bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fused Hexabenzocoronene‐Porphyrin Conjugates with Tailorable Excited‐State Lifetimes
Authors: Oleszak Christoph , Schol Peter R. , Ritterhoff Christian L. , Krug Marcel , Martin Max M. , Bo Yifan , Meyer Bernd , Clark Timothy , Guldi Dirk M. , Jux Norbert 
Published: August 2024

AbstractA new clear‐cut strategy for fusing N‐heterocyclic and carbon‐pure systems is introduced en route to a versatile platform of multi‐purpose tetrapyrrolic chromophores. In particular, three novel C−C bond‐fused porphyrin‐hexabenzocoronene (HBC) conjugates were synthesized under oxidative cyclodehydrogenation conditions, starting from tailor‐made nickel porphyrin precursors. The fusion of the individual aromatic systems via 5‐membered rings led to highly soluble π‐extended porphyrins in excellent yields. The resulting porphyrin‐HBC conjugates exhibit absorption cross‐sections that are of interdisciplinary interest in the ever‐growing field of organic photovoltaics and near‐infrared (NIR) dyes. Quantum chemical calculations show that the newly formed 5‐membered rings induce biradicaloid character in the porphyrin core, which has a strong impact on excited state lifetimes. This is confirmed by a thorough optoelectronic and time‐resolved characterization in order to understand these unique features better. Broadened absorption characteristics go hand‐in‐hand with short‐lived excited states with up to six orders of magnitude faster decay rates.
An Integrated Module Performs Selective ‘Online’ Epoxidation in the Biosynthesis of the Antibiotic Mupirocin
Authors: Winter Ashley J. , de Courcy‐Ireland Felix , Phillips Annabel P. , Barker Joseph M. , Bakar Nurfarhanim A. , Akter Nahida , Wang Luoyi , Song Zhongshu , Crosby John , Williams Christopher , Willis Christine L. , Crump Matthew P. 
Published: August 2024

AbstractThe delineation of the complex biosynthesis of the potent antibiotic mupirocin, which consists of a mixture of pseudomonic acids (PAs) isolated from Pseudomonas fluorescens NCIMB 10586, presents significant challenges, and the timing and mechanisms of several key transformations remain elusive. Particularly intriguing are the steps that process the linear backbone from the initial polyketide assembly phase to generate the first cyclic intermediate PA‐B. These include epoxidation as well as incorporation of the tetrahydropyran (THP) ring and fatty acid side chain required for biological activity. Herein, we show that the mini‐module MmpE performs a rare online (ACP‐substrate) epoxidation and is integrated (‘in‐cis’) into the polyketide synthase via a docking domain. A linear polyketide fragment with six asymmetric centres was synthesised using a convergent approach and used to demonstrate substrate flux via an atypical KS0 and a previously unannotated ACP (MmpE_ACP). MmpE_ACP‐bound synthetic substrates were critical in demonstrating successful epoxidation in vitro by the purified MmpE oxidoreductase domain. Alongside feeding studies, these results confirm the timing as well as chain length dependence of this selective epoxidation. These mechanistic studies pinpoint the location and nature of the polyketide substrate prior to the key formation of the THP ring and esterification that generate PA‐B.
Uncovering a Latent Bioactive Interleukin‐6 Glycoform
Authors: Liu Yanbo , Maki Yuta , Okamoto Ryo , Satoh Ayano , Todokoro Yasuto , Kanemitsu Yurie , Otani Keito , Kajihara Yasuhiro 
Published: August 2024

