jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Wolfgang H. Binder
Source: Macromolecular Rapid Communications (review, 2018-10-24)
Field: Chemistry — Organic Chemistry

The Past 40 Years of Macromolecular Sciences: Reflections on Challenges in Synthetic Polymer and Material Science Technology and science are often successful in discontinuities ("disruptive innovations" or "leapfrogging"), in turn allowing true, big societal development by entire changes in technology rather than by minuscule stepwise improvements. Examples are the emergence of modern computer science by inventing the field-effect transistor rather than further fine-tuning the "Röhrentransistor"; the development of (organic) light-emitting diodes in advance of the "Gasglühstrumpf"; CRISPR/Cas exceeding any previous genetic method or Ziegler-Natta polymerization enabling stereoregular polypropylene (PP) and high-density polyethylene (HDPE) in advance of free-radical polymerization. Where may the frogs in polymer science in the future "jump" to? Contemplating past achievements in (synthetic) polymer science, such as living polymerization, "click" chemistry, supramolecular chemistry, the potentially "leaping" areas of self-healing and (bio)degradable materials, amyloids, and biomaterials are reflected upon. Polymerization ; Nanotechnology ; Polymer science ; Materials science ; Polymer ; Polyethylene Advanced Polymer Synthesis and Characterization ; biodegradable polymer synthesis and properties ; Click Chemistry and Applications
Authors: Umberto Capasso Palmiero | Matteo Maraldi | Nicolò Manfredini | Davide Moscatelli
Source: Biomacromolecules (article, 2018-03-09)
Field: Materials Science — Biomaterials

Zwitterionic Polyester-Based Nanoparticles with Tunable Size, Polymer Molecular Weight, and Degradation Time Biodegradable polymer nanoparticles are an important class of materials used in several applications for their unique characteristics. In particular, the ones stabilized by zwitterionic materials are gaining increased interest in medicine as alternative to the more common ones based on poly(ethylene glycol) thanks to their superior stability and ability to avoid both the accelerated blood clearance and allergic reactions. In this work, a novel class of zwitterionic based NPs has been produced, and a method to independently control the nanoparticle size, degradation time, and polymer molecular weight has been developed and demonstrated. This has been possible by the synthesis and the fine-tuning of zwitterionic amphiphilic block copolymers obtained via the combination of ring-opening polymerization and reversible addition-fragmentation chain transfer polymerization. The final results showed that when two block copolymers contain the same number of caprolactone units, the one with longer oligoester lateral chains degrades faster. This phenomenon is in sharp contrast with the one seen so far for the common linear polyester systems where longer chains result in longer degradation times, and it can be used to better tailor the degradation behavior of the nanoparticles. Ethylene glycol ; Copolymer ; Nanoparticle ; Polyester ; Polymer ; Polymerization ; Polymer chemistry ; Amphiphile ; Chain transfer ; Materials science ; Degradation (telecommunications) ; Chemical engineering ; Chemistry ; Nanotechnology ; Organic chemistry ; Radical polymerization ; Composite material ; Computer science Nanoparticle-Based Drug Delivery ; Advanced Polymer Synthesis and Characterization ; Polymer Surface Interaction Studies
Authors: Longyu Li | Pengfei Zhang | Zhiyun Zhang | Qianming Lin | Yuyang Wu | Alexander Cheng | Yun‐Xiao Lin | Christina M. Thompson | Ronald A. Smaldone | Chenfeng Ke
Source: Angewandte Chemie International Edition (article, 2018-03-05)
Field: Materials Science — Biomaterials

Hierarchical Co‐Assembly Enhanced Direct Ink Writing Integrating intelligent molecular systems into 3D printing materials and transforming their molecular functions to the macroscale with controlled superstructures will unleash great potential for the development of smart materials. Compared to macromolecular 3D printing materials, self-assembled small-molecule-based 3D printing materials are very rare owing to the difficulties of facilitating 3D printability as well as preserving their molecular functions macroscopically. Herein, we report a general approach for the integration of functional small molecules into 3D printing materials for direct ink writing through the introduction of a supramolecular template. A variety of inorganic and organic small-molecule-based inks were 3D-printed, and their superstructures were refined by post-printing hierarchical co-assembly. Through spatial and temporal control of individual molecular events from the nano- to the macroscale, fine-tuned macroscale features were successfully installed in the monoliths. Inkwell ; Nanotechnology ; 3D printing ; Supramolecular chemistry ; Materials science ; Nano- ; Molecule ; Chemistry ; Composite material Supramolecular Self-Assembly in Materials ; Supramolecular Chemistry and Complexes ; Luminescence and Fluorescent Materials
Authors: Edward Ocansey | James Darkwa | Banothile C. E. Makhubela
Source: RSC Advances (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

