jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Mays Alhamami | Huu Doan | Chil‐Hung Cheng
Source:  (review, 2021-07-28)
Field: Chemistry — Inorganic Chemistry

A Review on Breathing Behaviors of Metal-Organic-Frameworks (MOFs) for Gas Adsorption Metal-organic frameworks (MOFs) are a new class of microporous materials that possess framework flexibility, large surface areas, “tailor-made” framework functionalities, and tunable pore sizes. These features empower MOFs superior performances and broader application spectra than those of zeolites and phosphine-based molecular sieves. In parallel with designing new structures and new chemistry of MOFs, the observation of unique breathing behaviors upon adsorption of gases or solvents stimulates their potential applications as host materials in gas storage for renewable energy. This has attracted intense research energy to understand the causes at the atomic level, using in situ X-ray diffraction, calorimetry, Fourier transform infrared spectroscopy, and molecular dynamics simulations. This article is developed in the following order: first to introduce the definition of MOFs and the observation of their framework flexibility. Second, synthesis routes of MOFs are summarized with the emphasis on the hydrothermal synthesis, owing to the environmental-benign and economically availability of water. Third, MOFs exhibiting breathing behaviors are summarized, followed by rationales from thermodynamic viewpoint. Subsequently, effects of various functionalities on breathing behaviors are appraised, including using post-synthetic modification routes. Finally, possible framework spatial requirements of MOFs for yielding breathing behaviors are highlighted as the design strategies for new syntheses. Metal-organic framework ; Microporous material ; Flexibility (engineering) ; Nanotechnology ; Materials science ; Adsorption ; Chemistry ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Boron and Carbon Nanomaterials Research ; Zeolite Catalysis and Synthesis
Authors: Adiki Raja Sekhar | Youhei Chitose | Jiří Janoš | Sahar Israeli Dangoor | Andrea Ramundo | Ronit Satchi Fainaro | Petr Slavı́ček | Petr Klán | Roy Weinstain
Source: ChemRxiv (preprint, 2021-08-05)
Field: Materials Science — Materials Chemistry

Porphyrin as a Versatile Visible-Light-Activatable Organic/Metal Hybrid Photoremovable Protecting Group Photoremovable protecting groups (PPGs) represent one of the main contemporary implementations of photochemistry in diverse fields of research and practical applications. For the past half century, organic and metal-complex PPGs were considered mutually exclusive classes, each of which providing unique sets of physical and chemical properties thanks to their distinctive structures. Here, we introduce the meso-methylporphyrin group as a prototype hybrid-class PPG that unites traditionally exclusive elements of organic and metal-complex PPGs within a single structure. We show that the porphyrin scaffold allows extensive modularity by functional separation of the metal-binding chromophore and up to four sites of leaving group release. The insertion of metal ions can be used to tune their spectroscopic, photochemical, and biological properties. We provide a detailed description of the photoreaction mechanism studied by steady-state and transient absorption spectroscopies and quantum-chemical calculations. Our approach applied herein could facilitate access to a hitherto untapped chemical space of potential PPG scaffolds. Porphyrin ; Chromophore ; Modularity (biology) ; Combinatorial chemistry ; Materials science ; Metal ; Metal ions in aqueous solution ; Photochemistry ; Group (periodic table) ; Chemistry ; Nanotechnology ; Organic chemistry Porphyrin and Phthalocyanine Chemistry ; Photochromic and Fluorescence Chemistry ; Luminescence and Fluorescent Materials
Authors: Lukas V. Hoff | Simon D. Schnell | Andrea Tomio | Anthony Linden | Karl Gademann
Source: ChemRxiv (preprint, 2021-05-12)
Field: Chemistry — Organic Chemistry