AbstractA bioinspired semisynthesis of human‐interleukin‐6 bearing N‐glycan at Asn143 (143glycosyl‐IL‐6) was performed by intentional glycosylation effects and protein folding chemistry for regioselective peptide‐backbone activation. 143Glycosyl‐IL‐6 is a genetically coded cytokine, but isolation was difficult owing to a tiny amount. IL6‐polypeptide (1–141‐position) with an intentionally inserted cysteine at 142‐position was expressed in E. coli. The expressed polypeptide was treated with a chemical folding process to make a specific helices bundle conformation through native two‐disulfide bonds (43–49 and 72–82). Utilizing the successfully formed free‐142‐cysteine, sequential conversions using cyanylation of 142‐cysteine, hydrazinolysis, and thioesterification created a long polypeptide (1–141)‐thioester. However, the resultant polypeptide‐thioester caused considerable aggregation owing to a highly hydrophobic peptide sequence. After the reduction of two‐disulfide bonds of polypeptide (1–141)‐thioester, an unprecedented hydrophilic N‐glycan tag was inserted at the resultant cysteine thiols. The N‐glycan tags greatly stabilized polypeptide‐thioester. The subsequent native chemical ligation and desulfurization successfully gave a whole 143glycosyl‐IL‐6 polypeptide (183‐amino acids). Removal of four N‐glycan tags and immediate one‐pot in vitro folding protocol efficiently produced the folded 143glycosyl‐IL‐6. The folded 143glycosyl‐IL‐6 exhibited potent cell proliferation activity. The combined studies with molecular dynamics simulation, semisynthesis, and bioassays predict the bioactive conformation of latent 143glycosyl‐IL‐6.
Quasi‐Planar Core Based Spiro‐Type Hole‐Transporting Material for Dopant‐Free Perovskite Solar Cells
Authors: Shao Guang , Wang Dian , Zhou Zu‐Kun , Yu Hui‐Juan , Kang Tao , Zhu Wei‐Hua , Xiao Jing , Yu Zhi‐Lan , Peng Lifen , Chen Jian , Ul Ain Qurat , Chen Yu , Yang Hua , Qiu Zeliang , Hu Ruiyuan , Khan Ammar Ahmed , A Alamry Khalid , Zhang Yi , Xia Jianxing , Nazeeruddin Mohammad Khaja 
Published: August 2024

AbstractHole‐transporting material (HTMs) are crucial for obtaining the stability and high efficiency of perovskite solar cells (PSCs). However, the current state‐of‐the‐art n‐i‐p PSCs relied on the use of 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (spiro‐OMeTAD) exhibit inferior intrinsic and ambient stability due to the p‐dopant and hydrophilic Li‐TFSI additive. In this study, a new spiro‐type HTM with a critical quasi‐planar core (Z‐W‐03) is developed to improve both the thermal and ambient stability of PSCs. The results suggest that the planar carbazole structure effectively passivates the trap states compared to the triphenylamine with a propeller‐like conformation in spiro‐OMeTAD. This passivation effect leads to the shallower trap states when the quasi‐planar HTMs interact with the Pb‐dimer. Consequently, the device using Z‐W‐03 achieves a higher Voc of 1.178 V compared to the spiro‐OMeTAD's 1.155 V, resulting in an enhanced efficiency of 24.02 %. In addition, the double‐column π–π stacking of Z‐W‐03 results in high hole mobility (~10−4 cm2 V−1 s−1) even without p‐dopant. Moreover, when the surface interface is modified, the undoped Z‐W‐03 device can achieve an efficiency of nearly 23 %. Compared to the PSCs using spiro‐OMeTAD, those with Z‐W‐03 exhibit enhanced stability under N2 and ambient conditions. This superior performance is attributed to the quasi‐planar core structure and the presence of multiple CH/π and π–π intermolecular stacking in Z‐W‐03. The multiple CH/π and π–π intermolecular contacts of HTMs can improve the hole hopping transport. Therefore, it is imperative to focus on further molecular structure design and optimization of spiro‐type HTMs incorporating quasi‐planar cores and carbazole moieties for the commercialization of PSCs.
Deoxygenative Geminal Silylboration of Amides Using Silylboronates: Synthesis and Use of α‐Boryl‐α‐Silylalkylamines
Authors: Watanabe Koh , Nagao Kazunori , Ohmiya Hirohisa 
Published: August 2024

Abstractα‐Silylalkylamines and α‐borylalkylamines are versatile synthetic intermediates and attractive scaffolds found in pharmaceutical drugs and agrochemicals. Despite great progress on synthetic methods for preparation of α‐silylalkylamines or α‐borylalkylamines, there are no general strategies for preparation of α‐boryl‐α‐silylalkylamines and the reactivity has not been explored. Here we report deoxygenative geminal silylboration of amides using silylboronates in the presence of alkoxide base catalyst, producing α‐boryl‐α‐silylalkylamines. The silicon and boron groups in α‐boryl‐α‐silylalkylamines are found to be utilized to chemoselective transformations, such as protonation and alkylation. This protocol serves various α‐silylalkylamines and α‐borylalkylamines from readily available amides.
Expansion of Structure Property in Cascade Nazarov Cyclization and Cycloexpansion Reaction to Diverse Angular Tricycles and Total Synthesis of Nominal Madreporanone
Authors: Fang Kun , Dou Bao‐Heng , Zhang Fu‐Min , Wang Yun‐Peng , Shan Zi‐Rui , Wang Xiao‐Yu , Hou Si‐Hua , Tu Yong‐Qiang , Ding Tong‐Mei 
Published: August 2024

