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juin 2023 – ChemDigest

Mois : juin 2023

N‐Alkylated Pyridoxal Derivatives as Negative Electrolyte Materials for Aqueous Organic Flow Batteries: Computational Screening

Par / 30 juin 2023 / Non classé
N-Alkylated Pyridoxal Derivatives as Negative Electrolyte Materials for Aqueous Organic Flow Batteries: Computational Screening**

N–functionalized pyridinium molecules derived from the three major vitamers of vitamin B6, pyridoxal, pyridoxamine and pyridoxine, have been screened computationally for consideration as negative electrode materials in aqueous organic flow batteries.

Abstract

N-functionalized pyridinium frameworks derived from the three major vitamers of vitamin B6, pyridoxal, pyridoxamine and pyridoxine, have been screened computationally for consideration as negative electrode materials in aqueous organic flow batteries. A molecular database including the structure and the one-electron standard reduction potential of related pyridinium derivatives has been generated using a computational protocol that combines semiempirical and DFT quantum chemical methods. The predicted reduction potentials span a broad range for the investigated pyridinium frameworks, but pyridoxal derivatives, particularly those involving electron withdrawing substituents, have potentials compatible with the electrochemical stability window of aqueous electrolytes. The stability of radicals formed upon one-electron reduction has been analyzed by a new computational tool proposed recently for large-scale computational screening.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Andrea Hamza, Flóra B. Németh, Ádám Madarász, Anton Nechaev, Petri M. Pihko, Pekka Peljo, Imre Pápai
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202300996

Orthogonal Strategies for Profiling Potential Cellular Targets of Anandamide and Cannabidiol

Par / 30 juin 2023 / Non classé
Orthogonal Strategies for Profiling Potential Cellular Targets of Anandamide and Cannabidiol

Affinity-based protein profiling (AfBPP) and ‘label-free’ 2D-TPP (2 Dimensional-Thermal Protein Profiling) platforms have been used to identify potential cellular targets of cannabinoids, especially cannabidiol (CBD), leading to the discovery of both shared and unique protein targets. Subsequent target validation led to the conclusion that this 2D-TPP strategy complements well with AfBPP.

Abstract

The human endocannabinoid system regulates a myriad of physiological processes through a complex lipid signaling network involving cannabinoids and their respective receptors, cannabinoid receptor 1 (hCB1R) and cannabinoid receptor 2 (hCB2R). Anandamide (AEA) and cannabidiol (CBD) are classical examples of cannabinoids that elicit a variety of effects, both beneficial and detrimental, through these receptors. Mounting evidence suggested the presence of other potential cannabinoid targets that may be responsible for other observable effects. However, prior pharmacological studies on these cannabinoid compounds provided scant evidence of direct engagement to these proposed targets. Moreover, to the best of our knowledge, no chemoproteomic studies have been demonstrated on CBD. Here we showed that, by taking advantage of a recently developed ‘label-free’ 2D-TPP (2 Dimensional-Thermal Protein Profiling) approach, we have identified several new putative targets of both AEA and CBD. Comparison of these interaction landscapes with those obtained from well-established affinity-based protein profiling (AfBPP) platforms has led to the discovery of both shared and unique protein targets. Subsequent target validation of selected proteins led us to conclude that this 2D-TPP strategy complements well with AfBPP.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Guanghui Tang, Ying‐Jie Lim, Wei Wang, Zi Ye, Chong‐Jing Zhang, Shao Q. Yao
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202300682

From Terminal to Spiro‐Phosphonium Acceptors, Remarkable Moieties to Develop Polyaromatic NIR Dyes

Par / 30 juin 2023 / Non classé
From Terminal to Spiro-Phosphonium Acceptors, Remarkable Moieties to Develop Polyaromatic NIR Dyes

Low energy absorption and emission were realized in a series of anthracene-derived donor-acceptor phosphonium dyes. The electron deficiency of the rare phospha-spiro architecture allowed to achieve fluorescence at 797 nm in dichloromethane and at 860 nm in the solid state.