Cross-coupling Reactions of Monosubstituted Tetrazines A fast and mild method for the Pd-catalyzed cross-coupling reaction of monosubstituted 3-bromo-1,2,4,5-tetrazine is presented. Investigation of silver-based additives revealed that Ag2CO3 is the optimal mediator, enabling the process without the need for strong bases or high temperatures. Electronic modification of the classical 1,1′- bis(diphenylphosphine)ferrocene (dppf) ligand proved to be a powerful strategy in tailoring the catalytic system to the requirements set by the process. Under the optimized conditions a scope comprising a variety of alkyl-, heteroatom-, and halide substituted aryl- and heteroaryl-tetrazines were prepared in good to excellent yields (29 examples, up to 87% yield). This method constitutes the first example of a direct cross-coupling reaction of monosubstituted tetrazines. Diphenylphosphine ; Heteroatom ; Yield (engineering) ; Ferrocene ; Chemistry ; Aryl ; Combinatorial chemistry ; Coupling reaction ; Catalysis ; Tetrazine ; Ligand (biochemistry) ; Alkyl ; Halide ; Organic chemistry ; Materials science ; Physical chemistry ; Phosphine ; Electrochemistry Click Chemistry and Applications ; Synthesis and Biological Evaluation ; Catalytic Cross-Coupling Reactions
Authors: Yaoting Wang | Corie M. McHale | Xiqu Wang | Chung‐Kai Chang | Yu‐Chun Chuang | Watchareeya Kaveevivitchai | Ognjen Š. Miljanić | Teng‐Hao Chen
Source: ChemRxiv (preprint, 2021-02-05)
Field: Materials Science — Materials Chemistry

Cyclotetrabenzoin Acetate: A Macrocyclic Porous Molecular Crystal for CO2 Separations by Pressure Swing Adsorption A porous molecular crystal (PMC) assembled by close-packing of macrocyclic cyclotetrabenzoin acetate is an efficient adsorbent for selective CO&lt;sub&gt;2&lt;/sub&gt; capture. The 7.1´7.1 Å square pore of PMC and its ester C=O group play important roles in improving its affinity for CO&lt;sub&gt;2&lt;/sub&gt; molecules. Thermodynamically, the benzene walls of macrocycle strongly promote CO&lt;sub&gt;2&lt;/sub&gt; adsorption via [p···p] interactions at low pressure. In addition, the polar carbonyl groups pointing inward the square channels reduce the size of aperture to a 5.0´5.0 Å square, which offers kinetic selectivity for CO&lt;sub&gt;2&lt;/sub&gt; capture. The PMC features water tolerance and high structural stability under vacuum and various gas adsorption conditions, which are rare among intrinsically porous organic molecules. In mixed-gas breakthrough experiments, it exhibits efficient CO&lt;sub&gt;2&lt;/sub&gt;/N&lt;sub&gt;2&lt;/sub&gt; and CO&lt;sub&gt;2&lt;/sub&gt;/CH&lt;sub&gt;4&lt;/sub&gt; separations under kinetic flow conditions. Most importantly, the moderate adsorbate–adsorbent interaction allows the PMC to be readily regenerated, and therefore applied to pressure swing adsorption (PSA) processes. The eluted N&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; are obtained with over 99.9% and 99.8% purity, respectively, and the separation performance is stable for 30 cycles. Coupled with its easy synthesis, these properties make cyclotetrabenzoin acetate a promising adsorbent for CO&lt;sub&gt;2&lt;/sub&gt; separations from flue and natural gases. Adsorption ; Chemistry ; Pressure swing adsorption ; Selectivity ; Molecule ; Vacuum swing adsorption ; Porosity ; Benzene ; Crystallography ; Crystal (programming language) ; Analytical Chemistry (journal) ; Physical chemistry ; Catalysis ; Chromatography ; Organic chemistry Covalent Organic Framework Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Porphyrin and Phthalocyanine Chemistry
Authors: Boon-Kui Ho | Suk Fun Chin | Samuel Lihan | S Chin | F Jimmy | S Pang | V Yih | N Ismail | S Gopinath | C Goh | M Citartan | T Lakshmipriya | M Arshad | F Faudzi | R Rahim | U Hashim | S Chinni | T Tang | B Yoo | J Chen | M Makha | C Raston | M Saunders | L Voon | A Romainor | S Lihan | P Panin | W Banlunara | N Chaichanawongsaroj | M Farrukh | M Gul | M Rahman | B Ho | Y Chang | X Meng | Y Zhao | K Li | B Zhao | M Zhu | Y Li | X Chen | J Wang | L Qi | Z Xu | X Jiang | C Hu | X Zou | G Dulger | C Aki | B Spellberg | R Guidos | D Gilbert | J Bradley | H Boucher | W Scheld | J Bartlett | J Edwards | M Ismail | N Kamarudin | M Abdul Samat | R Raja Abdul Rahman | S Saimun | T Tan | H Neoh | R Cohen | S Paikin | T Finn | F Babushkin | E Anuka | M Baum | A Rokney | L Lim | M Sum | D Perera | Z Yao | Y Peng | J Bi | X Ye | J Shi | Y Guo | G Song | M Sun | Y Wang | R Rajendran | A Tsujiwaki
Source: Biointerface Research in Applied Chemistry (article, 2021-12-09)
Field: Materials Science — Materials Chemistry

