jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Andreis Lau | Zhan Yang | Bo Wu | Zijie Qiu | Zheng Zhao | Ben Zhong Tang
Source: ChemRxiv (preprint, 2023-08-01)
Field: Materials Science — Materials Chemistry

Aggregation-induced emission materials based on restriction of intramolecular vibration Aggregation-induced emission (AIE) is a photophysical phenomenon wherein luminescent materials exhibit weak emission in solution but strong emission after aggregation. This phenomenon has garnered significant attention in the realm of multifunctional luminescent materials. Specifically, AIE molecules, which operate through the restriction of intramolecular vibration (RIV) mechanism, have emerged as a pivotal constituent of AIE materials, captivating the interest of both academia and industry. This review aims to present a comprehensive overview of recent advancements in the domain of RIV-type AIE and its associated areas. It encompasses a survey of the classifications, molecular design strategies, and mechanisms underlying RIV-type AIE molecules. Furthermore, the review delves into the prospects and challenges encountered in the realm. We hope this review can provide novel insights into the theory, materials, and applications in the field of biochemistry and organic photoelectric. Aggregation-induced emission ; Intramolecular force ; Realm ; Nanotechnology ; Luminescence ; Phenomenon ; Tetraphenylethylene ; Materials science ; Chemistry ; Physics ; Optoelectronics ; Political science ; Stereochemistry ; Fluorescence Luminescence and Fluorescent Materials ; Organoboron and organosilicon chemistry ; Synthesis and characterization of novel inorganic/organometallic compounds
Authors: Enas Taha Abdelhamed
Source: Egyptian Journal of Chemistry (article, 2023-03-16)
Field: Chemistry — Analytical Chemistry

Validated ATR-FTIR Method For Quantitative Simultaneous Estimation of Terbutaline Sulfate, Guaiphenesin and Bromhexine Hydrochloride, in Bulk and Pharmaceutical Dosage Form. Background: Using Attenuated Total Reflectance Fourier Transform Infrared Spectrometry ,the current study aimed to develop and successively validate a simple, accurate method for the simultaneous estimation of terbutaline sulphate, guaifenesin, and bromhexine hydrochloride in bulk, pharmaceutical preparation, or combination. Absorbance of the first derivative amplitude with a correlation coefficient (r) better than 0.99 was chosen for sample quantification after calibration models were established based on measurements of the three substances in their first derivative spectra zone at 4600-400 cm-1 Absorbance was determined at 1151cm-1, 1332cm-1, and 919 cm-1 for three compound respectively; after the spectra were transformed to first order derivative spectra (∆λ=1, scaling factor=10). this method was compared to the standard UV-visible spectrophotometry technique for quantitative sample analysis. the suggested technique shows promise as a quick screening tool due to a high correlation (r = 0.97) between the two approaches' predictions of content across samples. It was then shown that the installed method was suitable for determining the active ingredients in commercial and model cough syrup, with no interference from the formulation excipients being observed; these results suggested that this attenuated total Reflectance fourier transform Infrared could be used for the determination of the multiple active ingredients in their dosage form. Chemistry ; Dosage form ; Hydrochloride ; Chromatography ; Organic chemistry Analytical Methods in Pharmaceuticals ; Analytical Chemistry and Chromatography ; Pharmacological Effects and Assays
Authors: Ran Chen | Ahmad Hammoud | Paméla Aoun | Mayte A. Martínez‐Aguirre | Nicolas Vanthuyne | Régina Maruchenko | Patrick Brocorens | Laurent Bouteiller | Matthieu Raynal
Source: ChemRxiv (preprint, 2023-10-20)
Field: Chemistry — Inorganic Chemistry

