bluuebunny/crossref_metadata_2025_split huggingface dataset:
KIT‐related piebaldism in a Chinese girl
Authors: Zhu Lei , Yang Chao , Zhong Wei , Huang Yu‐Qi , Zhang Qi , Xu Wen‐Cong , Chen Yong‐Feng 
Published: March 2020

AbstractPiebaldism is a rare, autosomal dominant and congenital pigmentary disorder characterized by stable depigmentation of the skin and white forelock. Mutations in KIT or SNAI2 genes result in piebaldism. Most individuals with piebaldism have a family history of the disorder. Herein, we report a 5‐month‐old Chinese girl with severe piebaldism but no family history thereof. She has white forelock and large patches of depigmentation in the jaw, central anterior trunk, perineum and extremities. We performed whole‐exome and Sanger sequencing and identified a de novo KIT mutation (NM_000222.2: c.2657G>A, p.Gly886Val) in exon 18 of KIT in the proband. Currently, this mutation is located in the most extreme C‐terminal of the tyrosine kinase domain 2 of the KIT gene amongst all reported mutations and causes a severe clinical phenotype. We further reviewed literature on piebaldism and summarized 79 KIT gene mutations that lead to this disease. Our study may expand knowledge on the genotype–phenotype correlation in piebaldism and serve as a reference for genetic counseling and prenatal diagnosis of affected families.
Planar Chiral Organoboranes with Thermoresponsive Emission and Circularly Polarized Luminescence: Integration of Pillar[5]arenes with Boron Chemistry
Authors: Chen Jin‐Fa , Yin Xiaodong , Wang Bowen , Zhang Kai , Meng Guoyun , Zhang Songhe , Shi Yafei , Wang Nan , Wang Suning , Chen Pangkuan 
Published: March 2020

AbstractEnantiopure molecules based on macrocyclic architecture are unique for applications in enantioselective host‐guest recognition, chiral sensing and asymmetric catalysis. Taking advantage of the chiral transfer from the intrinsically planar chirality of pillar[5]arenes, we herein present an efficient and straightforward approach to achieve early examples of highly luminescent chiral systems (P5NN and P5BN). The optical resolution of their enantiomers has been carried out via preparative chiral HPLC, which was ascribed to the molecular functionalization of pillar[5]arenes with π‐conjugated, sterically bulky triarylamine (Ar3N) as an electron donor and triarylborane (Ar3B) as an acceptor. This crucial design enabled investigations of the chiroptical properties, including circular dichroism (CD) and circularly polarized luminescence (CPL) in the solid state. The intramolecular charge transfer (ICT) nature in P5BN afforded an interesting thermochromic shift of the emission over a wide temperature range.
Mehrfache katalytische C‐H‐Bindungsfunktionalisierungen in der Naturstoffsynthese
Authors: Baudoin Olivier 
Published: March 2020

AbstractWährend des letzten Jahrzehnts wurde die mehrfach katalytische C‐H‐Funktionalisierung erfolgreich in der Synthese von Naturstoffen angewandt, um die Anzahl der Synthesestufen zu reduzieren, die Gesamtausbeute zu erhöhen, sowie leichter zugängliche Ausgangsverbindungen zu verwenden. In diesem Kurzaufsatz werden ausgewählte Beispiele gezeigt, in welchen die mehrfach C‐H‐Funktionalisierung auf verschiedene konzeptuelle Weisen eingesetzt wird. Zuerst werden lineare Synthesen besprochen, in welchen die mehrfache C‐H‐Funktionalisierung entweder an einfachen (hetero)zyklischen Strukturen, als späte Modifikationen oder zum Aufbauen von polyzyklischen Systemen Verwendung findet. Anschließend wird demonstriert, wie der Gebrauch von mehrfachen C‐H‐Funktionalisierungen als strategisches Werkzeug in konvergenten Synthesen angewandt werden kann, um komplexe Fragmente zu erhalten und zu kuppeln. Informationen über die Skalierbarkeit der verwendeten Methoden ist gegeben, wenn verfügbar. Die ausgewählten Beispiele zeigen, dass die Verwendung von mehrfachen C‐H‐Funktionalisierungsstrategien eine wichtige Rolle in der Gestaltung von zukünftigen Synthesen funktioneller und komplexer Moleküle mit verbesserter Nachhaltigkeit sein sollten.
Ultraschnelle und kostengünstige Produktion von hochwertigem Graphen
Authors: Sun Zhuxing , Hu Yun Hang 
Published: March 2020

