jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: S. N. R. Donthireddy | Arnab Rit
Source: Chemistry - A European Journal (article, 2023-10-09)
Field: Chemistry — Inorganic Chemistry

Heteroditopic NHC Ligand Supported Manganese(I) Complexes: Synthesis, Characterization, and Activity as Non‐bifunctional Phosphine‐Free Catalyst for the α‐Alkylation of Nitriles In the present work, several manganese(I) complexes of chelating heteroditopic ligands Mn1-3, featuring ImNHC (imidazol-2-ylidene) connected to a 1,2,3-triazole-N or tzNHC (1,2,3-triazol-5-ylidene) donors via a methylene spacer, with possible modifications at the triazole backbone have been synthesized and completely characterized. Notably, the CO stretching frequencies, electrochemical analysis, and frontier orbital analysis certainly suggest that the chelating ImNHC-tzNHC ligands have stronger donation capabilities than the related ImNHC-Ntz ligand in the synthesized complexes. Moreover, these well-defined phosphine-free Mn(I)-NHC complexes have been found to be effective non-bifunctional catalysts for the α-alkylation of nitriles using alcohols and importantly, the catalyst Mn1 containing ImNHC connected to a weaker triazole-N donor displayed higher activity compared to Mn2/Mn3 containing an unsymmetrical bis-carbene donors (ImNHC and tzNHC). A wide range of aryl nitriles were coupled with diverse (hetero)aromatic as well as aliphatic alcohols to get the corresponding products in good to excellent yields (32 examples, up to 95 % yield). The detailed mechanistic studies including deuterium labelling experiments reveal that the reaction follows a Borrowing Hydrogen pathway. Bifunctional ; Phosphine ; Alkylation ; Manganese ; Ligand (biochemistry) ; Chemistry ; Catalysis ; Characterization (materials science) ; Combinatorial chemistry ; Organic chemistry ; Nanotechnology ; Materials science ; Biochemistry ; Receptor Asymmetric Hydrogenation and Catalysis ; N-Heterocyclic Carbenes in Organic and Inorganic Chemistry ; Catalytic Cross-Coupling Reactions
Authors: Kimberly A. Alley | Aidan J. Clarkson | Ayaka Uehara | Jeffrey S. Johnson
Source: Organic Letters (article, 2023-12-14)
Field: Chemistry — Organic Chemistry

A Site-Specific Synthetic Route to Substituted Inda(box) Ligands Aminoindanol-derived bis(oxazoline) ligands are widely used in metal-catalyzed transformations, but the synthesis of structural derivatives is challenging. We report the gram-scale, seven-step synthesis of five bromine-functionalized inda(box) ligands that have varied bridge substituents. The bromoinda(box) ligands undergo late-stage modification via Pd-catalyzed cross-couplings, which allows for the synthesis of twelve unique inda(box) ligands. This complementary synthetic route could enable the discovery of new asymmetric metal-catalyzed transformations through the modification of the inda(box) ligand architecture. Chemistry ; Combinatorial chemistry ; Ligand (biochemistry) ; Oxazoline ; Catalysis ; Bromine ; Stereochemistry ; Organic chemistry Catalytic C–H Functionalization Methods ; Catalytic Cross-Coupling Reactions ; Asymmetric Hydrogenation and Catalysis
Authors: Binbin Zhou | Mattias Rasmussen | Patrick R. Whelan | Jie Ji | Abhay Shivayogimath | Peter Bøggild | Peter Uhd Jepsen
Source: Sensors (article, 2023-03-31)
Field: Materials Science — Materials Chemistry

