jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Haoze Wang | Xiaokun Pei | Davide Μ. Proserpio | Omar M. Yaghi
Source: Israel Journal of Chemistry (article, 2021-10-21)
Field: Chemistry — Inorganic Chemistry

Design of MOFs with Absolute Structures: A Case Study Abstract Metal‐organic frameworks (MOFs) with absolute structures are of particular interest as the asymmetry of their crystal structures enables wide applications from asymmetric catalysis to enantioselective separation. Previous reports on the synthetic strategies toward MOFs with absolute structures always required the use of chiral precursors or chiral templates, however, it is not always easy to obtain enantiopure starting materials. Here in, we report a new non‐centrosymmetric MOF, MOF‐829, synthesized from aluminium salt and achiral organic linker. Further comparisons are made between MOF‐829 and a reported Al‐based chiral MOF (MOF‐520) that is composed of the same metal ion and linker, and similarly synthesized without using chiral compounds. The configurations of the building units, the absolute structures of both MOFs, and their topologies were investigated in detail. We found that (i) topology is one of the determining factors in the formation of non‐centrosymmetric MOFs; (ii) the formation of chiral MOFs further requires the directionality of chiral linkers but more importantly chiral secondary building units (SBUs), which can be realized by fine tuning of the synthetic conditions. We envision that both synthetic exploration of chiral SBUs and the design of non‐centrosymmetric topologies will open a new direction in the design of MOFs with absolute structures. SBus ; Enantiopure drug ; Chemistry ; Absolute configuration ; Linker ; Enantioselective synthesis ; Metal-organic framework ; Topology (electrical circuits) ; Nanotechnology ; Combinatorial chemistry ; Stereochemistry ; Catalysis ; Organic chemistry ; Materials science Metal-Organic Frameworks: Synthesis and Applications ; Magnetism in coordination complexes ; X-ray Diffraction in Crystallography
Authors: Lin Liang | Boyang Li | Wenyao Zhang | Anyang Li | Bo Zheng | Xiao‐Juan Yang | Biao Wu
Source: Angewandte Chemie (article, 2021-01-27)
Field: Chemistry — Organic Chemistry

Fine‐Tuning the Spring‐Like Motion of an Anion‐Based Triple Helicate by Tetraalkylammonium Guests Abstract Supramolecular springs are a class of molecular devices that may provide implications to the macroscopic spring behavior from the molecular level. Helical structures are suitable molecular springs because the specific twisting of the helical strands can cause spring‐like (extension‐contraction) movement along the axis upon external stimuli. Herein we report an anion‐based triple‐helicate spring, which can undergo reversible contraction–extension motion through introduction and removal of tetraalkylammonium cations, including TMA + and analogous irregular tetrahedral cations bearing different alkyl chains, while the relative orientation of the two phosphate ions changes to facilitate guest inclusion. Notably, the degree of contraction (shortening of the helical pitch) can be fine‐tuned by varying the shape and size of guest cation. However, with the larger cations (TEA + , TPA + and TBA + ), the meso‐helicate configuration is obtained, which interconverts with the helicate by addition/removal of TMA + ion. Supramolecular chemistry ; Chemistry ; Ion ; Crystallography ; Stereochemistry ; Crystal structure ; Organic chemistry Supramolecular Chemistry and Complexes ; Luminescence and Fluorescent Materials ; Molecular Sensors and Ion Detection
Authors: Anna Ya. Kozmenkova | Vladislava Timofeeva | Badma N. Mankaev | Andrey V. Lalov | Evgeniya A. Saverina | Mikhail P. Egorov | Sergey S. Karlov | Mikhail A. Syroeshkin
Source: European Journal of Inorganic Chemistry (article, 2021-05-27)
Field: Chemistry — Inorganic Chemistry