AbstractDie schnelle, großskalige und kostengünstige Produktion von hochwertigem Graphen ist stets eine große Herausforderung geblieben, auch wenn einige Ansätze das Potenzial für die Massensynthese von Graphen aufgezeigt haben. Erst kürzlich erzielten Tour und Mitarbeiter einen großen Durchbruch (Nature 2020, 577, 647–651): In nur einer Sekunde wurde aus kohlenstoffreichen Spezies durch kostengünstige Flash‐Joule‐Erwärmung mit einem geringen Energieaufwand von 7.2 kJ pro Gramm Graphen auf einfache Weise exfoliertes und hochkristallines Graphen hergestellt. Solch ein ultraschneller, wirtschaftlicher und skalierbarer Prozess für die Herstellung von hochwertigem Graphen kann als ein Meilenstein im Graphensektor angesehen werden und wird in diesem Highlight vorgestellt.
Tracking Structural Evolution during Symmetry‐Breaking Charge Separation in Quadrupolar Perylene Bisimide with Time‐Resolved Impulsive Stimulated Raman Spectroscopy
Authors: Kim Woojae , Kim Taeyeon , Kang Seongsoo , Hong Yongseok , Würthner Frank , Kim Dongho 
Published: March 2020

AbstractElucidating structural roles in photoinduced charge transfer is indispensable, as nuclear rearrangements are simultaneously usually involved in the dynamics. However, it is hard to evaluate whether the structural changes occur or not by using conventional time‐resolved electronic spectroscopy. Here, time‐resolved impulsive stimulated Raman spectroscopy is applied to record the evolution of vibrational snapshots during charge‐separation dynamics of donor–acceptor–donor‐type quadrupolar perylene bisimide in real time. Drastic frequency shifts were observed for several Raman bands with their population kinetics, thus symmetry‐breaking charge separation accompanies significant structural changes, as supported by (TD)‐DFT calculations. A comparison between time‐resolved Raman spectra of the neutral S1 state and the radical anion species shows that the spectral signatures, especially in high‐frequency regions, provide important clues to bond length alternation patterns in the PBI core.
Ketones as Molecular Co‐catalysts for Boosting Exciton‐Based Photocatalytic Molecular Oxygen Activation
Authors: Wang Hui , Jiang Shenlong , Liu Wenxiu , Zhang Xiaodong , Zhang Qun , Luo Yi , Xie Yi 
Published: March 2020

AbstractExcitonic processes in semiconductors open up the possibility for pursuing photocatalytic organic synthesis. However, the insufficient spin relaxation and robust nonradiative decays in semiconductors place restrictions on both quantum yield and selectivity of these reactions. Herein, by taking polymeric carbon nitride (PCN)/acetone as a prototypical system, we propose that extrinsic aliphatic ketones can serve as molecular co‐catalysts for promoting spin‐flip transition and suppressing non‐radiative energy losses. Spectroscopic investigations indicate that hot excitons in PCN can be transferred to ketones, while triplet excitons in ketones can be transferred to PCN. As such, the PCN/ketone systems exhibit considerable triplet‐exciton accumulation and extended visible‐light response, leading to excellent performance in exciton‐based photocatalysis, such as singlet oxygen generation. This work provides a fundamental understanding of energy harvesting in semiconductor/molecule systems, and paves the way for optimizing exciton‐based photocatalysis via molecular co‐catalyst design.
Unusual Skeletal Reorganization of Oxetanes for the Synthesis of 1,2‐Dihydroquinolines
Authors: Wang Guannan , Huang Hai , Guo Wengang , Qian Chenxiao , Sun Jianwei 
Published: March 2020

