journal
https://read.qxmd.com/read/38525656/chiral-spiro-tetrathiafulvalenes-synthesis-chiroptical-properties-conformational-issues-and-charge-transfer-complexes
#21
JOURNAL ARTICLE
Alexandra Bogdan, Ionut-Tudor Moraru, Nicolas Vanthuyne, Pascale Auban-Senzier, Ion Grosu, Narcis Avarvari, Flavia Pop
Within this work we have investigated spiro-based tetrathiafulvalenes (TTFs) obtained as mixtures of stereoisomers from racemic spiro[5.5]undeca-1,8-dien-3-one. Compared to previously described spiro-TTFs, enantiomeric and diastereoisomeric forms have been here separated by chiral HPLC and fully characterized both experimentally and theoretically. The two types of spiro-based chiral derivatives contain either one (2) or three (1) chiral centres out of each one is spiro-type. Experimental CD, supported by TD-DFT calculations, shows differences in the optical activity between the 1 and 2 and their intermediates...
March 25, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38523568/ferromagnetically-coupled-chromium-iii-dimer-shows-luminescence-and-sensitizes-photon-upconversion
#22
JOURNAL ARTICLE
Simon Trippmacher, Serhiy Demeshko, Alessandro Prescimone, Franc Meyer, Oliver S Wenger, Cui Wang
There has been much progress on mononuclear chromium(III) complexes featuring luminescence and photoredox activity, but dinuclear chromium(III) complexes have remained underexplored in these contexts until now. We identified a tridentate chelate ligand able to accommodate both meridional and facial coordination of chromium(III), to either access a mono- or a dinuclear chromium(III) complex depending on reaction conditions. This chelate ligand causes tetragonally distorted primary coordination spheres around chromium(III) in both complexes, entailing comparatively short excited-state lifetimes in the range of 400 to 800 ns in solution at room temperature and making photoluminescence essentially oxygen insensitive...
March 25, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38520385/the-utilization-of-metal-organic-frameworks-and-their-derivatives-composite-in-supercapacitor-electrodes
#23
JOURNAL ARTICLE
Qianwen Liu, Ruidong Li, Jie Li, Bingyue Zheng, Shuxin Song, Lihua Chen, Tingxi Li, Yong Ma
Up to now, the mainstream adoption of renewable energy has brought about substantial transformations in the electricity and energy sector. This shift has garnered considerable attention within the scientific community. Supercapacitors, known for their exceptional performance metrics like good charge/discharge capability, strong power density, as well as extended cycle longevity, have gained widespread traction across various sectors, including transportation and aviation. Metal-organic frameworks (MOFs) with unique traits including adaptable structure, highly customizable synthetic methods, and high specific surface area, have emerged as strong candidates for electrode materials...
March 23, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38519425/push-pull-bis-norbornadienes-for-solar-thermal-energy-storage
#24
JOURNAL ARTICLE
Roza R Weber, Charlotte N Stindt, Anne-Lot M J van der Harten, Ben L Feringa
The norbornadiene/quadricyclane (NBD/QC) photoswitch pair represents a promising system for application in molecular solar thermal energy storage (MOST). Often, the NBD derivatives have very limited overlap with the solar spectrum, and substitution to redshift the absorption leads to a decrease in the gravimetric energy density. Dimeric systems mitigate this factor because two switches can 'share' a substituent. Here, we present five new NBD dimers with red-shifted absorption spectra. One dimer features the most red-shifted absorption onsets (539 nm) and a significantly red-shifted absorption maximum (404 nm) for NBD systems reported so far, without compromising thermal half-life...
March 22, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38517333/boosting-electrocatalytic-n2%C3%A2-reduction-to-nh3-by-enhancing-n2-activation-via-interaction-between-au-nanoparticles-and-mil-101-fe-in-neutral-electrolytes
#25
JOURNAL ARTICLE
Ziyang Ni, Fengxiang Yin, Jie Zhang, Gideon Kofie, Guoru Li, Biaohua Chen, Pengju Guo, Liuliu Shi
Electrocatalytic nitrogen reduction reaction (NRR) has attracted much attention as a sustainable ammonia production technology, but it needs further exploration due to its slow kinetics and the existence of competitive side reactions. In this research, xAu/MIL-101(Fe) catalysts were obtained by loading gold nanoparticles (Au NPs) onto MIL-101(Fe) using a one-step reduction strategy. Herein, MIL-101(Fe), with high specific surface area and strong N2 adsorption capacity, is used as a support to disperse Au NPs to increase the electrochemical active surface area...
