its stoichiometry, charge, and spectra. It also acidifies its nearby alkyne to promote H/D exchange, suggesting a silver-alkyne complex. Finally, it is markedly more efficient when compared with related multinuclear DNA-silver complexes. The Ag<sub>10</sub><sup>6+</sup> is trapped within its C<sub>4</sub>AC<sub>4</sub>TC<sub>3</sub>GT<sub>4</sub> host, which governs the catalytic activity in two ways. The DNA has orthogonal functional groups for both the alkyne and cluster, and these can be systematically separated to quench the click reaction. It is also a polydentate ligand that imprints an elongated shape on its cluster adduct. This extended structure suggests that DNA may pry apart the cluster to open coordination sites for the alkyne and azide reactants. These studies indicate that this DNA/silver cluster pair work together with catalysis directly driven by the silver cluster and indirectly guided by the DNA host. DNA ; Catalysis ; Alkyne ; Cluster (spacecraft) ; Click chemistry ; Azide ; Chemistry ; Conjugate ; Combinatorial chemistry ; Nanoscopic scale ; Nanotechnology ; Materials science ; Biochemistry ; Organic chemistry Nanocluster Synthesis and Applications ; Click Chemistry and Applications ; Advanced biosensing and bioanalysis techniques
Authors: Xinyan Ding | Li‐Guo Gao
Source: Zeitschrift für Kristallographie - New Crystal Structures (article, 2024-02-06)
Field: Chemistry — Inorganic Chemistry

Crystal structure of <i>catena</i>-poly[aqua-(<i>μ</i> <sub>2</sub>-4,4′-diimidazole diphenyl ether-<i>κ</i> <sup>2</sup> <i>N</i>:<i>N</i>′)-(sulfato-<i>κ</i> <sup>1</sup> <i>O</i>)-cobalt(II)] – dimethylformamide (2/1), C<sub>39</sub>H<sub>37</sub>CoN<sub>9</sub>O<sub>8</sub>S Abstract C 39 H 37 CoN 9 O 8 S, monoclinic, P 2 1 / m (no. 11), a = 8.5267(5) Å, b = 20.1577(12) Å, c = 11.2333(7) Å, β = 105.493(7)°, V = 1860.6(2) Å 3 , Z = 2, R gt ( F ) = 0.0443, w R ref ( F 2 ) = 0.0968, T = 293(2) K. Monoclinic crystal system ; Chemistry ; Crystal structure ; Ether ; Crystallography ; Stereochemistry ; Medicinal chemistry ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Magnetism in coordination complexes ; Polyoxometalates: Synthesis and Applications
Authors: Sandra Barhoum | Marta García-Cortés | Marine Boudias | Mohamed Guerrouache | Hélène Isnard | Erwan Dupuis | Benjamin Carbonnier | Anne Van der Meeren | Carole Bresson
Source: Microchimica Acta (article, 2024-03-12)
Field: Chemistry — Inorganic Chemistry

Immobilization of controlled Pu:Am ratio on actinide-specific affinity monolith support developed in capillary and coupled to inductively coupled plasma mass spectrometry Monolith ; Chemistry ; Inductively coupled plasma mass spectrometry ; Mass spectrometry ; Inductively coupled plasma ; Chromatography ; Capillary action ; Capillary electrophoresis ; Actinide ; Analytical Chemistry (journal) ; Nuclear chemistry ; Materials science ; Plasma ; Catalysis ; Organic chemistry Radioactive element chemistry and processing ; Radiopharmaceutical Chemistry and Applications ; Analytical chemistry methods development
Authors: Cheng-Po Kao | Jhen‐Yi Lee | Min-Cheng Tang | Hon Man Lee
Source: Dalton Transactions (article, 2024-01-01)
Field: Chemistry — Organic Chemistry