Asymmetric stereodivergent catalysis achieved by means of a switchable asymmetric catalyst built on supramolecular helices Despite recent developments on the design of dynamic catalysts, none of them have been exploited for the in-situ control of multiple stereogenic centers in a single molecular scaffold. We report herein that it is possible to select one major amongst four possible stereoisomers of an amino alcohol by means of a switchable asymmetric catalyst built on supramolecular helices. Hydrogen-bonded assemblies between a benzene-1,3,5-tricarboxamide (BTA) achiral phosphine ligand coordinated to copper and an enantiopure BTA monomer are engaged in a concomitant copper-hydride catalyzed hydrosilylation and hydroamination process, yielding mainly one of the possible stereoisomers in good yield. The nature of the product stereoisomer is related to the handedness of the helices and can thus be directed in a predictable way by the nature of the major enantiopure BTA present in the assemblies. Accordingly, a sequential reaction, during which the handedness of the supramolecular helices is switched in between the hydrosilylation and hydroamination steps, mainly yields the diastereoisomer that cannot be obtained in the aforementioned concomitant process. The strategy allows all stereoisomers to be obtained with similar selectivities. This work paves the way for the development of supramolecular helical catalysts as a platform to readily access molecules embedding several stereogenic centers. Enantiopure drug ; Stereocenter ; Hydroamination ; Supramolecular chemistry ; Hydrosilylation ; Chemistry ; Enantioselective synthesis ; Combinatorial chemistry ; Stereochemistry ; Catalysis ; Molecule ; Organic chemistry Asymmetric Hydrogenation and Catalysis ; Surface Chemistry and Catalysis ; Asymmetric Synthesis and Catalysis
Authors: Daniel Vogler | Maurice Schenker | Kim Hao Ng | Elisabeth Kaifer | Hans‐Jörg Himmel
Source: European Journal of Inorganic Chemistry (article, 2023-10-06)
Field: Chemistry — Organic Chemistry

On the Coordination Chemistry of Triazolyl‐substituted Diborane Ligands, Prepared by 1,3‐dipolar Cycloaddition Reactions between Diazido‐diboranes and Alkynes Abstract Metal‐free cycloaddition reactions between a diazido‐diborane and alkynes are used to synthesize new ditriazolyl‐diborane molecules, a bis(ferrocenyl‐1,2,3‐triazolyl)‐diborane and a bis(2‐pyridyl‐1,2,3‐triazolyl)‐diborane. Then, the bis(2‐pyridyl‐1,2,3‐triazolyl)‐diborane was used as polydentate ligand for the synthesis of larger architectures. Reaction with ditriflato‐diborane yielded a tetracationic hexaboron compound, and reaction with metal salts yielded dicationic ring compounds with two hexacoordinate metal atoms and two integrated diborane units. Diborane ; Chemistry ; Cycloaddition ; Hexacoordinate ; Denticity ; Coordination complex ; Metal ; Molecule ; Medicinal chemistry ; Boron ; Organic chemistry ; Catalysis ; Silicon Click Chemistry and Applications ; Organoboron and organosilicon chemistry ; Chemical Synthesis and Analysis
Authors: Pooja Sah | Aakash Kumar Gond | Gaurav Saini | Manmohan Kapur
Source: ChemRxiv (preprint, 2023-10-25)
Field: Chemistry — Organic Chemistry

A Sequential Transition Metal and Organocatalytic Approach to the Enantioselective Synthesis of C2-spiroindoline Systems We report herein an organocatalyzed, enantioselective spirocyclization process for the construction of spiroindolines. This methodology creates a new avenue for the easy access to valuable C2-spiroindoline scaffolds bearing a quaternary stereocenter, via an aza-Michael addition reaction, wherein the acid additives play a role of dual functionality. The substrates for this key step were put together by an exo-selective, Pd-catalyzed gamma-arylation of silyldienol ethers of the corresponding cyclohexenones. A close alliance between a low catalyst loading and a sluggish reaction yields the spiroindolines in very good enantioselectivity. Stereocenter ; Enantioselective synthesis ; Catalysis ; Organocatalysis ; Transition metal ; Combinatorial chemistry ; Chemistry ; Michael reaction ; Alliance ; Organic chemistry ; Political science Asymmetric Synthesis and Catalysis ; Oxidative Organic Chemistry Reactions ; Axial and Atropisomeric Chirality Synthesis
Authors: Masatoshi Hasegawa | Shunichi Horii
Source: Macromol—A Journal of Macromolecular Research (article, 2023-05-12)
Field: Materials Science — Polymers and Plastics