March 22, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38517291/designing-powerful-biindole-based-inherently-chiral-selectors-enhancing-enantiodiscrimination-by-core-functionalization-with-additional-coordination-elements
#26
JOURNAL ARTICLE
Sara Grecchi, Giorgia Bonetti, Elisa Emanuele, Jiří Ludvík, Lucie Koláčná, Alan Liška, Magdaléna Hromadová, Serena Arnaboldi, Roberto Cirilli, Patrizia R Mussini, Tiziana Benincori
Among inherently chiral selectors of axial stereogenicity, usually resulting in very good enantiodiscrimination performances, the biindole-based family has the additional advantage of very easy functionalization of the two nitrogen atoms with a variety of substituents with desirable properties. Aiming to evaluate the possibility of exploiting such feature to enhance the enantiodiscrimination ability of the archetype structure, a series of three inherently chiral monomers were designed and synthesized, characterised by a 2,2'-biindole atropisomeric core conjugated to bithiophene wings enabling fast and regular electrooligomerization, and functionalised at the nitrogen atoms with an ethyl, a methoxyethyl, or a hydroxyethyl substituent...
March 22, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38517288/perfect-polar-alignment-of-parallel-beloamphiphile-layers-improved-structural-design-bias-realized-in-ferroelectric-crystals-of-the-novel-methoxyphenyl-series-of-acetophenone-azines
#27
JOURNAL ARTICLE
Harmeet Bhoday, Nathan Knotts, Rainer Glaser
An improved design is described for ferroelectric crystals and implemented with the "methoxyphenyl series" of acetophenone azines, (MeO-Ph, Y)-azines with Y=F (1), Cl (2), Br (3), or I (4). The crystal structures of these azines exhibit polar stacking of parallel beloamphiphile monolayers (PBAMs). Azines 1, 3, and 4 form true racemates whereas chloroazine 2 crystallizes as a kryptoracemate. Azines 1-4 are helical because of the N-N bond conformation. In true racemates the molecules of opposite helicity (M and P) are enantiomers A(M) and A*(P) while in kryptoracemates they are diastereomers A(M) and B*(P)...
March 22, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38517282/flowmicro-in-line-analysis-driven-design-of-reactions-mediated-by-unstable-intermediates-flash-monitoring-approach
#28
JOURNAL ARTICLE
Yosuke Ashikari, Rikako Yoshioka, Yuya Yonekura, Dong-Eun Yoo, Kazuhiro Okamoto, Aiichiro Nagaki
Invited for the cover of this issue is the group of Aiichiro Nagaki, Yosuke Ashikari and co-workers at Hokkaido University. The image depicts flash monitoring of reactive intermediate in a flow microreactor. Read the full text of the article at 10.1002/chem.202303774.
March 22, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38517200/structure-property-relationships-for-potential-inversion-from-electron-acceptors-based-on-thiophene-fused-triptycene-quinones-1-4-diketones-and-their-malononitrile-adducts
#29
JOURNAL ARTICLE
Stefan Warrington, Stephanie Montanaro, Mark R J Elsegood, Gary S Nichol, Iain A Wright
The synthesis and properties of a series of 11,11,12,12-tetracyano-9,10-anthraquinodimethane (TCAQ) inspired electron acceptors based on thiophene-fused quinone and triptycene motifs is presented. This has yielded insights into structure-property relationships for establishing and modulating simultaneous two electron reduction processes in TCAQ analogues. These new compounds were synthesised using a Friedel-Crafts acylation between triptycene and thiophene-3,4-dicarbonyl chloride. Isomeric para-quinones featuring a [c]-fused thiophene on one side and a β,β- or α,β-fused triptycene on the other were isolated alongside a thiophene-3,4-diketone which bears two triptycene fragments...
