jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Samuel Tetteh
Source: Heliyon (article, 2019-07-01)
Field: Chemistry — Organic Chemistry

Imidazol-2-ylidene stabilized tetrahedral cobalt carbonyl complexes: A computational and structural database study A combined crystallographic database and computational chemistry analyses of tetrahedral cobalt (Co) carbonyl (CO) complexes bearing substituted imidazol-2-ylidene (Im) ligands were studied. These group of compounds are potential catalysts in the hydroformylation of alkenes as well as effective precursors for both chemical vapour deposition and atomic layer deposition in integrated circuit manufacture. A substructure search revealed seventeen (17) crystal structures in the Cambridge Structural Database (CSD). Generally, there was a positive correlation between the Im-Co bond length and the Co-CO bond length implying that a strong Im-CO bonding interaction could give rise to a more stable carbonyl complex. The gas phase structures of these complexes were further studied computationally at the BP86 level of the density functional theory. The def2-TZVPP basis set was used for cobalt with 6-31G (d,p) for all other atoms. It was observed that the Co-CO bond length increased with increase in bulkiness of alkyl substituents at the <i>ortho</i> positions of the Im ligands. Subsequent natural bond orbital (NBO) and chemical reactivity parameter analyses revealed that the chemical softness, electronic chemical potential and the ease of ionization also increased with increase in bulkiness of the alkyl substituents. This property has useful applications in catalytic systems and for the design of precursors in integrated circuit manufacture. Chemistry ; Natural bond orbital ; Cobalt ; Reactivity (psychology) ; Bond length ; Alkyl ; Catalysis ; Density functional theory ; Chemical bond ; Crystallography ; Computational chemistry ; Crystal structure ; Organic chemistry N-Heterocyclic Carbenes in Organic and Inorganic Chemistry ; Organometallic Complex Synthesis and Catalysis ; Carbon dioxide utilization in catalysis
Authors: Hayriye Nevin Genç
Source: European Journal of Science and Technology (article, 2019-10-26)
Field: Chemistry — Organic Chemistry

