jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Naohiro Kameta | Masaki Kogiso
Source: Chemistry - A European Journal (article, 2021-07-23)
Field: Materials Science — Biomaterials

Self‐Assembly of a Pyridine‐Based Amphiphile Complexed with Regioisomeric Dihydroxy Naphthalenes into Supramolecular Nanotubes with Different Inner Diameters A pyridine-based amphiphile complexed with 1,5-, 1,6-, 2,6-, or 2,7-dihydroxy naphthalene self-assembled in water to form nanotubes with inner diameters of 46, 38, 24, 18, and 11 nm in which the naphthalene molecules formed J-type aggregates. In contrast, the amphiphile complexed with 1,2-, 1,3-, 1,4-, 1,7-, 1,8-, or 2,3-dihydroxy naphthalene formed nanofibers in which the naphthalene molecules formed H-type aggregates. The inner diameter of the nanotubes strongly depended on the regioisomeric dihydroxy naphthalene. UV-vis, fluorescence, infrared spectroscopy, X-ray diffraction analysis, and differential scanning calorimetry showed that nanotubes with smaller inner diameters had weaker intermolecular hydrogen bonds between the tilted amphiphiles complexed with the naphthalene molecules within the membrane walls and showed larger Stokes shifts in the excimer fluorescence of the naphthalene moiety. These findings should be useful not only for fine-tuning the inner diameters of supramolecular nanotubes but also for controlling the aggregation states of functional aromatic molecules to generate nanostructures with useful optical and electronic properties in water. Supramolecular chemistry ; Pyridine ; Amphiphile ; Chemistry ; Self-assembly ; Stereochemistry ; Organic chemistry ; Molecule ; Copolymer Supramolecular Self-Assembly in Materials ; Polydiacetylene-based materials and applications ; Luminescence and Fluorescent Materials
Authors: Pierre Frangville | Shiv Kumar | Michel Gelbcke | Kristof Van Hecke | F. Meyer
Source: Preprints.org (preprint, 2021-10-27)
Field: Materials Science — Materials Chemistry

Multi Stimuli Responsive Materials Supported by Orthogonal Hydrogen and Halogen Bonding or I···Alkene Interaction Smart materials represent an elegant class of (macro)-molecules endowed with the ability to react to chemical/physical changes in the environment. Herein, we prepared new photo responsive azobenzenes possessing halogen bond donor groups. The X-ray structures of two molecules highlight supramolecular organizations governed by unusual noncovalent bonds. In azo dye I-azo-NO2, the nitro group is engaged in orthogonal H&amp;middot;&amp;middot;&amp;middot;O&amp;middot;&amp;middot;&amp;middot;I halogen and hydrogen bonding, linking the units in parallel undulating chains. As concern parent I-azo-NH-MMA, a non-centrosymmetric pattern is formed due to a very rare I&amp;middot;&amp;middot;&amp;middot;&amp;pi; interaction involving the alkene group supplemented by hydrogen bonds. The Cambridge Structural Database contains only four structures with the same I&amp;middot;&amp;middot;&amp;middot;CH2=C contact. For all compounds, a 19F NMR spectroscopic analysis confirms the formation of halogen bonds in solution through a recognition process with chloride anion, and the reversible photo-responsiveness is demonstrated upon exposing a solution to UV light irradiation. Finally, intermediate I-azo-NO2 also shows a pronounced color change due to pH variation. These azobenzenes are thereby attractive building blocks to design multi-stimuli responsive materials for highly functional devices. Hydrogen bond ; Alkene ; Molecule ; Halogen ; Supramolecular chemistry ; Non-covalent interactions ; Chemistry ; Nitro ; Photochemistry ; Crystallography ; Organic chemistry ; Catalysis Luminescence and Fluorescent Materials ; Photochromic and Fluorescence Chemistry ; Crystallography and molecular interactions
Authors: Irem Bolukbasi
Source: ScholarWorks@UMassAmherst (University of Massachusetts Amherst) (article, 2021-04-01)
Field: Materials Science — Surfaces, Coatings and Films