AbstractSkeletal reorganization is a type of fascinating transformations owing to their intriguing mechanisms and utility in complex molecule synthesis. However, only a limited amount of examples are known for most functional groups. Herein, we describe such an unusual process of oxetanes. In the presence of In(OTf)3as catalyst, oxetane‐tethered anilines reacted unexpectedly to form 1,2‐dihydroquinolines. This process not only provides expedient access to dihydroquinolines, but also represents a new reaction of oxetane. Mechanistically, it is believed that the reaction proceeds through initial nitrogen attack rather than arene attack followed by a series of bond cleavage and formation events. Control experiments provided important insights into the mechanism.
Pigmentation Chemistry and Radical‐Based Collagen Degradation in Alkaptonuria and Osteoarthritic Cartilage
Authors: Chow Wing Ying , Norman Brendan P. , Roberts Norman B. , Ranganath Lakshminarayan R. , Teutloff Christian , Bittl Robert , Duer Melinda J. , Gallagher James A. , Oschkinat Hartmut 
Published: March 2020

AbstractAlkaptonuria (AKU) is a rare disease characterized by high levels of homogentisic acid (HGA); patients suffer from tissue ochronosis: dark brown pigmentation, especially of joint cartilage, leading to severe early osteoarthropathy. No molecular mechanism links elevated HGA to ochronosis; the pigment's chemical identity is still not known, nor how it induces joint cartilage degradation. Here we give key insight on HGA‐derived pigment composition and collagen disruption in AKU cartilage. Synthetic pigment and pigmented human cartilage tissue both showed hydroquinone‐resembling NMR signals. EPR spectroscopy showed that the synthetic pigment contains radicals. Moreover, we observed intrastrand disruption of collagen triple helix in pigmented AKU human cartilage, and in cartilage from patients with osteoarthritis. We propose that collagen degradation can occur via transient glycyl radicals, the formation of which is enhanced in AKU due to the redox environment generated by pigmentation.
Asymmetric Reductive and Alkynylative Heck Bicyclization of Enynes to Access Conformationally Restricted Aza[3.1.0]bicycles
Authors: Huang Xiaolei , Nguyen Minh Hieu , Pu Maoping , Zhang Luoqiang , Chi Yonggui Robin , Wu Yun‐Dong , Zhou Jianrong Steve 
Published: March 2020

AbstractConformationally restricted azabicycles are becoming increasingly important in medicinal research. Asymmetric Heck bicyclization of enynes proceeds to give medicinally useful aza[3.1.0] and aza[4.1.0] bicycles with excellent enantioselectivity. The key organopalladium species after bicyclization can be trapped by silanes and terminal alkynes.
A Structurally Robust Chiral Borate Ion: Molecular Design, Synthesis, and Asymmetric Catalysis
Authors: Uraguchi Daisuke , Ueoka Fumito , Tanaka Naoya , Kizu Tomohito , Takahashi Wakana , Ooi Takashi 
Published: March 2020

AbstractCatalysis by chiral weakly‐coordinating anions (WCAs) remains underdeveloped due to the lack of a molecular design strategy for exploiting their characteristics, such as the non‐nucleophilic nature. Here, we report the development of a chiral borate ion comprising an O,N,N,O‐tetradentate backbone, which ensures hitherto unattainable structural robustness. Upon pairing with a proton, the hydrogen borate acts as an effective catalyst for the asymmetric Prins‐type cyclization of vinyl ethers, providing access to structurally and stereochemically defined dihydropyrans. The key to selectivity control is the distinct ability of the borate ion to discriminate the prochiral faces of the acyclic oxonium ion intermediate and dictate the regiochemical outcome. We anticipate that this study paves the way for exploring the untapped potential of WCA catalysis for selective chemical synthesis.
Lasing from an Organic Micro‐Helix
Authors: Sun Chun‐Lin , Li Jun , Song Qi‐Wei , Ma Yu , Zhang Ze‐Qi , De Jian‐Bo , Liao Qing , Fu Hongbing , Yao Jiannian , Zhang Hao‐Li 
Published: March 2020