Abstract

Phosphonium-based compounds gain attention as promising photofunctional materials. As a contribution to the emerging field, we present a series of donor-acceptor ionic dyes, which were constructed by tailoring phosphonium (A) and extended π-NR2 (D) fragments to an anthracene framework. The alteration of the π-spacer of electron-donating substituents in species with terminal −+PPh2Me groups exhibits a long absorption wavelength up to λabs=527 nm in dichloromethane and shifted the emission to the near-infrared (NIR) region (λ=805 nm for thienyl aniline donor), although at low quantum yield (Φ<0.01). In turn, the introduction of a P-heterocyclic acceptor substantially narrowed the optical bandgap and improved the efficiency of fluorescence. In particular, the phospha-spiro moiety allowed to attain NIR emission (797 nm in dichloromethane) with fluorescence efficiency as high as Φ=0.12. The electron-accepting property of the phospha-spiro constituent outperformed that of the monocyclic and terminal phosphonium counterparts, illustrating a promising direction in the design of novel charge-transfer chromophores.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Iida Partanen, Andrey Belyaev, Bo‐Kang Su, Zong‐Ying Liu, Jarkko J. Saarinen, Ishfaq Ibni Hashim, Andreas Steffen, Pi‐Tai Chou, Carlos Romero‐Nieto, Igor O. Koshevoy
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202301073

Highly Cooperative CO2 Adsorption via a Cation Crowding Mechanism on a Cesium‐Exchanged Phillipsite Zeolite

Par / 30 juin 2023 / Non classé
Highly Cooperative CO2 Adsorption via a Cation Crowding Mechanism on a Cesium-Exchanged Phillipsite Zeolite

Highly cooperative CO2 adsorption on a flexible cesium-exchanged phillipsite, a channel-based small-pore zeolite, is operated by an unprecedented adsorption phenomenon: structural breathing (the narrow-to-wide pore) is associated with the crowding and dispersal of large Cs+ ions, depending on the CO2 pressure, termed the ‘cation crowding’ mechanism.

Abstract

An understanding of the CO2 adsorption mechanisms on small-pore zeolites is of practical importance in the development of more efficient adsorbents for the separation of CO2 from N2 or CH4. Here we report that the CO2 isotherms at 25–75 °C on cesium-exchanged phillipsite zeolite with a Si/Al ratio of 2.5 (Cs-PHI-2.5) are characterized by a rectilinear step shape: limited uptake at low CO2 pressure (PCO2) is followed by highly cooperative uptake at a critical pressure, above which adsorption rapidly approaches capacity (2.0 mmol g−1). Structural analysis reveals that this isotherm behavior is attributed to the high concentration and large size of Cs+ ions in dehydrated Cs-PHI-2.5. This results in Cs+ cation crowding and subsequent dispersal at a critical loading of CO2, which allows the PHI framework to relax to its wide pore form and enables its pores to fill with CO2 over a very narrow range of PCO2. Such a highly cooperative phenomenon has not been observed for other zeolites.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Hyun June Choi, Elliott L. Bruce, Kevin S. Kencana, Jingeon Hong, Paul A. Wright, Suk Bong Hong
onlinelibrary.wiley.com/doi/10.1002/anie.202305816

Consecutive Single‐Crystal‐to‐Single‐Crystal Isomerization of Novel Octamolybdate Anions within a Microporous Hybrid Framework with Robust Water Sorption Properties

Par / 30 juin 2023 / Non classé
Consecutive Single-Crystal-to-Single-Crystal Isomerization of Novel Octamolybdate Anions within a Microporous Hybrid Framework with Robust Water Sorption Properties

Three sequential thermally-triggered single-crystal-to-single-crystal isomerizations of novel octamolybdate anions occur within a hybrid coordination network formed by the assembly of polyoxometalate clusters and copper(II)-complexes of a macrocyclic tetraaza ligand. Up to three different microporous phases with accessible voids can be isolated, which exhibit robust water sorption properties.