Design and synthesis of versatile ligand precursors based on phosphonium ylides for palladalactam formation and catalytic investigation A new series of ligand precursors designed for the synthesis of palladalactams has been developed. These precursors are easily accessible through a one-step reaction involving 2-chloro-<i>N</i>-phenylacetamide and a wide choice of various monophosphines, offering tunable electronic and steric properties within the ligand framework. The stability of both ligand precursors and resulting palladalactams in ambient air enhances their practical applicability. A newly synthesized palladalactam, featuring an electron-donating triethylphosphine moiety on the anionic phosphonium ylide ligand scaffold exhibited promising catalytic activities in the Mizoroki-Heck coupling reaction between aryl chlorides and alkenes. Theoretical calculations further affirmed that the ligand system in the complex is the most electron-donating, forming the strongest Pd-C bond compared to other complexes with alternative phosphine moieties. Phosphonium ; Ligand (biochemistry) ; Catalysis ; Combinatorial chemistry ; Chemistry ; Organic chemistry ; Receptor Synthetic Organic Chemistry Methods ; N-Heterocyclic Carbenes in Organic and Inorganic Chemistry ; Catalytic Cross-Coupling Reactions
Authors: Carsten Steiner | Vladimir Malashchuk | David Kubinski | Gunter Hagen | Ralf Moos
Source: Sensors (article, 2024-06-24)
Field: Materials Science — Materials Chemistry

Microwave-Based State Diagnosis of Three-Way Catalysts: Impact Factors and Application Recommendations This study reassesses an overview of the potential of the radio frequency (RF)-based state diagnostics of three-way catalysts (TWC) based on a previous study with an emphasis on the defect chemistry of the catalyst material during reoxidation and reduction. Some data are based on the previous works but are newly processed, and the signal parameters resonant frequency and inverse quality factor are evaluated with respect to applicability. The RF-based method uses electromagnetic resonances in a cavity resonator to provide information on the storage level of the oxygen storage component. The analysis focuses on a holistic investigation and evaluation of the major effects influencing the RF signal during operation. On the one hand, the response to the oxygen storage behavior and the resolution of the measurement method are considered. Therefore, this study merges original data from multiple former publications to provide a comprehensive insight into important measurement effects and their defect chemistry background. On the other hand, the most important cross-sensitivities are discussed and their impact during operation is evaluated. Additionally, the effect of catalyst aging is analyzed. The effects are presented separately for the two resonant parameters: resonant frequency and (unloaded) quality factor. Overall, the data suggest that the quality factor has a way higher signal quality at low temperatures (<400 °C) and the resonant frequency is primarily suitable for high operating temperatures. At most operating points, the quality factor is even more robust against interferences such as exhaust gas stoichiometry and water content. Correctly estimating the catalyst temperature is the most important factor for reliable results, which can be achieved by combining the information of both resonant signals. In the end, the data indicate that microwave-based state diagnosis is a powerful system for evaluating the oxygen storage level over the entire operating range of a TWC. As a research tool and in its application, the system can therefore contribute to the improvement of the emission control of future gasoline vehicles. State (computer science) ; Computer science ; Engineering ; Environmental science Catalytic Processes in Materials Science ; Catalysis and Hydrodesulfurization Studies ; Ammonia Synthesis and Nitrogen Reduction
Authors: Xin Wu
Source: Research Square (preprint, 2024-02-19)
Field: Materials Science — Materials Chemistry

