The Role of Lysozyme in the Formation of Bioinspired Silicon Dioxide
Chemistry. 2024 May 9:e202401249. doi: 10.1002/chem.202401249. Online ahead of print.ABSTRACTSeveral organisms are able to polycondensate tetraoxosilicic(IV) acid to form silicon (IV) dioxide using polycationic molecules. According to an earlier mechanistic proposal, these molecules undergo a phase-separation and recent experimental evidence appears to confirm this model. At the same time, polycationic proteins like lysozyme can also promote polycondensation of silicon (IV) dioxide, and they do so under conditions that are not compatible with liquid-liquid phase separation. In this manuscript we investigate this conundrum ...
Source: Chemistry - May 9, 2024 Category: Chemistry Authors: Marina Macchiagodena Marco Fragai Angelo Gallo Marco Pagliai Enrico Ravera Source Type: research
Synthesis of (Hetero)biaryls via Nickel Catalyzed Reductive Cross-Electrophile Coupling Between (Hetero)aryl Iodides and Bromides
Chemistry. 2024 May 9:e202401552. doi: 10.1002/chem.202401552. Online ahead of print.ABSTRACT(Hetero)biaryls are fundamental building blocks in the pharmaceutical industry and rapid access to these scaffolds is imperative for the success of numerous medicinal chemistry campaigns. Herein, a highly general, mild, and chemoselective reductive cross-electrophile coupling between (hetero)aryl iodides and heteroaryl bromides is reported. By employing more reactive (hetero)aryl halides, a broad range of successful substrates (45 examples) were identified. The reaction was also found to be chemoselective for C(sp2)-C(sp2) bond for...
Source: Chemistry - May 9, 2024 Category: Chemistry Authors: Richard Robert Surgenor Hyelee Lee Source Type: research
Post-synthetic Metalation on the Ionic TiO2 Surface to Enhance Metal-CO2 Interaction During Photochemical CO2 Reduction
Chemistry. 2024 May 7:e202400428. doi: 10.1002/chem.202400428. Online ahead of print.ABSTRACTDuring the photochemical CO2 reduction reaction, CO2 adsorption on the catalyst's surface is a crucial step where the binding mode of the [metal-CO2] adduct directs the product selectivity and efficiency. Herein, an ionic TiO2 nanostructure stabilized by polyoxometalates (POM), ([POM]x@TiO2), is prepared and the sodium counter ions present on the surface to balance the POMs' charge are replaced with copper(II) ions, (Cux[POM]@TiO2). The microscopic and spectroscopic studies affirm the copper exchange without altering the TiO2 core ...
Source: Chemistry - May 8, 2024 Category: Chemistry Authors: Laxmikanta Kanti Mallick Krishna Samanta Biswarup Chakraborty Source Type: research
Ruthenium(II) polypyridyl complexes with benzoxazole derivatives and non-innocent ligands as effective antioxidants in human neuroblasts
Chemistry. 2024 May 8:e202400834. doi: 10.1002/chem.202400834. Online ahead of print.ABSTRACTRuthenium(II) polypyridyl complexes continue to raise increasing interest for the encouraging results in several biomedical areas. Considering their vast chemical-physical repertoire, in particular the possibility to switch from the sensitization of reactive oxygen species (ROS) to ROS-scavenging abilities by tuning the nature of their ligands, it is therefore surprising that their potential as antioxidants has not been largely investigated so far. Herein, we explored the antioxidant behaviour of the novel ruthenium compound [Ru(db...
Source: Chemistry - May 8, 2024 Category: Chemistry Authors: Gina Elena Giacomazzo Luca Conti Daniele Paderni Patrick Severin Sfragano Lorenzo Quadrini Eleonora Macedi Camilla Andreini Chiara Donati Caterina Bernacchioni Gloria Mulas Barbara Valtancoli Ilaria Palchetti Luca Giorgi Vieri Fusi Francesca Cencetti Clau Source Type: research
Telescoped Flow Synthesis of Azacyclic Scaffolds Exploiting the Chromoselective Photolysis of Vinyl Azides and Azirines
Chemistry. 2024 May 8:e202401491. doi: 10.1002/chem.202401491. Online ahead of print.ABSTRACTAn efficient chromoselective photochemical process is presented for the synthesis of 2H-azirines and 1,3-diazabicylo[3.1.0]hex-3-enes from readily available vinyl azides. The method exploits continuous flow photochemistry to enable the safe consumption of the hazardous azide group and provides uniform irradiation using high-power LEDs at 365-450 nm. Additionally, a scaled telescoped process has been developed providing access to drug-like 1,6-dihydropyrimidines and pyrimidines via integrated ring-expansion and oxidation reactions. ...