Abstract

The 3D hybrid framework [{Cu(cyclam)}3(κ-Mo8O27)] ⋅ 14H2O (1) (cyclam=1,4,8,11-tetraazacyclotetradecane) undergoes sequential single-crystal-to-single-crystal transformations upon heating to afford two different anhydrous phases (2 a and 3 a). These transitions modify the framework dimensionality and enable the isomerization of κ-octamolybdate (κ-Mo8) anions into λ (2 a) and μ (3 a) forms through metal migration. Hydration of 3 a involves condensation of one water molecule to the cluster to afford the γ-Mo8 isomer in 4, which dehydrates back into 3 a through the 6 a intermediate. In contrast, 2 a reversibly hydrates to form 5, exhibiting the same Mo8 cluster as that of 1. It is remarkable that three of the Mo8 clusters (κ, λ and μ) are new and that up to three different microporous phases can be isolated from 1 (2 a, 3 a, and 6 a). Water vapor sorption analyses show high recyclability and the highest uptake values for POM-based systems. The isotherms display an abrupt step at low humidity level desirable for humidity control devices or water harvesting in drylands.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Estibaliz Ruiz‐Bilbao, Amaia Iturrospe, Santiago Reinoso, Beñat Artetxe, Garikoitz Beobide, Leire San Felices, Luis Lezama, Juan M. Gutiérrez‐Zorrilla, Shaza Darwish, Debobroto Sensharma, Michael J. Zaworotko
onlinelibrary.wiley.com/doi/10.1002/anie.202307436

Unraveling the Oxidation Behaviors of MXenes in Aqueous Systems by Active‐Learning‐Potential Molecular‐Dynamics Simulation

Par / 30 juin 2023 / Non classé
Unraveling the Oxidation Behaviors of MXenes in Aqueous Systems by Active-Learning-Potential Molecular-Dynamics Simulation

The oxidation kinetics of MXenes were studied using active-learning-potential molecular dynamics. MXenes spontaneously oxidize to transition-metal oxides in water, which form oxide protection layers on the surface to further inhibit the oxidation process. The free protons in water also impair the water’s motility, inhibiting its attack on the MXene surface.

Abstract

MXenes are 2D materials with great potential in various applications. However, the degradation of MXenes in humid environments has become a main obstacle in their practical use. Here we combine deep neural networks and an active learning scheme to develop a neural network potential (NNP) for aqueous MXene systems with ab initio precision but low cost. The oxidation behaviors of super large aqueous MXene systems are investigated systematically at nanosecond timescales for the first time. The oxidation process of MXenes is clearly displayed at the atomic level. Free protons and oxides greatly inhibit subsequent oxidation reactions, leading to the degree of oxidation of MXenes to exponentially decay with time, which is consistent with the oxidation rate of MXenes measured experimentally. Importantly, this computational study represents the first exploration of the kinetic process of oxidation of super-sized aqueous MXene systems. It opens a promising avenue for the future development of effective protection strategies aimed at controlling the stability of MXenes.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Pengfei Hou, Yumiao Tian, Yu Xie, Fei Du, Gang Chen, Aleksandra Vojvodic, Jianzhong Wu, Xing Meng
onlinelibrary.wiley.com/doi/10.1002/anie.202304205

Polyketide Synthase‐Mediated O‐Methyloxime Formation in the Biosynthesis of the Oximidine Anticancer Agents

Par / 30 juin 2023 / Non classé
Polyketide Synthase-Mediated O-Methyloxime Formation in the Biosynthesis of the Oximidine Anticancer Agents

The anticancer agent oximidine I and three novel variants were discovered as products of a cryptic trans-AT PKS/NRPS in Pseudomonas baetica. By manipulating the biosynthetic pathway, a key intermediate was identified that retains potent anticancer properties. A combination of bioinformatics analysis and genetic and biochemical experiments illuminated the oximidine biosynthetic pathway, including a novel mechanism for O-methyloxime formation.