Heat-Resistant Polymers with Intense, Visible Photoluminescence Functionality and Fluorescence Probing Application Heat-resistant polymers with an intense, visible photoluminescence (PL) functionality are presented. A polybenzoxazole (PBO) containing hexafluoroisopropylidene (HFIP) side groups exhibited an intense purple PL with a quantum yield, ΦPL, of 0.22 (22%), owing to the effectively disturbed concentration quenching (CQ) in the fluorophore units by the bulky HFIP side groups. The chain ends of a wholly cycloaliphatic polyimide (PI), derived from 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA) and 4,4′-methylenebis(cyclohexylamine) (MBCHA), were modified with conjugated monoamines. The PI derived from 2,3,6,7-naphthalenetetracarboxylic dianhydride (2,3,6,7-NTDA) and MBCHA exhibited a very high glass transition temperature (Tg = 376 °C) and purple fluorescence from the S1(π,π*) state. However, its ΦPL value was lower than expected. A pronounced effect of fluorophore dilution using CBDA on the PL enhancement was observed. This is closely related to the planar structure of the 2,3,6,7-NTDA-based diimide units. By contrast, the counterpart using an 2,3,6,7-NTDA isomer, 1,4,5,8-NTDA, was virtually non-fluorescent, despite its sufficient dilution using CBDA. The PI film obtained using 3,3″,4,4″-p-terphenyltetracarboxylic dianhydride (TPDA) with a non-coplanar structure and MBCHA exhibited an intense blue fluorescence spectrum (ΦPL = 0.26) peaking at 434 nm. The dilution approach using CBDA enhanced its fluorescence up to a high ΦPL value of 0.41. Even when TPDA was combined with an aromatic diamine, 2,2′-bis(trifluoromethyl)benzidine (TFMB), the intense blue fluorescence was observed without charge-transfer fluorescence. A semi-cycloaliphatic PI derived from TFMB and a novel cycloaliphatic tetracarboxylic dianhydride, which was obtained from a hydrogenated trimellitic anhydride derivative and 4,4′-biphenol, was used as another host polymer for 9,10-bis(4-aminophenyl)anthracene (BAPA). The BAPA-incorporating PI film resulted in a significant PL enhancement with a considerably high ΦPL of 0.48. This PI film also had a relatively high Tg (265 °C). A reactive dye, N,N′-bis[4-(4-amino-3-methylbenzyl)-2-methylphenyl]-3,4,9,10-perylenetetracarboxydiimide, was harnessed as a fluorescence probe to explore transamidation between polyimide precursors in solution. Fluorescence ; Fluorophore ; Quantum yield ; Photoluminescence ; Photochemistry ; Materials science ; Polymer ; Quenching (fluorescence) ; Polyimide ; Benzidine ; Conjugated system ; Bathochromic shift ; Polymer chemistry ; Chemistry ; Organic chemistry ; Nanotechnology ; Optics ; Optoelectronics Synthesis and properties of polymers ; Silicone and Siloxane Chemistry ; Organic Electronics and Photovoltaics
Authors: Shaikha S. AlNeyadi | Mohammed Alhassani | Ali Aleissaee | Ibrahim Al Mujaini
Source: Preprints.org (preprint, 2023-12-27)
Field: Materials Science — Materials Chemistry

Pyrene-Derived Covalent Organic Framework Films: Advancements in Acid Vapor Detection Abstract: The expansion of global industries results in the release of harmful volatile acid vapors into the environment, posing a threat to various life forms. Hence, it&amp;#039;s crucial to prioritize the development of swift sensing systems capable of monitoring these volatile acid vapors. This initiative holds great importance in safeguarding a clean and safe environment. This paper presents the synthesis and characterization of pyrene-based covalent organic frameworks (COFs) demonstrating exceptional crystallinity, thermal stability, and intense fluorescence. Three COFs—PP-COF, PT-COF, and PE-COF—were synthesized, showcasing large surface areas and robust thermal stability up to 400 °C. The fluorescence properties and intramolecular charge transfer within these COFs were significantly influenced by their Schiff base bonding types and π-stacking degrees between COF layers. Notably, PE-COF emerged as the most fluorescent among the three COFs and exhibited exceptional sensitivity and rapid response as a fluorescent chemosensor for detecting HCl in solution. The reversible protonation of imine bonds in these COFs allowed for the creation of highly sensitive acid vapor sensors, showcasing a shift in spectral absorption while maintaining structural integrity. This research highlights the potential of COFs as reliable and reusable sensors for detecting harmful acid vapors, addressing environmental concerns arising from industrial activities. Covalent organic framework ; Stacking ; Imine ; Covalent bond ; Pyrene ; Fluorescence ; Thermal stability ; Intramolecular force ; Chemistry ; Protonation ; Crystallinity ; Materials science ; Chemical engineering ; Nanotechnology ; Photochemistry ; Organic chemistry Covalent Organic Framework Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Gas Sensing Nanomaterials and Sensors
Authors: Samuel H. Newman-Stonebraker | T. Judah Raab | Abigail G. Doyle
Source: Organometallics (article, 2023-12-13)
Field: Chemistry — Organic Chemistry