Tailoring nanoparticles and polymers for cooperative interfacial and surface interactions Climatic change threatens biodiversity worldwide. In the forests of the northeastern United States, climate change is expected to increase mean annual temperatures by up to 4.5˚C and change precipitation seasonality. These changes in climate are likely to have impacts on the biodiversity of the region. In order to better understand the impacts of climate change on biodiversity, I used ants, an indicator taxonomic group, to predict how ant communities and ant-mediated ecosystem processes change as the climate warms. In the first chapter of this dissertation, I review the major ecosystem processes and services mediated by ants using the Millennium Ecosystem Assessment framework. In chapter two of this dissertation I present the results of a major ant sampling effort along environmental gradients of the Appalachian region of the northeastern United States. In 2010 I sampled ant communities in forested and open habitats at 67 localities from Virginia north to Maine and developed macroecological models which show that ant community composition in forested habitats can be explained by the region’s climatic properties. In chapter three, I intensively sampled open and forested plots at Harvard Forest LTER and Myles Standish State Forest in eastern Massachusetts. In chapter four, I present the results of a warming mesocosm experiment using the ant species <em>Formica subsericea</em>. I found that as warming increases, soil movement and soil respiration increases but decomposition and nitrogen availability decreases. In the final chapter of this dissertation, I use different functional diversity and species distribution models to classify the ant communities of the region into different functional groups and explore how their distributions will change in future climates. In this dissertation, I show that ant diversity and ant-mediated ecosystem processes are likely to change under future environmental and climatic conditions. I used observational, experimental and modeling approaches to evaluate and predict the consequences of climatic change on the biodiversity of ants in the northeastern U.S. Ants are considered to be amongst the little things that run the world, and the impacts of climatic change on their communities, abundances, distributions are likely to have major impacts on the forests of the region. Nanoparticle ; Polymer ; Nanotechnology ; Surface (topology) ; Materials science ; Polymer science ; Composite material ; Mathematics Polymer Surface Interaction Studies ; Electrophoretic Deposition in Materials Science
Authors: Jacopo Perego | Charl X. Bezuidenhout | Irène Villa | Francesca Cova | Roberta Crapanzano | I.M. Frank | F. Pagano | N. Kratochwil | E. Auffray | Silvia Bracco | A. Vedda | Christophe Dujardin | Piero Sozzani | Francesco Meinardi | Angiolina Comotti | Angelo Monguzzi
Source: ChemRxiv (preprint, 2021-12-13)
Field: Materials Science — Materials Chemistry

Highly luminescent hetero-ligand MOF nanocrystals with engineered massive Stokes shift for photonic applications. A high efficiency emission with a massive Stokes shift is obtained by fluorescent conjugated acene building blocks arranged in nanocrystals. The two ligands of equal molecular length and connectivity, yet complementary electronic properties, are co-assembled by zirconium oxy-hydroxy clusters, generating highly crystalline hetero-MOF nanoparticles The fast diffusion of singlet molecular excitons in the framework, coupled with the fine matching of ligands absorption and emission properties, enables to achieve an ultrafast activation of the low energy emission by diffusion-mediated non-radiative energy transfer in the 100 ps time scale, by using a low amount of co-ligands. This allow to obtain MOF nanocrystals with a fluorescence quantum efficiency of ̴ 70% and an actual Stokes shift as large as 750 meV. This large Stokes shift suppresses the reabsorption of fast emission issues in bulk devices, pivotal for a plethora of applications in photonics and photon managing spacing from solar technologies, imaging, and detection of high energy radiation. These features allowed to realize a prototypal fast nanocomposite scintillator that shows an enhanced performance with respect to the homo-ligand nanocrystals, achieving benchmark. values which compete with those of some inorganic and organic commercial systems. Stokes shift ; Nanocrystal ; Materials science ; Photonics ; Absorption (acoustics) ; Luminescence ; Quantum dot ; Optoelectronics ; Nanotechnology Luminescence Properties of Advanced Materials ; Metal-Organic Frameworks: Synthesis and Applications ; Machine Learning in Materials Science
Authors: Yousif Alcheikhhamdon
Source: Open Collections (article, 2021-01-01)
Field: Chemistry — Inorganic Chemistry