Synthesis, characterization and evaluation of bulky bis(pyrazolyl)palladium complexes in Suzuki–Miyaura cross-coupling reactions Pyrazole-containing compounds have been used in recent times as ligands to stabilize metal complexes used as pre-catalysts in cross-coupling reactions. With various substituents at various positions in the pyrazole ring, the overall electrophilic and steric properties of the metal complexes can be fine-tuned. Herein, we report the synthesis of bulky pyrazole-based ligands by condensation of methyl 4-(bromomethyl)benzoate or benzyl bromide with various substituted pyrazole compounds. These ligands were utilised in the synthesis of bis(pyrazolyl)palladium(ii) complexes. The complexes' catalytic activity in Suzuki-Miyaura cross-coupling reactions was evaluated. Phenyl bearing pre-catalyst 7, at a catalyst loading of 0.33 mol%, successfully converted 98% of bromobenzene and phenylboronic acid to biphenyl in 4 h at 140 °C, while the tertiary butyl bearing pre-catalyst 8 converted up to 81% of the same substrates to biphenyl. An increase in conversion was seen for all pre-catalysts when an electron-withdrawing substituent was present on the aryl halide substrate, and the opposite was observed when the electron-withdrawing group was present on the phenyl boronic acid. Palladium ; Coupling reaction ; Chemistry ; Pyrazole ; Catalysis ; Coupling (piping) ; Metal ; Combinatorial chemistry ; Polymer chemistry ; Organic chemistry ; Materials science ; Metallurgy Catalytic Cross-Coupling Reactions ; Catalytic Alkyne Reactions ; Catalytic C–H Functionalization Methods
Authors: Bingying Han | Xue Feng | Lixia Ling | Maohong Fan | Ping Liu | Riguang Zhang | Baojun Wang
Source: Physical Chemistry Chemical Physics (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

CO oxidative coupling to dimethyl oxalate over Pd–Me (Me = Cu, Al) catalysts: a combined DFT and kinetic study CO oxidative coupling to dimethyl oxalate (DMO) on Pd(111), Pd-Cu(111) and Pd-Al(111) surfaces was systematically investigated by means of density functional theory (DFT) together with periodic slab models and micro-kinetic modeling. The binding energy results show that Cu and Al can be fine substrates to stably support Pd. The favorable pathway for DMO synthesis on these catalysts starts from the formation of two COOCH<sub>3</sub> intermediates, followed by the coupling to each other, and the catalytic activity follows the trend of Pd-Al(111) > Pd(111) > Pd-Cu(111). Additionally, the formation of DMO is far favorable than that of dimethyl carbonate (DMC) on these catalysts. The results were further demonstrated by micro-kinetic modeling. Therefore, Pd-Al bimetallic catalysts can be applied in practice to effectively enhance the catalytic performance and greatly reduce the cost. This study can help with fine-tuning and designing of high-efficient and low-cost Pd-based bimetallic catalysts. Bimetallic strip ; Catalysis ; Density functional theory ; Kinetic energy ; Oxalate ; Chemistry ; Dimethyl carbonate ; Oxidative coupling of methane ; Oxidative phosphorylation ; Inorganic chemistry ; Physical chemistry ; Combinatorial chemistry ; Computational chemistry ; Organic chemistry Catalytic Processes in Materials Science ; Carbon dioxide utilization in catalysis ; Catalysis and Oxidation Reactions
Authors: Qianxiang Ai | Karol Jarolimek | Samuel M. Mazza | John E. Anthony | Chad Risko
Source: Chemistry of Materials (article, 2018-01-17)
Field: Materials Science — Materials Chemistry

