Room Temperature Phosphorescence in Crystalline Iodinated Eumelanin Monomer
We report the room temperature phosphorescence upon iodination on a crystalline eumelanin monomer with shielded hydroxyl moieties, ethyl 5,6-dimethoxyindole-2-carboxylate (DMICE). Ultrafast intersystem crossing (ISC) is observed in the iodinated (IDMICE) as well as brominated (BDMICE) analogues of the eumelanin monomer derivative in solution. The triplet quantum yields (Ο•T) and intersystem crossing rates (kISC) of the halogenated eumelanin derivatives are πœ™π΅π·π‘€πΌπΆπΈπ‘‡ =25.4Β±1.1%; π‘˜πΌπ‘†πΆπ΅π·π‘€πΌπΆπΈ=1.95Γ—109 s-1 and πœ™πΌπ·π‘€πΌπΆπΈπ‘‡ =59.1Β±1.6%; π‘˜πΌπ‘†πΆπ...
Source: Chemistry - March 19, 2024 Category: Chemistry Authors: Kavya Vinod Sohan D Jadhav Mahesh Hariharan Source Type: research

Unravelling the Role of Free Radicals in Photocatalysis
Chemistry. 2024 Mar 19:e202400001. doi: 10.1002/chem.202400001. Online ahead of print.ABSTRACTFree radicals are increasingly recognized as active intermediate reactive species that can participate in various redox processes, significantly influencing the mechanistic pathways of reactions. Numerous researchers have investigated the generation of one or more distinct photogenerated radicals, proposing various hypotheses to explain the reaction mechanisms. Notably, recent research has demonstrated the emergence of photogenerated radicals in innovative processes, including organic chemical reactions and the photocatalytic diss...
Source: Chemistry - March 19, 2024 Category: Chemistry Authors: Yao Chen Shuyang Xu Chun Fang Wen Hanyun Zhang Ting Zhang Fujian Lv Yinghong Yue Zhenfeng Bian Source Type: research

From Criegee to Breslow: How Ο€-Donors Steer the Route of Olefin Ozonolysis
Chemistry. 2024 Mar 19:e202400026. doi: 10.1002/chem.202400026. Online ahead of print.ABSTRACTWhile Ο€-bonds typically undergo cycloaddition with ozone, resulting in the release of much-noticed carbonyl O-oxide Criegee intermediates, lone-pairs of electrons tend to selectively accept a single oxygen atom from O3, producing singlet dioxygen. We questioned whether the introduction of potent electron-donating groups, akin to N-heterocyclic olefins, could influence the reactivity of double bonds - shifting from cycloaddition to oxygen atom transfer or generating lesser-known, yet stabilized, donor-substituted Criegee intermedi...
Source: Chemistry - March 19, 2024 Category: Chemistry Authors: Serhii Medvedko Jan Philipp Wagner Source Type: research

Bimodal glycosyl donors as an emerging approach towards a general glycosylation strategy
Chemistry. 2024 Mar 19:e202400399. doi: 10.1002/chem.202400399. Online ahead of print.ABSTRACTOrganic synthesis provides an accessible route to preparative scale biological glycans, although schemes to access these complex structures are often complicated by preparation of multiple monosaccharide building blocks. Bimodal glycosyl donors capable of forming both Ξ±- and Ξ²-anomers selectively, are an emerging tactic to reduce the required number of individual synthetic components in glycan construction. This review discusses examples of bimodal donors in the literature, and how they achieve their stereocontrol for both anome...
Source: Chemistry - March 19, 2024 Category: Chemistry Authors: Matthew E Warnes Martin Anthony Fascione Source Type: research

Interfacial Bonding Induced Charge Transfer in Two-dimensional Amorphous MoO3-x/Graphdiyne Oxide Non-van der Waals Heterostructures for Dominant SERS Enhancement
Chemistry. 2024 Mar 19:e202400227. doi: 10.1002/chem.202400227. Online ahead of print.ABSTRACTTwo-dimensional semiconductor-based nanomaterials have shown to be an effective substrate for Surface-enhanced Raman Scattering (SERS) spectroscopy. However, the enhancement factor (EF) tends to be relatively weak compared to that of noble metals and does not allow for trace detection of molecules. In this work, we report the successful preparation of two-dimensional (2D) amorphous non-van der Waals heterostructures MoO3-x/GDYO nanomaterials using supercritical CO2. Due to the synergistic effect of the localized surface plasmon re...
Source: Chemistry - March 19, 2024 Category: Chemistry Authors: Jian Yang Pengfei Yan Zongwei Chen Wei Liu Zhaoxi Liu Zijian Ma Qun Xu Source Type: research