Antibacterial Studies of Penicillin G Loaded Carboxylic Cellulose Acetate Nanoparticles Cellulose acetate nanoparticles (CCA NPs) with mean particles sizes of 97 nm were synthesized via the nanoprecipitation process. The antibacterial properties of these CCA NPs were evaluated against Gram (+) and Gram (-) bacteria, respectively. The CCA NPs exhibited good antibacterial activity against Methicillin-resistant Staphylococcus aureus (MRSA) (+), Staphylococcus epidermis (+), Escherichia coli (-), Bacillus cereus (+), and Salmonella typhimurium (-) in range of MIC of 2.5×102 to 5.0×102 µg.mL-1 and MBC of 5.0×102 to 1.0×103 µg.mL-1. Penicillin G (PenG)-loaded CCA NPs demonstrated synergistic antibacterial activities against Gram (+) and Gram (-) bacteria. PenG-loaded CCA NPs also exhibited promising antimicrobial activity against the Methicillin-resistant staphylococcus aureus (MRSA) superbug, which is resistant to penicillin G. These promising antibacterial properties suggested that CCA NPs could potentially serve as an alternative potent antimicrobial agent for both Gram (+) and Gram (-) bacteria as well as the superbug MRSA. Bacillus cereus ; Staphylococcus aureus ; Antibacterial activity ; Penicillin ; Antimicrobial ; Microbiology ; Chemistry ; Bacteria ; Gram-positive bacteria ; Antibacterial agent ; Minimum bactericidal concentration ; Pathogenic bacteria ; Escherichia coli ; Antibiotics ; Minimum inhibitory concentration ; Biology ; Biochemistry Nanoparticles: synthesis and applications ; Nanocomposite Films for Food Packaging ; Antimicrobial agents and applications
Authors: G. Tamás Gál | Nóra V. May | László Trif | Judith Mihály | Petra Bombicz
Source: CrystEngComm (article, 2021-01-01)
Field: Chemistry — Physical and Theoretical Chemistry

Solvatomorph and polymorph screening of clopamide drug and its copper(<scp>ii</scp>) complex crystals The anhydrate and hemihydrate structures of the marketed drug, clopamide, are described the first time. Structural landscape of its copper complexes is presented: three polymorphic modifications and an isostructural series of its alcohol clathrates. Isostructural ; Copper ; Crystallography ; Alcohol ; Chemistry ; Drug ; Stereochemistry ; Crystal structure ; Materials science ; Organic chemistry ; Biology ; Pharmacology Crystallography and molecular interactions ; Crystal structures of chemical compounds ; Molecular spectroscopy and chirality
Authors: Luqman Hakim Mohd Azmi | Pavani Cherukupally | Elwin Hunter‐Sellars | Bradley P. Ladewig | Daryl R. Williams
Source: ChemRxiv (preprint, 2021-03-25)
Field: Chemistry — Inorganic Chemistry

