jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Madher N. Alfindee | Zainab J. Sweah | Tahseen A. Saki
Source: Egyptian Journal of Chemistry (article, 2021-01-30)
Field: Materials Science — Biomaterials

Preparation and Characterization of Polymer Blends Based on Carboxymethyl Cellulose, Polyvinyl Alcohol, and Polyvinylpyrrolidone Two libraries of crosslinked polymer blends were synthesized and characterized. The polymer blends were prepared from carboxymethyl cellulose, polyvinyl alcohol, and polyvinylpyrrolidone in 1:1:1 ratio using solvent casting method. Two crosslinking agents were used: glyoxal and glutaraldehyde for the first and second libraries respectively. Both crosslinking agents were used in three different ratios (10,15, and 20%). The mechanical properties of the polymer blends were tested using morphology, and swelling ratio methods for the crosslinked polymer blends only. The results confirm that the degree of crystallinity was altered during blending and crosslinking when the original polymer blend compared to itself after crosslinking. The maximum elongation εM% was found when the crosslinking agent ratio was 15%. The polymer blend D with glutaraldehyde as the crosslinking agent had the maximum elongation εM% =17.533, and about 0.565 Mpa Young modulus. While polymer blend B with glyoxal as crosslinking agent had maximum elongation εM% = 11.115, and about 0.593 Mpa Young modulus. Finally, the prepared blends are suitable for adsorption and as an excipient material in pharmaceutical industries. Materials science ; Carboxymethyl cellulose ; Polyvinyl alcohol ; Polyvinylpyrrolidone ; Glutaraldehyde ; Crystallinity ; Polymer ; Polymer blend ; Polymer chemistry ; Composite material ; Chemical engineering ; Chemistry ; Organic chemistry biodegradable polymer synthesis and properties ; Advanced Polymer Synthesis and Characterization ; Polymer Nanocomposites and Properties
Authors: Michael J. Tilby | Damien F. Dewez | Adrian Hall | Carolina Martínez Lamenca | Michael C. Willis
Source: Angewandte Chemie (article, 2021-09-24)
Field: Chemistry — Organic Chemistry

Exploiting Configurational Lability in Aza‐Sulfur Compounds for the Organocatalytic Enantioselective Synthesis of Sulfonimidamides Abstract Methods for establishing the absolute configuration of sulfur‐stereogenic aza‐sulfur derivatives are scarce, often relying on cumbersome protocols and a limited pool of enantioenriched starting materials. We have addressed this by exploiting, for the first time, a feature of sulfonimidamides in which it is possible for tautomeric structures to also be enantiomeric. Such sulfonimidamides can readily generate prochiral ions, which we have exploited in an enantioselective alkylation process. Selectivity is achieved using a readily prepared bis‐quaternized phase‐transfer catalyst. The overall process establishes the capability of configurationally labile aza‐sulfur species to be used in asymmetric catalysis. Enantioselective synthesis ; Stereocenter ; Chemistry ; Sulfur ; Tautomer ; Alkylation ; Catalysis ; Combinatorial chemistry ; Lability ; Enantiomer ; Organocatalysis ; Organic chemistry Synthesis and Catalytic Reactions ; Asymmetric Hydrogenation and Catalysis ; Catalytic C–H Functionalization Methods
Authors: Tianbao Yang | Niu Tang | Qizhong Wan | Shuang‐Feng Yin | Renhua Qiu
Source: Molecules (review, 2021-03-05)
Field: Chemistry — Organic Chemistry

