jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Biping Xu | Xiaojie Liu | Lei Deng | Yaping Shang | Xiaoming Jie | Weiping Su
Source: Science Advances (article, 2024-05-01)
Field: Chemistry — Organic Chemistry

Dehydrogenative synthesis of <i>N</i> -functionalized 2-aminophenols from cyclohexanones and amines: Molecular complexities via one-shot assembly Polyfunctionalized arenes are privileged structural motifs in both academic and industrial chemistry. Conventional methods for accessing this class of chemicals usually involve stepwise modification of phenyl rings, often necessitating expensive noble metal catalysts and suffering from low reactivity and selectivity when introducing multiple functionalities. We herein report dehydrogenative synthesis of <i>N</i>-functionalized 2-aminophenols from cyclohexanones and amines. The developed reaction system enables incorporating amino and hydroxyl groups into aromatic rings in a one-shot fashion, which simplifies polyfunctionalized 2-aminophenol synthesis by circumventing issues associated with traditional arene modifications. The wide substrate scope and excellent functional group tolerance are exemplified by late-stage modification of complex natural products and pharmaceuticals that are unattainable by existing methods. This dehydrogenative protocol benefits from using 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) as oxidant that offers interesting chemo- and regio-selective oxidation processes. More notably, the essential role of in situ generated water is disclosed, which protects aliphatic amine moieties from overoxidation via hydrogen bond-enabled interaction. Shot (pellet) ; One shot ; Nanotechnology ; Combinatorial chemistry ; Chemistry ; Materials science ; Organic chemistry ; Engineering Catalytic C–H Functionalization Methods ; Synthesis and Catalytic Reactions ; Asymmetric Hydrogenation and Catalysis
Authors: Nicola Sargentoni | Rossana Galassi | Lorenzo Luciani | Frank Röminger | Matthias Rudolph | A. Stephen K. Hashmi
Source: Advanced Synthesis & Catalysis (article, 2024-09-02)
Field: Chemistry — Organic Chemistry

Oxidation State and Halogen Influence on the NHC‐Gold‐Halide‐Catalyzed Cyclization of Propargylic Amides Abstract The homogeneously catalyzed cycloisomerization reaction of propargylic amides was tested as benchmark reaction for two homologous series of Au(I) and Au(III) complexes with NHC ligands. This reaction is known to afford either aromatic oxazoles or dihydrooxazoles, depending on the oxidation state of the applied gold catalysts. For this purpose, symmetric and unsymmetric NHC ligands with mixed alkyl or benzyl substituents (1,3‐dimethyl‐imidazolyl‐2yl or 1‐benzyl‐3‐methyl‐imidazolyl‐2‐yl) and the corresponding Au(I) and Au(III) derivatives were prepared and characterized by analytical methods, IR and 1 H and 13 C NMR spectroscopies, and by X‐ray diffraction methods. Ten NHC‐gold(I) and NHC‐gold(III) complexes were tested on the cyclization reactions by adding gold catalysts in the presence and absence of AgPF 6 . Noteworthy, only the 1‐benzyl‐3‐methyl‐gold(III) trichloride was able to give selectively the aromatic oxazole without the addition of the silver salt. Interestingly, on contrary to what is reported in the literature, the use of gold(I) or gold(III) complexes does not influence the chemoselectivity of the cyclization reaction, while the halide bound to the metal does. In this regard, a mechanism purposing the dihydrooxazole as an intermediate for the formation of aromatic oxazole is proposed. Chemistry ; Halide ; Halogen ; Catalysis ; Oxidation state ; Combinatorial chemistry ; Organic chemistry ; Medicinal chemistry ; Photochemistry Catalytic Alkyne Reactions ; Synthetic Organic Chemistry Methods ; Catalytic Cross-Coupling Reactions
Authors: Antonia Di Mola | Mohammad Sadeq Mousavi | Lorenzo Simeone | Giovanni Pierri | António Massa
Source: Advanced Synthesis & Catalysis (article, 2024-11-05)
Field: Chemistry — Organic Chemistry

