jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Robin Stuhr | Patrick Bayer | Christian B. W. Stark | Axel Jacobi von Wangelin
Source: ChemSusChem (article, 2021-06-29)
Field: Chemistry — Organic Chemistry

Light‐Driven Waste‐To‐Value Upcycling: Bio‐Based Polyols and Polyurethanes from the Photo‐Oxygenation of Cardanols The upcycling of waste biomass into valuable materials by resource-efficient chemical transformations is a prime objective for sustainable chemistry. This approach is demonstrated in a straightforward light-driven synthesis of polyols and polyurethane foams from the multi-ton waste products of cashew nut processing. The photo-oxygenation of cardanol from nutshell oil results in the formation of synthetically versatile hydroperoxides. The choice of the workup method (i. e., reduction, hydrogenation, epoxidation) enables access to a diverse range of alcohols with tunable alkene and OH functions. Condensation with isocyanates to give rigid polyurethane foams provides a resource-efficient waste-to-value chain that benefits from the availability of cardanol and installation of OH groups from aerial O<sub>2</sub> . Cardanol ; Polyurethane ; Materials science ; Biomass (ecology) ; Organic chemistry ; Chemistry ; Chemical engineering ; Engineering Oxidative Organic Chemistry Reactions ; Ginkgo biloba and Cashew Applications ; Polyoxometalates: Synthesis and Applications
Authors: Laurent Latxague | Sébastien Benizri | Alexandra Gaubert | James Tolchard | Dênis Martinez | Estelle Morvan | Axelle Grélard | Ahmad Saad | Birgit Habenstein | Antoine Loquet | Philippe Barthélémy
Source: Journal of Colloid and Interface Science (article, 2021-03-17)
Field: Materials Science — Biomaterials

Bolaamphiphile-based supramolecular gels with drugs eliciting membrane effects Supramolecular chemistry ; Chemistry ; Drug delivery ; Membrane ; Nanotechnology ; Supramolecular assembly ; Biophysics ; Combinatorial chemistry ; Biochemistry ; Materials science ; Organic chemistry ; Biology ; Molecule Supramolecular Self-Assembly in Materials ; Antimicrobial Peptides and Activities ; Neuropeptides and Animal Physiology
Authors: Mohammad R. Momeni | Zeyu Zhang | David Dell’Angelo | Farnaz A. Shakib
Source: APL Materials (article, 2021-05-01)
Field: Chemistry — Inorganic Chemistry