Synthesis of Superbulky Amide Ligands by Addition of Polar Reagents to Sila-Imine
Chemistry. 2024 Mar 19:e202400715. doi: 10.1002/chem.202400715. Online ahead of print.ABSTRACTThe chemistry of extremely bulky amide ligands is troubled by difficulties in deprotonation of the parent amine. As an alternative route to superbulky amide reagents, the addition of polar reagents to a sila-imine has been investigated. Attempts to synthesize the superbulky amide anion (tBu3Si)2N- by addition of tBuLi to tBu2Si=N(SitBu3) failed and gave tBu3Si(tBu2HSi)NLi and isobutene. Reaction of the sila-imine with KOtBu successfully led to tBu3Si[tBu2(tBuO)Si]NK which crystallized as a separated ion-pair. Reaction with the sli...
Source: Chemistry - March 19, 2024 Category: Chemistry Authors: Christian Kn ΓΌpfer Lukas Klerner Michael Raucheisen Jens Langer Sjoerd Harder Source Type: research

The divalent lanthanoid triflates Ln(CF3SO3)2(CH3CN) (Ln = Sm, Eu): Structure, luminescence, and magnetism
Chemistry. 2024 Mar 19:e202400462. doi: 10.1002/chem.202400462. Online ahead of print.ABSTRACTThe reaction of the trivalent lanthanide triflates Ln(OTf)3 (Ln = Sm, Eu; OTf = CF3SO3-) with the respective metals in acetonitrile leads to the Ln(II)-triflates Eu(OTf)2(CH3CN) (monoclinic, P21/n, Z = 4, a = 1053.54(1), b = 610.28(5), c = 1946.92(2) pm, b = 98.611(4)) and Sm(OTf)2(CH3CN) (monoclinic, P21/n, Z = 4, a = 1054.41(4), b = 612.16(2), c = 1952.65(7) pm, b = 98.524(2)). The isotypic strontium compound Sr(OTf)2(CH3CN) (monoclinic, P21/n, Z = 4, a = 1056.39(5), b = 610.05(3), c = 1950.1(1) pm, b = 98.900(2)Β°) has been obt...
Source: Chemistry - March 19, 2024 Category: Chemistry Authors: Niko Flosbach Bertold Rasche Leonhard Rochels Sabrina Disch Claudia Wickleder Matthias Adlung Pia Fischer Mathias Wickleder Source Type: research

Genetically Fusing Order-Promoting and Thermoresponsive Building Blocks to Design Hybrid Biomaterials
Chemistry. 2024 Mar 19:e202400582. doi: 10.1002/chem.202400582. Online ahead of print.ABSTRACTThe unique biophysical and biochemical properties of intrinsically disordered proteins (IDPs) and their recombinant derivatives, intrinsically disordered protein polymers (IDPPs) offer opportunities for producing multistimuli-responsive materials; their sequence-encoded disorder and tendency for phase separation facilitate the development of multifunctional materials. This review highlights the strategies for enhancing the structural diversity of elastin-like polypeptides (ELPs) and resilin-like polypeptides (RLPs), and their self...
Source: Chemistry - March 19, 2024 Category: Chemistry Authors: Sai S Patkar Bin Wang Ana Maria Mosquera Kristi L Kiick Source Type: research

Achieving Dendrite-Free Zinc Metal Anodes via Molecule Anchoring and lon-Transport pumping
Chemistry. 2024 Mar 19:e202400567. doi: 10.1002/chem.202400567. Online ahead of print.ABSTRACTThe potential for scale-up application has been acknowledged by researchers for rechargeable aqueous zinc-ion batteries (ZIBs). Nonetheless, the progress of the development is significantly impeded due to the instability of the interface between the zinc anode and electrolyte. Herein, efficient and environmentally benign valine (Val) were introduced as aqueous electrolyte additive to stabilize the electrode/electrolyte interface (EEI) via functional groups in additive molecules, thus achieving reversible dendrite-free zinc anode. ...
Source: Chemistry - March 19, 2024 Category: Chemistry Authors: Zhongqian He Huaming Yu Dongping Chen Xuyan Ni Chunshuang Yan Chade Lv Yuejiao Chen Source Type: research

Room Temperature Phosphorescence in Crystalline Iodinated Eumelanin Monomer
We report the room temperature phosphorescence upon iodination on a crystalline eumelanin monomer with shielded hydroxyl moieties, ethyl 5,6-dimethoxyindole-2-carboxylate (DMICE). Ultrafast intersystem crossing (ISC) is observed in the iodinated (IDMICE) as well as brominated (BDMICE) analogues of the eumelanin monomer derivative in solution. The triplet quantum yields (Ο•T) and intersystem crossing rates (kISC) of the halogenated eumelanin derivatives are πœ™π΅π·π‘€πΌπΆπΈπ‘‡ =25.4Β±1.1%; π‘˜πΌπ‘†πΆπ΅π·π‘€πΌπΆπΈ=1.95Γ—109 s-1 and πœ™πΌπ·π‘€πΌπΆπΈπ‘‡ =59.1Β±1.6%; π‘˜πΌπ‘†πΆπ...
Source: Chemistry - March 19, 2024 Category: Chemistry Authors: Kavya Vinod Sohan D Jadhav Mahesh Hariharan Source Type: research