Catalyst Deactivation of a Monoligated CyJohnPhos-Bound Nickel(0) Complex Cross-coupling catalysts are prone to unproductive side reactivity that can limit their practical use in synthetic chemistry. A detailed understanding of these pathways and the conditions that enable them is important for reaction optimization and rational catalyst design. In this work, we report the off-cycle reactivity of a monoligated, CyJohnPhos-bound Ni<sup>0</sup> complex following product-forming reductive elimination. In the absence of substrate, free phosphine ligand, or π-accepting additives, dimerization of (CyJohnPhos)Ni<sup>0</sup> occurs, followed by C-P bond activation of the ligand to form a phosphido-bridged Ni<sup>0</sup>/Ni<sup>II</sup> dimer; both the Ni<sup>0</sup>/Ni<sup>0</sup> and Ni<sup>0</sup>/Ni<sup>II</sup> dimers were structurally characterized. Monomeric (CyJohnPhos)Ni<sup>0</sup> must be intercepted by substrate or free ligand to prevent irreversible dimerization and catalyst deactivation. Chemistry ; Nickel ; Catalysis ; Photochemistry ; Polymer chemistry ; Organic chemistry Organometallic Complex Synthesis and Catalysis ; Catalytic Cross-Coupling Reactions ; Asymmetric Hydrogenation and Catalysis
Authors: Grzegorz Vetter | Agata Białońska | Aneta Jezierska | Jarosław J. Panek | Ewa Pacholska‐Dudziak
Source: Chemical Communications (article, 2023-01-01)
Field: Materials Science — Materials Chemistry

Heterobimetallic 21,23-dimetallaporphyrin: activation of metal–metal interactions within the porphyrinoid macrocycle Two core-modified porphyrins containing metal atoms, namely platinum(II) or platinum(IV) and rhodium(III), in place of two NH units, have been obtained by a post-synthetic modification of the 21,23-ditelluraporphyrin. The products of the tellurium-to-metal exchange, 21-platina-23-rhodaporphyrins, incorporate rhodacyclopentadiene and platinacyclopentadiene units with the metal atoms facing each other. The two molecules exhibit different degrees of metal-metal interaction depending on the oxidation state of platinum, with the NBO bond order being 0.04 for platinum(IV) and 0.15 for platinum(II). Consistently, the Quantum Theory of Atoms in Molecules analysis revealed the presence of the bond determinant, the bond critical point, in the platinum(II) species, in contrast to the platinum(IV) congener. The two porphyrinoids are interconvertible in redox reactions. They both exhibit fluxional behaviour in solution, studied by <sup>1</sup>H NMR, involving alteration in the metal ion coordination sphere accompanied by the macrocyclic skeleton conformation change. Metal ; Crystallography ; Chemistry ; Materials science ; Organic chemistry Porphyrin and Phthalocyanine Chemistry ; Surface Chemistry and Catalysis ; Molecular Sensors and Ion Detection
Authors: Marvin Langlais | Nicolas Baulu | Séverin Dronet | Charlotte Dire | F. Jean-Baptiste-Dit-Dominique | David F. Albertini | Franck D’Agosto | Damien Montarnal | Christophe Boisson
Source: Angewandte Chemie (article, 2023-08-29)
Field: Materials Science — Biomaterials

Multiblock Copolymers Based on Highly Crystalline Polyethylene and Soft Poly(ethylene‐<i>co</i>‐butadiene) Segments: Towards Polyolefin Thermoplastic Elastomers Abstract Block copolymers based on polyethylene (PE) and ethylene butadiene rubber (EBR) were obtained by successive controlled coordinative chain transfer polymerization (CCTP) of a mixture of ethylene and butadiene (80/20) and pure ethylene. EBR‐ b ‐PE diblock copolymers were synthesized using the {Me 2 Si(C 13 H 8 ) 2 Nd(BH 4 ) 2 Li(THF)} 2 complex in combination with n‐butyl,n‐octyl magnesium (BOMAG) used as both the alkylating and chain transfer agent (CTA). Triblock and multiblock copolymers featuring highly semi‐crystalline PE hard segments and soft EBR segments were further obtained by the development of a bimetallic CTA, the pentanediyl‐1,5‐di(magnesium bromide) (PDMB). These new block copolymers undergo crystallization‐driven organization into lamellar structures and exhibit a variety of mechanical properties, including excellent extensibility and elastic recovery in the case of triblock and multiblock copolymers. Copolymer ; Thermoplastic elastomer ; Materials science ; Polymer chemistry ; Polyolefin ; Polyethylene ; Elastomer ; Ethylene ; Lamellar structure ; Polymerization ; Magnesium bromide ; Chemical engineering ; Polymer ; Magnesium ; Chemistry ; Composite material ; Organic chemistry ; Catalysis biodegradable polymer synthesis and properties ; Organometallic Complex Synthesis and Catalysis ; Advanced Polymer Synthesis and Characterization
Authors: Tobias Bens | Biprajit Sarkar
Source: Preprints.org (preprint, 2023-11-30)
Field: Chemistry — Organic Chemistry

