jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Anna Grünert
Source: Dokumentenrepositorium der RUB (Ruhr University Bochum) (article, 2020-01-01)
Field: Chemistry — Organic Chemistry

Synthesis of oxymethylene ethers Oxymethylenether (OME) sind eine Klasse von synthetischen Kraftstoffen mit rußmindernder Wirkung. Die vorliegende Arbeit beschreibt die Synthese von OME aus Methanol und Formaldehyd in der Gasphase als Alternative zum etablierten Flüssigphasen-Prozess. In einer kontinuierlich betriebenen Anlage wurde eine Auswahl fester Katalysatoren getestet. Zeolithe und geträgerte Phosphorsäure wurden als geeignete Katalysatoren identifiziert. Für die Gruppe der Zeolithe wurde eine Beziehung zwischen Reaktivität und der Konzentration der Säuregruppen aufgezeigt. Deaktivierungsstudien zeigten eine erhöhte Standzeit von geträgerter Phosphorsäure im Vergleich zu Zeolithen. Zuletzt wurde die Synthese von OME aus Methanol ohne Abtrennung der Zwischenprodukte demonstriert. Chemistry ; Stereochemistry Chemical Synthesis and Reactions ; Oxidative Organic Chemistry Reactions
Authors: Haider Hadi Jasim | Read Abd Al-Hussain | Ahmed Shawqi Sadeq
Source: Al-Nahrain Journal for Engineering Sciences (article, 2020-11-21)
Field: Materials Science — Materials Chemistry

Evaluation the Efficiency of Various Types of Corrosion Inhibitors Used for Basrah Water Storage Tanks In this paper, the efficiency of six different types of corrosion inhibitors used in Basrah drinking water tanks was assessed using a potentiostatic test method. The mechanism of adsorption of silicate and phosphate inhibitors in AISI 316 stainless steel surfaces and the effects of different water components in inhibitors are discussed in detail. The values of corrosion rate obtained from the Potentiostatic test showed that the protection against corrosion in the presence of inhibitors is better compared to the case of absence of inhibitors. The results of the six types of corrosion inhibitors tested showed that the inhibitory efficacy is higher below the temperatures 45oC, but when raise the temperature above 45oC the inhibitory efficiency becomes to decrease. Also, the test results indicated that the corrosion inhibitor involves silicate products provided more inhibited efficiency compared to the phosphate inhibitor alone or used the combined silicate/phosphate corrosion inhibitor. The inspection of the surface of the tested samples using optical methods shows that the pitting corrosion is demonstrated on the specimen surfaces after testing with or without inhibitors. Corrosion ; Phosphate ; Corrosion inhibitor ; Silicate ; Adsorption ; Chemistry ; Metallurgy ; Materials science ; Nuclear chemistry ; Biochemistry ; Organic chemistry Corrosion Behavior and Inhibition
Authors: Hao Yin | Li-Qing Zheng | Wei Fang | Yin‐Hung Lai | Nikolaus Porenta | Guillaume Goubert | Hua Zhang | Hai‐Sheng Su | Bin Ren | Richardson O. Jeremy | Jian‐Feng Li | Renato Zenobi
Source: ChemRxiv (preprint, 2020-05-22)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Nanometer Scale Spectroscopic Visualization of Catalytic Sites During a Hydrogenation Reaction on a Pd/Au Bimetallic Catalyst Understanding the mechanism of catalytic hydrogenation at the local environment requires chemical and topographic information involving catalytic sites, active hydrogen species and their spatial distribution. Here, tip-enhanced Raman spectroscopy (TERS) was employed to study the catalytic hydrogenation of chloro-nitrobenzenethiol on a well-defined Pd(sub-monolayer)/Au(111) bimetallic catalyst (pH2=1.5 bar, 298 K), where the surface topography and chemical fingerprint information were simultaneously mapped with nanoscale resolution (≈10 nm). TERS imaging of the surface after catalytic hydrogenation confirms that the reaction occurs beyond the location of Pd sites. The results demonstrate that hydrogen spillover accelerates hydrogenation at the Au sites within 20 nm from the bimetallic Pd/Au boundary. Density functional theory was used to elucidate the thermodynamics of interfacial hydrogen transfer. We demonstrate that TERS as a powerful analytical tool provides a unique approach to spatially investigate the local structure-reactivity relationship in catalysis. Bimetallic strip ; Catalysis ; Hydrogen spillover ; Hydrogen ; Chemical physics ; Materials science ; Raman spectroscopy ; Atomic units ; Nanoscopic scale ; Monolayer ; Heterogeneous catalysis ; Chemical engineering ; Nanometre ; Chemistry ; Nanotechnology ; Organic chemistry ; Composite material Gold and Silver Nanoparticles Synthesis and Applications ; Machine Learning in Materials Science ; Innovative Microfluidic and Catalytic Techniques Innovation
Authors: Sheng Chu Kuo | Kuo Hsiung Lee | Susan L. Morris‐Natschke | Li Huang | Yi Lin | Hui‐Yi Lin | Li Chen Chou | Yu Zhao | Ting Shen | Yi‐Fong Chen | Chen Fang Wei | Mei Hua Hsu
Source: UNC Libraries (article, 2020-11-01)
Field: Chemistry — Organic Chemistry