Regio‐ and Diastereoselective One‐pot Double Cascade Hybrid Formation/[3+3] Spirocyclization for the Synthesis of 3‐Spiropiperidines Under Phase Transfer Conditions Abstract Herein, we report an efficient approach to synthesizing hybrid 3‐spiropiperidine heterocycles that incorporate both 3‐isochromanone and 3‐isoindolinone units through a one‐pot, double cascade reaction facilitated by an economical K 2 CO 3 /TBAB catalytic system. By examining the nucleophilicity of the lactone 3‐isochromanone, we developed a cascade reaction pathway that first generates a bi‐nucleophilic hybrid intermediate, which then undergoes [3+3] spirocyclization with α,β‐unsaturated aldehydes. The regioselectivity of the spirocyclization strongly depends on the substitution pattern of lactam ring.The process exhibits high diastereoselectivity, even with the formation of three or four stereocenters, including two contiguous tetra‐substituted carbons. These sequential cascade reactions were successfully scaled up, and the subsequent reactivity was readily analyzed, enabling the transformation of existing functional groups into valuable new functionalities. Chemistry ; Cascade ; Phase (matter) ; Combinatorial chemistry ; Stereochemistry ; Organic chemistry Chemical synthesis and alkaloids ; Axial and Atropisomeric Chirality Synthesis ; Asymmetric Synthesis and Catalysis
Authors: Dejun Zhang | Lingyun Wang | Wanqing Wu | Derong Cao | Hao Tang
Source: Chemical Communications (review, 2024-12-02)
Field: Chemistry — Organic Chemistry

Macrocyclic catalysis mediated by water: opportunities and challenges Nanospaces within enzymes play a crucial role in chemical reactions in biological systems, garnering significant attention from supramolecular chemists. Inspired by the highly efficient catalysis of enzymes, artificial supramolecular hosts have been developed and widely employed in various reactions, paving the way for innovative and selective catalytic processes and offering new insights into enzymatic catalytic mechanisms. In supramolecular macrocycle systems, weak non-covalent interactions are exploited to enhance substrate solubility, increase local concentration, and stabilize the transition state, ultimately accelerating reaction rates and improving product selectivity. In this review, we will focus on the opportunities and challenges associated with the catalysis of chemical reactions by supramolecular macrocycles in the aqueous phase. Key issues to be discussed include limitations in molecular interaction efficiency in aqueous media, product inhibition, and the incompatibility of catalysts or conditions in "one-pot" reactions. Catalysis ; Chemistry ; Nanotechnology ; Combinatorial chemistry ; Chemical engineering ; Materials science ; Organic chemistry ; Engineering Supramolecular Chemistry and Complexes ; Molecular Sensors and Ion Detection ; Chemical Synthesis and Analysis
Authors: Dario Marchionni | Daniele Gernini | Alireza Nazari Khodadadi | Ejdi Cela | Fan Huang | Luigi Vaccaro
Source: Green Chemistry (article, 2024-01-01)
Field: Chemistry — Inorganic Chemistry

A waste-minimized approach for the synthesis of iodinated organic borazines We herein report a waste-minimized process for the synthesis of iodinated hexa-aryl borazines in different iodination patterns and amounts. Chemistry ; Organic synthesis ; Waste management ; Organic chemistry ; Combinatorial chemistry ; Environmental science ; Catalysis ; Engineering Radioactive element chemistry and processing ; Covalent Organic Framework Applications ; Luminescence Properties of Advanced Materials
Authors: An Sofie Narmon | Lilliana M. Jenisch | Jérôme Rey | Ibrahim Khalil | Michaël Badawi | Michiel Dusselier
Source: ChemSusChem (article, 2024-06-21)
Field: Materials Science — Biomaterials