Polydimethyl siloxane/MIL-101 Composites for Enhanced Toluene Adsorption in the Presence of Humidity Competition between atmospheric moisture and volatile organic compounds (VOCs) for an adsorbent’s sites can significantly impact its VOC removal efficiency. The development of moisture-tolerant adsorbents is essential to address this issue. A vapor phase deposition process using polydimethylsiloxane (PDMS) has created a hydrophobic form of the highly porous, normally hydrophilic, MOF MIL-101. After optimizing the PDMS vapor deposition time and molecular weights, hydrophobicity index calculations verified the improved hydrophobicity of the coated MOF (MIL-PDMS-Sigma-0.25) over its pristine form. The surface area, pore volume as well as single component vapor adsorption of water and toluene capacities were also preserved, resulting to similar performance to MIL-101. Toluene-water vapor co-adsorption experiments were conducted at 40% RH using two toluene concentrations: 0.5% P/P0 and 10% P/P0, mimicking environmental VOC and industrial concentrations, respectively. At 0.5% P/P0, MIL-PDMS-Sigma-0.25 exhibited 60% higher adsorption capacity and twice the rate of toluene capture relative to pristine MIL-101, as well as a 3-fold higher toluene uptake relative to a commercial activated carbon. Preliminary adsorbent regeneration experiments confirm the stability and performance of MIL-PDMS-Sigma-0.25. Using a simple vapor phase modification, this new MOF-composite material offers superior competitive toluene vapor uptake in humidified real-world conditions at VOC concentrations. Toluene ; Adsorption ; Chemical engineering ; Water vapor ; Polydimethylsiloxane ; Siloxane ; Chemical vapor deposition ; Relative humidity ; Materials science ; Chemistry ; Organic chemistry ; Polymer Metal-Organic Frameworks: Synthesis and Applications ; Gas Sensing Nanomaterials and Sensors ; Membrane Separation and Gas Transport
Authors: Ilaria D’Auria | Zeinab Saki | Claudio Pellecchia
Source: Preprints.org (preprint, 2021-03-24)
Field: Materials Science — Polymers and Plastics

Iminopyridine Ni(II) Catalysts Affording Oily Hyperbranched Oligoethylenes and/or Crystalline Polyethylenes Depending on the Reaction Conditions: Possible Role of In Situ Catalyst Structure Modifications Nickel-based ethylene polymerization catalysts have unique features, being able to produce macromolecules with a variable content of branches, resulting in polymers ranging from semicrystalline plastics to elastomers to hyperbranched amorphous waxes and oils. In addition to Brookhart's &amp;alpha;-diimine catalysts, iminopyridine Ni(II) complexes are among the most investigated systems. We report that Ni(II) complexes bearing aryliminopyridine ligands with bulky substituents both at the imino moiety and in the 6-position of pyridine afford either hyperbranched low molecular weight polyethylene oils or prevailingly linear crystalline polyethylenes or both depending on the ligand structure and the reaction conditions. The formation of multiple active species in situ is suggested by analysis of the post-polymerization catalyst residues, showing the partial reduction of the imino function. Some related arylaminopyridine Ni(II) complexes were also synthesized and tested, showing a peculiar behavior, i.e. the number of branches of the produced polyethylenes increases while ethylene pressure increases. Catalysis ; Polymer chemistry ; Polyethylene ; Polymerization ; Ethylene ; Diimine ; Polymer ; Materials science ; Wax ; Chemistry ; Moiety ; Pyridine ; Nickel ; Organic chemistry Dendrimers and Hyperbranched Polymers ; Synthetic Organic Chemistry Methods ; Ferrocene Chemistry and Applications
Authors: Siyuan Sun | Nicolás Díaz | Pavel Nagorny
Source: Symmetry (article, 2021-09-09)
Field: Chemistry — Organic Chemistry