Tuning electronic properties of conductive 2D layered metal–organic frameworks via host–guest interactions: Dioxygen as an electroactive chemical stimuli Thermodynamics and kinetics of O2 adsorption and its impacts on structural features and conductive behavior of 2D π-stacked layered metal–organic frameworks (MOFs) are studied using periodic PBE-D3 quantum mechanical calculations. Our computed O2 adsorption energies of Co3(HTTP)2 (HTTP = hexathiotriphenylene), as a representative of the 2D MOFs family, show that not only open-Co(II) sites but also redox-active HTTP linkers take part in chemisorption of O2 by forming strong S=O bonds. This is in contrast to conventional 3D Co2(OH)2(BBTA) and Fe2(dobdc) MOFs with similar hexagonal 1D channels where O2 adsorption occurs solely via coordination to the open-metal sites. Due to the adsorptive capability of its redox-active linkers, Co3(HTTP)2 is superior to the analogues 3D MOFs where the change in the oxidation state of the transition metal centers is suggested to result in hindering both the kinetics and thermodynamics of the adsorption process. Our calculated band structures and density of states show that the conductive behavior of the studied Co3(HTTP)2 2D MOF changes dramatically from metallic in the parent system to semiconducting under oxygen rich conditions, with direct bandgap openings that range from 123 to 251 meV. The results presented in this work are helpful in understanding the effects of different electroactive guest molecules on the structure and conductive behavior of 2D layered MOFs and related nonporous materials. Adsorption ; Materials science ; Metal-organic framework ; Chemisorption ; Chemical physics ; Metal ; Redox ; Electrical conductor ; Molecule ; Transition metal ; Nanotechnology ; Chemical engineering ; Catalysis ; Physical chemistry ; Chemistry ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Covalent Organic Framework Applications ; 2D Materials and Applications
Authors: Takayuki Ishida | Saki Ito | Yuta Homma | Yukiya Kyoden
Source: Inorganics (article, 2021-01-20)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Molecular S = 2 High-Spin, S = 0 Low-Spin and S = 0 ⇄ 2 Spin-Transition/-Crossover Nickel(II)-Bis(nitroxide) Coordination Compounds Heterospin systems have a great advantage in frontier orbital engineering since they utilize a wide diversity of paramagnetic chromophores and almost infinite combinations and mutual geometries. Strong exchange couplings are expected in 3d–2p heterospin compounds, where the nitroxide (aminoxyl) oxygen atom has a direct coordination bond with a nickel(II) ion. Complex formation of nickel(II) salts and tert-butyl 2-pyridyl nitroxides afforded a discrete 2p–3d–2p triad. Ferromagnetic coupling is favored when the magnetic orbitals, nickel(II) dσ and radical π*, are arranged in a strictly orthogonal fashion, namely, a planar coordination structure is characterized. In contrast, a severe twist around the coordination bond gives an orbital overlap, resulting in antiferromagnetic coupling. Non-chelatable nitroxide ligands are available for highly twisted and practically diamagnetic complexes. Here, the Ni–O–N–Csp2 torsion (dihedral) angle is supposed to be a useful metric to describe the nickel ion dislocated out of the radical π* nodal plane. Spin-transition complexes exhibited a planar coordination structure in a high-temperature phase and a nonplanar structure in a low-temperature phase. The gradual spin transition is described as a spin equilibrium obeying the van’t Hoff law. Density functional theory calculation indicates that the energy level crossing of the high- and low-spin states. The optimized structures of diamagnetic and high-spin states well agreed with the experimental large and small torsions, respectively. The novel mechanism of the present spin transition lies in the ferro-/antiferromagnetic coupling switch. The entropy-driven mechanism is plausible after combining the results of the related copper(II)-nitroxide compounds. Attention must be paid to the coupling parameter J as a variable of temperature in the magnetic analysis of such spin-transition materials. For future work, the exchange coupling may be tuned by chemical modification and external stimulus, because it has been clarified that the parameter is sensitive to the coordination structure and actually varies from 2J/kB = +400 K to −1400 K. Chemistry ; Dihedral angle ; Antiferromagnetism ; Paramagnetism ; Nitroxide mediated radical polymerization ; Spin transition ; Diamagnetism ; Crystallography ; Spin crossover ; Atomic orbital ; Molecular orbital ; Chemical physics ; Computational chemistry ; Condensed matter physics ; Hydrogen bond ; Molecule ; Physics ; Magnetic field Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Metal-Catalyzed Oxygenation Mechanisms
Authors: C. Roques | S. Li | E.V. Batrakova | A.V. Kabanov | T.K. Bronich | A. Schulz | R. Jordan | R. Luxenhofer
Source: UNC Libraries (article, 2021-11-17)
Field: Materials Science — Polymers and Plastics

Doubly amphiphilic poly(2-oxazoline)s as high-capacity delivery systems for hydrophobic drugs Solubilization of highly hydrophobic drugs with carriers that are non-toxic, non-immunogenic and well-defined remains a major obstacle in pharmaceutical sciences. Well-defined amphiphilic di- and triblock copolymers based on poly(2-oxazolines) were prepared and used for the solubilization of Paclitaxel (PTX) and other water-insoluble drugs. Probing the polymer micelles in water with the fluorescence probe pyrene, an unusual high polar microenvironment of the probe was observed. This coincides with an extraordinary large loading capacity for PTX of 45. wt.% active drug in the formulation as well as high water solubility of the resulting formulation. Physicochemical properties of the formulations, ease of preparation and stability upon lyophilization, low toxicity and immunogenicity suggest that poly(2-oxazoline)s are promising candidates for the delivery of highly challenging drugs. Furthermore, we demonstrate that PTX is fully active and provides superior tumor inhibition as compared to the commercial micellar formulation. Amphiphile ; Oxazoline ; Chemistry ; Hydrophobic effect ; Drug delivery ; Polymer chemistry ; Organic chemistry ; Copolymer ; Polymer Synthesis and properties of polymers ; Advanced Polymer Synthesis and Characterization ; Synthesis and Characterization of Heterocyclic Compounds
Authors: Areetha D’Souza | Surajit Bhattacharjya
Source: Biochemistry (review, 2021-02-03)
Field: Materials Science — Biomaterials