Monothiolactide, a New Monomer for the Synthesis of Recyclable, Alternating Ester‐Thioester Polymers Aliphatic polyesters and polythioesters are very interesting alternatives for current fossil-based and degradation-resistant plastics, due to their high (bio)degradability and (chemical) recyclability potential. Two important examples include polylactide (PLD), currently leading the synthetic bioplastics market, and its sulfur analog polythiolactide (PTLD). Both polymers can be made by ring-opening polymerization (ROP) of their corresponding (thio)dilactones, lactide (LD) and thiolactide (TLD) respectively. In this work, the benefits of esters and thioesters were combined in one material by the successful catalytic synthesis and ROP of monothiolactide (MTL), an unprecedented monomer containing half a LD and half a TLD structural unit. MTL can be obtained by a simple direct condensation of biobased lactic acid and thiolactic acid aided by Brønsted acid catalysis. The novel, but simple monomer showed to be easily polymerized with triethylamine to materials containing alternating lactic and thiolactic ester units with a very high molar mass. The lower stability of MTL (vs. TLD) resulted in improved ROP thermodynamics, while also fast and controllable polymerization kinetics were observed. The new polymers feature a good chemical recycling and hydrolytic degradation potential with important improvements compared to PTLD and PLD. Finally, a successful co-polymerization with commercial LD was shown, paving the way towards industrialization. Monomer ; Polymerization ; Polymer ; Polyester ; Ring-opening polymerization ; Chemistry ; Condensation polymer ; Polymer chemistry ; Hydrolysis ; Organic chemistry ; Copolymer ; Lactic acid ; Catalysis ; Triethylamine ; Lactide ; Materials science biodegradable polymer synthesis and properties ; Carbon dioxide utilization in catalysis ; Polyoxometalates: Synthesis and Applications
Authors: You‐Song Ding | Qiwei Chen | Jia‐Qi Huang | Xiaofei Zhu | Zhiping Zheng
Source: Chinese Journal of Chemistry (article, 2024-08-08)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Sandwich‐Type Single‐Molecule Magnets Complexes of Er(<scp>III</scp>) with <i>Ansa</i>‐Cyclooctatetraenyl Ligands<sup>†</sup> Comprehensive Summary Many sandwich‐type lanthanide complexes show extremely high energy barriers ( U eff ) for the reversal of magnetization and high blocking temperatures, being the star molecules in the research area of single‐molecule magnets. Herein, the preparation, structural determination, and magnetic property studies of two ansa ‐bridged Er‐COT (COT = cyclooctatetraenyl dianion) complexes [KDME 2 ][Er((η 8 ‐COT‐Si Me2 ) 2 O)] ( 1 ) and [KDME 2 ][Er((η 8 ‐COT‐Si i Pr2 ) 2 O)]K[Er((η 8 ‐COT‐Si i Pr2 ) 2 O)] ( 2 ) were reported. The Er(III) ions in both complexes are sandwiched by two COT rings which are ansa ‐bridged by a [Si‐O‐Si] group. Magnetic studies reveal both complexes display slow magnetic relaxations with comparable energy barriers (228(5) K for 1 , and 196(4) K for 2 ) and blocking temperatures (10.5 K for both complexes). The difference in the relaxation times ( τ ) for the two complexes was studied in details: different molecular vibrations induced by the substituents are the main reason for τ for 1 being about 10 times longer than for 2 at the same temperature above 10 K, while the quantum tunnelling of magnetization relaxation time ( τ QTM ) for 2 is about 10 times longer than for 1 below 8 K, probably owing to the different dipolar interactions. Further rearrangement of molecular network with such ansa ‐bridged SMMs is promising to design molecular magnetic materials with enhanced properties or new properties. Chemistry ; Lanthanide ; Magnetization ; Crystallography ; Molecule ; Relaxation (psychology) ; Quantum tunnelling ; Ion ; Magnet ; Stereochemistry ; Condensed matter physics ; Magnetic field ; Organic chemistry Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Porphyrin and Phthalocyanine Chemistry
Authors: David G. Schauer | John Bredehoeft | Umar Yunusa | Ajith Pattammattel | Hans Jakob Wörner | Emily A. Sprague‐Klein
Source: Physical Chemistry Chemical Physics (article, 2024-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Targeted synthesis of gold nanorods and characterization of their tailored surface properties using optical and X-ray spectroscopy In recent years, nanophotonics have had a transformative impact on harnessing energy, directing chemical reactions, and enabling novel molecular dynamics for thermodynamically intensive applications. Plasmonic nanoparticles have emerged as a tool for confining light on nanometer-length scales where regions of intense electromagnetic fields can be precisely tuned for controlled surface chemistry. We demonstrate a precision pH-driven synthesis of gold nanorods with optical resonance properties widely tunable across the near-infrared spectrum. Through controlled electrostatic interactions, we can perform selective adsorbate molecule attachment and monitor the surface transitions through spectroscopic techniques that include ground-state absorption spectrophotometry, two-dimensional X-ray absorption near-edge spectroscopy, Fourier-transform infrared spectroscopy, and surface-enhanced Raman spectroscopy. We elucidate the electronic, structural, and chemical factors that contribute to plasmon-molecule dynamics at the nanoscale with broad implications for the fields of energy, photonics, and bio-inspired materials. Nanorod ; Characterization (materials science) ; Spectroscopy ; Materials science ; Nanotechnology ; X-ray photoelectron spectroscopy ; X-ray ; Chemical engineering ; Optics ; Physics Gold and Silver Nanoparticles Synthesis and Applications ; Nanocluster Synthesis and Applications ; Advanced Nanomaterials in Catalysis
Authors: Antonio Maggiore | Yangyang Qu | Piotr Pander | Fernando B. Dias | Gilles Clavier | Régis Guillot | Davide Altamura | Cinzia Giannini | Vincenzo Maiorano | Pierre Audebert | Fabien Miomandre
Source: Journal of Materials Chemistry C (article, 2024-01-01)
Field: Materials Science — Materials Chemistry