An Efficient Synthesis of Chiral Catalyst: Application in Enantioselective Michael Addition Reactions Asymmetric synthesis, also called stereoselective synthesis, chiral synthesis or enantioselective synthesis, is a form of organic synthesis which presentes one or more new elements of chirality. Use of catalysts is one of the most effective methods preferred by the researchers in recent years. It causes to the preferential formation of a stereoisomer rather than a constitutional isomer. In this study, tetraoxocalix[2]arene[2]triazine was synthesized firstly by using resorcinol and cyanuric chloride and then this starting material was derivatized with (R)-(-)-2-phenylglycinol to obtain tetraoxocalix[2]arene[2]triazine based chiral compound. Characterization of tetraoxocalix[2]arene[2]triazine was done by 1H and 13C NMR spectroscopy which is depicted in literature. Then, new organocatalyst, which possess an amino and a hydroxyl group, was designed and synthesized. The structure of the receptor characterized by FTIR, 1H spectroscopy, 13C NMR spectroscopy, optical rotation and elemental analysis measurement was also included. The newly prepared tetraoxocalix[2]arene[2]triazine derivative was employed as a chiral ligand in the enantioselective Michael addition of dimethylmalonate to conjugated nitroalkenes and good to excellent enantioselectivities were obtained. Various factors, (solvent, temperature, catalyst %) were examined and the reactions were optimized. The best condition for the Michael addition reaction was determined as room temperature, toluene as solvent and 10 mol% of heteroatom-bridged calixaromatic based chiral catalyst as organocatalyst loading. The catalytic efficiency of the chiral catalyst was analyzed by HPLC using chiral columns. The corresponding adducts were generally obtained in (S)-forms with great yields (up to 93%) and enantioselectivities (up to 95% ee). Enantioselective synthesis ; Chemistry ; Michael reaction ; Catalysis ; Triazine ; Nucleophile ; Cyanuric chloride ; Organocatalysis ; Chirality (physics) ; Nitroaldol reaction ; Organic chemistry ; Chiral ligand ; Solvent ; Combinatorial chemistry Chemical Reaction Mechanisms ; Asymmetric Synthesis and Catalysis ; Chemical Synthesis and Analysis
Authors: M. Halit | Mélissa Roger | Véronique Patinec | Said Yefsah | Carlos J. Gómez‐García | Smaı̈l Triki
Source: Magnetochemistry (article, 2019-03-07)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Spin Cross-Over (SCO) Complex Based on Unsymmetrical Functionalized Triazacyclononane Ligand: Structural Characterization and Magnetic Properties The unsymmetrical ligand 1-(2-aminophenyl)-4,7-bis(pyridin-2-ylmethyl)-1,4,7-triazacyclononane (L6) has been prepared and characterized by NMR spectroscopy. The L6 ligand is based on the triazamacrocycle (tacn) ring that is functionalized by two flexible 2-pyridylmethyl and one rigid 2-aminophenyl groups. Reaction of this ligand with Fe(ClO4)2·xH2O led to the complex [Fe(L6)](ClO4)2 (1), which was characterized as the first Fe(II) complex based on the unsymmetrical N-functionalized tacn ligand. The crystal structure revealed a discrete monomeric [FeL6]2+ entity in which the unsymmetrical N-functionalized triazacyclononane molecule (L6) acts as hexadentate ligand. As observed in the few parent examples that are based on the symmetrical N-functionalized tacn ligands, the triazacyclononane ring is facially coordinated and the N-donor atoms of the three functional groups (two pyridine and one aniline groups) are disposed in the same side of the tacn ring, leading to a distorted FeN6 environment. The magnetic studies of 1 revealed the presence of an incomplete spin crossover (SCO) transition above 425 K, whose progress would be prevented by a very exothermic thermal decomposition at ca. 472 K, as shown by thermogravimetric and DSC measurements. Ligand (biochemistry) ; Chemistry ; Spin crossover ; Pyridine ; Ring (chemistry) ; Aniline ; Crystallography ; Molecule ; Thermogravimetric analysis ; Thermal decomposition ; Crystal structure ; Stereochemistry ; Medicinal chemistry ; Organic chemistry Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Metal-Catalyzed Oxygenation Mechanisms
Authors: Dafna Knani
Source: Biomedical Journal of Scientific & Technical Research (article, 2019-01-09)
Field: Materials Science — Biomaterials

Low Molecular Weight Hydro-and Organo Gelators Used for Medical Applications Low molecular weight gelators (LMWGs) are molecules capable of forming gels in which they are self-assembled into a physical 3D network of fibers, held together by non-covalent interactions. In this mini-review, the difference between organo- and hydro gelators will be discussed, and their various medical applications. Covalent bond ; Nanotechnology ; Molecule ; Chemistry ; Organic chemistry ; Polymer science ; Materials science Supramolecular Self-Assembly in Materials ; Neuropeptides and Animal Physiology ; Peptidase Inhibition and Analysis
Authors: R.H. Ismayilov | Fuad Famil Valiyev | Nizami Vali Israfilov | Wen‐Zhen Wang | Gene‐Hsiang Lee | Shie‐Ming Peng | Baghir A. Suleimanov
Source: Chemical Problems (article, 2019-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

DEFECTIVE OCTANUCLEAR NICKEL COMPLEX WITH PYRAZINE AND NAPHTHYRIDINE MODULATED N 2 (PYRAZIN-2-YL)-N 7 -(2-(PYRAZIN-2- YLAMINO)-1,8-NAPHTHYRIDIN-7-YL)-1,8-NAPHTHYRIDINE-2,7-DIAMINE LIGAND Defective metal string complex with one nickel(II) metal absent in center [Ni 8 ( 8 -N 9 -2pz) 4 Cl 2 ](PF 6 ) 2 (2) was obtained on the basis a pyrazine and naphthyridine-containing triamino ligand Pyrazine ; Nickel ; Bridging ligand ; Ligand (biochemistry) ; Metal ; Chemistry ; Crystallography ; Molecule ; Diamine ; Stereochemistry ; Polymer chemistry ; Receptor ; Organic chemistry Magnetism in coordination complexes ; Molecular Junctions and Nanostructures ; Metal complexes synthesis and properties
Authors: Natalia Spinella | C. Galati | L. Renna
Source: Journal of Materials and Applications (article, 2019-05-13)
Field: Materials Science — Materials Chemistry