The Redox Properties of Germylenes Stabilized by N‐Donor Ligands Abstract Germylenes, organic compounds of divalent germanium, are often considered as promising catalytic systems efficient in reactions of oxidative addition and reductive elimination, including SET reactions. However, the systematic studies of their redox properties, allowing for the quantitative evaluation of the levels of frontier molecular orbitals and the stability of single electron transfer products, are extremely limited in number. In this work, a series of germylenes with various types of stabilization: N−Ge−N, (N→)C−Ge−C(←N), N−Ge−N(←N), O−Ge−O(←N) и (N→)O−Ge−O(←N) (“−“ ‐a covalent bond, stabilization is achieved by p ‐donation of a lone pair of electrons of N or O, “→” ‐donor‐acceptor bond) were characterized by cyclic voltammetry. The results were compared with UV/Vis spectroscopy data and DFT calculations. All germylenes studied in MeCN and THF with Bu 4 NPF 6 as a supporting electrolyte are chemically irreversibly oxidized in the potential range of 0.5–1.4 V vs. Ag/AgCl. In all cases, as estimated by the quantum chemical calculations, the HOMO remains at the covalently unsaturated germanium center although being significantly redistributed over the molecular system. In turn, electroreduction of germylenes is possible only in the presence of a strong electron‐withdrawing substituent or a pyridine ring depleted in electron density donated to germanium. In both cases, the LUMO is localized exactly on these moieties and is absent on the germanium. Thus, the use of stabilizing groups makes it possible both to improve germylene stability and to fine‐tune their HOMO level that determines their ability to participate in oxidative addition reactions. Chemistry ; Germanium ; HOMO/LUMO ; Substituent ; Redox ; Covalent bond ; Lone pair ; Pyridine ; Crystallography ; Photochemistry ; Inorganic chemistry ; Molecule ; Stereochemistry ; Medicinal chemistry ; Organic chemistry Synthesis and characterization of novel inorganic/organometallic compounds ; Inorganic Chemistry and Materials ; Organometallic Complex Synthesis and Catalysis
Authors: Sushmita Sushmita | Trapti Aggarwal | Kapil Mohan Saini | Akhilesh K. Verma
Source: Advanced Synthesis & Catalysis (article, 2021-08-15)
Field: Chemistry — Organic Chemistry

Radical Promoted Synthesis of Furoquinolines <i>via</i> Anomalous Dakin‐Type Reaction Abstract A radical promoted approach for the selective synthesis of furo[3,2‐ b ]quinolines and benzylidene‐1,3‐dihydrofuro[3,4‐ b ]quinolines have been achieved from 2‐alkynyl quinoline‐3‐carbaldehydes by fine‐tuning of base and oxidant in good yields. In the presence of an oxidant, the reaction afforded the 5‐endo‐dig cyclized furoquinolines by decarbonylative intramolecular cyclization via a Dakin‐type reaction; however, in the absence of oxidant, 5‐exo‐dig cyclized products were obtained selectively through reductive intramolecular cyclization. The formation of furoquinolines was further supported by X‐ray crystallographic studies. The proposed mechanism was well supported by the control experiments. magnified image Chemistry ; Intramolecular force ; Quinoline ; Dig ; Radical cyclization ; Stereochemistry ; Medicinal chemistry ; Base (topology) ; Combinatorial chemistry ; Organic chemistry Catalytic C–H Functionalization Methods ; Radical Photochemical Reactions ; Sulfur-Based Synthesis Techniques
Authors: Christian D. Buch | Steen Honoré Hansen | Dmitri Mitcov | Camilla Mia Tram | Gary S. Nichol | Euan K. Brechin | Stergios Piligkos
Source: Chemical Science (article, 2021-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Design of pure heterodinuclear lanthanoid cryptate complexes Heterolanthanide complexes are difficult to synthesize owing to the similar chemistry of the lanthanide ions. Consequently, very few purely heterolanthanide complexes have been synthesized. This is despite the fact that such complexes hold interesting optical and magnetic properties. To fine-tune these properties, it is important that one can choose complexes with any given combination of lanthanides. Herein we report a synthetic procedure which yields pure heterodinuclear lanthanide cryptates LnLn*LX<sub>3</sub> (X = NO<sub>3</sub> <sup>-</sup> or OTf<sup>-</sup>) based on the cryptand H<sub>3</sub>L = N[(CH<sub>2</sub>)<sub>2</sub>N[double bond, length as m-dash]CH-R-CH[double bond, length as m-dash]N-(CH<sub>2</sub>)<sub>2</sub>]<sub>3</sub>N (R = <i>m</i>-C<sub>6</sub>H<sub>2</sub>OH-2-Me-5). In the synthesis the choice of counter ion and solvent proves crucial in controlling the Ln-Ln* composition. Choosing the optimal solvent and counter ion afford pure heterodinuclear complexes with any given combination of Gd(iii)-Lu(iii) including Y(iii). To demonstrate the versatility of the synthesis all dinuclear combinations of Y(iii), Gd(iii), Yb(iii) and Lu(iii) were synthesized resulting in 10 novel complexes of the form LnLn*L(OTf)<sub>3</sub> with LnLn* = YbGd <b>1</b>, YbY <b>2</b>, YbLu <b>3</b>, YbYb <b>4</b>, LuGd <b>5</b>, LuY <b>6</b>, LuLu <b>7</b>, YGd <b>8</b>, YY <b>9</b> and GdGd <b>10</b>. Through the use of <sup>1</sup>H, <sup>13</sup>C NMR and mass spectrometry the heterodinuclear nature of YbGd, YbY, YbLu, LuGd, LuY and YGd was confirmed. Crystal structures of LnLn*L(NO<sub>3</sub>)<sub>3</sub> reveal short Ln-Ln distances of ∼3.5 Å. Using SQUID magnetometry the exchange coupling between the lanthanide ions was found to be anti-ferromagnetic for GdGd and YbYb while ferromagnetic for YbGd. Lanthanide ; Chemistry ; Rare earth ; Crystallography ; Combinatorial chemistry ; Organic chemistry ; Mineralogy ; Ion Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Metal complexes synthesis and properties
Authors: Qi Wang | Hongying Wang | Liang Wang | Ligai Bai | Chunliu Yang | Tao Zhu
Source: Microchemical Journal (article, 2021-08-03)
Field: Materials Science — Materials Chemistry