Recent Progress on Synthesis of N,N′-Chelate Organoboron Derivatives <i>N</i>,<i>N</i>'-chelate organoboron compounds have been successfully applied in bioimaging, organic light-emitting diodes (OLEDs), functional polymer, photocatalyst, electroluminescent (EL) devices, and other science and technology areas. However, the concise and efficient synthetic methods become more and more significant for material science, biomedical research, or other practical science. Here, we summarized the organoboron-<i>N</i>,<i>N</i>'-chelate derivatives and showed the different routes of their syntheses. Traditional methods to synthesize <i>N</i>,<i>N</i>'-chelate organoboron compounds were mainly using bidentate ligand containing nitrogen reacting with trivalent boron reagents. In this review, we described a series of bidentate ligands, such as bipyridine, 2-(pyridin-2-yl)-1<i>H</i>-indole, 2-(5-methyl-1<i>H</i>-pyrrol-2-yl)quinoline, <i>N</i>-(quinolin-8-yl)acetamide, 1,10-phenanthroline, and diketopyrrolopyrrole (DPP). Organoboron compounds ; Chelation ; Chemistry ; Combinatorial chemistry ; Stereochemistry ; Organic chemistry ; Boron Organoboron and organosilicon chemistry ; Luminescence and Fluorescent Materials ; Catalytic Cross-Coupling Reactions
Authors: Luca Vaghi | Mauro Monti | Marcello Marelli | Elisa Motto | Antonio Papagni | Laura Cipolla
Source: Gels (article, 2021-08-20)
Field: Chemistry — Organic Chemistry

Photoinduced Porcine Gelatin Cross-Linking by Homobi- and Homotrifunctional Tetrazoles Gelatin is a costless polypeptide material of natural origin, able to form hydrogels that are potentially useful in biomaterial scaffold design for drug delivery, cell cultures, and tissue engineering. However, gelatin hydrogels are unstable at physiological conditions, losing their features only after a few minutes at 37 °C. Accordingly, treatments to address this issue are of great interest. In the present work, we propose for the first time the use of bi- and trifunctional tetrazoles, most of them unknown to date, for photoinduced gelatin cross-linking towards the production of physiologically stable hydrogels. Indeed, after UV-B irradiation, aryl tetrazoles generate a nitrilimine intermediate that is reactive towards different functionalities, some of them constitutively present in the amino acid side chains of gelatin. The efficacy of the treatment strictly depends on the structure of the cross-linking agent used, and substantial improved stability was observed by switching from bifunctional to trifunctional cross-linkers. Gelatin ; Self-healing hydrogels ; Bifunctional ; Scaffold ; Chemistry ; Biomaterial ; Drug delivery ; Combinatorial chemistry ; Biophysics ; Polymer chemistry ; Biochemistry ; Organic chemistry ; Biomedical engineering Click Chemistry and Applications ; Nanofabrication and Lithography Techniques ; RNA Interference and Gene Delivery
Authors: Dominik Kolling | Marc Stierhof | Constanze Lasch | Maksym Myronovskyi | Andriy Luzhetskyy
Source: Molecules (article, 2021-10-14)
Field: Materials Science — Materials Chemistry

A Promiscuous Halogenase for the Derivatization of Flavonoids Halogenation often improves the bioactive properties of natural products and is used in pharmaceutical research for the generation of new potential drug leads. High regio- and stereospecificity, simple reaction conditions and straightforward downstream processing are the main advantages of halogenation using enzymatic biocatalysts compared to chemical synthetic approaches. The identification of new promiscuous halogenases for the modification of various natural products is of great interest in modern drug discovery. In this paper, we report the identification of a new promiscuous FAD-dependent halogenase, DklH, from <i>Frankia alni</i> ACN14a. The identified halogenase readily modifies various flavonoid compounds, including those with well-studied biological activities. This halogenase has been demonstrated to modify not only flavones and isoflavones, but also flavonols, flavanones and flavanonols. The structural requirements for DklH substrate recognition were determined using a feeding approach. The homology model of DklH and the mechanism of substrate recognition are also proposed in this paper. Halogenation ; Chemistry ; Flavones ; Derivatization ; Biorefinery ; Combinatorial chemistry ; Stereochemistry ; Organic chemistry ; Chromatography Enzyme Structure and Function ; Carbohydrate Chemistry and Synthesis ; Microbial Metabolites in Food Biotechnology
Authors: Ana B. Buades | Clara Viñas | Xavier Fontrodona | Francesç Teixidor
Source: Inorganic Chemistry (article, 2021-10-24)
Field: Chemistry — Inorganic Chemistry

