jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Kai Zhao | Li Yin | Zhihong Ma | Tingxuan Yang | Huidong Tang | Peng Cao | Saifang Huang
Source: Inorganic Chemistry (article, 2022-01-10)
Field: Materials Science — Materials Chemistry

Investigation of the Solid-Solution Limit, Crystal Structure, and Thermal Quenching Mitigation of Sr-Substituted Rb<sub>2</sub>CaP<sub>2</sub>O<sub>7</sub>:Eu<sup>2+</sup> Phosphors for White LED Applications Rb<sub>2</sub>CaP<sub>2</sub>O<sub>7</sub>:Eu<sup>2+</sup> is a bright reddish-orange-emitting phosphor, but its luminescence thermal stability is poor. In this study, we investigated the solid-solution limit and thermal quenching mitigation of Rb<sub>2</sub>CaP<sub>2</sub>O<sub>7</sub>:Eu<sup>2+</sup> phosphors by cation substitution with Sr<sup>2+</sup> and revisited their crystal structure. First, we carefully investigated the solid solution limit of Sr in the structure of Rb<sub>2</sub>CaP<sub>2</sub>O<sub>7</sub>. The results show that up to 80% of Ca can be substituted by Sr, whereas Ca hardly resides in the structure of Rb<sub>2</sub>SrP<sub>2</sub>O<sub>7</sub>. Consequently, the photoluminescence was fine-tuned from reddish-orange (612 nm) to yellow (580 nm) light emission by increasing the Sr<sup>2+</sup> concentration in the solid-solution phosphors Rb<sub>2</sub>Sr<sub>1-<i>x</i></sub>Ca<sub><i>x</i></sub>P<sub>2</sub>O<sub>7</sub>:Eu<sup>2+</sup> under excitation at 342 nm. The mechanism for the blue shift of the emission spectrum was discussed. With the associated modification of the local environment of the activator (as reflected by the changes in the effective coordination number, average bond length, distortion index, and quadratic elongation), the luminescence thermal quenching issue of Rb<sub>2</sub>CaP<sub>2</sub>O<sub>7</sub>:Eu<sup>2+</sup> was mitigated by substituting 20% Sr into the Ca site (Rb<sub>2</sub>Ca<sub>0.8</sub>Sr<sub>0.2</sub>P<sub>2</sub>O<sub>7</sub>:Eu<sup>2+</sup>). The integrated intensity of bright orange-emitting Rb<sub>2</sub>Ca<sub>0.8</sub>Sr<sub>0.2</sub>P<sub>2</sub>O<sub>7</sub>:Eu<sup>2+</sup> (603 nm) at 150 °C retained 53% of its initial value, 1.64 times that of Rb<sub>2</sub>CaP<sub>2</sub>O<sub>7</sub>:Eu<sup>2+</sup> (32.3%). Such an enhancement could be attributed to the improved rigidity of the crystal structure due to the local structure modification as evidenced by Rietveld refinement. The cation substitution is an effective approach for mitigating the thermal quenching issue of phosphors. Phosphor ; Chemistry ; Luminescence ; Crystal structure ; Photoluminescence ; Rietveld refinement ; Solid solution ; Thermal stability ; Activator (genetics) ; Quenching (fluorescence) ; Analytical Chemistry (journal) ; Crystallography ; Fluorescence ; Materials science ; Optics ; Optoelectronics ; Physics Luminescence Properties of Advanced Materials ; Perovskite Materials and Applications ; Microwave Dielectric Ceramics Synthesis
Authors: Jie Zhu | Laura Samperisi | Mark Kalaj | Jerika A. Chiong | Jake Bailey | Zhiyong Zhang | Chung-Jui Yu | R. Eric Sikma | Xiaodong Zou | Seth M. Cohen | Zhehao Huang | F. Akif Tezcan
Source: Dalton Transactions (article, 2022-01-01)
Field: Chemistry — Inorganic Chemistry