Synthesis and SAR studies of novel 6,7,8-substituted 4-substituted benzyloxyquinolin-2(1 H )-one derivatives for anticancer activity: Synthesis and anticancer activity of 2-quinolones 4-Phenylquinolin-2(1H)-one (4-PQ) derivatives can induce cancer cell apoptosis. Additional new 4-PQ analogs were investigated as more effective, less toxic antitumour agents. Chemistry ; Anticancer drug ; Combinatorial chemistry ; Pharmacology ; Medicine ; Drug Synthesis and Biological Evaluation ; Synthesis and biological activity ; Cancer therapeutics and mechanisms
Authors: Stefan Hellhake
Source: ELPUB (Universitat Wuppertal) (article, 2020-01-01)
Field: Chemistry — Spectroscopy

Analytik von Oxylipinen bei unterschiedlichen Ionisationsmethoden und fundamentale Analyse der Fragmentierungsprozesse in der Laser-Ionisation bei Atmosphärendruck Eicosanoids and other oxylipins play important roles in mediating inflammation and other biological processes. In order to investigate their biological roles, comprehensive analysis methods are required, with which these compounds can be reliably identified and quantified in biological matrices. Very different concentrations and different biological matrices pose enormous challenges for the modern analysis of oxylipins. In the first part of this work, a combination of solid phase extraction, charge switch derivatization, liquid chromatography, ion mobility, mass spectrometry, and bioinformatics was used to developing a novel strategy for the analysis of oxylipins. After developing and characterizing the method, it was applied to the biological matrices of cells, serum, and plasma. The results were compared with current methods of analytics of oxylipins. Subsequently, further derivatization reagents were developed in order to expand the possible analysis spectrum via stable isotope labeled derivatives, derivatives for specific functional groups, or derivatives for other ionization methods such as laser ionization at atmospheric pressure (APLI). In the second part of the thesis the APLI and the fundamental mechanisms of fragmentation during the ionization process were dealt with. In contrast to laser ionization at low pressure (multi photon ionization, MPI), APLI leads to very little fragmentation of the analytes. Both the quenching of highly excited states and the collision-induced loss of charge of the fragment ions by charge transfer were hypothesized as possible causes. These hypotheses have not been elucidated in the past to the extent that unequivocal conclusions were drawn. Through experiments and calculations with both APLI and MPI, this process was examined in more detail and basic knowledge was provided to clarify the fragmentation pathways. Chemistry ; Ionization ; Derivatization ; Fragmentation (computing) ; Mass spectrometry ; Chromatography ; Analytical Chemistry (journal) ; Ion ; Organic chemistry Mass Spectrometry Techniques and Applications ; Analytical Chemistry and Chromatography ; Chemical Reactions and Isotopes
Authors: Gopal Sharma | Rajni Kant
Source: Oriental Journal of Physical Sciences (article, 2020-12-30)
Field: Chemistry — Physical and Theoretical Chemistry