Removal of heavy metals from wastewater using 2D MXenes: A theoretical study Abstract Water is an indispensable material for human life. Unfortunately, the developments of industrial activities have reduced the quality of water resources in the world. Meantime, heavy metals are an important factor in water pollution due to their toxicity. This study highlights the method for the capture of heavy metal ions from wastewater using the procedure of adsorption. The adsorption of toxic heavy metal ions (Pb 2+ , Hg 2+ , and Cd 2+ ) on Ca 2 C and Cr 2 C MXene monolayers is investigated using the density functional theory. We have optimized the considered MXenes by nine DFT functionals: PBE, TPSS, BP86, B3LYP, TPSSh, PBE0, CAM-B3LYP, M11, and LC-WPBE. Our results have shown a good agreement with previously measured electronic properties of the Ca2C and Cr 2 C MXene layers and PBE DFT method. The calculated cohesive energy for the Ca2C and Cr 2 C MXene monolayers are − 4.12 eV and − 4.20 eV, respectively, which are in agreement with the previous studies. The results reveal that the adsorbed heavy metal ions have a substantial effect on the electronic properties of the considered MXene monolayers. Besides, our calculations show that the metal/MXene structures with higher electron transport rates display higher binding energy and charge transfers between the metal and Ca 2 C and Cr 2 C layers. Time-dependent density functional analysis also displayed “ligand to metal charge transfer” excitations for the metal/MXene systems. The larger Ebin for the Pb@Ca 2 C as well as Pb@Cr 2 C are according to larger redshifts which are expected (∆λ = 45 nm and 71 nm, respectively). Our results might be helpful for future research toward the application of MXene-based materials for removing wastewater pollutants. MXenes ; Heavy metals ; Wastewater ; Environmental science ; Environmental chemistry ; Environmental engineering ; Chemistry ; Materials science ; Nanotechnology MXene and MAX Phase Materials ; Graphene and Nanomaterials Applications ; Graphene research and applications
Authors: Vignesh Natarajan
Source: Current Drug Delivery (article, 2024-10-16)
Field: Materials Science — Biomaterials

Alleviation of Tumor Invasion by the Development of Natural Polymer-based Low-risk Chemotherapeutic Systems – review on the Malignant Carcinoma Treatments The review extensively covers safe chemotherapeutic systems with significant advantages (tumor volume shrinkage of 4T1 cells from 1000 mm3 to 200 mm<sup>3</sup>) in clinical applications of carcinoma treatments using natural polymers. Drug delivery ; Drug ; Medicine ; Pharmacology ; Stromal cell ; Distribution (mathematics) ; Chemotherapy ; Cancer research ; Chemistry ; Internal medicine Nanoparticle-Based Drug Delivery ; Cancer Research and Treatments ; Cancer, Hypoxia, and Metabolism
Authors: Thapelo Ephraim Seimela | Justine S. Nyarige | Nolwazi Nombona | Mmantsae Diale
Source: Nano-Horizons Journal of Nanosciences and Nanotechnologies (article, 2024-12-31)
Field: Materials Science — Polymers and Plastics

Enhancing the Efficiency of Organic Solar Cell By Incorporating Copper Nanoparticles in PEDOT:PSS The performance of bulk heterojunction organic solar cell can be enhanced by incorporating plasmonic copper nanoparticles. In this study, a device with the architecture ITO/PEDOT:PSS:CuNPs/P3HT:PCBM/Ag was fabricated, where PEDOT:PSS was treated with copper nanoparticles synthesised by chemical reduction. Transmission electron microscopy revealed spherical copper nanoparticles with increasing average particle size as the concentration of copper sulphate increases. A face-centred cubic structure with (111), (200) and (220) phases for copper nanoparticles was confirmed using X-ray diffraction. The incorporation of copper nanoparticles induced the plasmonic resonance at 562 nm resulting in light scattering, which was not observed for pristine PEDOT:PSS. The copper nanoparticles are uniformly dispersed in PEDOT:PSS as displayed by scanning electron microscopy. The increase in concentration and annealing temperature of copper nanoparticles improved the intensity of Cα = Cβ vibration mode for PEDOT:PSS and P3HT:PCBM. Incorporating copper nanoparticles in PEDOT:PSS has improved the power conversion efficiency of ITO/PEDOT:PSS:CuNPs/P3HT:PCBM/Ag solar cell from 0.09 to 5.44% as a result of the induced plasmonic resonance observed in the ultraviolet-visible spectra. PEDOT:PSS ; Organic solar cell ; Copper ; Nanoparticle ; Materials science ; Solar cell ; Nanotechnology ; Chemical engineering ; Optoelectronics ; Metallurgy ; Polymer ; Composite material ; Engineering ; Layer (electronics) Conducting polymers and applications ; Organic Electronics and Photovoltaics ; Transition Metal Oxide Nanomaterials