AbstractOrganic solid‐state semiconductor lasers are attracting ever‐increasing interest for their potential application in future photonic circuits. Despite the great progress made in recent years, an organic laser from 3D chiral structures has not been achieved. Now, the first example of an organic nano‐laser from the micro‐helix structure of an achiral molecule is presented. Highly regular micro‐helixes with left/right‐handed helicity from a distyrylbenzene derivative (HM‐DSB) were fabricated and characterized under microscope spectrometers. These chiral micro‐helixes exhibit unique photonic properties, including helicity‐dependent circularly polarized luminescence (CPL), periodic optical waveguiding, and length‐dependent amplified spontaneous emission (ASE) behavior. The successful observation of laser behavior from the organic micro‐helix extends our understanding to morphology chirality of organic photonic materials and provides a new design strategy towards chiral photonic circuits.
Follow‐up imaging observations of comet 2I/Borisov
Authors: Mugrauer Markus , Bischoff Richard , Stenglein Wolfgang , Trautmann Julius , Baghdasaryan Baghdasar , Schlagenhauf Saskia 
Published: March 2020

AbstractFollow‐up imaging observations of the first detected interstellar comet 2I/Borisov are presented, which were carried out with the Schmidt‐Teleskop‐Kamera at the University Observatory Jena in 11 observing epochs in October and November 2019. The orbital solution of the comet, derived from the obtained astrometric measurements, confirms its highly eccentric (e = 3.3570 ± 0.0006) and inclined (i = 44.0524 ± 0.0004°) orbit, that proves the interstellar origin of the comet. According to our best‐fitting orbital solution, comet 2I/Borisov reaches its perihelion on 2019 Dec 8 (q = 2.0066 au) and its closest encounter with Earth on 2019 Dec 28 (Δmin = 1.9368 au). The distance corrected brightness of the nucleus of the comet clearly exhibits a linear correlation with its phase angle. The slope of this correlation indicates the activity of the comet, which is also detected in deep imaging data, taken in five observing epochs, showing the coma and the tail of the comet. During our observing campaign the coma of comet 2I/Borisov exhibits on average a diameter of (4.57 ± 0.38) · 104 km, and the length of the tail of the comet measures (1.52 ± 0.12) · 105 km, assuming an anti‐solar orientation.
The role of ownership structure in integrated reporting policies
Authors: Raimo Nicola , Vitolla Filippo , Marrone Arcangelo , Rubino Michele 
Published: March 2020

AbstractIntegrated reporting (IR) is used to demonstrate a firm's capacity to create value in the short, medium, and long term. It can better represent existing relationships between the company and its stakeholders, with a particular focus on investors. Attention to IR has grown considerably in recent years. However, studies on the determinants of IR quality are still limited. This study aims to bridge this literature gap by being the first study to analyse the role of ownership structure in IR context. To this end, it uses agency theory and is based on a sample of 152 international companies that have adopted IR. The results indicate a positive effect of institutional ownership and a negative effect of ownership concentration, managerial ownership and state ownership on the quality of integrated reports. These results are also consistent with the level of alignment of integrated reports with the <IR> framework. To our knowledge, this is the first study that analyses the role of ownership structure in the IR policies.
Hydrogels in the clinic
Authors: Mandal Abhirup , Clegg John R. , Anselmo Aaron C. , Mitragotri Samir 
Published: March 2020