Quantitative Lattice Energy Analysis of Intermolecular Interactions in Crystal Structures of Some Benzimidazole Derivatives The benzimidazole moiety found in a large number of biologically important drugs has not been completely realized as yet in respect of its strength and directionality of its molecular interactions. To understand the role played by the intermolecular interactions in the benzimidazole derivatives, lattice energy of a series of five important molecules has been computed and results accrued thereof have been discussed. Analysis of molecular packing based on the intermolecular interaction energies suggests existence of different molecular pairs that play an important role in the stabilization of the crystal structures. Interaction energy analysis of such motifs reveals that intermolecular interactions of the type N-H…N and C-H…N happen to be the major contributors to the stabilization of molecular packing in the unit cell. N-H…π and C-H…π type edge-to-face stacking interactions also contribute significantly to the stabilization of crystal packing. The pairs of N-H…N intermolecular hydrogen bonds link the molecules into centrosymmetric dimers making a contribution of -14 to -18.52 kcal/mol towards stabilization, whereas C-H…N bonds link the molecules into dimers in the energy range of -2 to -5 kcal/mol. Additionally, the role of π…π interactions has also been investigated in molecular stabilization. Intermolecular force ; Stacking ; Molecule ; Hydrogen bond ; Lattice energy ; Crystal structure ; Crystallography ; Benzimidazole ; Interaction energy ; Moiety ; Intermolecular interaction ; Crystal (programming language) ; Chemistry ; Materials science ; Stereochemistry ; Organic chemistry Crystallography and molecular interactions ; Crystal structures of chemical compounds ; Crystallization and Solubility Studies
Authors: Alexander V. Kabanov | Hardeep S. Oberoi | N. V. Nukolova | Tatiana K. Bronich
Source: UNC Libraries (article, 2020-10-29)
Field: Materials Science — Biomaterials

Nanocarriers for delivery of platinum anticancer drugs Platinum based anticancer drugs have revolutionized cancer chemotherapy, and continue to be in widespread clinical use especially for management of tumors of the ovary, testes, and the head and neck. However, several dose limiting toxicities associated with platinum drug use, partial anti-tumor response in most patients, development of drug resistance, tumor relapse, and many other challenges have severely limited the patient quality of life. These limitations have motivated an extensive research effort towards development of new strategies for improving platinum therapy. Nanocarrier-based delivery of platinum compounds is one such area of intense research effort beginning to provide encouraging preclinical and clinical results and may allow the development of the next generation of platinum chemotherapy. This review highlights current understanding on the pharmacology and limitations of platinum compounds in clinical use, and provides a comprehensive analysis of various platinum–polymer complexes, micelles, dendrimers, liposomes and other nanoparticles currently under investigation for delivery of platinum drugs. Nanocarriers ; Anticancer drug ; Pharmacology ; Platinum ; Platinum compounds ; Chemistry ; Drug ; Nanotechnology ; Medicine ; Materials science ; Biochemistry Nanoparticle-Based Drug Delivery ; Graphene and Nanomaterials Applications
Authors: Barbara Tessier
Source: theses.fr (ABES) (preprint, 2020-12-18)
Field: Materials Science — Materials Chemistry