Porous graphene oxide functionalized by covalent organic framework for the application in adsorption and electrochemical: The effect of C-F bonds to structure Adsorption ; Graphene ; Mesoporous material ; Materials science ; Covalent organic framework ; Oxide ; Chemical engineering ; Cyclic voltammetry ; Specific surface area ; Covalent bond ; Melamine ; Microporous material ; Electrochemistry ; Porosity ; Composite material ; Nanotechnology ; Chemistry ; Organic chemistry ; Physical chemistry ; Electrode Covalent Organic Framework Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Conducting polymers and applications
Authors: Dina Pinsky | Noam Ralbag | Ramesh K. Singh | Meirav Mann–Lahav | Gennady E. Shter | Dario R. Dekel | Gideon S. Grader | David Avnir
Source: Nanoscale Advances (article, 2021-01-01)
Field: Chemistry — Organic Chemistry

Metal nanoparticles entrapped in metal matrices We developed synthetic methods for the doping of metals (M) with metallic nanoparticles (NPs). To the best of our knowledge - unlike oxides, polymers and carbon-based supports - metals were not used so far as supporting matrices for metallic NPs. The composites (denoted M1-NPs@M2) comprise two separate phases: the metallic NPs (the dopant) and the entrapping 3D porous metallic matrix, within which the NPs are intimately held and well dispersed. Two different general synthetic strategies were developed, each resulting in a group of materials with characteristic structure and properties. The first strategy uses pre-prepared NPs and these are entrapped during reductive formation of the metallic matrix from its cation. The second strategy is <i>in situ</i> growth of the doped metallic NPs within the pre-prepared entrapping metallic matrix. These two methods were developed for two types of entrapping metallic matrices with different morphologies: porous aggregated metallic matrices and metallic foams. The leading case in this study was the use of Pt as the NP dopant and Ag as the entrapping matrix, using all of the four combinations - entrapment or growth within aggregated Ag or Ag foam matrices. Full physical and chemical properties analysis of these novel types of materials was carried out, using a wide variety of analytical methods. The generality of the methods developed for these bi-metallic composites was investigated and demonstrated on additional metallic pairs: Au NPs within Ag matrices, Pd NPs within Ni matrices and Ir-NPs within a Rh matrix. As the main application of metallic NPs is in catalysis, the catalytic activity of M1-NPs@M2 is demonstrated successfully for entrapped Pt within Ag for reductive catalytic reactions, and for Pd within Ni for the electrocatalytic hydrogen oxidation reaction. Metal ; Nanoparticle ; Materials science ; Catalysis ; Ceramic ; Chemical engineering ; Porosity ; Nanotechnology ; Metallurgy ; Chemistry ; Organic chemistry ; Composite material Nanomaterials for catalytic reactions ; Electrocatalysts for Energy Conversion ; Catalytic Processes in Materials Science
Authors: Barbara Farkaš | Nora H. de Leeuw
Source: Materials (review, 2021-06-28)
Field: Materials Science — Biomaterials