AbstractInjectable hydrogels are one of the most widely investigated and versatile technologies for drug delivery and tissue engineering applications. Hydrogels’ versatility arises from their tunable structure, which has been enabled by considerable advances in fields such as materials engineering, polymer science, and chemistry. Advances in these fields continue to lead to invention of new polymers, new approaches to crosslink polymers, new strategies to fabricate hydrogels, and new applications arising from hydrogels for improving healthcare. Various hydrogel technologies have received regulatory approval for healthcare applications ranging from cancer treatment to aesthetic corrections to spinal fusion. Beyond these applications, hydrogels are being studied in clinical settings for tissue regeneration, incontinence, and other applications. Here, we analyze the current clinical landscape of injectable hydrogel technologies, including hydrogels that have been clinically approved or are currently being investigated in clinical settings. We summarize our analysis to highlight key clinical areas that hydrogels have found sustained success in and further discuss challenges that may limit their future clinical translation.
Tailoring the Voltage Gap of Organic Battery Materials Based on a Multi‐Electron Redox Chemistry
Authors: Zhang Fei , Cheng Yajuan , Niu Zhihui , Ye Jing , Dai Gaole , Zhang Xiaohong , Zhao Yu 
Published: March 2020

AbstractRedox‐active organics based on a multi‐electron mechanism are of great interest in battery electrode materials as they are capable of delivering high capacity per molecular weight. However, most of such organics shows huge voltage gap that is inherited from their stepwise redox reactions occurring in the same conjugated redox moiety. This study focuses on the voltage tailoring of polymeric dihydrophenazine derivative, which shows high specific capacity as a cathode electrode material and decent cycling stability, but suffers huge voltage gap of ca. 0.8 V. We demonstrate a strategy to modify the voltage gap of dihydrophenazine derivatives through the incorporation of functional groups with different electron affinity near the redox moiety. The as‐designed dihydrophenazine derivatives are further copolymerized to yield a polymeric material with significantly smoothened charge‐discharge profiles and good capacity retention. We further demonstrate through theoretical calculation based on density‐functional theory that the substitute site and types of functional groups are of great importance in voltage tailoring as well as structural stability of the dihydrophenazine derivatives.
Metal‐Free, N‐Iodosuccinimide‐Induced Regioselective Iodophosphoryloxylation of Alkenes with P(O)−OH Bonds
Authors: Xiong Biquan , Xu Shipan , Zhu Yu , Yao Lei , Zhou Congshan , Liu Yu , Tang Ke‐Wen , Wong Wai‐Yeung 
Published: March 2020

AbstractA simple and efficient method for the regioselective iodophosphoryloxylation of alkenes with P(O)−OH bonds has been established by using NIS (N‐iodosuccinimide) as the iodination reagent under transition‐metal‐free conditions. The present protocol is compatible with different functional groups, and suitable for various alkenes and P(O)−OH compounds. A variety of functionalized β‐iodo‐1‐ethyl phosphinic/phosphoric acid esters are obtained in good to excellent yields, which could be further transformed to diversified building blocks for the synthesis of bioactive compounds, pharmaceuticals and functional materials.
Towards Atomically Precise Supported Catalysts from Monolayer‐Protected Clusters: The Critical Role of the Support
Authors: Longo Alessandro , de Boed Ewoud J. J. , Mammen Nisha , van der Linden Marte , Honkala Karoliina , Häkkinen Hannu , de Jongh Petra E. , Donoeva Baira 
Published: March 2020

AbstractControlling the size and uniformity of metal clusters with atomic precision is essential for fine‐tuning their catalytic properties, however for clusters deposited on supports, such control is challenging. Here, by combining X‐ray absorption spectroscopy and density functional theory calculations, it is shown that supports play a crucial role in the evolution of monolayer‐protected clusters into catalysts. Based on the acidic nature of the support, cluster‐support interactions lead either to fragmentation of the cluster into isolated Au–ligand species or ligand‐free metallic Au0 clusters. On Lewis acidic supports that bind metals strongly, the latter transformation occurs while preserving the original size of the metal cluster, as demonstrated for various Aun sizes. These findings underline the role of the support in the design of supported catalysts and represent an important step toward the synthesis of atomically precise supported nanomaterials with tailored physico‐chemical properties.
Multi‐Color Fluorescent Carbon Dots: Graphitized sp2 Conjugated Domains and Surface State Energy Level Co‐Modulate Band Gap Rather Than Size Effects
Authors: Wei Siqi , Yin Xinghang , Li Haoyi , Du Xiaoyu , Zhang Limei , Yang Qiang , Yang Rui 
Published: March 2020