1.3 V Inorganic Sequential Redox Chain with an All-Anionic Couple 1–/2– in a Single Framework The relatively low symmetry of [3,3'-Co(1,2-C<sub>2</sub>B<sub>9</sub>H<sub>11</sub>)<sub>2</sub>]<sup>-</sup> ([<b>1</b>]<sup>-</sup>), along with the high number of available substitution sites, 18 on the boron atoms and 4 on the carbon atoms, allows a fairly regioselective and stepwise chlorination of the platform and therefore a very controlled tuning of the electrochemical potential tuning. This is not so easily found in other systems, e.g., ferrocene. In this work, we show how a single platform with boron and carbon in the ligand, and only cobalt can produce a tuning of potentials in a stepwise manner in the 1.3 V range. The platform used is made of two icosahedra sharing one vertex. The <i>E</i><sub>1/2</sub> tuning has been achieved from [<b>1</b>]<sup>-</sup> by sequential chlorination, which has given potentials whose values increase sequentially and linearly with the number of chloro groups in the platform. [<b>Cl</b><sub><b>8</b></sub><b>-1</b>]<sup>-</sup>, [<b>Cl</b><sub><b>10</b></sub><b>-1</b>]<sup>-</sup>, and [<b>Cl</b><sub><b>12</b></sub><b>-1</b>]<sup>-</sup> have been obtained, which are added to the existing [<b>Cl-1</b>]<sup>-</sup>, [<b>Cl</b><sub><b>2</b></sub><b>-1</b>]<sup>-</sup>, [<b>Cl</b><sub><b>4</b></sub><b>-1</b>]<sup>-</sup>, and [<b>Cl</b><sub><b>6</b></sub><b>-1</b>]<sup>-</sup> described earlier to give the 1.3 V range. It is envisaged to extend this range also sequentially by changing the metal from cobalt to iron. The last successful synthesis of the highest chlorinated derivatives of cobaltabis(dicarbollide) dates back to 1982, and since then, no more advances have occurred toward more substituted metallacarborane chlorinated compounds. [<b>Cl</b><sub><b>8</b></sub><b>-1</b>]<sup>-</sup>, [<b>Cl</b><sub><b>10</b></sub><b>-1</b>]<sup>-</sup>, and [<b>Cl</b><sub><b>12</b></sub><b>-1</b>]<sup>-</sup> are made with an easy and fast method. The key point of the reaction is the use of the protonated form of [Co(C<sub>2</sub>B<sub>9</sub>H<sub>11</sub>)<sub>2</sub>]<sup>-</sup>, as a starting material, and the use of sulfuryl chloride, a less hazardous and easier to use chlorinating agent. In addition, we present a complete, spectroscopic, crystallographic, and electrochemical characterization, together with a study of the influence of the chlorination position in the electrochemical properties. Chemistry ; Protonation ; Boron ; Redox ; Ligand (biochemistry) ; Cobalt ; Electrochemistry ; Carbon fibers ; Metal ; Ferrocene ; Vertex (graph theory) ; Combinatorial chemistry ; Inorganic chemistry ; Crystallography ; Physical chemistry ; Organic chemistry ; Electrode ; Ion ; Combinatorics Radioactive element chemistry and processing ; Boron Compounds in Chemistry ; Metal-Organic Frameworks: Synthesis and Applications
Authors: Luca Bellucci | Gregorio Bottaro | Luca Labella | Fabio Marchetti | Simona Samaritani | Daniela Belli Dell’Amico | Lidia Armelao
Source: Materials (article, 2021-10-27)
Field: Materials Science — Materials Chemistry

