jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Ilia Kochetygov | Jocelyn Roth | Jordi Espín | Sophia Pache | Anita Justin | Till Schertenleib | Nazanin Taheri | Dmitry Chernyshov | Wendy L. Queen
Source: Angewandte Chemie International Edition (article, 2023-02-15)
Field: Chemistry — Inorganic Chemistry

A Simple, Transition Metal Catalyst‐Free Method for the Design of Complex Organic Building Blocks Used to Construct Porous Metal–Organic Frameworks The design of metal-organic frameworks (MOFs) having large pore sizes and volumes often requires the use of complex organic ligands, currently synthesized using costly and time-consuming palladium-catalyzed coupling chemistry. Thus, in the present work, a new strategy for ligand design is reported, where piperazine and dihydrophenazine units are used as substitutes for benzene rings, which are the basic building block of most MOF ligands. This chemistry, which is based on simple, nucleophilic aromatic substitution (S<sub>N</sub> Ar) reactions, is used for the transition metal catalyst-free construction of 21 new, carboxylate-based ligands with varying sizes, shapes, and denticity and 15 linear di- and tetra-nitriles. Moreover, to demonstrate the utility of the ligands as building blocks, 16 new structurally diverse MOFs having surface areas up to 3100 m<sup>2</sup> g<sup>-1</sup> were also synthesized. Transition metal ; Denticity ; Catalysis ; Palladium ; Ligand (biochemistry) ; Piperazine ; Metal-organic framework ; Combinatorial chemistry ; Chemistry ; Materials science ; Organic chemistry ; Metal ; Adsorption Metal-Organic Frameworks: Synthesis and Applications ; Magnetism in coordination complexes ; Dendrimers and Hyperbranched Polymers
Authors: J. Adámek | Paulina H. Marek‐Urban | Krzysztof Woźniak | Krzysztof Durka | Sergiusz Luliński
Source: Chemical Science (article, 2023-01-01)
Field: Materials Science — Materials Chemistry

Highly electron-deficient 3,6-diaza-9-borafluorene scaffolds for the construction of luminescent chelate complexes The synthesis and characterization of two fluorinated 3,6-diaza-9-hydroxy-9-borafluorene oxonium acids featuring improved hydrolytic stability and the strong electron-deficient character of the diazaborafluorene core is reported. These boracycles served as precursors of fluorescent spiro-type complexes with (O,N)-chelating ligands which revealed specific properties such as delayed emission, white light emission in the solid state and photocatalytic performance in singlet oxygen-mediated oxidation reactions. Oxonium ion ; Singlet oxygen ; Chelation ; Luminescence ; Fluorescence ; Chemistry ; Photochemistry ; Solid-state ; Characterization (materials science) ; Polymer chemistry ; Combinatorial chemistry ; Materials science ; Inorganic chemistry ; Oxygen ; Nanotechnology ; Organic chemistry ; Ion ; Physical chemistry Luminescence and Fluorescent Materials ; Organic Light-Emitting Diodes Research ; Organoboron and organosilicon chemistry
Authors: Renata Siedlecka
Source: Catalysts (article, 2023-01-05)
Field: Chemistry — Inorganic Chemistry

Selectivity in the Aliphatic C–H Bonds Oxidation (Hydroxylation) Catalyzed by Heme- and Non-Heme Metal Complexes—Recent Advances The oxyfunctionalization of non-activated C-H bonds has attracted considerable attention for several years. Following the example of enzymatic systems, a multitude of catalytic systems capable of carrying out such a transformation efficiently and selectively have been described. The great discoveries in this area were described at the beginning of the 21st century, but due to the growing demand for precise syntheses (e.g., for the needs of the pharmaceutical industry), new solutions or new applications for already known catalytic systems are constantly being sought. This review article summarizes the development of metal complex-catalyzed selective functionalization of saturated C-H bonds since 2010. However, brief references to previous studies are also made for clarity. There is a huge amount of literature reports in this area, so we intend to highlight only the most important findings in the selective hydroxylation of saturated C–H bonds. Their practical applications in synthesis will also be pointed out. Hydroxylation ; Catalysis ; Combinatorial chemistry ; Chemistry ; Selectivity ; Nanotechnology ; Organic chemistry ; Materials science ; Enzyme Metal-Catalyzed Oxygenation Mechanisms ; Catalytic C–H Functionalization Methods ; Oxidative Organic Chemistry Reactions
Authors: Kuntrapakam Hema | Angela B. Grommet | Michał J. Białek | Jinhua Wang | Laura Schneider | Christoph Drechsler | Oksana Yanshyna | Yael Diskin‐Posner | Guido H. Clever | Rafał Klajn
Source: Journal of the American Chemical Society (article, 2023-11-02)
Field: Chemistry — Organic Chemistry