Sonocrystallization induced thermally activated delayed fluorescence <i>via</i> distortion of molecular geometry We present a donor–acceptor molecule Phx-BzN which displays virtually no photoluminescence in solution but shows strong thermally activated delayed fluorescence (TADF) in form of microcrystals obtained by sonicating water suspension of the compound. Fluorescence ; Materials science ; Photoluminescence ; Distortion (music) ; Molecule ; Suspension (topology) ; Acceptor ; Photochemistry ; Crystallography ; Molecular physics ; Chemical physics ; Optoelectronics ; Optics ; Chemistry ; Condensed matter physics ; Organic chemistry ; Physics Luminescence and Fluorescent Materials ; Organic Light-Emitting Diodes Research ; Perovskite Materials and Applications
Authors: Lukas Maurer | Chuyen Van Pham | Birk Fritsch | Henrik S. Jeppesen | Martin Etter | Andreas Hutzler | Reinhard B. Neder | Moritz Wolf | Franziska Auer | Simon Thiele | Peter Wasserscheid
Source: ChemCatChem (article, 2024-05-15)
Field: Chemistry — Inorganic Chemistry

Improving Hydrogen Release From Oxygen‐Functionalized LOHC Molecules by Ru Addition to Pt/C Catalysts Abstract Bimetallic PtRu/C catalysts have been prepared by depositing Ru onto a commercial Pt/C catalyst and subsequent thermal annealing. Different Pt : Ru ratios of 1 : 1, 2 : 1, 4 : 1, 8 : 1, and 16 : 1 have been investigated with annealing temperatures of 350 and 500 °C. Using X‐ray diffraction (XRD), synchrotron powder X‐ray diffraction (SPXRD) combined with pair distribution function (PDF) analysis and scanning transmission electron microscopy with energy dispersive X‐ray spectrum imaging (STEM‐EDXS), we show that diffusion of Ru into the fcc crystal structure of the Pt nanoparticles takes place during thermal annealing. Partial segregation and the formation of Pt nanoclusters on the bimetallic surface was observed depending on the Pt : Ru ratio. The annealing process does not only cause a high Pt dispersion but also affects the electronic structure of the Pt surface by broadening the d‐band thus facilitating the product's desorption from the surface of the bimetallic particle. These beneficial effects have been exemplified for the catalytic dehydrogenation of dicyclohexylmethanol, a promising hydrogen carrier compound with 7.2 wt% hydrogen capacity. The most active catalyst material among the tested supported alloys and monometallic reference materials was Pt 4 Ru 1 /C after annealing at 500 °C, which increased the hydrogen release productivity by 65 % compared to the unmodified Pt/C catalyst. Catalysis ; Oxygen ; Chemistry ; Hydrogen ; Molecule ; Hydrogen storage ; Ruthenium ; Hydrogen molecule ; Combinatorial chemistry ; Inorganic chemistry ; Chemical engineering ; Organic chemistry Asymmetric Hydrogenation and Catalysis ; Catalytic Processes in Materials Science ; Carbon dioxide utilization in catalysis
Authors: Prerna Chettri | Anup Singhania | Sudeshna Kalita | Hidenobu Nakao | Bharati Bora | Ponkaj Saikia | Sanghamitra Dutta | Anirban Bandyopadhyay | Subrata Ghosh
Source: Advanced Optical Materials (article, 2024-07-31)
Field: Materials Science — Materials Chemistry