March 22, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38516955/synthesis-and-structural-revision-of-a-natural-tetrasaccharide-from-starfish-asterias-rollestoni-bell
#30
JOURNAL ARTICLE
Ao Liu, Longwei Gao, Xintong Tang, Xudong Yang, Xianglai Liu, Weijia Xie, Jin Qi, Wei Li
Starfish provide important saponins with diverse bioactivities as the secondary metabolites, among which 2-O-glycosylated glycosides are commonly found. Preparation of those 1,2-trans 2-O-glycosylated glycosides usually relies on 2-O-acyl participation requiring the selective installation and cleavage of 2-O-acyl groups. A convergent synthesis using 2-O-glycosylated oligosaccharide donors would be more straightforward but also pose greater challenges. Herein, we report a convergent synthesis of a distinctive tetrasaccharide isolated from starfish Asterias rollestoni Bell...
March 22, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38515307/aunp-mil-88b-nh2-nanocomposite-for-the-valorization-of-nitroarene-by-green-catalytic-hydrogenation
#31
JOURNAL ARTICLE
Sorraya Najma Kinza Lelouche, Ignacio Daniel Lemir, Catalina Biglione, Tim Craig, Sara Bals, Patricia Horcajada
The efficiency of a catalytic process is assessed based on conversion, yield, and time effectiveness. However, these parameters are insufficient for evaluating environmentally sustainable research. As the world is urged to shift towards green catalysis, additional factors such as reaction media, raw material availability, sustainability, waste minimization and catalyst biosafety, need to be considered to accurately determine the efficacy and sustainability of the process. By combining the high porosity and versatility of metal organic frameworks (MOFs) and the activity of gold nanoparticles (AuNPs), efficient, cyclable and biosafe composite catalysts can be achieved...
March 21, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38512657/development-of-biocompatible-cu-i-microdevices-for-bioorthogonal-uncaging-and-click-reactions
#32
JOURNAL ARTICLE
Melissa van de L'Isle, Stephen Croke, Teresa Valero, Asier Unciti-Broceta
Transition-metal-catalysed bioorthogonal reactions emerged a decade ago as a novel strategy to implement spatiotemporal control over enzymatic functions and pharmacological interventions. The use of this methodology in experimental therapy is driven by the ambition of improving the tolerability and PK properties of clinically-used therapeutic agents. The preclinical potential of bioorthogonal catalysis has been validated in vitro and in vivo with the in situ generation of a broad range of drugs, including cytotoxic agents, anti-inflammatory drugs and anxiolytics...
March 21, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38512639/diastereoselective-dearomatizing-cyclizations-of-5-arylpentan-2-ones-by-samarium-diiodide-a-computational-analysis
#33
JOURNAL ARTICLE
Luca Steiner, Andreas Achazi, Anne-Marie Kelterer, Beate Paulus, Hans-Ulrich Reissig
This study analyzes the samarium diiodide-promoted cyclizations of 5-arylpentan-2-ones to dearomatized bicyclic products utilizing density functional theory. The reaction involves a single electron transfer to the carbonyl group, which occurs synchronously with the rate determining cyclization event, and a second subsequent proton-coupled electron transfer. These redox reactions are accurately computed employing small core pseudo potentials explicitly involving all f-electrons of samarium. Comparison of the energies of the possible final products rules out thermodynamic control of the observed regio- and diastereoselectivities...
March 21, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38511968/pressure-induced-structural-optical-and-magnetic-modifications-in-lanthanide-smms
#34
JOURNAL ARTICLE
Fabrice Pointillart, Boris Le Guennic, Olivier Cador
Lanthanide Single-Molecule Magnets are fascinating objects that break magnetic performance records with observable magnetic bistability at the boiling temperature of liquid nitrogen, paving the way for potential applications in high-density data storage. The switching of lanthanide SMM has been successfully achieved using several external stimuli such as redox reaction, pH titration, light irradiation or solvation/desolvation thanks to the high sensitivity of the magnetic anisotropy to any structural change in the lanthanide surrounding...
March 21, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38507278/solid-state-glass-nanopipette-modification-and-application
#35
JOURNAL ARTICLE
Hao Wang, Haoran Tang, Xia Qiu, Yongxin Li
Solid-state glass nanopipettes provide a promising confined space that offers several advantages such as controllable size, simple preparation, low cost, good mechanical stability, and good thermal stability. These advantages make them an ideal choice for various applications such as biosensors, DNA sequencing, and drug delivery. In this review, we first delve into the functionalized nanopipettes for sensing various analytes and the methods used to develop detection means with them. Next, we provide an in-depth overview of the advanced functionalization methodologies of nanopipettes based on diversified chemical kinetics...