1D-Zigzag Eu3+/Tb3+ Coordination Chains as Luminescent Ratiometric Thermometers Endowed with Multicolor Emission Two homometallic Coordination Polymers (CPs) with composition [Ln(hfac)<sub>3</sub>bipy]<sub>n</sub> (Ln<sup>3+</sup> = Eu<sup>3+</sup>, <b>1</b>, and Tb<sup>3+</sup>, <b>2</b>; hfac = hexafluoroacetylacetonato, bipy = 4,4'-bipyridine) were used to develop a family of ratiometric luminescent thermometers containing Eu<sup>3+</sup> and Tb<sup>3+</sup> as red and green emitters, respectively. The thermometric properties of pure CPs and of their mixtures having an Eu<sup>3+</sup>/Tb<sup>3+</sup> molar ratio of 1:1, 1:3, 1:5, and 1:10 (samples: <b>Eu1Tb1</b>, <b>Eu1Tb3</b>, <b>Eu1Tb5</b>, and <b>Eu1Tb10</b>) were studied in the 83-383 K temperature range. Irrespective of the chemical composition, we observed similar thermometric responses characterized by broad applicative temperature ranges (from 100 to 165 K wide), and high relative thermal sensitivity values (S<sub>r</sub>), up to 2.40% K<sup>-1</sup>, in the physiological temperature range (298-318 K). All samples showed emissions endowed with peculiar and continuous color variation from green (83 K) to red (383 K) that can be exploited to develop a colorimetric temperature indicator. At fixed temperature, the color of the emitted light can be tuned by varying composition and excitation wavelength. Luminescence ; Zigzag ; Atmospheric temperature range ; Analytical Chemistry (journal) ; Materials science ; Phosphor ; Excitation ; Polymer ; Excitation wavelength ; Composition (language) ; Coordination polymer ; Molar ratio ; Chemistry ; Wavelength ; Optoelectronics ; Organic chemistry ; Thermodynamics ; Physics Lanthanide and Transition Metal Complexes ; Luminescence Properties of Advanced Materials ; Magnetism in coordination complexes
Authors: Xiaoqian Wang | Ai Lin Chin | Rong Tong
Source: Organic Materials (article, 2021-01-01)
Field: Materials Science — Biomaterials

Controlled Ring-Opening Polymerization of O-Carboxyanhydrides to Synthesize Functionalized Poly(α-Hydroxy Acids) Poly(α-hydroxy acids), as a family of biodegradable polyesters, are valuable materials due to their broad applications in packaging, agriculture, and biomedical engineering. Herein we highlight and explore recent advances of catalysts in controlled ring-opening polymerization of O-carboxyanhydrides towards functionalized poly(α-hydroxy acids), especially metal catalyst-mediated controlled polymerization. Limitations of current polymerization strategies of O-carboxyanhydrides are discussed. Polymerization ; Ring-opening polymerization ; Polyester ; Polymer chemistry ; Chemistry ; Catalysis ; Polymer ; Materials science ; Organic chemistry biodegradable polymer synthesis and properties ; Carbon dioxide utilization in catalysis ; Organometallic Complex Synthesis and Catalysis
Authors: Zoltán Juvancz | Rita Bodáné-Kendrovics | Lajos Szente | Dóra Maklári
Source: Periodica Polytechnica Chemical Engineering (article, 2021-08-12)
Field: Chemistry — Spectroscopy

Cyclodextrins as Dominant Chiral Selective Agents in the Capillary Separation Techniques This review paper shows the dominant role of the cyclodextrins in the chiral separations using capillary columns (GC, SFC, CE). The cyclodextrins (CDs) have extremely broad chiral selectivity spectra because they have several different chiral recognition sites in various arrangements and various interaction modes. Their chiral selectivity features can further improve with their various substitutions. Their selectivities are moderate therefore they need high efficiency separations (capillary columns) for good chiral resolutions. The shape selectivity of cyclodextrins is also shown with non-chiral isomers too. The utility of the cyclodextrins is demonstrated with several examples based on the personal observations of authors and critical review of literature. The theoretical backgrounds of their chiral recognitions (e.g. H-bond interaction, inclusion, induced fit) are discussed in depth. This paper is not application oriented but is dealing with mostly on the physical and chemical background of separations using CDs. Selectivity ; Chemistry ; Capillary action ; Cyclodextrin ; Combinatorial chemistry ; Computational chemistry ; Organic chemistry ; Materials science ; Catalysis Analytical Chemistry and Chromatography ; Microfluidic and Capillary Electrophoresis Applications ; Crystallization and Solubility Studies
Authors: Francesco Caddeo | Vanesa Fernández‐Moreira | Massimiliano Arca | Anna Pintus | Antonio Laguna | Vito Lippolis | M. Concepción Gimeno
Source: Dalton Transactions (article, 2021-01-01)
Field: Chemistry — Organic Chemistry