Fluorescent Nanowires from Dual‐State Emitting Fluorophores Directed by Molecular Motors and Aggregation‐Induced Emission: Produce Quantized Light Spectrum Abstract Luminescent materials require systems that exhibit both dual‐state emission (DSE) and aggregation‐induced emission (AIE) to overcome the limitation of aggregation‐caused quenching (ACQ). Herein, a molecular assembler capable of crafting nanowires that exhibit programmable fluorescence across a broad spectrum of colors in a precisely quantized manner is reported. Because it is a starburst dendritic box made of PAMAM dendrimer (P), controller (C) molecules, and motor (M) molecules, the assembler is called PCM. Here, Nile red is chosen as C and placed into the hollow core of the dendrimer; a double ratchet motor (DRM) is chosen as M and is connected to the N ‐terminals of the PAMAM dendrimer. While aqueous dispersed PCM assemblers have broad fluorescence bands beyond 300 nm, their crafted nanowires produce quantized cyan‐green, yellow, and orange‐red light emission in the spectra. These PCM assemblers are shown to hold long‐term memory, rapid switching, and energy harvesting by modulating photonic bandgaps, causing a longer redshift in the solid phase. The DSE of PCM can yield versatile photonics applications like bioimaging and energy harvesting. As PCM nanowires can modulate photonic bandgaps to cause a longer redshift, PCM fluorophores hold promise for drug delivery and cell separation like infrared‐sensitive operations. Fluorescence ; Materials science ; Cyan ; Photonics ; Optoelectronics ; Dendrimer ; Nanowire ; Nile red ; Nanotechnology ; Quenching (fluorescence) ; Tetraphenylethylene ; Photoluminescence ; Luminescence ; Aggregation-induced emission ; Optics ; Physics Luminescence and Fluorescent Materials ; Supramolecular Chemistry and Complexes ; Dendrimers and Hyperbranched Polymers
Authors: Nongluck Jaito | Suthathip Phetlum | Titiporn Saeoung | Thanat Tiyasakulchai | Nitipol Srimongkolpithak | Tanaporn Uengwetwanit
Source: Frontiers in Bioengineering and Biotechnology (article, 2024-07-30)
Field: Chemistry — Organic Chemistry