Delimited Polyacenes: Edge Topology as a Tool To Modulate Carbon Nanoribbon Structure, Conjugation, and Mobility Carbon nanoribbons offer the potential of semiconducting materials that maintain the large charge-carrier mobilities of graphene. Here, starting with polyacene as a reference, we present a theoretical investigation as to how polycyclic aromatic hydrocarbons inserted into the polymer structure modulate the edge topology of the zigzag polyacene. The variations in edge topology, in turn, produce nanoribbon structures that have electronic properties that span insulators to narrow-gap semiconductors. Clear connections are made among foundational models in aromatic chemistry, namely, descriptions in terms of Clar formulas and bond-length alternation patterns, and the nanoribbon electronic, phonon, and charge-carrier mobility characteristics. These relationships, for systems that are synthetically feasible from bottom-up, solution-based approaches, offer a priori and rational design paradigms for the creation of new nanoribbon architectures. Zigzag ; Graphene ; Topology (electrical circuits) ; Enhanced Data Rates for GSM Evolution ; Semiconductor ; Electronic structure ; Materials science ; Electron mobility ; Charge carrier ; Charge (physics) ; Chemical physics ; Graphene nanoribbons ; Carbon fibers ; Organic semiconductor ; Nanotechnology ; Polymer ; Chemistry ; Computational chemistry ; Optoelectronics ; Computer science ; Physics ; Mathematics ; Quantum mechanics Graphene research and applications ; Carbon Nanotubes in Composites ; Synthesis and Properties of Aromatic Compounds
Authors: Michael Zeets | Daniel E. Resasco | Bin Wang
Source: Catalysis Today (article, 2018-03-01)
Field: Chemistry — Inorganic Chemistry

Enhanced chemical activity and wettability at adjacent Brønsted acid sites in HZSM-5 Catalysis ; Zeolite ; Chemistry ; Delocalized electron ; Adsorption ; Brønsted–Lowry acid–base theory ; Selectivity ; Hydronium ; Molecule ; Density functional theory ; Polarization (electrochemistry) ; Chemical physics ; Computational chemistry ; Charge density ; Proton affinity ; Wetting ; Inorganic chemistry ; Physical chemistry ; Ion ; Chemical engineering ; Organic chemistry ; Protonation Zeolite Catalysis and Synthesis ; Metal-Organic Frameworks: Synthesis and Applications ; Advanced Battery Materials and Technologies
Authors: Bo Yang | Donald G. Truhlar
Source: Organometallics (article, 2018-10-26)
Field: Chemistry — Organic Chemistry

Computational Design of an Iron Catalyst for Olefin Metathesis Olefin metathesis is a versatile reaction in synthetic chemistry. The use of iron compounds as olefin metathesis catalysts has attracted interest but has not succeeded because most Fe complexes catalyze cyclopropanation reactions preferentially to cycloreversion, which is a key step in the metathesis reaction cycle. In the present study, we performed density functional theory calculations to study the catalytic effect of ancillary pincer ligands in an Fe organometallic catalyst for olefin metathesis. We show here that the partial atomic charge on Fe in the metallocyclobutane intermediate is a descriptor for the tendency of the Fe complex to favor olefin metathesis over cyclopropanation. The results suggest that the pincer ligands can decrease the partial atomic charge on the Fe ion and that decreasing this charge can make the desired cycloreversion reaction more energetically favorable than the cyclopropanation side reaction. In this way, we found that the Fe carbene stabilized by N-heterocyclic dicarbene ligands (Fe(C–N–C)(═CHCH3), where C–N–C denotes 2,6-bis(methylimidazol-2-ylidene)pyridine), is a potential candidate for catalyzing the olefin metathesis reaction. We then calculated the whole catalytic cycle for the propylene metathesis reaction catalyzed by the Fe(C–N–C) carbene, and the results indicate that the cyclopropanation reaction is disfavored by ∼4 kcal/mol. We verified the stability of the proposed Fe(C–N–C) catalyst by considering two possible deformation pathways: the transformation of the carbene ligand to a coordinated alkene molecule and the formation of a hydride carbyne intermediate followed by the insertion of a propylene molecule. We found that neither deformation pathway is energetically favorable. Finally we propose a viable route to synthesize the Fe(C–N–C) carbene complex by utilizing the already available Fe(N2)2 complex stabilized by an N-heterocyclic dicarbene ligand. Cyclopropanation ; Carbene ; Chemistry ; Metathesis ; Catalysis ; Catalytic cycle ; Olefin fiber ; Pincer ligand ; Pincer movement ; Alkene ; Medicinal chemistry ; Salt metathesis reaction ; Photochemistry ; Organic chemistry ; Polymerization Synthetic Organic Chemistry Methods ; Cyclopropane Reaction Mechanisms ; Organometallic Complex Synthesis and Catalysis
Authors: Matteo Di Giosia | Francesco Valle | Andrea Cantelli | Andréa Bottoni | Francesco Zerbetto | Matteo Calvaresi
Source: Materials (article, 2018-04-27)
Field: Chemistry — Organic Chemistry