A Perspective on Modelling Metallic Magnetic Nanoparticles in Biomedicine: From Monometals to Nanoalloys and Ligand-Protected Particles The focus of this review is on the physical and magnetic properties that are related to the efficiency of monometallic magnetic nanoparticles used in biomedical applications, such as magnetic resonance imaging (MRI) or magnetic nanoparticle hyperthermia, and how to model these by theoretical methods, where the discussion is based on the example of cobalt nanoparticles. Different simulation systems (cluster, extended slab, and nanoparticle models) are critically appraised for their efficacy in the determination of reactivity, magnetic behaviour, and ligand-induced modifications of relevant properties. Simulations of the effects of nanoscale alloying with other metallic phases are also briefly reviewed. Nanoparticle ; Materials science ; Magnetic nanoparticles ; Nanoscopic scale ; Nanotechnology ; Ligand (biochemistry) ; Magnetic hyperthermia ; Cobalt ; Magnetic resonance imaging ; Biomedicine ; Chemistry ; Metallurgy ; Bioinformatics ; Medicine Nanoparticle-Based Drug Delivery ; Nanomaterials for catalytic reactions ; Gold and Silver Nanoparticles Synthesis and Applications
Authors: Artyom A. Astafiev | Olga V. Repina | Boris S. Tupertsev | Alexey A. Nazarov | Maria R. Gonchar | Анна В. Вологжанина | Valentine G. Nenajdenko | Andreii S. Kritchenkov | Victor N. Khrustalev | В. А. Надточенко | Alexander G. Tskhovrebov
Source: Molecules (article, 2021-03-20)
Field: Materials Science — Materials Chemistry

Unprecedented Coordination-Induced Bright Red Emission from Group 12 Metal-Bound Triarylazoimidazoles Arylazoimidazoles are important dyes which were intensively studied in the past. In contrast, triarylazoimidazoles (derivatives which carry aryl substituents at the imidazole core) received almost no attention in the scientific literature. Here, we report a new family of simple and easily accessible triarylazoimidazole-group 12 metal complexes, which feature highly efficient photo-luminescence emission (Φ up to 0.44). Novel compounds exhibit bright red emission in solution, which could be excited with a visible light. Imidazole ; Luminescence ; Aryl ; Group (periodic table) ; Excited state ; Metal ; Coordination complex ; Chemistry ; Red light ; Photochemistry ; Crystallography ; Stereochemistry ; Materials science ; Optoelectronics ; Physics ; Atomic physics ; Organic chemistry ; Biology Luminescence and Fluorescent Materials ; Organic Light-Emitting Diodes Research ; Radical Photochemical Reactions
Authors: Josina L. Bohlen | Bragavie Kulendran | Hannah Rothfuß | Christopher Barner‐Kowollik | Peter W. Roesky
Source: Polymer Chemistry (article, 2021-01-01)
Field: Materials Science — Materials Chemistry

Heterobimetallic Au(<scp>i</scp>)/Y(<scp>iii</scp>) single chain nanoparticles as recyclable homogenous catalysts Au(<sc>i</sc>)/Y(<sc>iii</sc>) single chain nanoparticles (SCNPs) are potent homogenous, recyclable catalysts for the hydroamination. The SCNPs consist of terpolymer chains with orthogonal ligand units, enabling the selective embedding of different metals. Hydroamination ; Catalysis ; Single chain ; Chemistry ; Nanoparticle ; Ligand (biochemistry) ; Chain (unit) ; Polymer chemistry ; Chemical engineering ; Combinatorial chemistry ; Nanotechnology ; Materials science ; Organic chemistry ; Physics ; Biochemistry ; Receptor Nanocluster Synthesis and Applications ; Asymmetric Hydrogenation and Catalysis ; Nanomaterials for catalytic reactions
Authors: Evernice Shelter Chikukwa | Edson L. Meyer | Johannes Z. Mbese | Nyengerai Zingwe
Source: Molecules (article, 2021-07-09)
Field: Materials Science — Materials Chemistry

Colloidal Synthesis and Characterization of Molybdenum Chalcogenide Quantum Dots Using a Two-Source Precursor Pathway for Photovoltaic Applications The drawbacks of utilizing nonrenewable energy have quickened innovative work on practical sustainable power sources (photovoltaics) because of their provision of a better-preserved decent environment which is free from natural contamination and commotion. Herein, the synthesis, characterization, and application of Mo chalcogenide nanoparticles (NP) as alternative sources in the absorber layer of QDSSCs is discussed. The successful synthesis of the NP was confirmed as the results from the diffractive peaks obtained from XRD which were positive and agreed in comparison with the standard. The diffractive peaks were shown in the planes (100), (002), (100), and (105) for the MoS<sub>2</sub> nanoparticles; (002), (100), (103), and (110) for the MoSe<sub>2</sub> nanoparticles; and (0002), (0004), (103), as well as (0006) for the MoTe<sub>2</sub> nanoparticles. MoSe<sub>2</sub> presented the smallest size of the nanoparticles, followed by MoTe<sub>2</sub> and, lastly, by MoS<sub>2</sub>. These results agreed with the results obtained using SEM analysis. For the optical properties of the nanoparticles, UV-Vis and PL were used. The shift of the peaks from the red shift (600 nm) to the blue shift (270-275 nm and 287-289 nm (UV-Vis)) confirmed that the nanoparticles were quantum-confined. The application of the MoX<sub>2</sub> NPs in QDSSCs was performed, with MoSe<sub>2</sub> presenting the greatest PCE of 7.86%, followed by MoTe<sub>2</sub> (6.93%) and, lastly, by MoS<sub>2</sub>, with the PCE of 6.05%. Chalcogenide ; Nanoparticle ; Photovoltaics ; Materials science ; Molybdenum ; Chalcogen ; Quantum dot ; Nanotechnology ; Chemical engineering ; Photovoltaic system ; Optoelectronics ; Chemistry ; Metallurgy ; Crystallography Quantum Dots Synthesis And Properties ; Chalcogenide Semiconductor Thin Films ; 2D Materials and Applications
Authors: Melinda David | Iwona Budziak-Wieczorek | Dariusz Karcz | Monica Florescu | Arkadiusz Matwijczuk
Source: European Biophysics Journal (article, 2021-09-13)
Field: Chemistry — Physical and Theoretical Chemistry