Synthèse et formulation de nanoconjugués de poly(acide malique)-budésonide intégrés dans des microparticules troyennes pour l’administration pulmonaire A new formulation for the administration of glucocorticoids through inhalation has been developed from poly(malic acid) (PMA) conjugates and budesonide. PMA was selected for its biodegradability, biocompatibility, and the presence of lateral carboxylic acid functions on each repeating unit, resulting in a high budesonide conjugation rate (up to 73 wt%). Nanoconjugates were formulated from these conjugates by nanoprecipitation in the absence of surfactants. They proved to be stable with a slow and progressive release of the drug in physiological conditions. In vitro evaluation demonstrated the ability of RAW 264.7 macrophages to internalize nanoconjugates which have an anti-inflammatory effect and are not cytotoxic at efficient doses. Trojan microparticles were then prepared by spray-drying the nanoconjugates with a solution of L-leucine. These particles are characterized by a low density due to their hollow structure and the presence of the nanoconjugates and the excipient on the surface only. They have been optimized to have a suitable aerodynamic diameter and fine particle fraction in order to obtain a powder deposition in the pulmonary alveoli mainly. In vivo tests were performed to evaluate the pharmacokinetics of the microparticles and to demonstrate the safety of this new treatment. The objective of this new formulation is to improve the activity of glucocorticoids and reduce their systemic adverse effects by increasing the pulmonary deposition and retention of the powder, as well as by targeting the alveolar macrophages that orchestrate pulmonary inflammation, by using nanoconjugates. Malic acid ; Administration (probate law) ; Trojan ; Medicine ; Chemistry ; Computer science ; Computer security ; Political science ; Organic chemistry Mesoporous Materials and Catalysis ; Microwave-Assisted Synthesis and Applications ; Inhalation and Respiratory Drug Delivery
Authors: Alice Domenichini | Ilaria Casari | Peter V. Simpson | Nima Maheshkumar Desai | Lingfeng Chen | Christopher M. Dustin | Jeanne S. Edmands | Albert van der Vliet | Moosa Mohammadi | Massimiliano Massi | Marco Falasca
Source: Research Square (preprint, 2020-08-11)
Field: Chemistry — Organic Chemistry

Rhenium N-heterocyclic Carbene Complexes Block Growth of Aggressive Cancers by Inhibiting FGFR- and SRC-Mediated Signalling Rhenium ; Carbene ; Proto-oncogene tyrosine-protein kinase Src ; Chemistry ; Fibroblast growth factor receptor ; Cancer research ; Phosphorylation ; Signalling ; Medicine ; Biology ; Cell biology ; Fibroblast growth factor ; Biochemistry ; Receptor ; Organic chemistry Quinazolinone synthesis and applications ; N-Heterocyclic Carbenes in Organic and Inorganic Chemistry ; Histone Deacetylase Inhibitors Research
Authors: Alexey E. Nazarov | А. И. Иванов | Eric Vauthey
Source: Archive ouverte UNIGE (University of Geneva) (article, 2020-01-01)
Field: Chemistry — Physical and Theoretical Chemistry

Modeling Infrared Spectral Dynamics upon Symmetry Breaking of a Photo-Excited Quadrupolar Dye A significant number of quadrupolar dyes with a D-$pi$-A-$pi$-D or A-$pi$-D-$pi$-A structure, where D and A are electron donor and acceptor groups, were shown to undergo symmetry breaking (SB) upon optical excitation. During this process, the electronic excitation, originally distributed evenly over the molecule, concentrates on one D-$pi$-A branch, and the molecule becomes dipolar. This process can be monitored by time resolved infra-red (TRIR) spectroscopy and causes significant spectral dynamics. A theoretical model of excited-state SB developed earlier ( extit{J. Phys. Chem. C}, extbf{2018}, extit{132}, 29165) is extended to account for the temporal changes taking place in the IR spectrum upon SB. This model can reproduce the IR spectral dynamics observed in the $-mathrm{C}equiv mathrm{C}-$ stretching region with a D-$pi$-A-$pi$-D dye in two polar solvents using a single set of molecular parameters. This approach allows estimating the degree of asymmetry of the excited state in different solvents as well as its change during SB. Additionally, the relative contribution of the different mechanisms responsible for the splitting of the symmetric and antisymmetric $-mathrm{C}equiv mathrm{C}-$ stretching bands, which are both IR active upon SB, can be determined. Chemistry ; Excited state ; Infrared ; Excitation ; Acceptor ; Molecule ; Dipole ; Antisymmetric relation ; Symmetry breaking ; Asymmetry ; Symmetry (geometry) ; Molecular physics ; Infrared spectroscopy ; Polar ; Spectroscopy ; Atomic physics ; Condensed matter physics ; Optics ; Physics ; Quantum mechanics Photochemistry and Electron Transfer Studies ; Spectroscopy and Quantum Chemical Studies ; Photoreceptor and optogenetics research
Authors: Koen Veys | Daniel Escudero
Source: ChemRxiv (preprint, 2020-06-05)
Field: Chemistry — Physical and Theoretical Chemistry