C60 Bioconjugation with Proteins: Towards a Palette of Carriers for All pH Ranges The high hydrophobicity of fullerenes and the resulting formation of aggregates in aqueous solutions hamper the possibility of their exploitation in many technological applications. Noncovalent bioconjugation of fullerenes with proteins is an emerging approach for their dispersion in aqueous media. Contrary to covalent functionalization, bioconjugation preserves the physicochemical properties of the carbon nanostructure. The unique photophysical and photochemical properties of fullerenes are then fully accessible for applications in nanomedicine, sensoristic, biocatalysis and materials science fields. However, proteins are not universal carriers. Their stability depends on the biological conditions for which they have evolved. Here we present two model systems based on pepsin and trypsin. These proteins have opposite net charge at physiological pH. They recognize and disperse C<sub>60</sub> in water. UV-Vis spectroscopy, zeta-potential and atomic force microscopy analysis demonstrates that the hybrids are well dispersed and stable in a wide range of pH&rsquo;s and ionic strengths. A previously validated modelling approach identifies the protein-binding pocket involved in the interaction with C<sub>60</sub>. Computational predictions, combined with experimental investigations, provide powerful tools to design tailor-made C<sub>60</sub>@proteins bioconjugates for specific applications. Bioconjugation ; Palette (painting) ; Materials science ; Nanotechnology ; Chemistry ; Biophysics ; Computer science ; Biology Fullerene Chemistry and Applications ; Polymer Nanocomposite Synthesis and Irradiation ; Graphene research and applications
Authors: Sanju Gupta | Sara B. Carrizosa | Jacek B. Jasiński | Nicholas Dimakis
Source: AIP Advances (article, 2018-06-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Charge transfer dynamical processes at graphene-transition metal oxides/electrolyte interface for energy storage: Insights from in-situ Raman spectroelectrochemistry Hybrids consisting of supercapacitive functionalized graphene (graphene oxide; GO reduced graphene oxide; rGO multilayer graphene; MLG, electrochemically reduced GO; ErGO) and three-dimensional graphene scaffold (rGOHT; hydrothermally prepared) decorated with cobalt nanoparticles (CoNP), nanostructured cobalt (CoO and Co3O4) and manganese (MnO2) oxide polymorphs, assembled electrochemically facilitate chemically bridged interfaces with tunable properties. Since Raman spectroscopy can capture variations in structural and chemical bonding, Raman spectro-electrochemistry in operando i.e. under electrochemical environment with applied bias is employed to 1) probe graphene/metal bonding and dynamic processes, 2) monitor the spectral changes with successive redox interfacial reactions, and 3) quantify the associated parameters including type and fraction of charge transfer. The transverse optical (TO) and longitudinal optical (LO) phonons above 500 cm−1 belonging to Co3O4, CoO, MnO2 and carbon-carbon bonding occurring at 1340 cm-1, 1590 cm−1 and 2670 cm-1 belonging to D, G, and 2D bands, respectively, are analyzed with applied potential. Consistent variation in Raman band position and intensity ratio reveal structural modification, combined charge transfer due to localized orbital re-hybridization and mechanical strain, all resulting in finely tuned electronic properties. Moreover, the heterogeneous basal and edge plane sites of graphene nanosheets in conjunction with transition metal oxide ‘hybrids’ reinforce efficient surface/interfacial electron transfer and available electronic density of states near Fermi level for enhanced performance. We estimated the extent and nature (n− or p−) of charge transfer complemented with Density Functional Theory calculations affected by hydration and demonstrate the synergistic coupling between graphene nanosheets and nanoscale cobalt (and manganese) oxides for applied electrochemical applications. Graphene ; Raman spectroscopy ; Materials science ; Oxide ; Electron transfer ; Fermi level ; Cobalt oxide ; Electrochemistry ; Carbon nanotube ; Chemical physics ; Nanotechnology ; Electrode ; Chemistry ; Photochemistry ; Physical chemistry ; Electron Supercapacitor Materials and Fabrication ; Advancements in Battery Materials ; Graphene research and applications
Authors: Rubén Solórzano | Olivia Tort | Javier García‐Pardo | Tuixent Escribà | Júlia Lorenzo | Mireia Arnedo | Daniel Ruiz‐Molina | Ramón Alibés | Félix Busquè | Fernando Novio
Source: Biomaterials Science (article, 2018-11-15)
Field: Chemistry — Inorganic Chemistry