Inkjet Printing of Controlled ZnO Nanoparticles Layering Controlled layering of functional material can produced a versatile film with specific chemical and physical proprieties for desirable applications. This article presented inkjet multilayer structures of ZnO nanoparticles of specific layer morphology and thickness for the development of devices where a high surface-to-volume ratio is required (e.g. micro gas sensors). Stacked multilayers were stratified through a multi-run printing process suitable to produce large-square pattern on flat silicon support. The formation of a multilayer structure was demonstrate through an extended structural characterization of the resulting film. Printed layer morphology was investigated with optical and scanning electron microscopies; atomic force microscopy profiling characterizations were conducted over the entire printed area to evaluate the pattern reproducibility. Finally, a preliminary study as gas sensing film was performed, using the alcohol/ZnO interaction experiments. Materials science ; Layering ; Scanning electron microscope ; Nanotechnology ; Nanoparticle ; Characterization (materials science) ; Layer (electronics) ; Silicon ; Optoelectronics ; Composite material ZnO doping and properties ; Nanomaterials and Printing Technologies ; Gas Sensing Nanomaterials and Sensors
Authors: Lisa Zappe | Charles Lochenie | Thomas Martin | Birgit Weber
Source: Open Chemistry Journal (article, 2019-03-22)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Iron(II) Spin Crossover Polymers of Planar N2O2 Schiff Base Templates and 4,4’-bis(pyridyl)urea Bridges Introduction: The synthesis of four new iron(II) coordination polymers [Fe(L1a)(bpua)] ( 1 ), [Fe(L1b)(bpua)](0.5bpua) ( 2 ), [Fe(L2a)(bpua)] ( 3 ), [Fe(L1b)(bpua)](yEtOH) ( 5 ) and one trinuclear complex [{Fe(L1a)(bpua)(MeOH)} 2 -µ{Fe(L1a)}](xMeOH) ( 4 ) with Schiff base-like N 2 O 2 coordinating equatorial ligands (L1a, L1b and L2a) and 4,4’-bis(pyridyl)urea (bpua) as bridging axial ligand is described. Materials and Methods: Single crystal X-ray structure elucidation of the trinuclear module 4 and of the coordination polymer 5 reveals the presence of HS-LS-HS chains and all-HS infinite 1-D strands, respectively. As anticipated the presence of the bridging urea supports the supramolecular concatenation within an extended hydrogen-bonding network. Magnetic measurements reveal spin crossover behavior for four of the five complexes ( 1 – 4 ) that is strongly solvent dependent. Results and Conclusion: Interestingly, in two cases, complete removal of the solvent from the crystal packing leads to wider thermal hysteresis loops. Schiff base ; Spin crossover ; Supramolecular chemistry ; Crystallography ; Materials science ; Hydrogen bond ; Polymer ; Solvent ; Crystal structure ; Ligand (biochemistry) ; Polymer chemistry ; Chemistry ; Molecule ; Organic chemistry Magnetism in coordination complexes ; Metal complexes synthesis and properties ; Metal-Catalyzed Oxygenation Mechanisms
Authors: Ying Tian | Jianxin Jiao | Xin Feng | Mingming Xing | Yong Peng | Xixian Luo
Source: Journal of Nanomaterials (article, 2019-10-07)
Field: Materials Science — Materials Chemistry