AbstractA cascade Nazarov cyclization/dicycloexpansions reaction was developed for the precise synthesis of the angularly fused M/5/N (M=5, 6; N=4–9, 13) tricyclic skeletons. The prioritized expansion of the first ring played a critical role in the transformations, due to the release of ring strain, and the nature of the substituents present on the substrate is another influencing factor. This pioneering cascade reaction features broad substrates scope (33 examples), short reaction time, exceptional yields (up to 95 %), and remarkable regioselectivities (>20 : 1). Exploiting the synthetic application of this cascade reaction, we successfully executed a succinct total synthesis of nominal madreporanone for the first time.
Reconstruction of Ferromagnetic/Paramagnetic Cobalt‐Based Electrocatalysts under Gradient Magnetic Fields for Enhanced Oxygen Evolution
Authors: Ma Shengyu , Wang Kaixi , Rafique Moniba , Han Jiecai , Fu Qiang , Jiang Sida , Wang Xianjie , Yao Tai , Xu Ping , Song Bo 
Published: August 2024

AbstractThe rational manipulation of the surface reconstruction of catalysts is a key factor in achieving highly efficient water oxidation, but it is a challenge due to the complex reaction conditions. Herein, we introduce a novel in situ reconstruction strategy under a gradient magnetic field to form highly catalytically active species on the surface of ferromagnetic/paramagnetic CoFe2O4@CoBDC core–shell structure for electrochemical oxygen evolution reaction (OER). We demonstrate that the Kelvin force from the cores’ local gradient magnetic field modulates the shells’ surface reconstruction, leading to a higher proportion of Co2+ as active sites. These Co sites with optimized electronic configuration exhibit more favorable adsorption energy for oxygen‐containing intermediates and lower the activation energy of the overall catalytic reaction. As a result, a significant enhancement in OER performance is achieved with a large current density increment about 128 % at 1.63 V and an overpotential reduction by 28 mV at 10 mA cm−2 after reconstruction. Interestingly, after removing the external magnetic field, the activity could persist for over 100 h. This work showcases the directional surface reconstruction of catalysts under a gradient magnetic field for enhanced water oxidation.
Organocatalytic Atroposelective Synthesis of Axially Chiral Indolyl Ketosulfoxonium Ylides
Authors: Zhang Ji‐Wei , Zhang Yichi , Huang Yong 
Published: August 2024

AbstractDespite recent advancements in the catalytic generation of axial chirality, reports on non‐biaryl atropisomers remain limited because of the stringent steric requirements necessary to establish effective rotational brakes. Herein, we present a novel class of monoaryl atropisomers, indolyl ketosulfoxonium ylides, and describe an organocatalytic protocol for their synthesis. We discovered that a chiral phosphoric acid (CPA) serves as an effective catalyst for the highly enantioselective iodination of ortho‐aminophenylethynyl sulfoxonium ylides. Under the optimized reaction conditions, a strong preference for the intended iodination process over the competing protonation was observed. Subsequently, intramolecular amide cyclization enabled the formation of sterically congested indole fragments. Furthermore, the synthetic utility of the products was demonstrated by showcasing versatile transformations into other chiral scaffolds with complete retention of optical purity.
Palladium(0) and Brønsted Acid Co‐Catalyzed Enantioselective Hydro‐Cyclization of 2,4‐Dienyl Hydrazones and Oximes
Authors: Li Yu‐Fan , Gui Wu‐Tao , Pi Fu , Chen Zhi , Zhu Lei , Ouyang Qin , Du Wei , Chen Ying‐Chun 
Published: August 2024

AbstractThe transition metal‐catalyzed asymmetric hydro‐functionalization of 1,3‐dienes has been well explored, but most reactions focus on electron‐neutral substrates in an intermolecular manner. Here we first demonstrate that readily available 2,4‐dienyl hydrazones and oximes can be efficiently utilized in the hydro‐cyclization reaction under co‐catalysis of a Brønsted acid and a chiral palladium complex, furnishing multifunctional dihydropyrazones and dihydroisoxazoles, respectively. Diverse substitution patterns for both types of electron‐deficient diene compounds are tolerated, and corresponding heterocycles were generally constructed with moderate to excellent enantioselectivity, which can be elaborated to access products with higher molecular complexity and diversity. Control experiments and density functional theory calculations support that α‐regioselective protonation of dienyl substrates by acid and concurrent π‐Lewis base activation of Pd0 complex is energetically favoured in the formation of active π‐allylpalladium intermediates, and an outer‐sphere allylic amination or etherification mode is adopted to deliver the observed cyclized products enantioselectively.
Programmable Reconfiguration of Supramolecular Bottlebrush Block Copolymers: From Solution Self‐Assembly to Co‐Crystallization‐Assistant Self‐Assembly
Authors: Zhang Kaixing , Wu Yanggui , Chen Senbin , Zhu Jintao 
Published: August 2024