Guest Encapsulation Alters the Thermodynamic Landscape of a Coordination Host The architecture of self-assembled host molecules can profoundly affect the properties of the encapsulated guests. For example, a rigid cage with small windows can efficiently protect its contents from the environment; in contrast, tube-shaped, flexible hosts with large openings and an easily accessible cavity are ideally suited for catalysis. Here, we report a "Janus" nature of a Pd<sub>6</sub>L<sub>4</sub> coordination host previously reported to exist exclusively as a tube isomer (<b>T</b>). We show that upon encapsulating various tetrahedrally shaped guests, <b>T</b> can reconfigure into a cage-shaped host (<b>C</b>) in quantitative yield. Extracting the guest affords empty <b>C</b>, which is metastable and spontaneously relaxes to <b>T</b>, and the <b>T</b>⇄<b>C</b> interconversion can be repeated for multiple cycles. Reversible toggling between two vastly different isomers paves the way toward controlling functional properties of coordination hosts "on demand". Chemistry ; Janus ; Metastability ; Host (biology) ; Nanotechnology ; Catalysis ; Organic chemistry ; Ecology Supramolecular Chemistry and Complexes ; Supramolecular Self-Assembly in Materials ; Porphyrin and Phthalocyanine Chemistry
Authors: Shuai Li | Johannes M. Scheiger | Zhenwu Wang | Birgit Huber | Maxi Hoffmann | Manfred Wilhelm | Pavel A. Levkin
Source: ACS Applied Materials & Interfaces (article, 2023-09-07)
Field: Materials Science — Surfaces, Coatings and Films

Diapers to Thickeners and Pressure-Sensitive Adhesives: Recycling of Superabsorbers via UV Degradation Superabsorbers based on crosslinked sodium polyacrylate polymers cannot be easily recycled, resulting in 2 million tons of superabsorbers being landfilled or burned every year. A fast and efficient strategy to recycle superabsorbers would significantly alleviate environmental pollution and promote a sustainable use of these polymers. Herein, the rapid recycling of crosslinked sodium polyacrylate hydrogels based on their inherent UV degradation is demonstrated without the need for chemicals besides water. A quantitative conversion of crosslinked sodium polyacrylate into soluble sodium polyacrylate is achieved in minutes, almost 200 times faster than a previous approach based on de-esterification. The obtained soluble sodium polyacrylate can be used, for example, as a thickener for aqueous dyes or can be esterified with <i>n</i>-butanol or 2-ethylhexanol to serve as a pressure-sensitive adhesive. The UV photodegradation and esterification of superabsorbers is fast, scalable, safe, and economical and yields polymers with controllable molecular weight in the range of 100-400 kg/mol. It thus offers distinct advantages over the chemical de-crosslinking strategies presented previously. Sodium polyacrylate ; Materials science ; Polymer ; Adhesive ; Degradation (telecommunications) ; Aqueous solution ; Sodium ; Photodegradation ; Chemical engineering ; Environmental pollution ; Self-healing hydrogels ; Organic chemistry ; Polymer chemistry ; Chemistry ; Composite material ; Environmental science ; Raw material ; Photocatalysis ; Catalysis Surface Modification and Superhydrophobicity ; Advanced Cellulose Research Studies ; Flame retardant materials and properties
Authors: Keita Funayama | Atsushi Miura | Hiroya Tanaka
Source: Scientific Reports (article, 2023-04-20)
Field: Materials Science — Surfaces, Coatings and Films