A Computational Protocol to Predict Anti-Kasha Emissions: The Case of Azulene Derivatives In this contribution we present a computational protocol to predict anti-Kasha photoluminescence. The herein developed protocol is based on state-of-the-art quantum chemical calculations and excited state decay rate theories (i.e., thermal vibration correlation function formalism), along with appropriate kinetic models which include all relevant electronic states. This protocol is validated for a series of azulene derivatives. For this series, we have computed absorption and emission spectra for both their first and second excited states, their radiative and non-radiative rates as well as fluorescence yields from the two different excited states. All the studied azulene derivatives are predicted to exclusively display anomalous anti-Kasha S2 emission. A quantitative agreement for the herein computed excited state spectra, lifetimes and fluorescence quantum yieldsis obtained with respect to the experimental values. Given the increasing interest on anti-Kasha emitters, we foresee that the herein developed computational protocol can be used to pre-screen dyes with the desired aforementioned anomalous photoluminescence properties. Azulene ; Excited state ; Radiative transfer ; Chemistry ; Quantum ; Chemical physics ; Physics ; Computational chemistry ; Atomic physics ; Photochemistry ; Quantum mechanics Photochemistry and Electron Transfer Studies ; Molecular Junctions and Nanostructures ; Porphyrin and Phthalocyanine Chemistry
Authors: Maurizio Del Poeta
Source: UNC Libraries (article, 2020-10-30)
Field: Chemistry — Organic Chemistry

Structure-In Vitro Activity Relationships of Pentamidine Analogues and Dication-Substituted Bis-Benzimidazoles as New Antifungal Agents Twenty analogues of pentamidine, 7 primary metabolites of pentamidine, and 30 dicationic substituted bis-benzimidazoles were screened for their inhibitory and fungicidal activities against Candida albicans and Cryptococcus neoformans. A majority of the compounds had MICs at which 80% of the strains were inhibited (MIC80s) comparable to those of amphotericin B and fluconazole. Unlike fluconazole, many of these compounds were found to have potent fungicidal activity. The most potent compound against C. albicans had an MIC80 of ≤0.09 μg/ml, and the most potent compound against C. neoformans had an MIC80 of 0.19 μg/ml. Selected compounds were also found to be active against Aspergillus fumigatus, Fusarium solani, Candida species other than C. albicans, and fluconazole-resistant strains of C. albicans and C. neoformans. It is clear from the data presented here that further studies on the structure-activity relationships, mechanisms of action and toxicities, and in vivo efficacies of these compounds are warranted to determine their clinical potential. Pentamidine ; Antifungal ; In vitro ; Dication ; Chemistry ; Combinatorial chemistry ; Stereochemistry ; Microbiology ; Biochemistry ; Biology ; Medicine ; Organic chemistry ; Molecule ; Internal medicine Synthesis and Biological Evaluation ; Synthesis and biological activity ; Phenothiazines and Benzothiazines Synthesis and Activities
Authors: 禄禄 徐 | 馨瑶 王 | 维萍 张
Source: Journal of Molecular Catalysis(China) (article, 2020-10-01)
Field: Chemistry — Inorganic Chemistry