Efficient Color Tuning of Upconversion Luminescence from Core-Shell Oxysulfide Nanoparticles The Y 2 O 2 S:Er 3+ @Y 2 O 2 S:Yb 3+ ,Ho 3+ core-shell up-conversion (UC) nanoparticles were successfully synthesized by the homogeneous co-precipitation method. The Y 2 O 2 S:Er 3+ @Y 2 O 2 S:Yb 3+ ,Ho 3+ core-shell nanoparticles exhibit bright green emissions under 980 nm excitation, while the triple-ion doped Y 2 O 2 S:Er 3+ ,Yb 3+ ,Ho 3+ sample presents mainly red emissions. The intensity ratio of green-to-red emission of the core-shell and conventional triple-ion doped samples are 2.8 and 0.3, respectively. Investigations on the UC mechanisms show that emissions from Er 3+ and Ho 3+ ions are achieved simultaneously in the core-shell nanoparticles. This is due to the efficient energy transfers of Yb 3+ →Ho 3+ within the shell layer and Yb 3+ →Er 3+ between the shell and the core. While the triple-ion doped Y 2 O 2 S: Er 3+ ,Yb 3+ ,Ho 3+ sample exhibits mainly the emissions of Er 3+ along with weak luminescence of Ho 3+ ion. Since the cross relaxation between Er 3+ and Ho 3+ ions in the Y 2 O 2 S:Er 3+ ,Yb 3+ ,Ho 3+ nanoparticles can effectively suppress the emissions of Ho 3+ ions. Yet, in the core-shell structure, this cross relaxation can be successfully restrained in the core-shell structure where Er 3+ is in the core and Ho 3+ is in the shell. Therefore, the construction of core-shell structure can improve the luminescence efficiency and provide a route for adjustment of emission color. Materials science ; Ion ; Photon upconversion ; Nanoparticle ; Luminescence ; Doping ; Analytical Chemistry (journal) ; Shell (structure) ; Emission intensity ; Core (optical fiber) ; Excitation ; Nanotechnology ; Optoelectronics ; Composite material ; Physics ; Chemistry Luminescence Properties of Advanced Materials ; Luminescence and Fluorescent Materials ; Perovskite Materials and Applications
Authors: Dingjun Zhang | Yuxian Chen | Xue Bai | Xianwen Li | Yingxia Ma | Zhenbin Chen
Source: Materials Science (article, 2019-05-10)
Field: Materials Science — Polymers and Plastics

Preparation and Electrochemical Testing of Polyaniline (PANI) Nanoparticles with Uniform Morphology and Good Dispersion in a Water-task-specific Ionic Liquid Medium Polyaniline (PANI) nanoparticles with uniform morphology and good dispersion were prepared by using the task-specific Ionic Liquid (IL) 1-ester-3-methyl-imidazolium tetrafluoroborate ([EAMIM]BF4) as a soft template by chemical oxidation in a water-IL medium. The morphological, structural and electronic properties of polyaniline (PANI) products, controlled by the IL [EAMIM]BF4, were synthesized and investigated. Products were characterized by SEM, FT-IR and the measurements of conductivity. The addition of [EAMIM]BF4 strongly influenced the morphology, uniformity, and conductivity of the PANI. Depending on the [EAMIM]BF4:ANI ratio, various nanostructures of PANI could be prepared and the dominant morphologies are the rod-like and fiber-like elongated structures under most experimental conditions. Samples prepared in the presence of IL [EAMIM]BF4 show uniform morphology, good dispersion and good electrochemical performance. At the current density of 0.5 A/g, the specific capacitance of PANI was 396 F.g-1. Compared with the PANI without ionic liquids, the specific capacitance was increased by 165 F.g-1. DOI: http://dx.doi.org/10.5755/j01.ms.25.3.19145 Polyaniline ; Ionic liquid ; Tetrafluoroborate ; Materials science ; Dispersion (optics) ; Morphology (biology) ; Capacitance ; Chemical engineering ; Electrochemistry ; Nanoparticle ; Conductivity ; Nanocomposite ; Nanotechnology ; Composite material ; Polymer ; Chemistry ; Electrode ; Organic chemistry ; Physical chemistry Conducting polymers and applications ; Electrochemical sensors and biosensors ; Analytical Chemistry and Sensors
Authors: Benjamin P. Burton‐Pye | Mateusz Dembowski | Wayne W. Lukens | Anthony Cruz | Alrasheed Althour | Gustavo E. López | Ramsey Salcedo | Colleen M. B. Gallagher | Donna McGregor | Lynn C. Francesconi
Source: European Journal of Inorganic Chemistry (article, 2019-11-26)
Field: Chemistry — Inorganic Chemistry