Metal-hydrogen-pi-bonded organic frameworks We report the synthesis and characterization of a new series of permanently porous, three-dimensional metal-organic frameworks (MOFs), M-HAF-2 (M = Fe, Ga, or In), constructed from tetratopic, hydroxamate-based, chelating linkers. The structure of M-HAF-2 was determined by three-dimensional electron diffraction (3D ED), revealing a unique interpenetrated <b>hcb</b>-a net topology. This unusual topology is enabled by the presence of free hydroxamic acid groups, which lead to the formation of a diverse network of cooperative interactions comprising metal-hydroxamate coordination interactions at single metal nodes, staggered π-π interactions between linkers, and H-bonding interactions between metal-coordinated and free hydroxamate groups. Such extensive, multimodal interconnectivity is reminiscent of the complex, noncovalent interaction networks of proteins and endows M-HAF-2 frameworks with high thermal and chemical stability and allows them to readily undergo postsynthetic metal ion exchange (PSE) between trivalent metal ions. We demonstrate that M-HAF-2 can serve as versatile porous materials for ionic separations, aided by one-dimensional channels lined by continuously π-stacked aromatic groups and H-bonding hydroxamate functionalities. As an addition to the small group of hydroxamic acid-based MOFs, M-HAF-2 represents a structural merger between MOFs and hydrogen-bonded organic frameworks (HOFs) and illustrates the utility of non-canonical metal-coordinating functionalities in the discovery of new bonding and topological patterns in reticular materials. Metal-organic framework ; Hydrogen bond ; Topology (electrical circuits) ; Metal ; Ionic bonding ; Non-covalent interactions ; Chemistry ; Materials science ; Crystallography ; Molecule ; Ion ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Crystallography and molecular interactions ; Magnetism in coordination complexes
Authors: Belén Lerma‐Berlanga | Carolina R. Ganivet | Neyvis Almora‐Barrios | Rebecca Vismara | Jorge A. R. Navarro | Sergio Tatay | Natalia M. Padial | Carlos Martí‐Gastaldo
Source: Angewandte Chemie International Edition (article, 2022-08-16)
Field: Chemistry — Inorganic Chemistry

Tetrazine Linkers as Plug‐and‐Play Tags for General Metal‐Organic Framework Functionalization and C<sub>60</sub> Conjugation The value of covalent post-synthetic modification in expanding the chemistry and pore versatility of reticular solids is well documented. Here we use mesoporous crystals of the metal-organic framework (MOF) UiO-68-TZDC to demonstrate the value of tetrazine connectors for all-purpose inverse electron-demand Diels-Alder ligation chemistry. Our results suggest a positive effect of tetrazine reticulation over its reactivity for quantitative one-step functionalization with a broad scope of alkene or alkyne dienophiles into pyridazine and dihydropyridazine frameworks. This permits generating multiple pore environments with diverse chemical functionalities and the expected accessible porosities, that is also extended to the synthesis of crystalline fulleretic materials by covalent conjugation of fullerene molecules. Tetrazine ; Surface modification ; Bioorthogonal chemistry ; Alkene ; Covalent bond ; Alkyne ; Chemistry ; Combinatorial chemistry ; Molecule ; Cycloaddition ; Metal-organic framework ; Reactivity (psychology) ; Nanotechnology ; Materials science ; Organic chemistry ; Click chemistry ; Catalysis Metal-Organic Frameworks: Synthesis and Applications ; Covalent Organic Framework Applications ; Molecular Sensors and Ion Detection
Authors: Anna Pla‐Quintana | Anna Roglans
Source: Molecules (review, 2022-02-16)
Field: Chemistry — Organic Chemistry

The Choice of Rhodium Catalysts in [2+2+2] Cycloaddition Reaction: A Personal Account [2+2+2] Cycloaddition reaction is a captivating process that assembles six-membered rings from three unsaturations with complete atom economy. Of the multiple transition metals that can be used to catalyze this reaction, rhodium offers many advantages. These include high activity and versatility, but especially the ability to easily tune the reactivity and selectivity by the modification of the ligands around the metal. In this personal account, we summarize our endeavours in the development of efficient and sustainable [2+2+2] cycloaddition reactions to prepare products of interest, develop conditions in which the catalyst can be recovered and reused, and understand the mechanistic details that govern the selectivity of the processes. Cycloaddition ; Rhodium ; Catalysis ; Selectivity ; Atom economy ; Reactivity (psychology) ; Chemistry ; Transition metal ; Combinatorial chemistry ; Personal account ; Organic chemistry Catalytic Alkyne Reactions ; Asymmetric Hydrogenation and Catalysis ; Cyclopropane Reaction Mechanisms
Authors: Manal Ibrahim | Nada Y. Tashkandi | Nikos Hadjichristidis | Nazeeha S. Alkayal
Source: Polymers (article, 2022-03-11)
Field: Materials Science — Materials Chemistry