Non-Linear Conductivity Response of Graphene on Thin-Film PET Characterized by Transmission and Reflection Air-Plasma THz-TDS We demonstrate that the conductivity of graphene on thin-film polymer substrates can be accurately determined by reflection-mode air-plasma-based THz time-domain spectroscopy (THz-TDS). The phase uncertainty issue associated with reflection measurements is discussed, and our implementation is validated by convincing agreement with graphene electrical properties extracted from more conventional transmission-mode measurements. Both the reflection and transmission THz-TDS measurements reveal strong non-linear and instantaneous conductivity depletion across an ultra-broad bandwidth (1-9 THz) under relatively high incident THz electrical field strengths (up to 1050 kV/cm). Terahertz radiation ; Conductivity ; Graphene ; Materials science ; Reflection (computer programming) ; Optoelectronics ; Thin film ; Transmission (telecommunications) ; Plasma ; Optics ; Nanotechnology ; Physics ; Electrical engineering ; Computer science ; Engineering Graphene research and applications ; Nanowire Synthesis and Applications ; Molecular Junctions and Nanostructures
Authors: Juan Carlos Pérez‐Sánchez | Raquel P. Herrera | M. Concepción Gimeno
Source: Dalton Transactions (review, 2023-12-07)
Field: Chemistry — Organic Chemistry

Unlocking the catalytic potential of gold(<scp>ii</scp>) complexes: a comprehensive reassessment Gold(II) complexes, unlike their gold(I) and gold(III) counterparts, have been sparsely employed in the field of catalysis. This is primarily due to the challenges associated with isolating and characterising these open-shell species. However, these complexes offer a wide range of possibilities. On one hand, this intermediate oxidation state has proven to be more easily accessible through reduction and oxidation processes compared to the gold(I)/gold(III) redox couple, thereby facilitating potential homo-coupling and cross-coupling reactions. On the other hand, gold(II) exhibits Lewis acid behaviour, bridging the characteristics of the soft acid gold(I) and the hard acid gold(III). In this review, we focus on mono- and dinuclear gold(II) complexes, whether they are isolated and well-studied or proposed as intermediates in cross-coupling reactions induced by the action of oxidants or light. We delve into the unique reactivity and potential applications of these gold(II) species, shedding light on their role in this field. This comprehensive exploration aims to underscore the latent promise of gold(II) complexes in catalysis, offering insights into their structural and mechanistic aspects while highlighting their relevance in contemporary chemical transformations. Catalysis ; Chemistry ; Business ; Biochemistry Catalytic Alkyne Reactions ; Organometallic Complex Synthesis and Catalysis ; Asymmetric Hydrogenation and Catalysis
Authors: Yu-Ming Tseng | Jian‐Hong Liao | Tzu‐Hao Chiu | Hao Liang | Samia Kahlal | Jean‐Yves Saillard | C. W. Liu
Source: Inorganic Chemistry (article, 2023-02-21)
Field: Materials Science — Materials Chemistry

Superatom Pruning by Diphosphine Ligands as a Chemical Scissor A two-electron silver superatom, [Ag<sub>6</sub>{S<sub>2</sub>P(O<sup><i>i</i></sup>Pr)<sub>2</sub>}<sub>4</sub>(dppm)<sub>2</sub>] (<b>1</b>), was synthesized by adding dppm (bis(diphenylphosphino)methane) into [Ag<sub>20</sub>{S<sub>2</sub>P(O<sup><i>i</i></sup>Pr)<sub>2</sub>}<sub>12</sub>] (8e). It was characterized by single-crystal crystallography, multinuclear NMR spectroscopy, electrospray ionization-mass spectrometry, density functional theory (DFT), and time-dependent DFT calculations. The added dppm ligands, which carry out the nanocluster-to-nanocluster transformation, act as a chemical scissor to prune the nanocluster geometrically from an icosahedron-based Ag<sub>20</sub> nanocluster (NC) to an octahedral Ag<sub>6</sub> NC and electronically from eight-electron to two-electron. Eventually, dppm was involved in the protective shell to form a new heteroleptic NC. The temperature-dependent NMR spectroscopy confirms its fluxional behavior, showing the fast atomic movement at ambient temperature. Compound <b>1</b> exhibits a bright yellow emission under UV irradiation at ambient temperature with a quantum yield of 16.3%. This work demonstrates a new methodology to achieve nanocluster-to-nanocluster transformation via stepwise synthesis. Chemistry ; Superatom ; Dodecahedron ; X-ray photoelectron spectroscopy ; Crystallography ; Nuclear magnetic resonance spectroscopy ; Spectroscopy ; Density functional theory ; Octahedron ; Electrospray ionization ; Yield (engineering) ; Crystal structure ; Mass spectrometry ; Photochemistry ; Computational chemistry ; Stereochemistry ; Nuclear magnetic resonance Nanocluster Synthesis and Applications ; Pharmacological Effects and Toxicity Studies ; Advanced Nanomaterials in Catalysis
Authors: Fabrizio Medici | Valerio Chiroli | Laura Raimondi | Maurizio Benaglia
Source: Tetrahedron Chem (article, 2023-12-25)
Field: Chemistry — Organic Chemistry