Luminescent gold–thallium derivatives with a pyridine-containing 12-membered aza-thioether macrocycle The coordination modes of the ligand 2,5,8-trithia[9](2,6)pyridinophane (L) to thallium(i), gold(iii) and gold(i) have been studied. Thallium(i) is coordinated by the macrocyclic ligand in [Tl(L)](PF6) (1) through all the sulfur and nitrogen atoms, in a distorted square-pyramidal geometry with the thallium(i) ion in the apical position and with the presence of an inert lone pair. Gold(iii) is bonded by the ligand only through the nitrogen of the pyridine group in [AuCl3(L)] (2), whereas two AuI-C6F5 fragments coordinate the sulfur atoms next to the pyridine moiety of the ligand in [{Au(C6F5)}2(μ-L)] (3), which form a linear polymer through intermolecular aurophilic contacts. The heterometallic TlI/AuI complex {[Au(C6F5)2Tl]2(L)}n (4) features a polymeric structural nature with a metallic pseudo-rhombic Au2Tl2 core, which repeats itself forming a zig-zag polymer. In each Au2Tl2 unit only one thallium atom is bonded by the NS3 donor set of the macrocyclic ligand and also forms two unsupported Au-Tl bonds with two [Au(C6F5)2]- units in an overall pseudo-octahedral geometry. The other thallium atom similarly bridges the same [Au(C6F5)2]- units and links a neighbouring Au2Tl2 moiety, thus exhibiting a distorted trigonal planar geometry being bonded only to three gold atoms with unsupported Au-Tl interactions. This complex displays an interesting thermochromic behaviour showing emissions mainly resulting from MM'CT transitions at room temperature. At 77 K a dual emission appears, probably arising from the two different thallium environments. DFT calculations have been carried out in the attempt to investigate the origin of the emissions of complex 4. Thioether ; Thallium ; Pyridine ; Luminescence ; Chemistry ; Polymer chemistry ; Photochemistry ; Medicinal chemistry ; Materials science ; Organic chemistry Organometallic Complex Synthesis and Catalysis ; Metal complexes synthesis and properties ; Organometallic Compounds Synthesis and Characterization
Authors: Mieczysław Łapkowski
Source: Materials (review, 2021-11-15)
Field: Materials Science — Materials Chemistry

Perinone—New Life of an Old Molecule A review of publications on the synthesis and properties of a family of compounds called perinones was carried out. The basic molecule has been known for several decades mainly as a photostable pigment, and in recent years it has become increasingly used in organic electronics. This paper describes the methods of synthesis of low molecular weight compounds and polymers based on that molecule; the basic spectroscopic, photochemical, electrochemical and electronic properties important for the construction of organic electronics and optoelectronics devices are also discussed. Molecule ; Electronics ; Organic molecules ; Nanotechnology ; Molecular electronics ; Materials science ; Polymer ; Organic electronics ; Electrochemistry ; Chemistry ; Organic chemistry ; Engineering ; Physical chemistry ; Electrode ; Electrical engineering ; Transistor ; Composite material Photochromic and Fluorescence Chemistry ; Organic Electronics and Photovoltaics ; Porphyrin and Phthalocyanine Chemistry
Authors: Mathias H. Linden | H. Bernhard Linden | Jürgen H. Gross
Source: Analytical and Bioanalytical Chemistry (article, 2021-09-07)
Field: Chemistry — Spectroscopy