Versatile iron–catechol-based nanoscale coordination polymers with antiretroviral ligand functionalization and their use as efficient carriers in HIV/AIDS therapy A novel chemical approach integrating the benefits of nanoparticles with versatility of coordination chemistry is reported herein to increase the effectiveness of well-known HIV antiretroviral drugs. The novelty of our approach is illustrated using a catechol ligand tethered to the known antiretroviral azidothymidine (AZT) as a constitutive building block of the nanoparticles. The resulting nanoscale coordination polymers (NCPs) ensure good encapsulation yields and equivalent antiretroviral activity while significantly diminishing its cytotoxicity. Moreover, this novel family of nanoparticles also offers (i) long-lasting drug release that is dissimilar inside and outside the cells depending on pH, (ii) triggered release in the presence of esterases, activating the antiviral activity in an on-off manner due to a proper chemical design of the ligand and (iii) improved colloidal stabilities and cellular uptakes (up to 50-fold increase). The presence of iron nodes also adds multifunctionality as possible contrast agents. The present study demonstrates the suitability of NCPs bearing pharmacologically active ligands as an alternative to conventional antiretroviral treatments. Catechol ; Human immunodeficiency virus (HIV) ; Surface modification ; Antiretroviral therapy ; Drug delivery ; Nanoscopic scale ; Ligand (biochemistry) ; Polymer ; Nanotechnology ; Combinatorial chemistry ; Chemistry ; Materials science ; Medicine ; Virology ; Organic chemistry ; Biochemistry ; Receptor ; Viral load Metal-Organic Frameworks: Synthesis and Applications ; Dendrimers and Hyperbranched Polymers ; Pneumocystis jirovecii pneumonia detection and treatment
Authors: Petru Lunca‐Popa | João Ricardo Antunes Afonso | Patrick Grysan | Jonathan Crêpellière | Renaud Leturcq | D. Lenoble
Source: Scientific Reports (article, 2018-05-02)
Field: Materials Science — Materials Chemistry

Tuning the electrical properties of the p-type transparent conducting oxide Cu1−xCr1+xO2 by controlled annealing Off-stoichiometric copper chromium oxide delafossite received lately a great interest due to its high p-type electrical conductivity and adequate optical transmittance in the visible range. However, for a suitable integration in active devices such as p-n junctions, transistors or optoelectronic devices, the electronic properties must be efficiently tailored. Here, post-deposition thermal treatment is proven as an adequate approach for finely controlling the electrical properties of this former degenerate semiconducting material. The energetics of the annealing process are investigated using two different approaches, as a function of the annealing temperature and as a function of the annealing time, allowing the accurate determination of the activation energy of the annealing of defects. By using this method, the electrical carrier concentration was varied in the 10<sup>21</sup> - 10<sup>17</sup> cm<sup>-3</sup> range while the recorded changes in the drift mobility covered three orders of magnitude. Moreover, we demonstrate the ability to accurately manipulate the Fermi level of such materials, which is of great importance in controlling the carrier injection and extraction in optoelectronic active layers. Annealing (glass) ; Delafossite ; Materials science ; Optoelectronics ; Transmittance ; Transistor ; Electrical resistivity and conductivity ; Stoichiometry ; Oxide ; Chemistry ; Metallurgy ; Electrical engineering Copper-based nanomaterials and applications ; ZnO doping and properties ; Electronic and Structural Properties of Oxides
Authors: Jasmin Popara | Lisa Accomasso | Emanuela Vitale | Clara Gallina | Dorotea Roggio | Ambra Iannuzzi | Stefania Raimondo | Raffaella Rastaldo | Gabriele Alberto | Federico Catalano | Gianmario Martra | Valentina Turinetto | Pasquale Pagliaro | Claudia Giachino
Source: Nanomedicine (article, 2018-05-01)
Field: Materials Science — Biomaterials

Silica Nanoparticles Actively Engage With Mesenchymal Stem Cells in Improving Acute Functional Cardiac Integration These findings provide strong evidence that SiO<sub>2</sub>-NPs actively engage in mediating biological effects, ultimately resulting in augmented hMSC acute cardiac integration potential. Mesenchymal stem cell ; Nanoparticle ; Stem cell ; Nanotechnology ; Materials science ; Cell biology ; Biology Electrospun Nanofibers in Biomedical Applications ; Tissue Engineering and Regenerative Medicine ; 3D Printing in Biomedical Research
Authors: Hao Jie Jiang | Jiangang Lu
Source: Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy (article, 2018-02-06)
Field: Chemistry — Analytical Chemistry

Using an optimal CC-PLSR-RBFNN model and NIR spectroscopy for the starch content determination in corn Partial least squares regression ; Chemistry ; Mean squared error ; Near-infrared spectroscopy ; Correlation coefficient ; Biological system ; Starch ; Calibration ; Coefficient of determination ; Content (measure theory) ; Test set ; Data set ; Chemometrics ; Analytical Chemistry (journal) ; Statistics ; Chromatography ; Mathematics ; Food science Spectroscopy and Chemometric Analyses ; Meat and Animal Product Quality ; Water Quality Monitoring and Analysis