Synthesis and Evaluation of C2-Symmetric SPIROL-Based bis-Oxazoline Ligands This communication describes the synthesis of new bis-oxazoline chiral ligands (SPIROX) derived from the C2-symmetric spirocyclic scaffold (SPIROL). The readily available (R,R,R)-SPIROL (2) previously developed by our group was subjected to a three-step sequence that provided key diacid intermediate (R,R,R)-7 in 75% yield. This intermediate was subsequently coupled with (R)- and (S)-phenylglycinols to provide diastereomeric products, the cyclization of which led to two diastereomeric SPIROX ligands (R,R,R,R,R)-3a and (R,R,R,S,S)-3b in 85% and 79% yield, respectively. The complexation of (R,R,R,R,R)-3a and (R,R,R,S,S)-3b with CuCl and Cu(OTf)2 resulted in active catalysts that promoted the asymmetric reaction of α-diazopropionate and phenol. The resultant O–H insertion product was formed in 88% yield, and with excellent selectivity (97% ee) when ligand (R,R,R,R,R)-3a was used. Diastereomer ; Oxazoline ; Yield (engineering) ; Chemistry ; Ligand (biochemistry) ; Stereochemistry ; Phenol ; Catalysis ; Enantioselective synthesis ; Medicinal chemistry ; Organic chemistry ; Receptor ; Materials science Cyclopropane Reaction Mechanisms ; Synthesis and Catalytic Reactions ; Catalytic C–H Functionalization Methods
Authors: Alexandre Leclair | Rubén O. Torres‐Ochoa | Qian Wang | Jieping Zhu
Source: CHIMIA International Journal for Chemistry (article, 2021-04-27)
Field: Chemistry — Organic Chemistry

Iron-Catalysed Remote C(sp3)-H Azidation of O-Acyl Oximes and N -Acyloxy Imidates The azido group occupies an important position in modern organic chemistry, broadly used as amine surrogates and as anchors in bioconjugation. Despite their importance, examples of selective direct azidation of inert C(sp³)-H bonds remain limited and often require strong oxidative conditions. Herein, we highlight the use of <i>O</i>-acyl oximes and <i>N</i>-acyloxy imidates as directing groups for the selective iron-catalysed azidation of C(sp³)-H bond with trimethylsilyl azide, giving access to various γ-azido ketones and β-azido alcohols in moderate to excellent yields. The iron catalyst is assumed to play a dual role in these catalytic processes: as a reductant to generate the reactive iminyl and imidate radicals, respectively, and as a redox centre to mediate the azido transfer to the translocated carbon radical. Chemistry ; Bioconjugation ; Trimethylsilyl azide ; Catalysis ; Amine gas treating ; Radical ; Combinatorial chemistry ; Azide ; Primary (astronomy) ; Organic chemistry Radical Photochemical Reactions ; Catalytic C–H Functionalization Methods ; Synthesis and Catalytic Reactions
Authors: Renuka Tanmay Gupta
Source:  (preprint, 2021-05-22)
Field: Materials Science — Materials Chemistry

Surface-active solid lipid nanoparticles for emulsion stabilization Solid lipid nanoparticles (SLNs) consisting of the food grade surfactant lipid glyceryl stearate citrate (GSC) were prepared using hot melt emulsification and high-pressure homogenization. Flash-cooling of the resultant oil-in-water nanoemulsions led to the formation of GSC SLNs. The effective mean particle size of the SLNs was ~180 nm by dynamic light scattering and the volume-weighted mean particle size was ~152 nm by laser diffraction, with a zeta (ζ) potential of ~-49 mV. Effective mean particle size and ζ potential were stable for 24 wk. An equilibrium contact angle of ~108.7⁰ measured through oil phase was obtained, suggesting a wettable lipid surface. The melting curve of the SLNs obtained by differential scanning calorimetry showed a significantly lower melting point and broader peak as compared to the bulk GSC, which was attributed to the nano-scale particle size. Unusually, the cooling curve showed an identical crystallization temperature as that for the bulk GSC, which suggested surface heterogeneous crystallization of the SLNs. Subsequent heating-cooling cycles confirmed the existence of nanosized particles in the sample during thermal analysis. Transmission electron (TEM) and atomic force microscopy (AFM) both revealed anisometric, flattened SLNs with circular or elliptical shapes. SLNs were studied for their effectiveness as colloidal emulsifiers in oil-in-water (o/w) emulsions. The generated o/w emulsions had a volume-weighted mean droplet size of ~459 nm by laser diffraction and ζ potential of ~-43 mV. The emulsions were stable for up to 12 wk. as observed for macroscopic changes by inverted light microscopy. TEM images pointed to the presence of a Pickering-type network stabilizing the emulsions. With time, desorption of the SLNs from the oil droplet surface into the continuous aqueous environment, coupled with Ostwald ripening, resulted in destabilization of the emulsions. Overall, these results demonstrated that stabilization of o/w emulsions was achievable using SLNs as the sole emulsifiers. Materials science ; Differential scanning calorimetry ; Particle size ; Dynamic light scattering ; Crystallization ; Analytical Chemistry (journal) ; Zeta potential ; Contact angle ; Melting point ; Solid lipid nanoparticle ; Nanoparticle ; Transmission electron microscopy ; Emulsion ; Chemical engineering ; Chromatography ; Chemistry ; Nanotechnology ; Composite material ; Thermodynamics Pickering emulsions and particle stabilization ; Food Chemistry and Fat Analysis
Authors: Samaneh Farokhirad | Sreeja Kutti Kandy | Andrew Tsourkas | P. S. Ayyaswamy | David M. Eckmann | Ravi Radhakrishnan
Source: Research Square (preprint, 2021-05-24)
Field: Materials Science — Biomaterials