Latest updates in ElectroPhotoChemical reactions In the last twenty years, electrochemistry and photochemistry have attracted a renewed and still uprising interest in organic synthesis. Two of the most simple and abundant reagents, electrons and photons, became the key players in synthetic chemistry as cornerstones of developing greener and sustainable chemical processes. An interesting strategy that recently emerged is the possibility of merging the two worlds in what is called ElectroPhotoChemistry (EPC). In particular, this review will focus on the most recent contributions in the field. The basic principles of EPC will be presented along with a discussion of the published works of the last few years. Electrophotochemical oxidation/reduction reactions will be discussed, including in this section the transformations of a C–H bond to a C-X (X: heteroatom). In the C–H activation chapter the formation of C–C bond, starting from a C–H bond, will be considered. Finally, the miscellaneous chapter includes examples which do not clearly belong to the previous categories. Heteroatom ; Chemistry ; Nanotechnology ; Combinatorial chemistry ; Materials science ; Organic chemistry Radical Photochemical Reactions ; Fluorine in Organic Chemistry ; Oxidative Organic Chemistry Reactions
Authors: Enrico Lunghi | Pietro Ronco | Federico Della Negra | Beatrice Trucchi | Massimo Verzini | Daniele Merli | Emanuele Casali | C. Oliver Kappe | David Cantillo | Giuseppe Zanoni
Source: The Journal of Organic Chemistry (article, 2023-11-30)
Field: Chemistry — Organic Chemistry

Electrifying Friedel–Crafts Intramolecular Alkylation toward 1,1-Disubstituted Tetrahydronaphthalenes In this work, we successfully employed electrochemical conditions to promote a Hofer-Moest, intramolecular Friedel-Crafts alkylation sequence. The reaction proceeds under mild conditions, employing carboxylic acids as starting materials. Notably, the electrochemical process performed in batch was adapted to a continuous flow electrolysis apparatus to provide a significant improvement. This catalyst-free, electrochemical approach produces an array of tetrahydronaphthalenes that could be used for API synthesis. Friedel–Crafts reaction ; Intramolecular force ; Alkylation ; Chemistry ; Organic chemistry ; Catalysis Radical Photochemical Reactions ; Synthesis of Indole Derivatives ; Electrocatalysts for Energy Conversion
Authors: Paula S. Mateos | Claudia Ruscitti | Mónica L. Casella | Silvana R. Matkovic | Laura E. Briand
Source: Catalysts (article, 2023-08-30)
Field: Materials Science — Materials Chemistry