Improving stereoselectivity of phosphotriesterase (PTE) for kinetic resolution of chiral phosphates Specific stereoisomer is paramount as it is vital for optimizing drug efficacy and safety. The quest for the isolation of desired stereoisomer of active pharmaceutical ingredients or key intermediates drives innovation in drug synthetic and biocatalytic methods. Chiral phosphoramidate is an important building block for the synthesis of antiviral drugs such as remdesivir and sofosbuvir. Given the clinical potency of the (<i>S</i>p)-diastereomer of the drugs, an enzyme capable of completely hydrolyzing the (<i>R</i>p)-diastereomer is needed to achieve the purified diastereomers <i>via</i> biocatalytic reaction. In this study, protein engineering of phosphotriesterase (PTE) was aimed to improve the specificity. Employing rational design and site-directed mutagenesis, we generated a small library comprising 24 variants for activity screening. Notably, W131M and I106A/W131M variants demonstrated successful preparation of pure (<i>S</i>p)-diastereomer of remdesivir and sofosbuvir precursors within a remarkably short hydrolysis time (<20 min). Our work unveils a promising methodology for producing pure stereoisomeric compounds, utilizing novel biocatalysts to enable the chemoenzymatic synthesis of phosphoramidate nucleoside prodrugs. Phosphoramidate ; Stereoselectivity ; Chemistry ; Combinatorial chemistry ; Kinetic resolution ; Drug ; Potency ; Sofosbuvir ; Stereochemistry ; Pharmacology ; Organic chemistry ; Enantioselective synthesis ; Biochemistry ; Catalysis ; Medicine Chemical Reaction Mechanisms ; HIV/AIDS drug development and treatment ; Biochemical and Molecular Research
Authors: Fei Wang | Xue Wang | Xinchao Lu | Chengjun Huang
Source: Biosensors (article, 2024-01-12)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Nanophotonic Enhanced Chiral Sensing and Its Biomedical Applications Chiral sensing is crucial in the fields of biology and the pharmaceutical industry. Many naturally occurring biomolecules, i.e., amino acids, sugars, and nucleotides, are inherently chiral. Their enantiomers are strongly associated with the pharmacological effects of chiral drugs. Owing to the extremely weak chiral light-matter interactions, chiral sensing at an optical frequency is challenging, especially when trace amounts of molecules are involved. The nanophotonic platform allows for a stronger interaction between the chiral molecules and light to enhance chiral sensing. Here, we review the recent progress in nanophotonic-enhanced chiral sensing, with a focus on the superchiral near-field and enhanced circular dichroism (CD) spectroscopy generated in both the dielectric and in plasmonic structures. In addition, the recent applications of chiral sensing in biomedical fields are discussed, including the detection and treatment of difficult diseases, i.e., Alzheimer's disease, diabetes, and cancer. Nanophotonics ; Biomolecule ; Plasmon ; Circular dichroism ; Nanotechnology ; Enantiomer ; Materials science ; Chemistry ; Optoelectronics ; Stereochemistry Metamaterials and Metasurfaces Applications ; Photonic and Optical Devices ; Orbital Angular Momentum in Optics
Authors: Maurizio Chiminelli | Gabriele Scarica | Andrea Serafino | Luciano Marchiò | Rosanna Viscardi | Giovanni Maestri
Source: Molecules (article, 2024-01-25)
Field: Chemistry — Organic Chemistry

Visible-Light-Promoted Tandem Skeletal Rearrangement/Dearomatization of Heteroaryl Enallenes Access to complex three-dimensional molecular architectures via dearomatization of ubiquitous aryl rings is a powerful synthetic tool, which faces, however, an inherent challenge to overcome energetic costs due to the loss of aromatic stabilization energy. Photochemical methods that allow one to populate high-energy states can thus be an ideal strategy to accomplish otherwise prohibitive reaction pathways. We present an original dearomative rearrangement of heteroaryl acryloylallenamides that leads to complex fused tricycles. The visible-light-promoted method occurs under mild conditions and tolerates a variety of functional groups. According to DFT modeling used to rationalize the outcome of the cascade, the reaction involves a sequential [2+2] allene-alkene photocycloaddition, which is followed by a selective retro- [2+2] step that paves the way for the dearomatization of the heteroaryl partner. This scenario is original with respect to the reported photochemical reactivity of similar substrates and thus holds promise for ample future developments. Allene ; Chemistry ; Tandem ; Alkene ; Cascade reaction ; Combinatorial chemistry ; Aryl ; Reactivity (psychology) ; Photochemistry ; Cascade ; Cycloaddition ; Functional group ; Computational chemistry ; Organic chemistry ; Catalysis ; Materials science Radical Photochemical Reactions ; Catalytic C–H Functionalization Methods ; Sulfur-Based Synthesis Techniques