Abstract

Bacterial trans-acyltransferase polyketide synthases (trans-AT PKSs) are modular megaenzymes that employ unusual catalytic domains to assemble diverse bioactive natural products. One such PKS is responsible for the biosynthesis of the oximidine anticancer agents, oxime-substituted benzolactone enamides that inhibit vacuolar H+-ATPases. Here, we describe the identification of the oximidine gene cluster in Pseudomonas baetica and the characterization of four novel oximidine variants, including a structurally simpler intermediate that retains potent anticancer activity. Using a combination of in vivo, in vitro and computational approaches, we experimentally elucidate the oximidine biosynthetic pathway and reveal an unprecedented mechanism for O-methyloxime formation. We show that this process involves a specialized monooxygenase and methyltransferase domain and provide insight into their activity, mechanism and specificity. Our findings expand the catalytic capabilities of trans-AT PKSs and identify potential strategies for the production of novel oximidine analogues.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Eveline Vriens, Dries De Ruysscher, Angus N. M. Weir, Sofie Dekimpe, Gert Steurs, Ahmed Shemy, Leentje Persoons, Ana Rita Santos, Christopher Williams, Dirk Daelemans, Matthew P. Crump, Arnout Voet, Wim De Borggraeve, Eveline Lescrinier, Joleen Masschelein
onlinelibrary.wiley.com/doi/10.1002/anie.202304476

Stepwise O2‐Induced Rearrangement and Disassembly of the [NiFe4(OH)(μ3‐S)4] Active Site Cluster of CO Dehydrogenase

Par / 30 juin 2023 / Non classé
Stepwise O2-Induced Rearrangement and Disassembly of the [NiFe4(OH)(μ3-S)4] Active Site Cluster of CO Dehydrogenase

Carbon monoxide dehydrogenases (CODHs) are inactivated by dioxygen. High-resolution crystallography was used to show how O2 induces a stepwise rearrangement of the Ni,Fe-cluster in the active site, with evidence for a reversible and an irreversible phase of cluster destruction. The open coordination site on Ni renders the cluster vulnerable, and its protection offers strategies to prevent inactivation.

Abstract

Ni,Fe-containing carbon monoxide dehydrogenases (CODHs) catalyze the reversible reduction of carbon dioxide to carbon monoxide. CODHs are found in anaerobic microorganisms and can rapidly lose their activity when exposed to air. What causes the loss of activity is unclear. In this study, we analyzed the time-dependent structural changes induced by the presence of air on the metal centers of CODH-II. We show that inactivation is a multistep process. In a reversible step, the open coordination site on the Ni ion is blocked by a Ni,Fe-bridging μ-sulfido or chlorido ligand. Blocking this open coordination site with a cyanide ligand stabilizes the cluster against O2-induced decomposition, indicating that O2 attacks at the Ni ion. In the subsequent irreversible phase, nickel is lost, the Fe ions rearrange and the sulfido ligands disappear. Our data are consistent with a reversible reductive reactivation mechanism to protect CODHs from transient over-oxidation.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Yudhajeet Basak, Jae‐Hun Jeoung, Lilith Domnik, Holger Dobbek
onlinelibrary.wiley.com/doi/10.1002/anie.202305341

Thermal Stability and Outgassing Behaviors of High‐nickel Cathodes in Lithium‐ion Batteries

Par / 30 juin 2023 / Non classé
Thermal Stability and Outgassing Behaviors of High-nickel Cathodes in Lithium-ion Batteries

Thermal stability and outgassing as two critical safety metrics of high-nickel layered oxide cathodes are summarized from a chemical perspective. Thermal decomposition of high-Ni cathodes starts with ion migration, phase transition, and oxygen release, and ends up with electrolyte combustion. Gas evolution originates from the chemical decomposition of surface lithium carbonate residues and electrolytes under the attack of oxygen from the cathode.