Phosphotungstic Wells-Dawson Heteropolyacid as Potential Catalyst in the Transesterification of Waste Cooking Oil The esterification of oleic acid was applied in order to screen the suitability of a series of phosphotungstic-based Wells-Dawson types of compounds as potential catalysts in the heterogeneous transesterification of sunflower waste cooking oil. This test reaction indicated that the phosphotungstic Wells-Dawson heteropolyacid H6P2W18O62·xH2O, dispersed on titania oxide in a loading of 15 mg per m2 of oxide support (named 42% HPA/TiO2) and possessing exclusively Brønsted acid sites, was the most promising among the screened materials. In addition, the application of a nonlinear analysis methodology to find a surface that fits the specific activity of the oleic acid esterification with methanol at various temperatures, weights of catalyst, molar ratios of substrates, and stirring speeds, and also considering the active phase desorption out of the catalyst’s surface, allowed determining the optimum operative conditions that were applied in the transesterification of the waste cooking oil afterwards. The transesterification of the waste cooking oil at 60 °C and 1:9 WCO: methanol molar ratio in a batch reactor under stirring at 650 rpm for 3 h, catalyzed with 0.25 wt% of 42% HPA/TiO2 (20.0 g of oil and 49.6 mg of catalyst), presents 74.6% of conversion of glycerides and 74.4% yield towards fatty acid methyl esters. The catalyst was recovered and reused several times, maintaining a fairly constant catalytic performance. Transesterification ; Phosphotungstic acid ; Catalysis ; Methanol ; Oleic acid ; Chemistry ; Yield (engineering) ; Sunflower oil ; Organic chemistry ; Nuclear chemistry ; Materials science Polyoxometalates: Synthesis and Applications ; Chemical Synthesis and Reactions ; Biodiesel Production and Applications
Authors: Clara Sanchez‐Perez | Sriluxmi Srimurugananthan | Carlos Sotelo-Vázquez | Sanjayan Sathasivam | Mingyue Wang | Javier Marugán | Ivan P. Parkin | Claire J. Carmalt
Source: Materials Advances (article, 2023-01-01)
Field: Materials Science — Materials Chemistry

Self-textured ZnO <i>via</i> AACVD of alkyl alkoxides: a solution-based seed-less route towards optoelectronic-grade coatings Carbon-free, crystalline and transparent (002)-oriented ZnO films with thickness below 200 nm were deposited at 350 °C on plain glass via AACVD. ZnO films restricted to PVD-growth are achievable through a fast, cost-effective and scalable methodology. Materials science ; Alkyl ; Chemical engineering ; Chemical vapor deposition ; Optoelectronics ; Organic chemistry ; Chemistry ZnO doping and properties ; Ga2O3 and related materials ; Copper-based nanomaterials and applications
Authors: Romie C. Nguyen | Cassadee Stagliano | Aimin Liu
Source: Current Opinion in Chemical Biology (review, 2023-06-01)
Field: Chemistry — Inorganic Chemistry

Structural insights into the half-of-sites reactivity in homodimeric and homotetrameric metalloenzymes Reactivity (psychology) ; Ribonucleotide reductase ; Chemistry ; Biochemistry ; Enzyme ; Protein subunit ; Ribonucleotide ; Substrate (aquarium) ; Tryptophan synthase ; Escherichia coli ; Stereochemistry ; Biology ; Nucleotide Metal-Catalyzed Oxygenation Mechanisms ; Biochemical and Molecular Research ; Enzyme Structure and Function
Authors: Margherita Cacaci | Giacomo Biagiotti | Gianluca Toniolo | Martin Albino | Claudio Sangregorio | Mirko Severi | Maura Di Vito | Damiano Squitieri | Luca Contiero | Marco Paggi | Marcello Marelli | Stefano Cicchi | Francesca Bugli | Barbara Richichi
Source: Nanomaterials (article, 2023-05-09)
Field: Materials Science — Materials Chemistry

Shaping Silver Nanoparticles’ Size through the Carrier Composition: Synthesis and Antimicrobial Activity The increasing resistance of bacteria to conventional antibiotics represents a severe global emergency for human health. The broad-spectrum antibacterial activity of silver has been known for a long time, and silver at the nanoscale shows enhanced antibacterial activity. This has prompted research into the development of silver-based nanomaterials for applications in clinical settings. In this work, the synthesis of three different silver nanoparticles (AgNPs) hybrids using both organic and inorganic supports with intrinsic antibacterial properties is described. The tuning of the AgNPs' shape and size according to the type of bioactive support was also investigated. Specifically, the commercially available sulfated cellulose nanocrystal (CNC), the salicylic acid functionalized reduced graphene oxide (rGO-SA), and the commercially available titanium dioxide (TiO<sub>2</sub>) were chosen as organic (CNC, rGO-SA) and inorganic (TiO<sub>2</sub>) supports. Then, the antimicrobial activity of the AgNP composites was assessed on clinically relevant multi-drug-resistant bacteria and the fungus <i>Candida albicans</i>. The results show how the formation of Ag nanoparticles on the selected supports provides the resulting composite materials with an effective antibacterial activity. Antimicrobial ; Silver nanoparticle ; Nanoparticle ; Materials science ; Nanotechnology ; Composition (language) ; Chemistry ; Organic chemistry ; Art Nanoparticles: synthesis and applications ; Graphene and Nanomaterials Applications ; Laser-Ablation Synthesis of Nanoparticles
Authors: Qianqian Xie | Xiao Yang | Binoy Sarkar | Xiaomin Dou | Piumi Amasha Withana | Yong Sik Ok
Source: Biochar (article, 2023-12-12)
Field: Materials Science — Materials Chemistry