Investigations on the Influence of Two Pyridyl-Mesoionic Carbene Constitutional Isomers on the Electrochemical and Spectroelectrochemical Properties of Group 6 Metal Carbonyl Complexes Metal complexes of mesoionic carbenes (MICs) of the triazolylidene-type and their derivatives have gained increasing attention in the fields of electrocatalysis and photochemistry. The redox-activity of these metal complexes is critical for their applications in both the aforementioned fields. Easy accessibility and modular synthesis open a wide field for the design of ligands, such as bidentate ligands. The combination of a MIC with a pyridyl unit in a bidentate ligand setup increases the π-acceptor properties of the ligands while retaining their strong σ-donor properties. The analogy with the well-established 2,2&amp;#039;-bipyridine ligand allows conclusions to be drawn about the influence of the mesoionic carbene (MIC) moiety in tetracarbonyl group 6 complexes in cyclic voltammetry and (spectro-)electrochemistry (SEC). However, the effects of the different connectivity in pyridyl-MIC ligands remains underexplored. Based on our previous studies, we present here a thorough investigation of the influence of the two different pyridyl-MIC constitutional isomers on the electrochemical and the UV-vis-NIR/IR/EPR spectroelectrochemical properties of group 6 carbonyl complexes. Moreover, the presented complexes were investigated for the electrochemical conversion of CO2 using two different working electrodes, providing a fundamental understanding of the influence of the electrode material in the precatalytic activation. Mesoionic ; Chemistry ; Carbene ; Moiety ; Denticity ; Ligand (biochemistry) ; Electrochemistry ; Cyclic voltammetry ; Photochemistry ; Combinatorial chemistry ; Metal ; Crystallography ; Stereochemistry ; Medicinal chemistry ; Electrode ; Physical chemistry ; Organic chemistry ; Catalysis N-Heterocyclic Carbenes in Organic and Inorganic Chemistry ; CO2 Reduction Techniques and Catalysts ; Catalytic Cross-Coupling Reactions
Authors: Carsten S. Kramer | Thines Kanagasundaram | Jessica Matthias | Klaus Kopka
Source: Pharmaceuticals (article, 2023-03-07)
Field: Chemistry — Organic Chemistry

Efforts toward PET-Activatable Red-Shifted Silicon Rhodamines and Silicon Pyronine Dyes Tracers for bimodal optical imaging and positron emission tomography unite multiple advantages in a single molecule. Their tumor-specific uptake can be visualized after their PET activation by radiofluorination via PET/CT or PET/MRI allowing for staging or therapy planning, while their non-radioactive moiety additionally facilitates the visualization of malignant tissue during intraoperative fluorescence-guided surgery or in histological assessments. The silicon-bridged xanthene core offers the opportunity for radiofluorination with SiFA isotope exchange to obtain a small-molecule, PET-activatable NIR dye that can be linked to different target vectors. Herein, we demonstrate for the first time the PET-activation of a fluorinated silicon pyronine, belonging to a class of low-molecular-weight fluorescence dyes with a large Stokes shift (up to 129 nm) and solvent-dependent NIR dye properties, with a successful radiochemical conversion of 70%. The non-fluorinated pyronine precursor is easily accessible by a three-step sequence from commercially starting material with a 12% overall yield. Moreover, a library of seven unusually functionalized (by approximately 15 nm), red-shifted silicon rhodamines were synthesized in three- to four-step sequences and the optical properties of the novel dyes were characterized. It was also shown that the synthesized silicon rhodamine dyes can be easily conjugated by amide bond formation or 'click-reaction' approaches. Xanthene ; Rhodamine ; Silicon ; Fluorescence ; Conjugated system ; Materials science ; Molecule ; Chemistry ; Photochemistry ; Optoelectronics ; Organic chemistry ; Optics ; Polymer Click Chemistry and Applications ; Advanced biosensing and bioanalysis techniques ; Nanoplatforms for cancer theranostics