Abstract

LiNiO2-based high-nickel layered oxide cathodes are regarded as promising cathode materials for high-energy-density automotive lithium batteries. Most of the attention thus far has been paid towards addressing their surface and structural instability issues brought by the increase of Ni content (>90 %) with an aim to enhance the cycle stability. However, the poor safety performance remains an intractable problem for their commercialization in the market, yet it has not received appropriate attention. In this review, we focus on the gas generation and thermal degradation behaviors of high-Ni cathodes, which are critical factors in determining their overall safety performance. A comprehensive overview of the mechanisms of outgassing and thermal runaway reactions is presented and analyzed from a chemistry perspective. Finally, we discuss the challenges and the insights into developing robust, safe high-Ni cathodes.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Zehao Cui, Arumugam Manthiram
onlinelibrary.wiley.com/doi/10.1002/anie.202307243

Polymeric STING Pro‐agonists for Tumor‐Specific Sonodynamic Immunotherapy

Par / 30 juin 2023 / Non classé
Polymeric STING Pro-agonists for Tumor-Specific Sonodynamic Immunotherapy

Polymeric STING pro-agonists (PSPA), whose sono-immunotherapeutic efficacy is activated by sono-irradiation and elevated glutathione (GSH) within the tumor microenvironment (TME), were developed for precision cancer immunotherapy with minimized side effects.

Abstract

The efficacy of combination immunotherapy has been limited by tumor specificity and immune-related adverse events (irAEs). Herein, we report the development of polymeric STING pro-agonists (PSPA), whose sono-immunotherapeutic efficacy is activated by sono-irradiation and elevated glutathione (GSH) within the tumor microenvironment (TME). PSPA is composed of sonosensitizers (semiconducting polymer) and STING agonists (MSA-2) via the GSH-activatable linkers. Under sono-irradiation, PSPA serves as a sonosensitizer to generate 1O2 and induce immunogenic cell death (ICD) of malignant tumor cells. Furthermore, MSA-2 is released specifically in tumor microenvironment with highly expressed GSH, minimizing off-target side effects. The activation of the STING pathway elevates the interferon-β level and synergizes with SDT to enhance the anti-tumor response. Therefore, this work proposes a universal approach for spatiotemporal regulation of cancer sono-immunotherapy.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Jie Yu, Shasha He, Chi Zhang, Cheng Xu, Jingsheng Huang, Mengke Xu, Kanyi Pu
onlinelibrary.wiley.com/doi/10.1002/anie.202307272

Bioinspired Design of a Giant [Mn86] Nanocage‐Based Metal‐Organic Framework with Specific CO2 Binding Pockets for Highly Selective CO2 Separation

Par / 30 juin 2023 / Non classé
Bioinspired Design of a Giant [Mn86] Nanocage-Based Metal-Organic Framework with Specific CO2 Binding Pockets for Highly Selective CO2 Separation

Using a bioinspired design strategy, a CO2-selective metal–organic framework (MOF), NKMOF-9 a, is fabricated, which possesses unprecedented [Mn86] nanocage-based structure and high structure robustness. Attributed to the unique enzyme-like CO2-binding pockets, NKMOF-9 a can selectively remove CO2 from CO2/C2H2, CO2/CH4 and CO2/N2 mixtures with high selectivities.

Abstract

Adsorption-based removal of carbon dioxide (CO2) from gas mixtures has demonstrated great potential for solving energy security and environmental sustainability challenges. However, due to similar physicochemical properties between CO2 and other gases as well as the co-adsorption behavior, the selectivity of CO2 is severely limited in currently reported CO2-selective sorbents. To address the challenge, we create a bioinspired design strategy and report a robust, microporous metal–organic framework (MOF) with unprecedented [Mn86] nanocages. Attributed to the existence of unique enzyme-like confined pockets, strong coordination interactions and dipole-dipole interactions are generated for CO2 molecules, resulting in only CO2 molecules fitting in the pocket while other gas molecules are prohibited. Thus, this MOF can selectively remove CO2 from various gas mixtures and show record-high selectivities of CO2/CH4 and CO2/N2 mixtures. Highly efficient CO2/C2H2, CO2/CH4, and CO2/N2 separations are achieved, as verified by experimental breakthrough tests. This work paves a new avenue for the fabrication of adsorbents with high CO2 selectivity and provides important guidance for designing highly effective adsorbents for gas separation.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Shubo Geng, Hang Xu, Chun‐Shuai Cao, Tony Pham, Bin Zhao, Zhenjie Zhang
onlinelibrary.wiley.com/doi/10.1002/anie.202305390

Elusive Double Perovskite Iodides: Structural, Optical, and Magnetic Properties

Par / 30 juin 2023 / Non classé
Elusive Double Perovskite Iodides: Structural, Optical, and Magnetic Properties

Unicorn double perovskite iodides [A2MIM IIII6] are elusive, but with the help of rational design rules, can indeed be synthesized. The Cs2NaLnI6 (Ln=Ce, Nd, Gd, Tb, Dy) family demonstrate optical properties that are red shifted compared to related halide materials and their magnetic properties show weak interaction parameters.