Propylene - propane separation using mixed matrix films made of functionalized polymers and zeolitic-imidazolate frameworks The work presented in this thesis investigates the use of membrane technology in lieu of the energy-intensive distillation process for propylene - propane separation. The polymeric membranes lack the selectivity necessary for efficient separation. A recent breakthrough occurred when the metal-organic framework filler “ZIF-8” was mixed with Polymers of Intrinsic Microporosity (PIMs) to synthesize mixed-matrix films with high propylene selectivity. At high ZIF-8 loadings, the compatibility between the organic PIM and the semi-organic ZIF-8 deteriorates. This work was the first to propose functionalizing the PIM with a “carboxyl” (-COOH) group to enhance the compatibility with ZIF-8. Due to the carboxyl’s higher electronegativity, stronger H-bonding is induced between the mixed-matrix components compared to the hydroxyl (-OH) functionalization proposed in previous studies; the -COOH functionalized polymer “6FDA-TrMCA” was selected for this purpose. In this work, material development activities were limited to the pristine “6FDA-TrMCA” films preparation. The performance of the mixed-matrix membrane was approximated using the Maxwell model, meeting the targeted measures. Since membrane simulation software tools are exclusive to the commercial membrane suppliers, the “quantitative” impact of the selectivity boost on the process performance measures (e.g., purity, recovery, recycle) is not measurable. As part of this work, a novel HYSYS extension “MemCal” was matured in collaboration with a partner to support the simulation of membranes in Aspen HYSYS. The pure polymeric and the mixed-matrix membranes were simulated for their performance in single- and in two-stage designs meant for propylene’s commercial grades production; factors such as feed the propylene content and trans-membrane pressure ratio were accounted for in the analyses. The polymeric membranes were found incapable of producing neither the chemical nor the polymer grades of propylene, even in a two-stage process. Alternatively, the mixed-matrix membranes with the recommended selectivity of 35 (i.e., feasible using 6FDA-TrMCA and ZIF-8) were found capable of producing the chemical and the polymer grades at practical recovery when utilized in the single- and two-stage designs, respectively. The future research should grant more attention to the mixed-matrix high-pressure operation subject, as the latter is a prerequisite for technology’s success. Zeolitic imidazolate framework ; Propane ; Polymer ; Imidazolate ; Materials science ; Metal-organic framework ; Chemical engineering ; Matrix (chemical analysis) ; Polymer chemistry ; Chemistry ; Organic chemistry ; Composite material ; Adsorption Zeolite Catalysis and Synthesis ; Mesoporous Materials and Catalysis
Authors: Isabel Asenjo‐Sanz | Tatiana Claros | Edurne González | Ester Verde‐Sesto | José A. Pomposo
Source: Preprints.org (preprint, 2021-01-29)
Field: Chemistry — Organic Chemistry

“Clickase” Single-Chain Nanoparticles: Effect of Intra-Chain Distribution of Catalytic Sites on Catalytic Activity &amp;ldquo;Clickase&amp;rdquo; single-chain nanoparticles (Ck-SCNPs) are folded, enzyme-mimetic unimolecular polymeric nano-objects containing copper (Cu) ions able to catalyze the azide-alkyne Huisgen cycloaddition reaction in water and/or selected organic solvents, often in the presence of a reductant. Herein, we investigate the effect of morphology on catalytic activity of Ck-SCNPs synthesized by means of two different routes. An amphiphilic random copolymer composed of oligo(ethylene glycol) methyl ether methyl methacrylate (OEGMA) and 2-acetoacetoxy ethyl methacrylate (AEMA) units was used as precursor of these Ck-SCNPs. Folding was promoted through metal complexation between Cu(II) ions and beta-ketoester-containing AEMA moieties. The first route resulted in Ck-SCNPs1 containing Cu ions homogeneously distributed within each nanoparticle, whereas the second one promoted intra-chain clustering of Cu ions inside Ck-SCNPs2. A model fluorogenic &amp;ldquo;click&amp;rdquo; reaction between 9-(azidomethyl)anthracene and phenylacetylene, which was catalyzed either by Ck-SCNPs1 or Ck-SCNPs2, was used to unravel the effect of morphology on catalytic activity. This work paves the way to improve the catalytic activity of metallo-folded SCNPs through control of the intra-chain distribution of catalytic sites. Catalysis ; Chemistry ; Ethylene glycol ; Click chemistry ; Nanoparticle ; Polymer chemistry ; Methacrylate ; Alkyne ; Combinatorial chemistry ; Amphiphile ; Azide ; Copolymer ; Metal ions in aqueous solution ; Organic chemistry ; Polymer ; Ion ; Materials science ; Nanotechnology Click Chemistry and Applications ; Advanced biosensing and bioanalysis techniques ; Nanocluster Synthesis and Applications
Authors: Gerard M. Leteba | Eric van Steen
Source: Journal of the Southern African Institute of Mining and Metallurgy (article, 2021-06-30)
Field: Materials Science — Materials Chemistry