Biophysical Considerations in the Rational Design and Cellular Targeting of Flexible Polymeric Nanoparticles Rational design ; Nanotechnology ; Nanoparticle ; Computer science ; Materials science Nanoparticle-Based Drug Delivery ; RNA Interference and Gene Delivery ; 3D Printing in Biomedical Research
Authors: Ż. Wojnarowska | Shinian Cheng | Małgorzata Swadźba‐Kwaśny | Shannon McLaughlin | Yoan Delavoux | Marian Paluch
Source: Research Square (preprint, 2021-06-04)
Field: Materials Science — Materials Chemistry

Pressure-induced liquid-liquid transition in a family of ionic materials Ionic liquid ; Transition (genetics) ; Materials science ; Chemistry ; Organic chemistry ; Catalysis Material Dynamics and Properties ; Ionic liquids properties and applications ; Phase Equilibria and Thermodynamics
Authors: Johannes Morstein | Giovanna Romano | Belinda E. Hetzler | Ambrose Plante | Caleb Haake | Joshua Levitz | Dirk Trauner
Source:  (preprint, 2021-08-04)
Field: Materials Science — Materials Chemistry

Photoswitchable Serotonins for Optical Control of the 5-HT2A Receptor The serotonin receptor family of G protein-coupled receptors (GPCRs) and ligand-gated ion channels play central roles in neuromodulation and are critical drug targets for the treatment of psychiatric disorders. Optical control of serotonin receptor subtypes has the potential to greatly enhance our understanding of the spatiotemporal dynamics of receptor function both at the cellular level and within neural circuits. While other neuromodulatory receptors have been successfully rendered photoswitchable, reversible photocontrol of serotonin receptors has not been achieved, representing a major gap in GPCR photopharmacology. Herein, by designing and screening a family of azobenzene-conjugated serotonin analogues, we developed the first photopharmacological tools that allow for such control. Azo5HT-2 shows light-dependent 5-HT2AR agonism, inducing receptor-mediated calcium signaling in the light-activated cis-form. Based on computational docking and test compound analysis, we also synthesize and test photoswitchable orthogonal, remotely-tethered ligands (PORTLs). BG-Azo5HTn PORTLs provide rapid, reversible and repeatable optical control following conjugation to SNAP-tagged 5-HT2AR. Overall, this study both introduces new tools for the optical control of 5-HT2ARs and provides a foundation for the broad extension of photopharmacology to the serotonin receptor family. Serotonin ; Receptor ; 5-HT receptor ; G protein-coupled receptor ; Chemistry ; 5-HT2A receptor ; Serotonergic ; Neuroscience ; Biophysics ; Biology ; Biochemistry Photochromic and Fluorescence Chemistry ; Receptor Mechanisms and Signaling ; Photoreceptor and optogenetics research