Abstract

Halide double perovskites [A2MIMIIIX6] are an important class of materials that have garnered substantial interest as non-toxic alternatives to conventional lead iodide perovskites for optoelectronic applications. While numerous studies have examined chloride and bromide double perovskites, reports of iodide double perovskites are rare, and their definitive structural characterization has not been reported. Predictive models have aided us here in the synthesis and characterization of five iodide double perovskites of general formula Cs2NaLnI6 (Ln=Ce, Nd, Gd, Tb, Dy). The complete crystal structures, structural phase transitions, optical, photoluminescent, and magnetic properties of these compounds are reported.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Greggory T. Kent, Emily Morgan, Kaitlin R. Albanese, Anna Kallistova, Alexandra Brumberg, Linus Kautzsch, Guang Wu, Pratap Vishnoi, Ram Seshadri, Anthony K. Cheetham
onlinelibrary.wiley.com/doi/10.1002/anie.202306000

Atomic‐Scale Insights into the Interlayer Characteristics and Oxygen Reactivity of Bilayer Borophene

Par / 30 juin 2023 / Non classé
Atomic-Scale Insights into the Interlayer Characteristics and Oxygen Reactivity of Bilayer Borophene

Tip-enhanced Raman spectroscopy (TERS) was used to study the local chemical properties of bilayer synthetic two-dimensional boron (i.e., borophene) with atomic-scale spatial resolution. TERS established the chemical fingerprint of bilayer borophene that is correlated with the vibration of interlayer B−B bonds and revealed its chemical stability with single-bond (B−O) sensitivity by exposure to controlled oxidizing conditions in ultrahigh vacuum.

Abstract

Bilayer (BL) two-dimensional boron (i.e., borophene) has recently been synthesized and computationally predicted to have promising physical properties for a variety of electronic and energy technologies. However, the fundamental chemical properties of BL borophene that form the foundation of practical applications remain unexplored. Here, we present atomic-level chemical characterization of BL borophene using ultrahigh vacuum tip-enhanced Raman spectroscopy (UHV-TERS). UHV-TERS identifies the vibrational fingerprint of BL borophene with angstrom-scale spatial resolution. The observed Raman spectra are directly correlated with the vibrations of interlayer boron–boron bonds, validating the three-dimensional lattice geometry of BL borophene. By virtue of the single-bond sensitivity of UHV-TERS to oxygen adatoms, we demonstrate the enhanced chemical stability of BL borophene compared to its monolayer counterpart by exposure to controlled oxidizing atmospheres in UHV. In addition to providing fundamental chemical insight into BL borophene, this work establishes UHV-TERS as a powerful tool to probe interlayer bonding and surface reactivity of low-dimensional materials at the atomic scale.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Linfei Li, Jeremy F. Schultz, Sayantan Mahapatra, Xiaolong Liu, Xu Zhang, Mark C. Hersam, Nan Jiang
onlinelibrary.wiley.com/doi/10.1002/anie.202306590

Fluorenylidene‐Cyclopentadithiophene Based Asymmetric Bistricyclic Aromatic Ene Compounds: Synthesis and Substituents Effects

Par / 30 juin 2023 / Non classé
Fluorenylidene-Cyclopentadithiophene Based Asymmetric Bistricyclic Aromatic Ene Compounds: Synthesis and Substituents Effects

A series of asymmetric bistricyclic aromatic ene-based molecules were synthesized with fluoreneylidene-cyclopentadithiophene skeleton, and exhibited low bandgap characteristic with long wavelength absorption tail. The substituents effect revealed impact on their energy levels and charge transporting property, which provides a new idea for design of HTMs for perovskite solar cells.Fluorenylidene-Cyclopentadithiophene Based Asymmetric Bistricyclic Aromatic Ene Compounds: Synthesis and Substituents Effects (Yin, Qiao, et al.)