Synthesis of Naphthalene-Based Polyaminal-Linked Porous Polymers for Highly Effective Uptake of CO2 and Heavy Metals Studying the effect of functional groups on the porosity structure and adsorption efficiency of polymer materials is becoming increasingly interesting. In this work, a novel porous polyaminal-linked polymer, based on naphthalene and melamine (PAN-NA) building blocks, was successfully synthesized by a one-pot polycondensation method, and used as an adsorbent for both CO<sub>2</sub> and heavy metals. Fourier transform infrared spectroscopy, solid-state <sup>13</sup> C NMR, powder X-ray diffraction, and thermogravimetry were used to characterize the prepared polymer. The porous material structure was established by field-emission scanning electron microscope and N<sub>2</sub> adsorption-desorption methods at 77 K. The polymer exhibited excellent uptake of CO<sub>2</sub>, 133 mg/g at 273 K and 1 bar. In addition, the adsorption behavior of PAN-NA for different metal cations, including Pb(II), Cr(III), Cu(II), Cd(II), Ni(II), and Ba(II), was investigated; a significant adsorption selectivity toward the Pb(II) cation was detected. The influence of pH, adsorbent dose, initial concentrations, and contact time was also assessed. Our results prove that the introduction of naphthalene in the polymer network improves the porosity and, thus, CO<sub>2</sub> adsorption, as well as the adsorption of heavy metals. Naphthalene ; Porosity ; Polymer ; Heavy metals ; Chemical engineering ; Materials science ; Chemistry ; Environmental chemistry ; Organic chemistry Covalent Organic Framework Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Membrane Separation and Gas Transport
Authors: Luigi Menduti | Clara Baldoli | Simone Manetto | Michael Bolte | Hans‐Wolfram Lerner | Giovanna Longhi | Claudio Villani | Emanuela Licandro | Matthias Wagner
Source: Angewandte Chemie International Edition (article, 2022-11-21)
Field: Chemistry — Organic Chemistry

(BO)<sub>2</sub>‐Doped Tetrathia[7]helicene: A Configurationally Stable Blue Emitter Helicenes combine two central themes in chemistry: extended π-conjugation and chirality. Hetero-atom doping preserves both characteristics and allows modulation of the electronic structure of a helicene. Herein, we report the (BO)<sub>2</sub> -doped tetrathia[7]helicene 1, which was prepared from 2-methoxy-3,3'-bithiophene in four steps. 1 is formally derived by substituting two (Mes)B-O moieties in place of (H)C=C(H) fragments in two benzene rings of the parent tetrathia[7]helicene. X-ray crystallography revealed a dihedral angle of 50.26(9)° between the two terminal thiophene rings. The (P)-/(M)-1 enantiomers were separated by chiral HPLC and are configurationally stable at room temperature. The experimentally determined enantiomerization barrier of 27.4±0.1 kcal mol<sup>-1</sup> is lower than that of tetrathia[7]helicene (39.4±0.1 kcal mol<sup>-1</sup> ). The circular dichroism spectra of (P)- and (M)-1 show a perfect mirror-image relationship. 1 is a blue emitter (λ<sub>em</sub> =411 nm) with a photoluminescence quantum efficiency of Φ<sub>PL</sub> =6 % (cf. tetrathia[7]helicene: λ<sub>em</sub> ≈405 nm, Φ<sub>PL</sub> =5 %). Helicene ; Enantiomer ; Chirality (physics) ; Chemistry ; Crystallography ; Circular dichroism ; Thiophene ; Doping ; Pentalene ; Stereochemistry ; Dihedral angle ; Molecule ; Materials science ; Hydrogen bond ; Organic chemistry ; Physics ; Chiral symmetry Synthesis and Properties of Aromatic Compounds ; Photochromic and Fluorescence Chemistry ; DNA and Nucleic Acid Chemistry
Authors: Awais Khalid | Pervaiz Ahmad | Saleh Muhammad | Abdulhameed Khan | Mayeen Uddin Khandaker | Md. Mottahir Alam | Mohd Asim | Israf Ud Din | Jibran Iqbal | Ibad Ur Rehman | Zohaib Razzaq | Sivakumar Pandian | Rohit Sharma | Talha Bin Emran | M.I. Sayyed | Saad Aldawood | Abdelmoneim Sulieman
Source: Frontiers in Chemistry (article, 2022-07-12)
Field: Materials Science — Materials Chemistry