Conversion of biochar into sulfonate-bearing solid acids used for the hydrolysis of tylosin: the effect of aromaticity and degree of condensation Abstract In the last few decades, sulfonated carbon materials have garnered significant attention as Brønsted solid acid catalysts. The sulfonation process and catalytic activity of sulfonated biochar can be influenced by the aromaticity and degree of condensation exhibited by biochar. However, the relationships between the aromaticity, sulfonating ability, and resultant catalytic activity are not fully understood. In this study, biochar samples pyrolyzed at 300–650 °C exhibiting different aromaticity and degrees of condensation were sulfonated and employed as sulfonate-bearing solid catalysts for hydrolytically removing tylosin. They exhibited excellent hydrolytic performance and their kinetic constants were positively correlated with the total acidity and negatively correlated with their aromaticity. This study has uncovered the relationship between the structure, properties, sulfonating ability, and subsequent hydrolytic performance of biochar samples. It was observed that the aromaticity of biochar decreased as the pyrolysis temperature increased. Lower pyrolysis temperatures resulted in a reduced degree of condensation, smaller ring size, and an increased number of ring edge sites available for sulfonation, ultimately leading to enhanced catalytic performance. These findings provide valuable insights into the fundamental chemistry behind sulfonation upgrading of biochar, with the aim of developing functional catalysts for mitigating antibiotics in contaminated water. Graphical Abstract Biochar ; Aromaticity ; Chemistry ; Catalysis ; Pyrolysis ; Hydrolysis ; Tylosin ; Organic chemistry ; Molecule Covalent Organic Framework Applications ; Adsorption and biosorption for pollutant removal ; Pharmaceutical and Antibiotic Environmental Impacts
Authors: Tu N. Nguyen | Svetlana V. Eliseeva | I. Martinić | Peggy L. Carver | Timothée Lathion | Stéphane Pètoud | Vincent L. Pecoraro
Source: Chemistry - A European Journal (article, 2023-03-09)
Field: Materials Science — Materials Chemistry

Lower Energy Excitation of Water Soluble Near‐Infrared Emitting Mixed‐Ligand Metallacrowns By combining advantages of two series of lanthanide(III)/zinc(II) metallacrowns (MCs) assembled using pyrazine- (pyzHA<sup>2-</sup> ) and quinoxaline- (quinoHA<sup>2-</sup> ) hydroximate building blocks ligands, we created here water-soluble mixed-ligand MCs with extended absorption to the visible range. The Yb<sup>III</sup> analogue demonstrated improved photophysical properties in the near-infrared (NIR) range in cell culture media, facilitating its application for NIR optical imaging in living HeLa cells. Quinoxaline ; HeLa ; Ligand (biochemistry) ; Lanthanide ; Pyrazine ; Near-infrared spectroscopy ; Absorption (acoustics) ; Infrared ; Chemistry ; Photochemistry ; Zinc ; Range (aeronautics) ; Excitation ; Materials science ; Optoelectronics ; Stereochemistry ; Optics ; Organic chemistry ; Ion ; Cell ; Receptor ; Physics ; Biochemistry Lanthanide and Transition Metal Complexes ; Nanoplatforms for cancer theranostics ; Luminescence and Fluorescent Materials
Authors: Yang Su | Bin Wu | Ming‐Peng Zhuo | Qiang Lv | Ji‐Hao Sun | Yu‐Dong Zhao | Min Chen | Zuoshan Wang | Xuedong Wang
Source: Matter (article, 2023-11-28)
Field: Materials Science — Biomaterials