Source: Chemistry - May 8, 2024 Category: Chemistry Authors: Ruairi Crawford Marcus Baumann Source Type: research
The Complete Assessment of Small Molecule and Peptidomimetic Inhibitors of Sortase A Towards Antivirulence Treatment
Chemistry. 2024 May 8:e202401103. doi: 10.1002/chem.202401103. Online ahead of print.ABSTRACTThis review covers the most recent advances in the development of inhibitors for the bacterial enzyme sortase A (SrtA). Sortase A (SrtA) is a critical virulence factor present ubiquitously in Gram-positive bacteria of which many are considered pathogenic. Sortases are key enzymes regulating bacterial adherence to host cells, by anchoring extracellular matrix-binding proteins to the bacterial outer cell wall. By targeting virulence factors, effective treatment can be achieved, without inducing antibiotic resistance to the treatment....
Source: Chemistry - May 8, 2024 Category: Chemistry Authors: Jordi C J Hintzen Helal Abujubara Daniel Tietze Alesia Tietze Source Type: research
Advancements in Interfacial Engineering for Perovskite Light-Emitting Diodes
Chemistry. 2024 May 8:e202400372. doi: 10.1002/chem.202400372. Online ahead of print.ABSTRACTPerovskite light-emitting diodes (PeLEDs) have gained significant attention due to their promising optoelectronic properties and potential applications in the fields of lighting and display devices. Despite their potential, PeLEDs face challenges related to stability, high turn-on voltage, and low external quantum efficiency (EQE) which has restricted their broad acceptance. Most research efforts have predominantly focused on refining the properties of the perovskite films. However, it is becoming more apparent that interfacial lay...
Source: Chemistry - May 8, 2024 Category: Chemistry Authors: Jaeho Lee Zixi Xie Lianzhou Wang Jingwei Hou Source Type: research
Visible-Light-Driven Germyl Radical Generation via EDA-Catalyzed ET-HAT Process
Chemistry. 2024 May 8:e202401546. doi: 10.1002/chem.202401546. Online ahead of print.ABSTRACTWe have established a facile and efficient protocol for the generation of germyl radicals by employing photo-excited electron transfer (ET) in an electron donor-acceptor (EDA) complex to drive hydrogen-atom transfer (HAT) from germyl hydride (R3GeH). Using a catalytic amount of EDA complex of commercially available thiol and benzophenone derivatives, the ET-HAT cycle smoothly proceeds simply upon blue-light irradiation without any transition metal or photocatalyst. This protocol also affords silyl radical from silyl hydride.PMID:38...
Source: Chemistry - May 8, 2024 Category: Chemistry Authors: Kaito Yoshizawa Bi-Xiao Li Taro Matsuyama Chao Wang Masanobu Uchiyama Source Type: research
An Efficient and Scalable "Second Generation" Total Synthesis of the Marine Polyketide Limaol Endowed with Antiparasitic Activity
Chemistry. 2024 May 8:e202401429. doi: 10.1002/chem.202401429. Online ahead of print.ABSTRACTThe cluster of four skipped exo-methylene substituents on the "northern" wing of limaol renders this marine natural product unique in structural terms. This arguably non-thermodynamic array gains kinetic stability by populating conformations which impede isomerization to a partly or fully conjugated polyene. This analysis suggested that the difficulties encountered in our first total synthesis had not been caused by an overly fragile character of this unusual substructure; rather, an unfavorable steric microenvironment about the sp...
Source: Chemistry - May 8, 2024 Category: Chemistry Authors: Stephan N Hess Alois F ürstner Source Type: research
Photo-Induced Generation of Oxygenated Quaternary Centers via EnT Enabled Singlet O2 Addition to C3-Maleimidated Quinoxaline: A Reagent-Less Approach
Chemistry. 2024 May 8:e202400219. doi: 10.1002/chem.202400219. Online ahead of print.ABSTRACTDemonstrated here is an external photo-sensitizer-free (auto-sensitized) singlet oxygen-enabled solvent-dependent tertiary hydroxylation and aryl-alkyl spiro-etherification of C3-maleimidated quinoxalines. Such "reagent-less" photo-oxygenation at Csp3-H and etherification involving Csp3-H/Csp2-H are unparalleled. Possibly, the highly π-conjugated N-H tautomer allows the substrate to get excited by irradiation, and subsequently, it attains the triplet state via ISC. This excited triplet-state sensitized molecule then transfers its ...
Source: Chemistry - May 8, 2024 Category: Chemistry Authors: Subhendu Ghosh Tamanna Khandelia Anjali Mahadevan Pritishree Panigrahi Piyush Kumar Raju Mandal Deepjyoti Boruah Sugumar Venkataramani Bhisma K Patel Source Type: research
Chirality Sensing of Cryptochiral Guests with Prism[n]arenes
In this study, we demonstrate that the formation of host-guest complexes between cryptochiral molecules and planar chiral prismarenes triggers electronic circular dichroism (ECD) signals via host-guest complexation-induced chirality amplification. The absolute configuration of the most stable chiral macrocyclic host-guest complex has been established by resorting to both exciton model and DFT computations. Furthermore, we demonstrated that this supramolecular chirality sensing system can be employed to determine the enantiomeric composition of scalemic mixtures by measuring the ECD bands intensity. The information describe...