Synthesis of Boron-Doped Zinc Oxide Nanosheets by Using Phyllanthus Emblica Leaf Extract: A Sustainable Environmental Applications The use of <i>Phyllanthus emblica</i> (gooseberry) leaf extract to synthesize Boron-doped zinc oxide nanosheets (B-doped ZnO-NSs) is deliberated in this article. Scanning electron microscopy (SEM) shows a network of synthesized nanosheets randomly aligned side by side in a B-doped ZnO (15 wt% B) sample. The thickness of B-doped ZnO-NSs is in the range of 20-80 nm. B-doped ZnO-NSs were tested against both gram-positive and gram-negative bacterial strains including <i>Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia,</i> and <i>Escherichia coli</i>. Against gram-negative bacterium (<i>K. pneumonia</i> and <i>E. coli</i>), B-doped ZnO displays enhanced antibacterial activity with 26 and 24 mm of inhibition zone, respectively. The mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), mean free path (MFP), half-value layer (HVL), and tenth value layer (TVL) of B-doped ZnO were investigated as aspects linked to radiation shielding. These observations were carried out by using a PTW<sup>®</sup> electron detector and VARIAN<sup>®</sup> irradiation with 6 MeV electrons. The results of these experiments can be used to learn more about the radiation shielding properties of B-doped ZnO nanostructures. Zinc ; Klebsiella pneumonia ; Materials science ; Nuclear chemistry ; Doping ; Boron ; Phyllanthus emblica ; Attenuation coefficient ; Nanotechnology ; Chemistry ; Escherichia coli ; Optics ; Optoelectronics ; Physics ; Organic chemistry ; Metallurgy Nanoparticles: synthesis and applications ; ZnO doping and properties ; Magnesium Oxide Properties and Applications
Authors: Chengyu Liu | Lei Zhang | Liming Cao | Yan Xiong | Yueyue Ma | Ruihua Cheng | Jinxing Ye
Source: Communications Chemistry (article, 2022-05-19)
Field: Chemistry — Inorganic Chemistry

Iridium-catalyzed enantioselective synthesis of chiral γ-amino alcohols and intermediates of (S)-duloxetine, (R)-fluoxetine, and (R)-atomoxetine Chiral γ-amino alcohols are the prevalent structural motifs and building blocks in pharmaceuticals and bioactive molecules. Enantioselective hydrogenation of β-amino ketones provides a straightforward and powerful tool for the synthesis of chiral γ-amino alcohols, but the asymmetric transformation is synthetically challenging. Here, a series of tridentate ferrocene-based phosphine ligands bearing modular and tunable unsymmetrical vicinal diamine scaffolds were designed, synthesized, and evaluated in the iridium-catalyzed asymmetric hydrogenation of β-amino ketones. The system was greatly effective to substrates with flexible structure and functionality, and diverse β-tertiary-amino ketones and β-secondary-amino ketones were hydrogenated smoothly. The excellent reactivities and enantioselectivities were achieved in the asymmetric delivery of various chiral γ-amino alcohols with up to 99% yields, >99% ee values, and turnover number (TON) of 48,500. The gram-scale reactions with low catalyst loading showed the potential application in industrial synthesis of chiral drugs, such as (S)-duloxetine, (R)-fluoxetine, and (R)-atomoxetine. Enantioselective synthesis ; Asymmetric hydrogenation ; Chemistry ; Transfer hydrogenation ; Catalysis ; Combinatorial chemistry ; Amino acid ; Diamine ; Organic chemistry ; Ruthenium Asymmetric Hydrogenation and Catalysis ; Surface Chemistry and Catalysis ; Chemical Synthesis and Analysis
Authors: Ahmed E. Abasaeed | Mahmud S. Lanre | Samsudeen Olajide Kasim | Ahmed A. Ibrahim | Ahmed I. Osman | Anis H. Fakeeha | Abdulmajeed Alkhalifa | Rasheed Arasheed | Fahad Albaqi | Nadavala Siva Kumar | Wasim Ullah Khan | Rawesh Kumar | F. Frusteri | Ahmed S. Al‐Fatesh | Abdulaziz Bagabas
Source: International Journal of Hydrogen Energy (article, 2022-10-26)
Field: Materials Science — Materials Chemistry