Synthesis of Pt-based alloy nanostructures Optimizing the catalytic performance of multimetallic nanoparticle (NP) catalysts demands a concrete understanding of their design, while preferentially deploying wet chemical synthesis procedures to precisely control surface structural properties. Here we report the influence of reductants such as hydrogen-rich tetrabutylammonium borohydride (TBAB) and carbon monoxide-rich molybdenum carbonyl (Mo(CO)6) on the shape and morphological evolution of Pt-based binary (PtNi and PtCo) and ternary (PtNiAu and PtCoAu) nanostructures derived from a homogeneous solution of amine-based surface active agents (surfactants) in a high boiling point solvent. We successfully synthesized nanostructures exhibiting well-defined and composition-controlled surfaces deploying a one-pot synthetic approach. The development of the surface properties was, however, observed to be alloy-specific. The resultant highly monodisperse alloy NP with narrow size distributions and facet-oriented surfaces are expected to display enhanced functionality as catalysts for utilization in specific chemical reactions. Catalysis ; Nanostructure ; Materials science ; Alloy ; Ternary operation ; Dispersity ; Nanoparticle ; Chemical engineering ; Platinum ; Sodium borohydride ; Nanotechnology ; Carbon monoxide ; Organic chemistry ; Metallurgy ; Chemistry ; Polymer chemistry Catalytic Processes in Materials Science ; Advanced Materials Characterization Techniques
Authors: Elizaveta Sviridova | Alexandre Barras | Evgenii Plotnikov | Antonio Di Martino | D. Deresmes | Ksenia Nikiforova | Marina E. Trusova | Sabine Szunerits | Olga Guselnikova | Павел С. Постников | Rabah Boukherroub
Source: ChemRxiv (preprint, 2021-10-29)
Field: Materials Science — Materials Chemistry

Surface modification of carbon dots with tetraalkylammonium moieties for fine tuning their antibacterial activity In this contribution, we report a facile functionalization method of carbon dots (CDs) by tetraalkylammonium moieties using diazonium chemistry to improve their antibacterial activity against Gram-positive and Gram-negative bacteria. CDs were modified by novel diazonium salts bearing tetraalkylammonium moieties (TAA) with different alkyl chains (C2, C4, C9, C12) for the optimization of antibacterial activity. The functionalized CDs were characterized by X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV-vis) absorption spectrophotometry and fluorescence spectroscopy to confirm the covalent binding of TAA onto the CDs’ surface. Variation of the alkyl chain allows to reach the strongest antibacterial effect for CDs-C9 towards Gram-positive S. aureus (MIC 3.09±1.10 µg mL-1) and Gram-negative E. coli (MIC 7.93±0.17 µg mL-1) bacteria. In addition, the antibiofilm properties of the CDs-C9 were assessed; full biofilm inhibition was achieved after 6 h (64 µg mL-1) and 2 h (128 µg mL-1) treatment for S. aureus biofilm and >60% suppression of biofilm mass after 6 h (128 µg mL-1) for E. coli biofilm. CDs-C9 demonstrated good biocompatibility on mouse fibroblast (NIH/3T3), HeLa and U-87 MG cell lines for concentrations up to 256 µg mL-1. Collectively, our work highlights the correlation between the surface chemistry of CDs and their antimicrobial performance. Alkyl ; Chemistry ; Fourier transform infrared spectroscopy ; Antibacterial activity ; Surface modification ; Biofilm ; Nuclear chemistry ; X-ray photoelectron spectroscopy ; Biocompatibility ; Covalent bond ; HeLa ; Bacteria ; Organic chemistry ; Chemical engineering ; Biochemistry ; In vitro Carbon and Quantum Dots Applications ; Pineapple and bromelain studies ; Quantum Dots Synthesis And Properties
Authors: Pei‐Ming Cheng | Li‐Xuan Cai | Dan‐Ni Yan | Li‐Peng Zhou | Qing‐Fu Sun
Source: Catalysts (article, 2021-04-09)
Field: Chemistry — Organic Chemistry

Molecular Cage Promoted Aerobic Oxidation or Photo-Induced Rearrangement of Spiroepoxy Naphthalenone Herein, we report a Pd4L2-type molecular cage (1) and catalyzed reactions of spiroepoxy naphthalenone (2) in water, where selective formation of 2-(hydroxymethyl)naphthalene-1,4-dione (3) via aerobic oxidation, or 1-hydroxy-2-naphthaldehyde (4) via photo-induced rearrangement under N2 have been accomplished. Encapsulation of four molecules of guest 2 within cage 1, i.e., (2)4⊂1, has been confirmed by NMR, and a final host-guest complex of 3⊂1 has also been determined by single crystal X-Ray diffraction study. While the photo-induced ring-opening isomerization from 2 to 4 are known, appearance of charge-transfer absorption on the host-guest complex of (2)4⊂1 allows low-power blue LEDs irradiation to promote this process. Chemistry ; Photochemistry ; Isomerization ; Hydroxymethyl ; Cage ; Molecule ; Stereochemistry ; Crystallography ; Catalysis ; Organic chemistry Supramolecular Chemistry and Complexes ; Metal-Organic Frameworks: Synthesis and Applications ; Magnetism in coordination complexes
Authors: Joice Maria Joseph | Maria Rosa Gigliobianco | Bita Mahdavi Firouzabadi | Roberta Censi | Piera Di Martino
Source: Preprints.org (preprint, 2021-12-08)
Field: Materials Science — Materials Chemistry