Flexibly designable wettability gradient for passive control of fluid motion via physical surface modification Modified solid surfaces exhibit unique wetting behavior, such as hydrophobicity and hydrophilicity. Such behavior can passively control the fluid flow. In this study, we experimentally demonstrated a wettability-designable cell array consisting of unetched and physically etched surfaces by reactive ion etching on a silicon substrate. The etching process induced a significant surface roughness on the silicon surface. Thus, the unetched and etched surfaces have different wettabilities. By adjusting the ratio between the unetched and etched surface areas, we designed one- and two-dimensional wettability gradients for the fluid channel. Consequently, fine-tuned channels passively realized unidirectional and curved fluid motions. The design of a wettability gradient is crucial for practical and portable systems with integrated fluid channels. Wetting ; Surface modification ; Surface (topology) ; Motion (physics) ; Computer science ; Fluid motion ; Mechanics ; Control (management) ; Control theory (sociology) ; Materials science ; Chemical engineering ; Physics ; Artificial intelligence ; Mathematics ; Engineering ; Composite material Surface Modification and Superhydrophobicity ; Lattice Boltzmann Simulation Studies ; Micro and Nano Robotics
Authors: Naoto Inai | Shigehiro Yamaguchi | Takeshi Yanai
Source: ACS Physical Chemistry Au (article, 2023-10-24)
Field: Chemistry — Physical and Theoretical Chemistry

Theoretical Insight into the Effect of Phosphorus Oxygenation on Nonradiative Decays: Comparative Analysis of P-Bridged Stilbene Analogs Incorporation of the phosphorus element into a π-conjugated skeleton offers valuable prospects for adjusting the electronic structure of the resulting functional π-electron systems. Trivalent phosphorus has the potential to decrease the LUMO level through σ*-π* interaction, which is further enhanced by its oxygenation to the pentavalent P center. This study shows that utilizing our computational analysis to examine excited-state dynamics based on radiative/nonradiative rate constants and fluorescence quantum yield (Φ<sub>F</sub>) is effective for analyzing the photophysical properties of P-containing organic dyes. We theoretically investigate how the trivalent phosphanyl group and pentavalent phosphine oxide moieties affect radiative and nonradiative decay processes. We evaluate four variations of P-bridged stilbene analogs. Our analysis reveals that the primary decay pathway for photoexcited bis-phosphanyl-bridged stilbene is the intersystem crossing (ISC) to the triplet state and nonradiative. The oxidation of the phosphine moiety, however, suppresses the ISC due to the relative destabilization of the triplet states. The calculated rate constants match an increase in experimental Φ<sub>F</sub> from 0.07 to 0.98, as simulated from 0.23 to 0.94. The reduced HOMO-LUMO gap supports a red shift in the fluorescence spectra relative to the phosphine analog. The thiophene-fused variant with the nonoxidized trivalent P center exhibits intense emission with a high Φ<sub>F</sub>, 0.95. Our prediction indicates that the ISC transfer is obstructed owing to the relatively destabilized triplet state induced by the thiophene substitution. Conversely, the thiophene-fused analog with the phosphine oxide moieties triggers a high-rate internal conversion mediated by conical intersection, leading to a decreased Φ<sub>F</sub>. Intersystem crossing ; Thiophene ; Chemistry ; Photochemistry ; HOMO/LUMO ; Quantum yield ; Phosphine oxide ; Excited state ; Reaction rate constant ; Triplet state ; Phosphine ; Fluorescence ; Molecule ; Singlet state ; Organic chemistry ; Kinetics ; Catalysis Photochemistry and Electron Transfer Studies ; Luminescence and Fluorescent Materials ; Porphyrin and Phthalocyanine Chemistry
Authors: Ana Donaire-Arias | Martin L. Poulsen | Jaime Ramón-Costa | Ana Maria Montagut | Roger Estrada‐Tejedor | José I. Borrell
Source: Molecules (article, 2023-11-14)
Field: Chemistry — Organic Chemistry

Synthesis of Chalcones: An Improved High-Yield and Substituent-Independent Protocol for an Old Structure Chalcones are a type of molecule that can be considered as easily synthesizable through aldol condensation or that can be readily purchased from habitual commercial vendors. However, on reviewing the literature, one realizes that there are no standard procedures for such aldol condensations, that there exists a wide range of alternative methods for the aldol condensation (indicating that such a condensation is not always simple), and that, in many cases, low yields are obtained that involve purifications by recrystallization or column chromatography. To develop a robust standard protocol independent of the nature of the substituents present on the acetophenone or the benzaldehyde involved in the aldol condensation leading to the chalcone, we made a comparison between an aldol condensation in KOH/EtOH and a Wittig reaction between the corresponding ylide and benzaldehyde in water. We describe an improved procedure for the Wittig reaction and a protocol for the elimination of the Ph<sub>3</sub>P=O byproduct (and the excess of ylide used) by filtration of the crude reaction product through a silica gel plug. We thus demonstrate that such an improved procedure can be a general method for the synthesis of chalcones in high yield and excellent purity and is clearly an improvement on the classical aldol condensation. Aldol condensation ; Aldol reaction ; Wittig reaction ; Benzaldehyde ; Ylide ; Chemistry ; Condensation reaction ; Substituent ; Chalcone ; Organic chemistry ; Acetophenone ; Yield (engineering) ; Combinatorial chemistry ; Catalysis ; Materials science Synthesis and biological activity ; Synthesis and Biological Evaluation ; Multicomponent Synthesis of Heterocycles
Authors: Nizar B. Alsharif | Dániel Viczián | Aleksandra Szcześ | István Szilágyi
Source: The Journal of Physical Chemistry C (article, 2023-08-18)
Field: Materials Science — Materials Chemistry