Syngas production from methane dry reforming via optimization of tungsten trioxide-promoted mesoporous γ-alumina supported nickel catalyst Syngas production via dry reforming of methane was conducted over 5 wt%Ni + xWO3/γ-Al2O3 (x = 1, 3, 5, 7, or 9 wt%) catalysts at 700 °C and ambient pressure for 7.5 h in a tubular fixed-bed reactor. Textural, morphological, and catalytic properties were investigated in relation to the weight percent of tungsten trioxide loading. The physicochemical properties of the catalysts were evaluated using XRD, N2-physisorption, TGA, H2-TPR, CO2-TPD, NH3-TPD, SEM, EDX, and Raman techniques. N2-physisorption analysis showed that tungsten trioxide promoter had a minor impact on the textural properties upon varying its weight percentage loading. With increasing tungsten trioxide loading, the total amount of reducible NiO-interacting species was increased over the catalyst surface. 5Ni+5WO3/γ-Al2O3 catalyst showed stable 79% CH4 conversions and 83% CO2 conversion with the lowest carbon deposition due to the presence of stable metallic Ni species (derived from reducible NiAl2O4 and NiWOAl), the highly acidic sites, and moderate basic sites. Tungsten trioxide ; Physisorption ; Catalysis ; Syngas ; Carbon dioxide reforming ; Methane ; Tungsten ; Materials science ; Mesoporous material ; Chemical engineering ; Hydrogen production ; Nickel ; Non-blocking I/O ; Inorganic chemistry ; Chemistry ; Nuclear chemistry ; Metallurgy ; Organic chemistry Catalytic Processes in Materials Science ; Catalysts for Methane Reforming ; Catalysis and Oxidation Reactions
Authors: Lauren Hanna | Edgar Movsesian | Miguel Orozco | Anthony R. Bernot | Mona Asadinamin | Learnmore Shenje | Susanne Ullrich | Yiping Zhao | Nicholas Marshall | Jason A. Weeks | Michael B. Thomas | Joseph A. Teprovich | Patrick A. Ward
Source: Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy (article, 2022-04-28)
Field: Materials Science — Materials Chemistry

Spectroscopic investigation of the electronic and excited state properties of para-substituted tetraphenyl porphyrins and their electrochemically generated ions Porphyrin ; Photochemistry ; Chemistry ; Ultrafast laser spectroscopy ; Density functional theory ; Absorption spectroscopy ; Excited state ; Cyclic voltammetry ; Ionic bonding ; Spectroscopy ; Electrochemistry ; Ion ; Physical chemistry ; Computational chemistry ; Organic chemistry Porphyrin and Phthalocyanine Chemistry ; Photochemistry and Electron Transfer Studies ; Photosynthetic Processes and Mechanisms
Authors: Łukasz W. Ciszewski | Dorota Gryko
Source: Chemical Communications (article, 2022-01-01)
Field: Chemistry — Organic Chemistry