Insight into dual fluorescence effects induced by molecular aggregation occurring in membrane model systems containing 1,3,4-thiadiazole derivatives This work reports on biophysical insights into the excited state intramolecular proton transfer (ESIPT) processes taking place in three 1,3,4-thiadiazole derivatives that served as model compounds, on which electronic absorption, fluorescence, Fourier-transform infrared spectroscopy (FTIR), surface plasmon resonance (SPR) and electrochemical impedance spectroscopy (EIS) studies were performed. The fluorescence spectra recorded in various solvents revealed an interesting dual fluorescence effect. In molecules in their monomeric form, the effect is associated with the ESIPT phenomenon, and may be further enhanced by aggregation-related effects, such as aggregation-induced emissions. Other spectroscopic studies on the selected molecules in a liposomal medium as a model revealed that, in a biomimetic environment, they can exist in both monomeric and aggregated forms. In both cases, however, the effects observed are closely related to the lipid's main phase transition temperature and the structure of the molecule. Introduction of specific substituents to the phenyl moiety either allows or prevents proton transfer from occurring in the excited state. The hydrophobicity changes in a lipid environment may result in an emergence of specific molecular forms and therefore either facilitate or hinder ESIPT processes. SPR and EIS confirmed the significant hydrophobicity changes in the model lipid systems, while FTIR measurements revealed a notable influence of 1,3,4-thiadiazoles on the fluidity of liposomal membranes. The results obtained clearly show that the thiadiazole derivatives are very good model molecules for studying hydrophobic-hydrophilic environments, and particularly with polymers or liposomes used as drug delivery systems. Chemistry ; Lipid bilayer ; Monomer ; Liposome ; Molecule ; Fluorescence ; Intramolecular force ; Fluorescence spectroscopy ; Photochemistry ; Fourier transform infrared spectroscopy ; Moiety ; Membrane ; Polymer ; Organic chemistry ; Chemical engineering Photochemistry and Electron Transfer Studies ; Luminescence and Fluorescent Materials ; Porphyrin and Phthalocyanine Chemistry
Authors: Jeffery Wee Kiong Seah | Jeannie Xue Ting Lee | Yongxin Li | Sumod A. Pullarkat | Nguan Soon Tan | Pak‐Hing Leung
Source: Inorganic Chemistry (article, 2021-10-28)
Field: Chemistry — Inorganic Chemistry

Chelating Phosphine–N-Heterocyclic Carbene Platinum Complexes via Catalytic Asymmetric Hydrophosphination and Their Cytotoxicity Toward MKN74 and MCF7 Cancer Cell Lines A series of activated vinyl azoles was hydrophosphinated in the presence of a chiral palladacycle catalyst under mild conditions to give enantioenriched phosphine azoles with moderate enantioselectivities and yields. The racemic phosphine azoles were transformed into eleven novel chelating phosphine-N-heterocyclic carbene (NHC) platinum complexes. The drug efficacies of nine selected phosphine-NHC platinum(II) chlorides in two cancer cell lines (MKN74 and MCF7) were evaluated, and two were found to exhibit activities comparable to that of cisplatin. Phosphine ; Chemistry ; Carbene ; Platinum ; Chelation ; Catalysis ; Cisplatin ; Platinum compounds ; Medicinal chemistry ; Organic chemistry Asymmetric Hydrogenation and Catalysis ; N-Heterocyclic Carbenes in Organic and Inorganic Chemistry ; Catalytic Cross-Coupling Reactions