Abstract

Low band gap materials have always been a focus of attention due to their potential applications in various fields. In this work, a series of asymmetric bistricyclic aromatic ene (BAE) compounds with fluorenylidene-cyclopentadithiophene (FYT) skeleton were facially synthesized, which were modified with different substituents (−OMe, −SMe). The FYT core exhibit twisted C=C bond with dihedral angles around 30°, and the introduction of −SMe group can provide additional S⋅⋅⋅S interaction between molecules, which is conducive to the charge transporting. The UV-Vis spectra, electrochemistry and photoelectron spectroscopy revealed that these compounds have relatively narrow band gaps, particularly, the −SMe modified compounds have slightly lower HOMO and Fermi energy levels than that of the −OMe modified compounds. Furthermore, PSCs devices were fabricated with the three compounds as HTMs, and FYT-DSDPA exhibit the best performance among them, revealing the fine-tuning band structure could influence properties of HTMs.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Beibei Xiao, Yongrui Yang, Shengnan Chen, Ye Zou, Xing Chen, Kanglei Liu, Nan Wang, Yali Qiao, Xiaodong Yin
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202301055

Effect of Flexible Spacer and Alkyl Tail Length on the Liquid Crystalline Phase Behavior of Fullerene Block Molecules

Par / 30 juin 2023 / Non classé
Effect of Flexible Spacer and Alkyl Tail Length on the Liquid Crystalline Phase Behavior of Fullerene Block Molecules

A novel superlattice containing 3 hydrocarbon single layers alternating with 4 fullerene 2D crystals can be generated in a wide range of fullerene block molecules (n=10 or 12; m=5–7), owing to the cooperative effect of a long spacer and short terminal tails. This offers a practical way to construct unconventional semi-conductive superstructures.

Abstract

Here the supramolecular liquid crystalline (LC) phase behavior of a series of fullerene block molecules was investigated regarding spacer length, alkyl tail length and temperature. These compounds exhibit several lamellar LC phases with different packings of self-organized fullerene two-dimensional (2D) crystals. With a short hexamethylene spacer, they form sandwich-like structures with triple or quadruple fullerene layers. By increasing the spacer length to 10 or 12 carbons, a composite layers-in-lamella superlattice structure with alternating soft hydrocarbon single layers and fullerene single or double layers was obtained. As the molecular configurational freedom between incompatible moieties was enhanced by the elongated spacer, the required cross-sectional fullerene-to-hydrocarbon ratio for the superlattice could be achieved despite of different volume fractions of the blocks. The superlattice phase range is efficiently widened by the design principle of constructing LC molecules with a long spacer, which also provides a facile way to tailor novel superstructures.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Huanjun Lu, Xingwei Chen, Xiaohong Li, Wenxing Sun, Ying Wang, Yingfeng Tu
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202301015

Photochemically Mediated Toluene Oxidation through a Copper Complex

Par / 30 juin 2023 / Non classé
Photochemically Mediated Toluene Oxidation through a Copper Complex

A method to oxidize toluene selectively to benzaldehyde photochemically is described. A series of copper(I) complexes with different ligands were applied in combination with [Ru(bipy)3](PF6)2 and dioxygen as the oxidant. The copper(II) complexes obtained after oxidation were photochemically reduced to the starting copper(I) species, and the process can be repeated continuously.