Source: Chemistry - May 8, 2024 Category: Chemistry Authors: Paolo Della Sala Umberto Calice Veronica Iuliano Silvano Geremia Neal Hickey Sandra Belviso Francesco Ferdinando Summa Guglielmo Monaco Carmine Gaeta Stefano Superchi Source Type: research
UoC-7: A Bimetallic K-Zn-MOF with an Anionic Framework Based on Fluorinated Trimesate Ligands Exhibiting a Large CO2 Uptake
Chemistry. 2024 May 8:e202400445. doi: 10.1002/chem.202400445. Online ahead of print.ABSTRACTIn solvothermal reactions of Zn(NO3)2×6H2O with K(H2mF-BTC) or K(H2dF-BTC) in DMF/ethanol or DMA/ethanol solvent mixtures, single crystals of the MOFs UoC-7(1F) and UoC-7(2F) were obtained crystallizing in the hexagonal space group P63/m (no. 176) (H3BTC: 1,3,5-benzenetricarboxylic acid; mF-/dF: mono-/difluoro; DMF: N,N-dimethylformamide; DMA: N,N-dimethylacetamide; UoC: University of Cologne). According to the general composition [(CH3)2NH2][K2Zn3(mF-/dF-BTC)3(H2O)]×solvent, UoC-7 consists of an anionic bimetallic framework. The...
Source: Chemistry - May 8, 2024 Category: Chemistry Authors: Susanna Wenzel Aime é E L Cammiade Ronja K Christoffels Sean S Sebastian Tim Mattick Uwe Ruschewitz Source Type: research
Mixed Tin Valence in the Tin(II/IV)-Nitridophosphate Sn3P8N16
Chemistry. 2024 May 8:e202401428. doi: 10.1002/chem.202401428. Online ahead of print.ABSTRACTSn3P8N16 combines the structural versatility of nitridophosphates and Sn within one compound. It was synthesized as dark gray powder in a high-pressure high-temperature reaction at 800 °C and 6 GPa from Sn3N4 and P3N5. The crystal structure was elucidated from single-crystal diffraction data (space group C2/m (no. 12), a = 12.9664(4), b = 10.7886(4), c = 4.8238(2) Å, β = 109.624(1)°) and shows a 3D-network of PN4 tetrahedra, incorporating Sn in oxidation states +II and +IV. The Sn cations are located within eight-membered rings...
Source: Chemistry - May 8, 2024 Category: Chemistry Authors: Sebastian J Ambach Aylin Koldemir Kristian Witthaut Sandra Kreiner Thomas Br äuniger Rainer P öttgen Wolfgang Schnick Source Type: research
Unusual Stability of an end-on Superoxido Copper(II) Complex under Ambient Conditions
Chemistry. 2024 May 8:e202401634. doi: 10.1002/chem.202401634. Online ahead of print.ABSTRACTSuperoxido copper complexes play an important role as usually short-lived intermediates in biology and chemistry. The unusual stability of an end-on superoxido copper complex observed in an oxygen-enhanced atom transfer radical polymerization (ATRP) led to a detailed mechanistic investigation of the formation of [CuII(Me6tren)(O2•-)]+ (Me6tren = tris(2-dimethyl-aminoethyl)amine) under ambient conditions. The persistence of the superoxido copper complex could be explained by a reaction cycle including the peroxido complex [(Me6tre...
Source: Chemistry - May 8, 2024 Category: Chemistry Authors: Chiara Eleonora Campi Konstantinos Parkatzidis Athina Anastasaki Siegfried Schindler Source Type: research
Effect of Br ønsted Acids on the Activation of Mixed Anhydride/Mixed Carbonic Anhydride and C-Terminal-Free N-Methylated Peptide Synthesis in a Micro-Flow Reactor
In this study, we investigated the amidation of mixed (carbonic) anhydride in the presence of a base and/or Brønsted acids. The use of NMI·HCl significantly improved the conversion of the mixed carbonic anhydride, while expediting nucleophilic attacks on the desired carbonyl group. In contrast, in the case of mixed carbonic anhydrides, neither the conversion nor the desired nucleophilic attack improved significantly. We developed a C-terminus-free N-methylated peptide synthesis method using mixed carbonic anhydrides in a micro-flow reactor. Fourteen N-alkylated peptides were synthesized in moderate to high yields (55-99%...
Source: Chemistry - May 8, 2024 Category: Chemistry Authors: Ting-Ho Chen Akira Ando Otoka Shamoto Shinichiro Fuse Source Type: research