<i>De Novo</i>-Designed β-Sheet Heme Proteins The field of <i>de novo</i> protein design has met with considerable success over the past few decades. Heme, a cofactor, has often been introduced to impart a diverse array of functions to a protein, ranging from electron transport to respiration. In nature, heme is found to occur predominantly in α-helical structures over β-sheets, which has resulted in significant designs of heme proteins utilizing coiled-coil helices. By contrast, there are only a few known β-sheet proteins that bind heme and designs of β-sheets frequently result in amyloid-like aggregates. This review reflects on our success in designing a series of multistranded β-sheet heme binding peptides that are well folded in both aqueous and membrane-like environments. Initially, we designed a β-hairpin peptide that self-assembles to bind heme and performs peroxidase activity in membrane. The β-hairpin was optimized further to accommodate a heme binding pocket within multistranded β-sheets for catalysis and electron transfer in membranes. Furthermore, we <i>de novo</i> designed and characterized β-sheet peptides and miniproteins that are soluble in an aqueous environment capable of binding single and multiple hemes with high affinity and stability. Collectively, these studies highlight the substantial progress made toward the design of functional β-sheets. Heme ; Chemistry ; Protein design ; Beta sheet ; Biophysics ; Coiled coil ; Cofactor ; Hemeprotein ; Membrane ; Biochemistry ; Peptide ; Protein structure ; Enzyme ; Biology Supramolecular Self-Assembly in Materials ; Protein Structure and Dynamics ; Lipid Membrane Structure and Behavior
Authors: Franz A. Mautner | Florian Bierbaumer | Roland C. Fischer | Ana Torvisco | Ramón Vicente | Mercè Font-Bardı́a | Ànnia Tubau | Saskia Speed | Salah S. Massoud
Source: Inorganics (article, 2021-09-30)
Field: Materials Science — Materials Chemistry

Diverse Coordination Numbers and Geometries in Pyridyl Adducts of Lanthanide(III) Complexes Based on β-Diketonate Ten mononuclear rare earth complexes of formula [La(btfa)3(H2O)2] (1), [La(btfa)3(4,4′-Mt2bipy)] (2), [La(btfa)3(4,4′-Me2bipy)2] (3), [La(btfa)3(5,5′-Me2bipy)2] (4), [La(btfa)3(terpy)] (5), [La(btfa)3(phen)(EtOH)] (6), [La(btfa)3(4,4′-Me2bipy)(EtOH)] (7), [La(btfa)3(2-benzpy)(MeOH)] (8), [Tb(btfa)3(4,4′-Me2bipy)] (9) and (Hpy)[Eu(btfa)4] (10), where btfa = 4,4,4-trifuoro-1-phenylbutane-1,3-dionato anion, 4,4′-Mt2bipy = 4,4′-dimethoxy-2,2′-bipyridine, 4,4′-Me2bipy = 4,4′-dimethyl-2,2′-bipyridine, 5,5′-Me2bipy = 5,5′-dimethyl-2,2′-bipyridine, terpy = 2,2′:6′,2′-terpyridine, phen = 1,10-phenathroline, 2-benzpy = 2-(2-pyridyl)benzimidazole, Hpy = pyridiniumH+ cation) have been synthesized and structurally characterized. The complexes display coordination numbers (CN) eight for 1, 2, 9, 10, nine for 5, 6, 7, 8 and ten for 3 and 4. The solid-state luminescence spectra of Tb-9 and Eu-10 complexes showed the same characteristic bands predicted from the Tb(III) and Eu(III) ions. The Overall Quantum Yield measured (ϕTOT) at the excitation wavelength of 371 nm for both compounds yielded 1.04% for 9 and up to 34.56% for 10. Chemistry ; Lanthanide ; Luminescence ; Benzimidazole ; Adduct ; Ion ; Terpyridine ; Crystallography ; Solid-state ; Bipyridine ; Crystal structure ; Stereochemistry ; Metal ; Physical chemistry ; Materials science ; Organic chemistry Lanthanide and Transition Metal Complexes ; Magnetism in coordination complexes ; Radioactive element chemistry and processing
Authors: Rubén Pérez‐Aguirre | Beñat Artetxe | Garikoitz Beobide | Óscar Castillo | Imanol de Pedro | Antonio Luque | Sonia Pérez‐Yáñez | Stefan Wuttke
Source: Cell Reports Physical Science (article, 2021-04-30)
Field: Chemistry — Inorganic Chemistry