AbstractAchieving structural reconfiguration of supramolecular bottlebrush block copolymers toward topological engineering is of particular interest but challenging. Here, we address the creation of supramolecular architectures to discover how assembled topology influences the structured aggregates, combining hydrogen‐bonded (H‐bonded) bottlebrush block copolymers and electrostatic interaction induced polymer/inorganic eutectics. We first design H‐bonding linear‐brush block copolymer P(NBDAP‐co‐NBC)‐b‐P(NBPEO), bearing linear block P(NBDAP‐co‐NBC) (poly(norbornene‐terminated diaminopyridine‐co‐norbornene‐terminated hexane)) with pendant H‐bonding DAP (diaminopyridine) motifs, and PEO (poly(ethylene oxide)) densely grafted P(NBPEO) brush block. Thanks to H‐bonding association between DAP and thymine (Thy), incorporation of Thy‐functionalized polystyrene (Thy‐PS65) enables solution self‐assembly and formation of H‐bonded bottlebrush block copolymers, generating augmented nanospheres with increasing Thy‐PS65 amount. Noteworthy that integration of inorganic cluster silicotungstic acid (STA) to P(NBC‐co‐NBDAP)‐b‐P(NBPEO), endows the formation of PEO/STA eutectic core. Therefore, co‐crystallization‐assistant self‐assembly at the interfaces of polymeric, inorganic and supramolecular chemistry is realized, reflecting multi‐stage morphology transformation from hexagonal platelets, needle‐like, curved rod‐like micelles, finally to end‐to‐end closed rings, by gradually increasing Thy‐PS65 while fixing STA content. Interestingly, such solution self‐assembly to co‐crystallization‐assistant self‐assembly strategy not only endows unique nanostructure transition, also induce in‐to‐out reconfiguration of PS domains. These findings clearly provide unique methodology towards programmable fabrication of geometrical objects promising in smart materials.
Cell Surface Engineering by Phase‐Separated Coacervates for Antibody Display and Targeted Cancer Cell Therapy
Authors: Chen Hongfei , Bao Yishu , Li Xiaojing , Chen Fangke , Sugimura Ryohichi , Zeng Xiangze , Xia Jiang 
Published: August 2024

AbstractCell therapies such as CAR−T have demonstrated significant clinical successes, driving the investigation of immune cell surface engineering using natural and synthetic materials to enhance their therapeutic performance. However, many of these materials do not fully replicate the dynamic nature of the extracellular matrix (ECM). This study presents a cell surface engineering strategy that utilizes phase‐separated peptide coacervates to decorate the surface of immune cells. We meticulously designed a tripeptide, Fmoc−Lys−Gly−Dopa−OH (KGdelta; Fmoc=fluorenylmethyloxycarbonyl; delta=Dopa, dihydroxyphenylalanine), that forms coacervates in aqueous solution via phase separation. These coacervates, mirroring the phase separation properties of ECM proteins, coat the natural killer (NK) cell surface with the assistance of Fe3+ ions and create an outer layer capable of encapsulating monoclonal antibodies (mAb), such as Trastuzumab. The antibody‐embedded coacervate layer equips the NK cells with the ability to recognize cancer cells and eliminate them through enhanced antibody‐dependent cellular cytotoxicity (ADCC). This work thus presents a unique strategy of cell surface functionalization and demonstrates its use in displaying cancer‐targeting mAb for cancer therapies, highlighting its potential application in the field of cancer therapy.
Cobalt‐Catalyzed Intramolecular Markovnikov Hydrocarbonylation of Unactivated Alkenes via Hydrogen Atom Transfer
Authors: Jiang Donghao , Li Xinzhu , Xiao Mengdie , Cheng Li‐Jie 
Published: August 2024

AbstractA cobalt‐catalyzed intramolecular Markovnikov hydroalkoxycarbonylation and hydroaminocarbonylation of unactivated alkenes has been developed, enabling highly chemo‐ and regioselective synthesis of α‐alkylated γ‐lactones and α‐alkylated γ‐lactams in good yields. The mild reaction conditions allow use of mono‐, di‐ and trisubstituted alkenes bearing a variety of functional groups. Preliminary mechanistic studies suggest the reaction proceeds through a CO‐mediated hydrogen atom transfer (HAT) and radical‐polar crossover (RPC) process, in which a cationic acylcobalt(IV) complex is proposed as the key intermediate.
Thermotropic “Plumber's Nightmare”—A Tight Liquid Organic Double Framework
Authors: Li Ya‐Xin , Jia Ruo‐Yin , Ungar Goran , Ma Tao , Zhao Kai , Zeng Xiang‐Bing , Cheng Xiao‐Hong 
Published: August 2024