Abstract

A method is described to photochemically oxidize toluene selectively to benzaldehyde, an essential compound in the chemical industry. Copper(I) complexes with different ligands were applied in combination with [Ru(bipy)3](PF6)2 and dioxygen as the oxidant. As a result, a “dioxygen adduct” copper complex, for example, a peroxido complex, is formed as the active species. The copper(II) complex obtained after oxidation can be photochemically reduced to the starting copper(I) species, and the process can be repeated continuously. The ligand tris(2-methylpyridyl)amine (tmpa) led to the highest conversion rates.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Christian Noß, Richard Göttlich, Siegfried Schindler
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202301142

RNA‐Catalyzed RNA Ligation within Prebiotically Plausible Model Protocells

Par / 30 juin 2023 / Non classé
RNA-Catalyzed RNA Ligation within Prebiotically Plausible Model Protocells**

A ribozyme capable of functioning at low Mg2+ concentrations catalyzes efficient template-directed ligation of RNA substrates inside a prebiotically plausible fatty acid protocell. Compartmentalized RNA assembly catalyzed by ribozymes is central to the viability of spontaneously evolving protocells.

Abstract

Demonstrating RNA catalysis within prebiotically relevant models of primordial cells (protocells) remains a challenge in origins of life research. Fatty acid vesicles encapsulating genomic and catalytic RNAs (ribozymes) are attractive models for protocells; however, RNA catalysis has largely been incompatible with fatty acid vesicles due to their instability in the presence of Mg2+ at the concentrations required for ribozyme function. Here, we report a ribozyme that catalyzes template-directed RNA ligation at low Mg2+ concentrations and thus remains active within stable vesicles. Ribose and adenine, both prebiotically relevant molecules, were found to greatly reduce Mg2+-induced RNA leakage from vesicles. When we co-encapsulated the ribozyme, substrate, and template within fatty acid vesicles, we observed efficient RNA-catalyzed RNA ligation upon subsequent addition of Mg2+. Our work shows that RNA-catalyzed RNA assembly can occur efficiently within prebiotically plausible fatty acid vesicles and represents a step toward the replication of primordial genomes within self-replicating protocells.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Saurja DasGupta, Stephanie J. Zhang, Merrick P. Smela, Jack W. Szostak
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202301376

Turning the Imidazole Core into Three‐Dimensional Ring Systems: Mild Organocatalytic Entry to Enantiopure 6,7‐Dihydrobenzimidazoles

Par / 30 juin 2023 / Non classé
Turning the Imidazole Core into Three-Dimensional Ring Systems: Mild Organocatalytic Entry to Enantiopure 6,7-Dihydrobenzimidazoles

The challenging side of simplicity: Easily available imidazole-based substrates were coupled with β-aryl enals via eliminative [4+2] cycloaddition under mild aminocatalytic conditions to access rare chiral [d]-fused imidazole ring systems with optimal enantio- and regioselectivity and good potential for post-cycloaddition functional group editing.

Abstract

Organocatalytic asymmetric transformation of common aromatic heterocycles via in situ formation of highly reactive dearomatized ortho-quinodimethane diene species and subsequent [4+2] cycloaddition with suitable dienophiles has become a powerful tool to enter cyclohexane-fused heterocycles. Most of these reactions were previously applied to benzo-fused heterocycles or poorly aromatic rings. Herein, we disclose how previously intractable aromatic imidazole rings, equipped with removable methylidene malononitrile activating handle, could be involved as competent cycloaddends with β-aryl enals in efficient eliminative [4+2] cycloadditions under mild organocatalytic conditions. This method allowed the efficient and direct preparation of scantly represented 6,7-dihydrobenzo[d]imidazoles with optimal enantio- and regioselectivities. Post-cycloaddition chemical editing provided imidazole-based ring systems with diverse oxidation state and functional groups.

Wiley: Chemistry – A European Journal: Table of Contents
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chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202301200

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Journal of the American Chemical Society

Journal of the American Chemical Society: Latest Articles (ACS Publications)
Authors: Angela M. R. Mantovanelli, Oleksandr Glushonkov, Virgile Adam, Jip Wulffelé, Daniel Thédié, Martin Byrdin, Ingo Gregor, Oleksii Nevskyi, Jörg Enderlein, and Dominique Bourgeois
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Par / 30 juin 2023 / Non classé

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Journal of the American Chemical Society

Journal of the American Chemical Society: Latest Articles (ACS Publications)
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dx.doi.org/https://doi.org/10.1021/jacs.3c05311