Ferromagnetic supramolecular metal-organic frameworks for active capture and magnetic sensing of emerging drug pollutants Capture and sensing of emerging pollutants is one of the increasing environmental concerns due to the adverse ecological and human health effects. Here, we report the synthesis of a supramolecular metal-organic framework (SMOF) [CrCu6(μ-H2O)6(μ3-OH)6(μ-adeninato-κN33:κN9)6](SO4)1.5 which is able to capture anionic drugs and exhibits magnetic properties useful for sensing purposes. The features of the nucleobase decorated CrCu6 building block allow the incorporation of up to 9 drug molecules (i.e., ibuprofen and naproxen in this work) per heptameric entity. In addition, we provide a simple way to quantify the incorporated number of drug molecules through a magnetic sustentation experiment in which the field required to keep the particles attached to the electromagnet pole is linearly related to the total mass of the anionic counterion. In this way, it also provides an easy way to determine the amount of entrapped drug molecules, making this SMOF a promising candidate for environmental remediation technologies. Supramolecular chemistry ; Naproxen ; Pollutant ; Ferromagnetism ; Molecule ; Nanotechnology ; Materials science ; Environmental remediation ; Drug ; Chemistry ; Contamination ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Magnetism in coordination complexes ; Covalent Organic Framework Applications
Authors: Nelson Y. S. Lam | Tegan P. Stockdale | Matthew J. Anketell | Ian Paterson
Source: Chemical Communications (article, 2021-01-01)
Field: Chemistry — Organic Chemistry

Conquering peaks and illuminating depths: developing stereocontrolled organic reactions to unlock nature's macrolide treasure trove The structural complexity and biological importance of macrolide natural products has inspired the development of innovative strategies for their chemical synthesis. With their dense stereochemical content, high level of oxygenation and macrocyclic cores, we viewed the efficient total synthesis of these valuable compounds as an aspirational driver towards developing robust methods and strategies for their construction. Starting out from the initial development of our versatile asymmetric aldol methodology, this personal perspective reflects on an adventurous journey, with all its trials, tribulations and serendipitous discoveries, across the total synthesis, in our group, of a representative selection of six macrolide natural products of marine and terrestrial origin - swinholide A, spongistatin 1, spirastrellolide A, leiodermatolide, chivosazole F and actinoallolide A. Treasure ; Aldol reaction ; Selection (genetic algorithm) ; Perspective (graphical) ; Literature ; History ; Chemistry ; Computer science ; Art ; Organic chemistry ; Artificial intelligence ; Archaeology Synthetic Organic Chemistry Methods ; Chemical synthesis and alkaloids ; Advanced Synthetic Organic Chemistry
Authors: Montgomery Jaritz | Philipp Alizadeh | Stefan Wilski | Lara Kleines | Rainer Dahlmann
Source: Plasma Processes and Polymers (article, 2021-05-25)
Field: Materials Science — Materials Chemistry

Comparison of HMDSO and HMDSN as precursors for high‐barrier plasma‐polymerized multilayer coating systems on polyethylene terephthalate films Abstract Hexamethyldisiloxane (HMDSO)‐ and hexamethyldisilazane (HMDSN)‐based plasma polymeric coatings are compared as elements of multilayer barrier coatings, consisting of an alternating structure of organosilicon and silicon oxide layers. Furthermore, these coatings are examined with regard to their deposition rate, critical layer thickness, surface roughness, atomic composition, and gas permeability. It is investigated how these attributes correlate in the overall barrier performance of a multilayer coating system. The concluded examinations show that HMDSN delivers best overall barrier performances as a precursor at high energy densities. For lower energy densities, the use of HMDSO is preferable. Intermediate layer thickness should not exceed six nanometers for best barrier performance in the given experiment configuration. Hexamethyldisiloxane ; Materials science ; Organosilicon ; Polyethylene terephthalate ; Coating ; Plasma polymerization ; Barrier layer ; Layer (electronics) ; Composite material ; Polyethylene ; Silicon ; Silicon oxide ; Nanometre ; Contact angle ; Surface energy ; Plasma ; Surface roughness ; Surface finish ; Chemical engineering ; Polymerization ; Polymer chemistry ; Polymer ; Optoelectronics Diamond and Carbon-based Materials Research ; Metal and Thin Film Mechanics ; Copper Interconnects and Reliability
Authors: Jens Moons | Alexandra Loosen | Charlotte Simms | Francisco de Azambuja | Tatjana N. Parac‐Vogt
Source: Nanoscale (article, 2021-01-01)
Field: Materials Science — Materials Chemistry