AbstractFour types of carbon dots (CDs) with various color (blue, green, yellow, and red) emissions have been synthesized under solvent‐free conditions from citric acid and different nitrogen sources (DMF, urea, ethanamide, and formamide). By detailed characterization and comparison, it is confirmed that the graphitized sp2 conjugated domain and surface functional groups such as C−O and C=N play synergetic roles in adjusting the fluorescence properties. Notably, the size effect is not the dominant mechanism to achieve multi‐color fluorescence emissions in this work. The structural configuration of the carbon dots further influences the energy band structure, as demonstrated in simplified energy level diagrams. An absorption peak at approximately 560 nm appears in the visible light region for red‐emitting CDs, assigned to an n→π* transition of the aromatic structure, thus introducing a new surface state energy level, resulting in a reduction in the energy of electron transition and the expansion into the visible region of the UV/Vis spectrum. Taking advantage of the diverse absorption and emission properties, different CDs/TiO2 binary composites are obtained for photocatalytic degradation of organic dyes, and it is found that the absorption range in terms of visible light and the band gap of the carbon dots make a difference to the photocatalytic performance of the composites.
Understanding the 1,3‐Dipolar Cycloadditions of Allenes
Authors: Yu Song , Vermeeren Pascal , van Dommelen Kevin , Bickelhaupt F. Matthias , Hamlin Trevor A. 
Published: March 2020

AbstractWe have quantum chemically studied the reactivity, site‐, and regioselectivity of the 1,3‐dipolar cycloaddition between methyl azide and various allenes, including the archetypal allene propadiene, heteroallenes, and cyclic allenes, by using density functional theory (DFT). The 1,3‐dipolar cycloaddition reactivity of linear (hetero)allenes decreases as the number of heteroatoms in the allene increases, and formation of the 1,5‐adduct is, in all cases, favored over the 1,4‐adduct. Both effects find their origin in the strength of the primary orbital interactions. The cycloaddition reactivity of cyclic allenes was also investigated, and the increased predistortion of allenes, that results upon cyclization, leads to systematically lower activation barriers not due to the expected variations in the strain energy, but instead from the differences in the interaction energy. The geometric predistortion of cyclic allenes enhances the reactivity compared to linear allenes through a unique mechanism that involves a smaller HOMO–LUMO gap, which manifests as more stabilizing orbital interactions.
Structure and Bonding in a Diamond‐Shaped Tin Cluster Possessing a cyclo‐Sn4 Core
Authors: Handford Rex C. , Wheeler T. Alex , Tilley T. Don 
Published: March 2020

AbstractA tetrameric cluster composed entirely of (aryl)Sn units, [DMPSn]4 (DMP=2,6‐dimesitylphenyl), has been prepared by reduction of [DMPSnCl]2 with a variety of reductants. This cluster was characterized in solution by multinuclear NMR spectroscopies, as well as in the solid‐state by single crystal X‐ray diffraction analysis. This species is stereochemically nonrigid in solution and possesses a cyclo‐Sn4 core whose DMP substituents are equivalent at higher temperatures. The solid‐state molecular structure is remarkably unsymmetrical and possesses a nearly planar cyclo‐Sn4 core. The DMP substituents are arranged such that three are approximately coplanar, while one is nearly perpendicular to the cyclo‐Sn4 core. Density functional theory calculations for a [PhSn]4 model system show that this distorted geometry about the cyclo‐Sn4 core maximizes σ‐bonding between the Sn centers in a manner reminiscent of trans‐bent bonding in the heavy group 14 analogues of alkenes and alkynes.