Negative-ion field desorption revitalized by using liquid injection field desorption/ionization-mass spectrometry on recent instrumentation Field ionization (FI), field desorption (FD), and liquid injection field desorption/ionization (LIFDI) provide soft positive ionization of gaseous (FI) or condensed phase analytes (FD and LIFDI). In contrast to the well-established positive-ion mode, negative-ion FI or FD have remained rare exceptions. LIFDI provides sample deposition under inert conditions, i.e., the exclusion of atmospheric oxygen and water. Thus, negative-ion LIFDI could potentially be applied to highly sensitive anionic compounds like catalytically active transition metal complexes. This work explores the potential of negative-ion mode using modern mass spectrometers in combination with an LIFDI source and presents first results of the application of negative-ion LIFDI-MS. Experiments were performed on two orthogonal-acceleration time-of-flight (oaTOF) instruments, a JEOL AccuTOF GCx and a Waters Micromass Q-TOF Premier equipped with LIFDI sources from Linden CMS. The examples presented include four ionic liquids (ILs), i.e., N-butyl-3-methylpyridinium dicyanamide, 1-butyl-3-methylimidazolium tricyanomethide, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, and trihexyl(tetradecyl)phosphonium tris(pentafluoroethyl)trifluorophosphate), 3-(trifluoromethyl)-phenol, dichloromethane, iodine, polyethylene glycol diacid, perfluorononanoic acid, anionic surfactants, a tetraphosphazene silanol-silanolate, and two bis(catecholato)silanes. Volatile samples were delivered as vapors via the sample transfer capillary of the LIFDI probe or via a reservoir inlet. Condensed phase samples were applied to the emitter as dilute solutions via the sample transfer capillary. The compounds either yielded ions corresponding to their intact anions, A<sup>-</sup>, or the [M-H]<sup>-</sup> species formed upon deprotonation. This study describes the instrumental setups and the operational parameters for robust operation along with a discussion of the negative-ion LIFDI spectra of a variety of compounds. Field desorption ; Chemistry ; Desorption ; Mass spectrometry ; Analytical Chemistry (journal) ; Ionic liquid ; Dicyanamide ; Deprotonation ; Ion ; Ionization ; Chromatography ; Organic chemistry ; Adsorption Mass Spectrometry Techniques and Applications ; Analytical chemistry methods development ; Ionic liquids properties and applications
Authors: Zhongrui Chen | Simon Pascal | Morgane Daurat | Laure Lichon | Christophe Nguyen | Anastasia Godefroy | D. Durand | Lamiaa M. A. Ali | Nadir Bettache | Magali Gary‐Bobo | Philippe Arnoux | Jean‐François Longevial | Anthony D’Aléo | Gabriel Marchand | Denis Jacquemin | Olivier Siri
Source: ACS Applied Materials & Interfaces (article, 2021-06-23)
Field: Materials Science — Materials Chemistry

Modified Indulines: From Dyestuffs to <i>In Vivo</i> Theranostic Agents The efficient, versatile, and straightforward synthesis of the first N-alkyl analogues of induline 3B (8a and 8b) is reported. Thanks to the introduction of lipophilic substituents and their attractive photophysical properties (far-red emission and production of singlet oxygen), phenazinium 8b can be used as a theranostic agent and shows, at very low concentrations (100 nM), a remarkable ability to (i) image cells and zebrafish embryos with high quality under both mono- (514 nm) and biphotonic (790 and 810 nm) excitations, (ii) efficiently and quickly penetrate cancer cells rather than healthy fibroblasts, and (iii) induce a total or almost total cancer cell death in vitro and in vivo after illumination (λexc = 540–560 nm). The molecular structure of 8b is based on a triamino-phenazinium core only, with no need for additional components, highlighting the emergence of a minimalistic and versatile class of fluorescent probes for targeted photodynamic cancer therapy. In vivo ; Singlet oxygen ; Materials science ; Fluorescence ; Alkyl ; Photodynamic therapy ; Cancer cell ; Nanotechnology ; Zebrafish ; In vitro ; Combinatorial chemistry ; Biophysics ; Cancer ; Oxygen ; Chemistry ; Organic chemistry ; Biochemistry ; Biology ; Optics Luminescence and Fluorescent Materials ; Nanoplatforms for cancer theranostics ; Photochromic and Fluorescence Chemistry