Synthesis and Characterization of Non‐Aqueous [Tc<sup>X</sup>M‐PW<sub>11</sub>O<sub>39</sub>]<sup>n</sup><sup>–</sup> with M = O, N: Comparing Tc<sup>V</sup> and Tc<sup>VI</sup> in Metal Oxide Matrices Technetium‐99, a prevalent by‐product of the nuclear fuel cycle, is a transition metal with 9 accessible oxidation states and a half‐life of 2.1 × 10 5 years. 99 Tc VII has been found in the environment surrounding National Lab sites and fuel reprocessing centers, and its separation and long‐term storage is complicated by its extensive redox chemistry. In our prior work we have reported the synthesis and reduction of Tc V O to Tc IV O in α 1 ‐ and α 2 ‐Wells–Dawson P 2 W 17 O 61 10– polyoxometalates and reported on the polyoxometalate features that promote reduction and stabilization. In this work we report on the oxidation state stabilization of Tc V O, Tc VI O and Tc VI N within the α‐Keggin PW 11 O 39 7– polyoxometalate. Both Density Functional Theory and experimental results show that Tc in TBA 4 [Tc VI N‐PW 11 O 39 ] can be reduced to Tc V , but any subsequent electrons reduce the tungsten framework of the polyoxometalate. TBA 4 [Tc V O‐PW 11 O 39 ] however, can be theoretically reduced down to Tc I before reduction of the polyoxometalate occurs. Polyoxometalate ; Chemistry ; Tungstate ; Redox ; Aqueous solution ; Oxidation state ; Crystallography ; Tungsten ; Inorganic chemistry ; Nuclear chemistry ; Physical chemistry ; Metal ; Catalysis Radioactive element chemistry and processing ; Polyoxometalates: Synthesis and Applications ; Chemical Synthesis and Characterization
Authors: Angela Casini
Source: Chemistry - A European Journal (article, 2019-09-10)
Field: Chemistry — Physical and Theoretical Chemistry

<i>In My Element</i>: Gold The In My Element series celebrates the personal accounts from Chemistry – A European Journal Editorial Board members for the 2019 International Year of the Periodic Table. In this contribution, Angela Casini gives her story on gold. Element (criminal law) ; Editorial board ; Table (database) ; Series (stratigraphy) ; History ; Art ; Library science ; Computer science ; Geology ; Political science ; Law ; Data mining ; Paleontology History and advancements in chemistry
Authors: Francesca Nunzi | Benedetta Di Erasmo | Francesco Tarantelli | David Cappelletti | Fernando Pirani
Source: Preprints.org (preprint, 2019-11-10)
Field: Chemistry — Inorganic Chemistry

The Halogen-Bond Nature in Noble Gas-Dihalogen Complexes from Scattering Experiments and Ab-Initio Calculations In order to clarify the nature of the halogen bond (XB), we considered the prototype noble gas – dihalogen molecule (Ng-X2) systems, focusing on the nature, range and strength of the interaction. We exploited data gained from molecular beam scattering experiments with the measure of interference effects to obtain a suitable formulation of the interaction potential, with the support of high-level ab initio calculations, and charge displacement analysis. The essential interaction components involved in the Ng-X2 adducts have been characterized, pointing at their critical balance in the definition of the XB. Particular emphasis is devoted to the energy stability of the orientational Ng-X2 isomers, the barrier for the X2 hindered rotation, and the influence of the X2 electronic state. The present integrated study returns reliable force fields for molecular dynamics simulations in Ng-X2 complexes that can be extended to systems with increasing complexity and whose properties depend on the selective formation of XB. Chemistry ; Ab initio ; Scattering ; Chemical physics ; Halogen bond ; Ab initio quantum chemistry methods ; Molecule ; Noble gas ; Computational chemistry ; Physics ; Quantum mechanics ; Organic chemistry Inorganic Fluorides and Related Compounds ; Advanced Chemical Physics Studies ; Solid-state spectroscopy and crystallography
Authors: Rini Umiyati | Chusnul Hidayat | Ria Millati | Teguh Ariyanto
Source: E3S Web of Conferences (article, 2019-01-01)
Field: Materials Science — Biomaterials