Cascaded charge-transfer organic alloys for the controlled hierarchical self-assembly of low-dimensional heterostructures Heterojunction ; Charge (physics) ; Materials science ; Nanotechnology ; Transfer (computing) ; Self-assembly ; Optoelectronics ; Chemical physics ; Computer science ; Chemistry ; Physics ; Quantum mechanics ; Parallel computing Supramolecular Self-Assembly in Materials ; Conducting polymers and applications ; Polydiacetylene-based materials and applications
Authors: Igor A. Kurashov | Alisa D. Kharlamova | Anton S. Abel | Alexei D. Averin | I. P. Beletskaya
Source: Molecules (article, 2023-01-04)
Field: Chemistry — Spectroscopy

Polyoxa- and Polyazamacrocycles Incorporating 6,7-Diaminoquinoxaline Moiety: Synthesis and Application as Tunable Optical pH-Indicators in Aqueous Solution Synthetic approach to fluorescent polyaza- and polyoxadiazamacrocycles comprising a structural fragment of 6,7-diamino-2,3-diphenylquinoxaline has been elaborated using Pd-catalyzed amination providing target compounds in yields up to 77%. A series of nine novel <i>N</i>- and <i>N</i>,<i>O</i>-containing macrocyclic ligands differing by the number of donor sites and cavity size has been obtained. These compounds possess well-pronounced fluorescent properties with emission maxima in a blue region in aprotic solvents and high quantum yields of fluorescence, while in proton media, fluorescence shifts towards the green region of the spectrum. Using macrocycles <b>5c</b> and <b>5e</b> as examples, we have shown that such compounds can serve as dual-channel (colorimetric and fluorimetric) pH indicators in water media, with pH transition point and response being dependent on the macrocycle structure due to different sequences of protonation steps. Fluorescence ; Protonation ; Chemistry ; Moiety ; Amination ; Aqueous solution ; Aqueous medium ; Photochemistry ; Proton ; Combinatorial chemistry ; Stereochemistry ; Organic chemistry ; Catalysis ; Ion Molecular Sensors and Ion Detection ; Luminescence and Fluorescent Materials ; Synthesis and Biological Evaluation
Authors: Miao Zhao | Anton Uzunoff | Mark Green | Aliaksandra Rakovich
Source: Nanomaterials (review, 2023-05-04)
Field: Materials Science — Biomaterials

The Role of Stabilizing Copolymer in Determining the Physicochemical Properties of Conjugated Polymer Nanoparticles and Their Nanomedical Applications Conjugated polymer nanoparticles (CPNs) are a promising class of nanomaterials for biomedical applications, such as bioimaging, gene and drug delivery/release, photodynamic therapy (PDT), photothermal therapy (PTT), and environmental sensing. Over the past decade, many reports have been published detailing their synthesis and their various potential applications, including some very comprehensive reviews of these topics. In contrast, there is a distinct lack of overview of the role the stabilizing copolymer shells have on the properties of CPNs. This review attempts to correct this oversight by scrutinizing reports detailing the synthesis and application of CPNs stabilized with some commonly-used copolymers, namely F127 (Pluronic poly(ethylene glycol)-<i>block</i>-poly(propylene glycol)-<i>block</i>-poly(ethylene glycol) diacrylate), PSMA (poly(styrene-co-maleic anhydride)), PLGA (poly(D, L-lactide-co-glycolide)) and PEG (polyethylene glycol) derivatives. The analysis of the reported physicochemical properties and biological applications of these CPNs provides insights into the advantages of each group of copolymers for specific applications and offers a set of guidance criteria for the selection of an appropriate copolymer when designing CPNs-based probes. Finally, the challenges and outlooks in the field are highlighted. Copolymer ; Ethylene glycol ; Materials science ; Conjugated system ; Polymer ; Maleic anhydride ; Nanotechnology ; Nanoparticle ; Drug delivery ; Polyethylene glycol ; Nanomaterials ; Chemistry ; Organic chemistry Nanoparticle-Based Drug Delivery ; Advanced Polymer Synthesis and Characterization ; Nanoplatforms for cancer theranostics