Pyridine <i>N</i> -oxides as HAT reagents for photochemical C–H functionalization of electron-deficient heteroarenes Pyridine <i>N</i>-oxides have only recently marked their presence in the photocatalysis field, mainly serving as oxypyridinium salt precursors. Herein, their unique reactivity as a hydrogen atom transfer reagent in photochemical, Minisci-type alkylation of electron-deficient heteroarenes is unveiled. The formation of an EDA complex between a heterocyclic substrate and <i>N</i>-oxide precludes the need for a photocatalyst. The developed method allows for a broad range of radical precursors to be used, namely alkanes, alkenes, amides, and ethers, for efficient alkylation of azines. Reagent ; Chemistry ; Alkylation ; Photocatalysis ; Photochemistry ; Pyridine ; Reactivity (psychology) ; Hydrogen atom ; Surface modification ; Substrate (aquarium) ; Electron transfer ; Salt (chemistry) ; Oxide ; Combinatorial chemistry ; Organic chemistry ; Catalysis ; Alkyl Radical Photochemical Reactions ; Catalytic C–H Functionalization Methods ; Synthesis and Catalytic Reactions
Authors: Aritz Landart-Gereka | María Mar Quesada‐Moreno | María A. Palacios | Ismael F. Díaz‐Ortega | Hiroyuki Nojiri | Mykhaylo Ozerov | J. Krzystek | Enrique Colacio
Source: Chemical Communications (article, 2022-12-23)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Pushing up the easy-axis magnetic anisotropy and relaxation times in trigonal prismatic Co<sup>II</sup> mononuclear SMMs by molecular structure design The replacement of pyridine by 1-methyl-imidazol in the arms of a N<sub>6</sub>-tripodal ligand allows preparing two new Co<sup>II</sup> complexes with quasi-ideal triangular prismatic geometry, which behave as SIMs (Single Ion Magnets) at zero dc field with enhanced axial magnetic anisotropy, magnetic relaxation times and magnetic hysteresis. Magnetic anisotropy ; Magnetic relaxation ; Anisotropy ; Trigonal prismatic molecular geometry ; Magnet ; Relaxation (psychology) ; Crystallography ; Magnetic field ; Ligand (biochemistry) ; Ion ; Chemistry ; Pyridine ; Hysteresis ; Trigonal crystal system ; Nuclear magnetic resonance ; Materials science ; Condensed matter physics ; Magnetization ; Crystal structure ; Physics ; Receptor Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Advanced NMR Techniques and Applications
Authors: Andrey Belyaev | Bo‐Kang Su | Yu‐Hsuan Cheng | Zong‐Ying Liu | Nasrulla Majid Khan | Antti J. Karttunen | Pi‐Tai Chou | Igor O. Koshevoy
Source: Angewandte Chemie International Edition (article, 2022-02-11)
Field: Materials Science — Materials Chemistry

Multiple Emission of Phosphonium Fluorophores Harnessed by the Pathways of Photoinduced Counterion Migration In the emerging field of intramolecular charge transfer induced counterion migration, we report the new insights into photophysical features of luminescent donor-acceptor phosphonium dyes (D-π-)<sub>n</sub> A<sup>+</sup> [X<sup>-</sup> ] (π=-(C<sub>6</sub> H<sub>4</sub> )<sub>x</sub> -). The unique connectivity of the phosphorus atom affords multipolar molecules with a variable number of arms and the electronic properties of the acceptor group. In the ion-paired form, the transition from dipolar to quadrupolar configuration enhances the low energy migration-induced band by providing the additional pathways for anion motion. The multipolar architecture, adjustable lengths of the π-spacers and the nature of counterions allow for efficient tuning of the emission and achieving nearly pure white light with quantum yields around 30 %. The methyl substituent at the phosphorus atom reduces the rate of ion migration and suppresses the red shifted bands, simultaneously improving total emission intensity. The results unveil the harnessing of the multiple emission of phosphonium fluorophores by anion migration via structure and branching of donor-acceptor arms. Phosphonium ; Counterion ; Chemistry ; Intramolecular force ; Photochemistry ; Acceptor ; Ion ; Chemical physics ; Stereochemistry ; Organic chemistry Luminescence and Fluorescent Materials ; Porphyrin and Phthalocyanine Chemistry ; Molecular Sensors and Ion Detection