Nanotechnology as a Versatile Tool for &lt;sup&gt;19&lt;/sup&gt;F-MRI Agent’s Formulation: A Glimpse into the Use of Perfluorinated and Fluorinated Compounds in Nanoparticles Simultaneously being a non-radiative and non-invasive technique makes magnetic resonance imaging (MRI) one of the highly sought imaging techniques for the early diagnosis and treatment of diseases. Despite more than four decades of research on finding a suitable imaging agent from fluorine for clinical applications, it still lingers as a challenge to get the regulatory approval compared to its hydrogen counterpart. The pertinent hurdle is the simultaneous intrinsic hydrophobicity and lipophobicity of fluorine and its derivatives that make them insoluble in any liquids, strongly limiting their application in areas such as targeted delivery. A blossoming technique to circumvent the unfavorable physicochemical characteristics of perfluorocarbon compounds (PFCs) and guarantee a high local concentration of fluorine in the desired body part is to encapsulate them in nanosystems. In this review, we will be emphasizing different types of nanocarrier systems studied to encapsulate various PFCs and fluorinated compounds, headway to be applied as a contrast agent (CA) in fluorine-19 MRI (19F MRI). We would also scrutinize the different types of PFCs and their specific applications and limitations concerning the nanoparticle (NP) system used to encapsulate them studied over the last decade. A critical evaluation for future opportunities would be speculated. Nanocarriers ; Limiting ; Fluorine ; Nanotechnology ; Nanoparticle ; Materials science ; Chemistry ; Organic chemistry ; Engineering Lanthanide and Transition Metal Complexes ; Medical Imaging Techniques and Applications ; MRI in cancer diagnosis
Authors: Janesline Fernandes | Teotone Vaz | Tushar Anvekar
Source: Future Journal of Pharmaceutical Sciences (article, 2021-10-24)
Field: Materials Science — Materials Chemistry

Antimicrobial and antioxidant therapy with bioactive plant molecules on Fe3O4 phytohybrid nanoplatforms Abstract Background Nanobiomedicines have gained increasing attention for their potential to improve efficacy and are emerging as a promising therapeutic paradigm. Magnetic nanoconjugates loaded with bioactive drugs have the advantage of sustained circulation in the bloodstream and significantly reduced toxicity of therapeutic agents in a precise manner. The well-developed surface chemistry of Fe 3 O 4 has led to the development better tools, promoting them as nanoplatforms with potential technological applications in biomedical sciences. Results Fe 3 O 4 phytohybrids with Laxmitaru extract as the primary coating and loaded with Eugenol and Ylang-Ylang essential oils were successfully synthesized. The X-ray diffraction technique has revealed the high purity nanoparticle materials, as no additional impurity peaks were observed. Fourier transform infra-red spectra have confirmed the presence of a primary coating of Laxmitaru extract and a secondary layer of essential oil, as additional peaks and broadening are observed in drug-loaded Fe 3 O 4 nanoparticles. Magnetic susceptibility values indicate the material's superparamagnetic nature. Transmission electron microscopy images have ensured that the particles were spherical, monodispersed, and in the range of 4.30 nm to 13.98 nm. Antimicrobial studies show inhibition zones on the microorganisms S. Aureus and E. Coli with enhanced activity. Drug entrapment efficiency studies revealed the encapsulation of drug molecules onto Fe 3 O 4 -Laxmitaru composite. Dynamic light scattering studies confirm the increase in hydrodynamic size, indicating the loading of essential oils and the decrease in polydispersity index ensures monodispersed nanoparticles. The antioxidant study showed the essential oils retained their antioxidant activity even after they were conjugated on Fe 3 O 4 -Lax composites. Conclusions Laxmitaru phytochemical-coated Fe 3 O 4 nanoparticles were successfully conjugated with Eugenol and Ylang-Ylang essential oils. Our results provide a model therapeutic approach for the development of new alternative strategies for enhancing antimicrobial and antioxidant therapy, with potential advantages in the field of nanobiomedicine. Dispersity ; Dynamic light scattering ; Antimicrobial ; Superparamagnetism ; Nanoparticle ; Coating ; Nanotechnology ; Materials science ; Antioxidant ; Drug delivery ; Chemistry ; Magnetic nanoparticles ; Chemical engineering ; Nuclear chemistry ; Organic chemistry ; Magnetization Nanoparticles: synthesis and applications ; Moringa oleifera research and applications ; Phytochemistry and biological activities of Ficus species