March 20, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38507249/scaffold-oriented-asymmetric-catalysis-conformational-modulation-of-transition-state-multivalency-during-a-catalyst-controlled-assembly-of-a-pharmaceutically-relevant-atropisomer
#36
JOURNAL ARTICLE
Nicolò Tampellini, Brandon Mercado, Scott J Miller
A new class of superbasic, bifunctional peptidyl guanidine catalysts is presented, which enables the organocatalytic, atroposelective synthesis of axially chiral quinazolinediones. Computational modeling unveiled the conformational modulation of the catalyst by a novel phenyl urea N-cap, that preorganizes the structure into the active, folded state. A previously unanticipated noncovalent interaction involving a difluoroacetamide acting as a hybrid mono- or bidentate hydrogen bond donor emerged as a decisive control element inducing atroposelectivity...
March 20, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38507133/predisposition-in-dynamic-covalent-chemistry-the-role-of-non-covalent-interactions-in-the-assembly-of-tetrahedral-boronate-cages
#37
JOURNAL ARTICLE
Manuel Rondelli, Jorge Pasán, Israel Fernández, Tomás Martín
Directional bonding strategies guide the design of complex molecular architectures, yet challenges arise due to emergent behavior. Rigid structures face geometric constraints and sensitivity to mismatches, hindering the efficient assembly of molecular organic cages (MOCs). Harnessing intramolecular non-covalent interactions offers a promising solution, broadening geometrical possibilities and enhancing adaptability to boost assembly yields. However, identifying these interactions remains challenging, with their full potential sometimes latent until final assembly...
March 20, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38506412/fingerprints-of-chalcogen-bonding-revealed-through-77se-nmr
#38
JOURNAL ARTICLE
Thomas Fellowes, Marc Antoine Sani, Jonathan White
77Se-NMR is used to characterise several chalcogen bonded complexes of derivatives of the organoselenium drug ebselen, exploring a range of electron demand. NMR titration experiments support the intuitive understanding that chalcogen bond donors bearing more electron withdrawing substituents give rise stronger chalcogen bonds. The chemical shift of the selenium nucleus is also shown to move upfield as it participates in a chalcogen bond. Solid-state NMR is used to explore chalcogen bonding in co-crystals...
March 20, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38506349/a-ph-sensitive-double-chromophore-fluorescent-dye-for%C3%A2-live-tracking-of-lipophagy
#39
JOURNAL ARTICLE
Pascal M Engelhardt, Matteo Veronese, Alpay A Eryigit, Anushka Das, Alexander T Kaczmarek, Elena I Rugarli, Hans-Günther Schmalz
Lipid droplet (LD) degradation provides metabolic energy and important building blocks for various cellular processes. The two major LD degradation pathways include autophagy (lipophagy), which involves delivery of LDs to autolysosomes, and lipolysis, which is mediated by lipases. While abnormalities in LD degradation are associated with various pathological disorders, our understanding of lipophagy is still rudimentary. In this study, we describe the development of a lipophilic dye containing two fluorophores, one of which is pH-sensitive and the other pH-stable...
March 20, 2024: Chemistry: a European Journal
https://read.qxmd.com/read/38506263/64-cu-tumor-labeling-with-hexadentate-picolinic-acid-based-bispidine-immunoconjugates
#40
JOURNAL ARTICLE
Manja Kubeil, Christin Neuber, Miriam Starke, Claudia Arndt, Liliana R Loureiro, Lydia Hoffmann, Anja Feldmann, Michael Bachmann, Jens Pietzsch, Peter Comba, Holger Stephan
Discussed are two picolinate appended bispidine ligands (3,7-diazabicyclo[3.3.1]nonane derivatives) in comparison with an earlier described bis-pyridine derivative, which are all known to strongly bind CuII. The radiopharmacological characterization of the two isomeric bispidine complexes includes quantitative labeling with 64CuII at ambient conditions with high radiochemical purities and yields (molar activities > 200 MBq/nmol). Challenge experiments in presence of EDTA, cyclam, human serum and SOD demonstrate high stability and inertness of the 64Cu-bispidine complexes...
March 20, 2024: Chemistry: a European Journal
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