Formulation of Antioxidant Composites by Controlled Heteroaggregation of Cerium Oxide and Manganese Oxide Nanozymes Antioxidant composites based on nanozymes [manganese oxide microflakes (MnO<sub>2</sub> MFs) and cerium oxide nanoparticles (CeO<sub>2</sub> NPs)] were formulated by controlled heteroaggregation. The interparticle attraction via electrostatic forces was systematically tuned with surface functionalization by the poly(diallyldimethyl chloride) (PDADMAC) polyelectrolyte. The PDADMAC-coated MnO<sub>2</sub> MFs (PMn) were heteroaggregated with oppositely charged CeO<sub>2</sub> NPs to generate the Ce-PMn composite, while the PDADMAC-functionalized CeO<sub>2</sub> NPs (PCe) were immobilized onto bare MnO<sub>2</sub> MFs, resulting in the Mn-PCe composite. Both the adsorption of PDADMAC and the self-assembly of oppositely charged particles resulted in charge neutralization and charge reversal at appropriately high doses. The interparticle force regimes, the aggregation states, and the physicochemical properties of the relevant dispersions were also highly dependent on the dose of PDADMAC, as well as that of PDADMAC-functionalized metal oxides (PMO) enabling the fine-tuning and control of colloidal stability. The individual enzyme-like activity of either metal oxide was not compromised by PDADMAC adsorption and/or heteroaggregation, leading to the formation of broad-spectrum antioxidant composites exhibiting multiple enzyme-like activities such as superoxide dismutase, oxidase, and peroxidase-type functions. The low cost and ease of preparation, as well as controllable colloidal properties render such composites potential enzyme mimicking agents in various industrial fields, where processable antioxidant systems are needed. Adsorption ; Polyelectrolyte ; Cerium oxide ; Chemical engineering ; Oxide ; Chemistry ; Composite number ; Colloid ; Nanoparticle ; Materials science ; Manganese ; Nanotechnology ; Composite material ; Organic chemistry Advanced Nanomaterials in Catalysis ; Electrochemical sensors and biosensors ; Nanocluster Synthesis and Applications
Authors: Lyudmila V. Parfenova | Pavel V. Kovyazin | Almira Kh. Bikmeeva | Eldar R. Palatov | Pavel V. Ivchenko | Ilya E. Nifant’ev | Л. М. Халилов
Source: Molecules (article, 2023-03-07)
Field: Chemistry — Organic Chemistry