Heterogeneous nanozymatic activity of Hf oxo-clusters embedded in a metal–organic framework towards peptide bond hydrolysis Materials with enzyme-like activities and proteolytic potential are emerging as a robust and effective alternative to natural enzymes. Herein, a Hf<sub>6</sub>O<sub>8</sub>-based NU-1000 metal organic framework (Hf-MOF) is shown to act as a heterogeneous catalyst for the hydrolysis of peptide bonds under mild conditions. In the presence of Hf-MOF, a glycylglycine model dipeptide was hydrolysed with a rate constant of k<sub>obs</sub> = 8.33 × 10<sup>-7</sup> s<sup>-1</sup> (half-life (t<sub>1/2</sub>) of 231 h) at 60 °C and pD 7.4, which is significantly faster than the uncatalyzed reaction. Other Gly-X peptides (X = Ser, Asp, Ile, Ala, and His) were also smoothly hydrolysed under the same conditions with similar rates, except for the faster reactions observed for Gly-His and Gly-Ser. Moreover, the Hf<sub>6</sub>O<sub>8</sub>-based NU-1000 MOF also exhibits a high selectivity in the cleavage of a protein substrate, hen egg white lysozyme (HEWL). Our results suggest that embedding Hf<sub>6</sub>O<sub>8</sub> oxo-clusters is an efficient strategy to conserve the hydrolytic activity while smoothing the strong substrate adsorption previously observed for a discrete Hf oxo-cluster that hindered further development of its proteolytic potential. Furthermore, comparison with isostructural Zr-NU-1000 shows that although the Hf variant afforded the same cleavage pattern towards HEWL but slightly slower reaction rates, it exhibited a larger stability window and a better recyclability profile. The results suggest that these differences originate from the intrinsic differences between Hf<sup>IV</sup> and Zr<sup>IV</sup> centers, and from the lower surface area of Hf-NU-1000 in comparison to Zr-NU-1000. Lysozyme ; Hydrolysis ; Peptide bond ; Peptide ; Chemistry ; Metal-organic framework ; Metal ; Combinatorial chemistry ; Organic chemistry ; Adsorption ; Biochemistry Advanced Nanomaterials in Catalysis ; Metal-Organic Frameworks: Synthesis and Applications ; Nanocluster Synthesis and Applications
Authors: J. Velásquez-Cock | A. Serpa | Catalina Gómez Hoyos | Piedad Gañán | Manuel Romero‐Sáez | Lina María Vélez Acosta | Natalia Correa Hincapié | Robín Zuluaga
Source: Polymers (article, 2021-10-21)
Field: Materials Science — Biomaterials

Influence of a Non-Ionic Surfactant in the Microstructure and Rheology of a Pickering Emulsion Stabilized by Cellulose Nanofibrils Emulsion stabilization is a broad and relevant field with applications in oil, polymer and food industries. In recent years, the use of solid particles to stabilize emulsions or Pickering emulsions have been studied for their kinetic and physical properties. Nanomaterials derived from natural sources are an interesting alternative for this application. Cellulose nanofibrils (CNFs) have been widely explored as a Pickering emulsifier with potential food applications, however, in some cases the presence of surfactants is unavoidable, and the literature is devoid of an evaluation of the effect of a non-ionic food-grade surfactant, such as polysorbate 80, in the stabilization of a vegetable oil by CNFs. To better assess the possible interactions between CNFs and this surfactant emulsions containing coconut oil, an emerging and broadly used oil, were processed with and without polysorbate 80 and evaluated in their qualitative stability, morphological and physical properties. Fluorescence microscopy, dynamic light scattering and rheology were used for this assessment. Results indicate in absence of the surfactant, emulsion stability increased at higher CNFs content, creaming was observed at 0.15 and 0.3 wt.% of CNFs, while it was not evidenced when 0.7 wt.% was used. After the addition of surfactant, the droplets are covered by the surfactant, resulting in particles with a smaller diameter, entrapped in the cellulosic structure. Rheology indicates a lower network stiffness after adding polysorbate 80. Pulmonary surfactant ; Rheology ; Creaming ; Emulsion ; Pickering emulsion ; Chemical engineering ; Materials science ; Polymer ; Cellulose ; Cellulose fiber ; Dynamic light scattering ; Composite material ; Nanotechnology ; Nanoparticle Advanced Cellulose Research Studies ; Pickering emulsions and particle stabilization ; Polysaccharides and Plant Cell Walls
Authors: Ali Khosrozadeh | Li Tao | Peter Zhao | Mitchell B. Miller | Oleksandr Voznyy | Jian Liu
Source: Journal of Power Sources (article, 2021-05-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Water/acetonitrile hybrid electrolyte enables using smaller ions for achieving superior energy density in carbon-based supercapacitors Supercapacitor ; Electrolyte ; Capacitance ; Materials science ; Gravimetric analysis ; Activated carbon ; Carbon fibers ; Chemical engineering ; Specific surface area ; Chemistry ; Electrode ; Adsorption ; Composite material ; Organic chemistry Supercapacitor Materials and Fabrication ; Advanced Battery Materials and Technologies ; Advanced battery technologies research