Catalytic Performances of Mo/HZSM-5 Zeolites in Methane and Methanol Co-aromatization after Modification by Tetrapropylammonium hydroxide A series of HZSM-5 zeolites firstly were treated with different concentrations of tetrapropylammonium hydroxide(TPAOH),and then modified with Mo by incipient impregnation method.Their structures and acidity were systematically characterized by means of XRD,N2 adsorption,27Al MAS NMR,29Si MAS NMR and NH3-TPD.Their catalytic performances in methane and methanol non-oxidative co-aromatization reaction were evaluated.The structural characterization results show that the relative crystallinity of HZSM-5 increases after treating by a proper amount of TPAOH.Moreover,mesopores,weak and strong acid sites also increase obviously in the samples.At 700℃and methane volume space velocity(GHSV)of 2000 h-1,HZSM-5 modified with 6%Mo shows methane conversion of around 10%,benzene selectivity exceeding 70%and C7-C9 high-carbon aromatics selectivity of 4%in the presence of small amount of methanol(nCH4/nCH3OH=20).After modification by 0.1 mol/L TPAOH,the methane conversion decreases to 8%,the benzene selectivity exceeds 60%and the selectivity of C7-C9 high-carbon aromatics increases to 10%~17%.TG and TPO experiments were used to characterize the coke deposition of the samples after reaction.Methane and methanol co-feeding decrease the coke content from 15%of methane feed alone to 5%,and it further decreases to 1.4%after modification by 0.1 mol/L TPAOH.This may be due to the mesopores introduced by the TPAOH treatment and reduced polycyclic aromatics on the strong acid sites,thereby improving the stability of the catalyst and the utilization efficiency of carbon atoms. Aromatization ; Chemistry ; Catalysis ; Methane ; Methanol ; Hydroxide ; Zeolite ; Inorganic chemistry ; Organic chemistry Zeolite Catalysis and Synthesis ; Catalysis and Hydrodesulfurization Studies ; Catalytic Processes in Materials Science
Authors: T. Kendall Harden | Barkın Berk | Kenneth A. Jacobson | Рамачандран Баласубраманиан | Dilip K. Tosh | Hiroshi Maruoka | Stefano Costanzi | Lauren E. Burianek | Matthew O. Barrett | Artem Melman | Hyojin Ko
Source: UNC Libraries (article, 2020-11-04)
Field: Chemistry — Organic Chemistry

Pyrimidine Ribonucleotides with Enhanced Selectivity as P2Y 6 Receptor Agonists: Novel 4-Alkyloxyimino, (S)-Methanocarba, and 5′-Triphosphate γ-Ester Modifications † The P2Y6 receptor is a cytoprotective G protein-coupled receptor (GPCR) activated by UDP (EC50, 0.30 μM). We compared and combined modifications to enhance P2Y6 receptor agonist selectivity, including ribose ring constraint, 5-iodo and 4-alkyloxyimino modifications, and phosphate modifications such as α,β-methylene and extension of the terminal phosphate group into γ-esters of UTP analogues. The conformationally constrained (S)-methanocarba UDP is a full agonist (EC50 0.042 μM). 4-Methoxyimino modification of pyrimidine enhanced P2Y6, preserved P2Y2 and P2Y4, and abolished P2Y14 receptor potency, in the appropriate nucleotide. N4-Benzyloxy-CDP (15, MRS2964) and N4-methoxy-Cp3U (23, MRS2957) were potent, selective P2Y6 receptor agonists (EC50 0.026 μM and 0.012 μM, respectively). A hydrophobic binding region near the nucleobase was explored with receptor modeling and docking. UTP-γ-aryl and cycloalkyl phosphoesters displayed only intermediate P2Y6 receptor potency, but had enhanced stability in acid and cell membranes. UTP-glucose was inactive, but its (S)-methanocarba analogue and N4-methoxy-cytidine 5′-triphospho-γ-[1]glucose were active (EC50 of 2.47 μM and 0.18 μM, respectively). Thus, the potency, selectivity, and stability of pyrimidine nucleotides as P2Y6 receptor agonists may be enhanced by modest structural changes. Selectivity ; Chemistry ; Pyrimidine ; Receptor ; Nucleotide ; P2Y receptor ; Agonist ; Biophysics ; Biochemistry ; Biology ; Gene ; Catalysis Synthesis and Biological Evaluation ; Synthesis and Characterization of Heterocyclic Compounds ; DNA and Nucleic Acid Chemistry