Catalytic Properties of Zirconocene-Based Systems in 1-Hexene Oligomerization and Structure of Metal Hydride Reaction Centers Despite large-scale investigations of homogeneous single-site metallocene catalysts and systems based on them, there are still unsolved problems related to the control of their activity and chemo- and stereoselectivity. A solution to these problems is required to develop efficient methods for the synthesis of practically useful products of alkene transformations, such as dimers, oligomers, and polymers. Here we studied the catalytic activity of structurally diverse zirconocenes (L<sub>2</sub>ZrCl<sub>2</sub>, L = Cp, C<sub>5</sub>Me<sub>5</sub>, Ind, L<sub>2</sub> = Me<sub>2</sub>CCp<sub>2</sub>, Me<sub>2</sub>SiCp<sub>2</sub>, Me<sub>2</sub>C<sub>2</sub>Cp<sub>2</sub>, <i>rac</i>-Me<sub>2</sub>CInd<sub>2</sub>, <i>rac</i>-H<sub>4</sub>C<sub>2</sub>Ind<sub>2</sub>, BIPh(Ind)<sub>2</sub>, H<sub>4</sub>C<sub>2</sub>[THInd]<sub>2</sub>), and co-catalysts activating the system, namely HAlBu<sup>i</sup><sub>2</sub>, MMAO-12, and (Ph<sub>3</sub>C)[B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>], at low activator/Zr ratios in a 1-hexene oligomerization reaction. The influence of catalyst structure and system composition on the alkene conversion, the type of products, and the reaction stereoselectivity were investigated. The composition of hydride intermediates formed in the L<sub>2</sub>ZrCl<sub>2</sub>-HAlBu<sup>i</sup><sub>2</sub>-activator system (L<sub>2</sub> = ansa-Me<sub>2</sub>CCp<sub>2</sub>, Ind) was studied by NMR spectroscopy. Participation of the bis-zirconium hydride complex as the precursor of catalytically active sites of the alkene dimerization reaction was shown. Alkene ; Hydride ; Chemistry ; Metallocene ; Catalysis ; Stereoselectivity ; Hexene ; Zirconium ; Metal ; Combinatorial chemistry ; Polymer chemistry ; Organic chemistry ; Medicinal chemistry ; Polymerization ; Polymer ; Ethylene Organometallic Complex Synthesis and Catalysis ; Asymmetric Hydrogenation and Catalysis ; Synthetic Organic Chemistry Methods
Authors: Wenxiao Guo | Shufang Wang | Hongguo Hao | Xiangjin Kong | Hui Yan | Hongjie Zhu | Yunwu Li | Huawei Zhou | Di‐Chang Zhong | Fangna Dai
Source: Inorganic Chemistry Frontiers (article, 2023-01-01)
Field: Chemistry — Inorganic Chemistry

Introducing anthracene and amino groups into Ln-OFs for the photoreduction of Cr(<scp>vi</scp>) without additional photosensitizers or cocatalysts The stable LCUH-100 was designed and synthesized, by incorporating chromophores into lanthanide MOFs, as a high-efficiency photocatalyst, which can rapidly and efficiently reduce Cr( vi ) under visible-light irradiation and has good cycle stability. Lanthanide ; Chromophore ; Anthracene ; Photocatalysis ; Chemistry ; Irradiation ; Photochemistry ; Nuclear chemistry ; Combinatorial chemistry ; Organic chemistry ; Catalysis ; Ion Metal-Organic Frameworks: Synthesis and Applications ; Advanced Photocatalysis Techniques ; Ga2O3 and related materials
Authors: Bruno Lainer | Kuhali Das | Paweł Dydio
Source: Chemical Communications (review, 2023-01-01)
Field: Chemistry — Inorganic Chemistry

Variable structure diversification by multicatalysis: the case of alcohols Given that alcohol moieties are present in a great diversity of valuable fine chemicals from nature and synthesis, methods enabling their structure diversification are highly sought after. Catalysis proved to enable the development of new transformations that are beyond the inherent reactivity of alcohols. However, modifying the structure of alcohols at certain unbiased positions remains a major challenge or requires tedious multistep procedures. Recently, increased attention has been given to multicatalyis, which combines multiple reactions and catalysts within one system, creating room for discovering previously inaccessible reactivities or increasing the overall efficiency of multistep transformations. This feature article focuses on demonstrating various aspects of devising such multicatalytic systems that modify the structure of alcohol-containing compounds. Special attention is given to highlighting the challenges and advantages of multicatalysis, and in a broader context discussing how the field of catalysis may progress toward more complex systems. Diversification (marketing strategy) ; Variable (mathematics) ; Alcohol ; Diversity (politics) ; Chemistry ; Biochemical engineering ; Combinatorial chemistry ; Business ; Organic chemistry ; Engineering ; Mathematics ; Marketing ; Political science Asymmetric Hydrogenation and Catalysis ; Analytical Chemistry and Chromatography ; Crystallization and Solubility Studies
Authors: Iago W. Zapelini | Laura L. Silva | Svetlana Mintova | Dilson Cardoso
Source: Microporous and Mesoporous Materials (article, 2023-08-19)
Field: Chemistry — Inorganic Chemistry

Amine-grafted H-MFI zeolite precursors as acidic-basic catalysts for deacetalization-Knoevenagel condensation Knoevenagel condensation ; Zeolite ; Bifunctional ; Catalysis ; Crystallinity ; Chemistry ; Propylamine ; Organic chemistry ; Aluminosilicate ; Silane ; Amine gas treating ; Heterogeneous catalysis ; Polymer chemistry Zeolite Catalysis and Synthesis ; Covalent Organic Framework Applications ; Metal-Organic Frameworks: Synthesis and Applications