AbstractGyroid, double diamond and the body‐centred “Plumber's nightmare” are the three most common bicontinuous cubic phases in lyotropic liquid crystals and block copolymers. While the first two are also present in solvent‐free thermotropics, the latter had never been found. Containing six‐fold junctions, it was unlikely to form in the more common phases with rod‐like cores normal to the network columns, where a maximum of four branches can join at a junction. The solution has therefore been sought in side‐branched mesogens that lie in axial bundles joined at their ends by flexible “hinges”. But for the tightly packed double framework, geometric models predicted that the side‐chains should be very short. The true Plumber's nightmare reported here, using fluorescent dithienofluorenone rod‐like mesogen, has been achieved with, indeed, no side chains at all, but with 6 flexible end‐chains. Such molecules normally form columnar phases, but the key to converting a complex helical column–forming mesogen into a framework‐forming one was the addition of just one methyl group to each pendant chain. A geometry‐based explanation is given.
Self‐healing, low oil leakage and recyclable thermally conductive Al2O3/boron nitride@siloxane composites based on reversible dynamic network
Authors: Tu Zhiting , Wu Weijian , Hao Zhifeng , Chen Xiang , Chen Qiuling , Huang Xiaonan , Selim Mohamed S. , Yu Jian 
Published: August 2024

AbstractIn order to overcome the commercialized silicone‐based thermal interface materials' issues such as oil leakage and mechanical damage, we developed a thermoset silicone rubber matrix (SR) achieved through the condensation reaction of hydroxyl silicone oil and tetraethyl silicate. Additionally, we constructed a self‐healing and recyclable silicone rubber matrix (SCNR) by incorporating heat reversible ionic and hydrogen bonds between carboxyl and amino functionalized polydimethylsiloxane. Finally, the flexible, low oil leakage, self‐healing, and recyclable composites Al2O3/BN@SR/SCNR was prepared by adjusting the ratio of SR/SCNR and the spherical alumina and boron nitride (BN) fillers. The results indicated that with SR/SCNR mass ratio of 1/0.075 and filler content of 70 wt%, the thermal conductivity of the composite reaches 1.866 W m−1 K−1, 646% increasing over the SR/SCNR matrix. The self‐healing efficiency reaches 97% and the thermal conductivity remains essentially unchanged after being recycled for three times. The composites can be bent and twisted multiple times and still return to their original shape. Notably, the oil leakage of the Al2O3/BN@SR/SCNR composites is significantly lower than that of additive silicone composites. Therefore, the recyclable thermal conductivity composite developed in this study provides a promising solution for improving the durability of heat dissipation materials in electronic devices.
Excited‐State Dynamics and Optical Properties of Silica Under Ultrafast Laser Irradiation
Authors: Tsaturyan Arshak A. , Kachan Elena , Stoian Razvan , Colombier Jean‐Philippe 
Published: August 2024

AbstractExcited by intense infrared ultrafast light pulses, a wide bandgap material undergoes nonlinear ionization, generating a high density of free electrons in conduction states. As a result, the electronic band structure is critically modified and the bandgap shrinks. This induces rapid changes in optical properties, dramatically affecting the absorption spectrum during light coupling to the dielectric surface or during nonlinear propagation inside the bulk. This study analyzes the structural behavior and the modification of the optical properties of laser‐excited silica glass at the molecular cluster level through first‐principles simulations. Employing density functional theory and the GW approximations for band structure under nonequilibrium conditions, alongside the Bethe–Salpeter equation, the dynamics of the optical properties of fused silica are comprehensively explored. The behavior of excited fused silica in a wide photon energy range (from a few to 20 eV) is thus predicted. Laser‐induced electron excitation triggers a redistribution of charges between oxygen and silicon atoms, accompanied by a significant increase in electronic pressure, local atomic structure rearrangement, and material expansion. Molecular dynamics simulations offer a temporal perspective on the excited state dynamics, unveiling the intricate interplay between electronic and atomic effects on bandgap evolution. The analysis sheds light on excitonic resonances, intraband and interband transitions in fused silica under ultrafast laser irradiation, providing valuable insights into its excited state behavior and optical properties.