Physical and Antimicrobial Properties of Hydroxypropyl Starch Bio-plastics Incorporated with Nyamplung (Calophyllum inophyllum) Cake Extract as an Eco-Friendly Food Packaging Nyamplung (Calophyllum inophyllum) cake as a by-product of nyamplung oil production is still limited. This research aimed to evaluate characteristics of antimicrobial bio-plastic made from hydroxypropyl starch as a basic ingredient and Nyamplung cake extract as additive. Nyamplung cake extract addition affected bio-plastic mechanical property by reduction of tensile strength but improved physical properties by reduction of vapor and oxygen permeability, water solubility, and increased elongation. This was probably due to the extract serve as natural crosslinking. Fourier Transform Infrared Spectroscopy analysis showed no difference in five bio-plastic samples, which probably caused by low concentration of extract. Thermogravimetry analysis showed the highest weight reduction in control of 95.824% and the lowest on Ext2% of 84.471%. Morphology analysis showed agglomeration of the extract on sample surface due to uneven ingredient distribution in mixture. Bio-plastic was more sensitive against gram positive bacteria than gram negative with their respective largest inhibition zone of 30 mm (Staphylococcus aureus) and 23 mm (Escherichia coli). This was probably due to the content of the extract serve as natural crosslinking and antibacterial agent. Ingredient ; Food science ; Antimicrobial ; Food packaging ; Antibacterial activity ; Chemistry ; Active ingredient ; Starch ; Materials science ; Bacteria ; Organic chemistry Nanocomposite Films for Food Packaging ; Polysaccharides Composition and Applications ; Food composition and properties
Authors: George Vamvounis | Marina Fuhrer | Kevin Lane Keller | Lukas Willig | Ami Koizumi | Hsuan-Ming Hu | Mei Gao | Toby D. M. Bell
Source: European Polymer Journal (article, 2019-07-01)
Field: Materials Science — Materials Chemistry

The effect of the phenylene linkage in poly(fluorene-alt-phenylene)s on the thermodynamics and kinetics of nitroaromatic and nitroaliphatic sensing Fluorene ; Phenylene ; Quenching (fluorescence) ; Polymer ; Luminescence ; Photochemistry ; Materials science ; Moiety ; Photoluminescence ; Poly(p-phenylene) ; Polymer chemistry ; Chemistry ; Fluorescence ; Organic chemistry ; Physics Luminescence and Fluorescent Materials ; Molecular Sensors and Ion Detection ; Conducting polymers and applications
Authors: Detlef Klimm | Christo Guguschev | Steffen Ganschow | Matthias Bickermann | Darrell G. Schlom
Source: Crystal Research and Technology (article, 2019-09-18)
Field: Materials Science — Materials Chemistry

REScO<sub>3</sub> Substrates—Purveyors of Strain Engineering Abstract The thermodynamic and crystallographic background for the development of substrate crystals that are suitable for the epitaxial deposition of biaxially strained functional perovskite layers is reviewed. In such strained layers the elastic energy delivers an additional contribution to the Gibbs free energy, which allows the tuning of physical properties and phase transition temperatures to desired values. For some oxide systems metastable phases can even be accessed. Rare‐earth scandates, REScO 3 , are well suited as substrate crystals because they combine mechanical and chemical stability in the epitaxy process with an adjustable range of pseudo‐cubic lattice parameters in the 3.95 to 4.02 Å range. To further tune the lattice parameters, chemical substitution for the RE or Sc is possible. Metastability ; Epitaxy ; Materials science ; Strain engineering ; Lattice (music) ; Substrate (aquarium) ; Gibbs free energy ; Oxide ; Chemical stability ; Chemical physics ; Perovskite (structure) ; Elastic energy ; Nanotechnology ; Crystallography ; Optoelectronics ; Thermodynamics ; Chemistry ; Metallurgy ; Geology ; Physics Ferroelectric and Piezoelectric Materials ; Electronic and Structural Properties of Oxides ; Microwave Dielectric Ceramics Synthesis