Synthesis, Reactivity, and Complexation with Fe(0) of a Tight-bite Bis(N-heterocyclic silylene)
Chemistry. 2024 Mar 17:e202400389. doi: 10.1002/chem.202400389. Online ahead of print.ABSTRACTThe synthesis, reactivity, and complexation with Fe(0) precursor of a tight-bite bis(N-heterocyclic silylene) (bis(NHSi)) ligand 1 are reported. The reaction of 1 with p-toluidine led to the activation of both N-H bonds across Si(II) atoms to afford a rare four-membered heterocyclic cyclodisilazane 2, with hydride substituents attached to five-coordinate Si atoms. A 1:2 reaction of 1 with Fe(CO)5 led to an intriguing dinuclear complex 3 featuring a five-membered (N-Si-Fe-Fe-Si) ring with a Fe-Fe bond distance of 2.6892(13) Γ…. All...
Source: Chemistry - March 18, 2024 Category: Chemistry Authors: Zohreh Hendi Madhusudan K Pandey Katharina Rachuy Mukesh K Singh Regine Herbst-Irmer Dietmar Stalke Herbert W Roesky Source Type: research

Unrevealing the nitrogen elusive chirality of 3-sulfanyl and 3-sulfinyl N-tosyl isoindolinones by ECD spectra: an experimental and theoretical investigation
Chemistry. 2024 Mar 18:e202400232. doi: 10.1002/chem.202400232. Online ahead of print.ABSTRACTThe nitrogen-hybridization/pyramidalization of two solvated N-tosylisoindolinone derivatives having chiral residues in adjacent (I) or adjacent and distal (II) position has been investigated by a theoretical-computational procedure based on Molecular Dynamics simulations and Quantum-Chemical calculations. After validation of our strategy in providing a reliable repertory of conformations through the modeling of the electronic circular dichroism (EDC) spectra, the electronic features associated with N-pyramidalization were further ...
Source: Chemistry - March 18, 2024 Category: Chemistry Authors: Laura Palombi Marta Monti Erica Scarel Valerio Morlacci Mauro Stener Massimiliano Aschi Source Type: research

Masters of Mediation: MN(SiMe3)2 in Functionalization of C(sp3)-H Latent Nucleophiles
This article also emphasizes the unusual reactivity of MN(SiMe3)2 reagent in unreactive and robust C-X (X = O, N, F, C) bond cleavage reactions that occurred alongside the C(sp3)-H bond functionalization. Overall, this review encourages the community to exploit the untapped potential of MN(SiMe3)2 reagent and also inspires them to take up this subject to even greater heights.PMID:38497321 | DOI:10.1002/chem.202400435 (Source: Chemistry)
Source: Chemistry - March 18, 2024 Category: Chemistry Authors: Ramdas Sreedharan Thirumanavelan Gandhi Source Type: research

Design and Asymmetric Control of Orientational Chirality by using the Combination of C(sp2)-C(sp) Levers and Achiral N-Protecting Group
Chemistry. 2024 Mar 18:e202400005. doi: 10.1002/chem.202400005. Online ahead of print.ABSTRACTNew chiral targets of orientational chirality have been designed and asymmetrically synthesized by taking advantage of N-sulfinylimine-directed nucleophilic addition/oxidation, Suzuki-Miyaura and Sonogashira cross-coupling reactions. Orientation of single isomers has been selectively controlled by using aryl/alkynyl levers [C(sp2)-C(sp) axis] and tBuSO2- protecting group on nitrogen as proven by X-ray diffraction analysis. The key structural characteristic of resulting orientational products is shown by remote through-space blocki...
Source: Chemistry - March 18, 2024 Category: Chemistry Authors: Yu Wang Ting Xu Shengzhou Jin Jia-Yin Wang Qingkai Yuan Hao Liu Yao Tang Sai Zhang Guigen Li Source Type: research

A pH-Responsive Topological Switch Based on a DNA Quadruplex-Duplex Hybrid
Chemistry. 2024 Mar 18:e202400722. doi: 10.1002/chem.202400722. Online ahead of print.ABSTRACTA guanine-rich oligonucleotide based on a human telomeric sequence but with the first three-nucleotide intervening stretch replaced by a putative 15-nucleotide hairpin-forming sequence shows a pH-dependent folding into different quadruplex-duplex hybrids in a potassium containing buffer. At slightly acidic pH, the quadruplex domain adopts a chair-type conformation. Upon increasing the pH, a transition with a midpoint close to neutral pH to a major and minor (3+1) hybrid topology with either a coaxially stacked or orthogonally orie...
Source: Chemistry - March 18, 2024 Category: Chemistry Authors: Yoanes Maria Vianney Jagannath Jana Klaus Weisz Source Type: research