bluuebunny/crossref_metadata_2025 huggingface dataset:
Exome sequencing identifies a SREBF1 recurrent ARG557CYS mutation as the cause of hereditary mucoepithelial dysplasia in a family with high clinical variability
Authors: Chacon‐Camacho Oscar F. , Arce‐Gonzalez Rocio , Ordaz‐Robles Thania , Perezpeña‐Diazconti Mario , Nava‐Castañeda Angel , Zenteno Juan Carlos
Published: September 2020

Hereditary mucoepithelial dysplasia (HMD) is an uncommon autosomal dominant disease affecting skin, mucosae, hair, eyes, and lungs. Prominent clinical features include non‐scarring alopecia, mucosal erythema, perineal erythematous intertrigo, and involvement of the conjunctival mucosa. To date, 20 familial or sporadic HMD cases have been described, most of them originating from Caucasian ethnic groups. In this study, a novel HMD pedigree, including an affected father and his daughter, is reported. Clinical expression showed significant differences in affected subjects, especially in the distribution and severity of skin lesions. Exome sequencing demonstrated that both affected subjects carried a heterozygous c.1669C>T (p.Arg557Cys) pathogenic variant in the SREBF1 gene. Our results improve the knowledge of the clinical and genetic features of HMD. In addition, a comparative review of the clinical features of all published HMD cases is presented.
Hematologic presentation and the role of untargeted metabolomics analysis in monitoring treatment for riboflavin transporter deficiency
Authors: Pillai Nishitha R. , Amin Hitha , Gijavanekar Charul , Liu Ning , Issaq Niveen , Broniowska Katarzyna A. , Bertuch Alison A. , Sutton V. Reid , Elsea Sarah H. , Scaglia Fernando
Published: September 2020

Riboflavin transporter deficiency (RTD) (MIM #614707) is a neurogenetic disorder with its most common manifestations including sensorineural hearing loss, peripheral neuropathy, respiratory insufficiency, and bulbar palsy. Here, we present a 2‐year‐old boy whose initial presentation was severe macrocytic anemia necessitating multiple blood transfusions and intermittent neutropenia; he subsequently developed ataxia and dysarthria. Trio‐exome sequencing detected compound heterozygous variants in SLC52A2 that were classified as pathogenic and a variant of uncertain significance. Bone marrow evaluation demonstrated megaloblastic changes. Notably, his anemia and neutropenia resolved after treatment with oral riboflavin, thus expanding the clinical phenotype of this disorder. We reiterate the importance of starting riboflavin supplementation in a young child who presents with macrocytic anemia and neurological features while awaiting biochemical and genetic work up. We detected multiple biochemical abnormalities with the help of untargeted metabolomics analysis associated with abnormal flavin adenine nucleotide function which normalized after treatment, emphasizing the reversible pathomechanisms involved in this disorder. The utility of untargeted metabolomics analysis to monitor the effects of riboflavin supplementation in RTD has not been previously reported.
Facile Construction of 3,4‐dihydro‐2H‐1,2,4‐Benzothiadiazine 1,1‐Dioxides via Redox‐Neutral Cascade Condensation/[1,7]‐Hydride Transfer/Cyclization
Authors: Xing Yingying , Dong Fengying , Yin Xiangcong , Wang Liang , Li Shuai‐Shuai
Published: September 2020

The benzothiadiazine 1,1‐dioxides were highly efficiently constructed via a BF3.Et2O promoted redox‐neutral cascade condensation/[1,7]‐hydride transfer/cyclization, which featured novel substrate skeletons, broad substrate scope, [1,7]‐hydride transfer manner, metal‐free conditions and the facile introduction of aryl, heteroaryl, allyl and propargyl groups etc.
Adjunctive techniques to dacryocystorhinostomy: an evidence‐based review with recommendations
Authors: Yim Michael , Wormald Peter‐John , Doucet Manon , Gill Amarbir , Kingdom Todd , Orlandi Richard , Crum Alison , Marx Douglas , Alt Jeremiah
Published: September 2020

Background

Many adjunctive techniques exist for dacryocystorhinostomy (DCR), with varying levels of supportive evidence.

Methods

Literature from PubMed, EMBASE, and Cochrane Databases was reviewed between January 1990 and January 2020 to examine evidence regarding the utility of adjunctive techniques to DCR, including mucosal flap preservation, concurrent septoplasty, stenting, topical mitomycin C (MMC), and 5‐fluorouracil (5‐FU), as well as perioperative antibiotics and steroids. Recommendations were made based on the evidence found.

Results

Seven adjunctive techniques used in DCR were examined. The literature supported concurrent septoplasty when septal deviation is present. Silicone stents are recommended for external DCR approaches. MMC use is optional in external DCR and revision cases. The literature does not support the routine use of silicone stents or MMC in primary endoscopic DCR. Mucosal flap preservation is optional, with evidence showing comparable results with or without utilization. The level of evidence is limited for topical 5‐FU, as well as perioperative antibiotic and steroid use.

Conclusion

Recommendations for adjunctive techniques to external and endoscopic DCR surgeries can be made based on the current literature. Higher‐level studies are needed to better optimize perioperative approaches to DCR.
36‐month LipiDiDiet multinutrient clinical trial in prodromal Alzheimer's disease
Authors: Soininen Hilkka , Solomon Alina , Visser Pieter Jelle , Hendrix Suzanne B , Blennow Kaj , Kivipelto Miia , Hartmann Tobias ,   the LipiDiDiet clinical study group
Published: September 2020

Introduction

The LipiDiDiet trial investigates the effects of the specific multinutrient combination Fortasyn Connect on cognition and related measures in prodromal Alzheimer's disease (AD). Based on previous results we hypothesized that benefits increase with long‐term intervention.

Methods

In this randomized, double‐blind, placebo‐controlled trial, 311 people with prodromal AD were recruited using the International Working Group‐1 criteria and assigned to active product (125 mL once‐a‐day drink) or an isocaloric, same tasting, placebo control drink. Main outcome was change in cognition (Neuropsychological Test Battery [NTB] 5‐item composite). Analyses were by modified intention‐to‐treat, excluding (ie, censoring) data collected after the start of open‐label active product and/or AD medication.

Results

Of the 382 assessed for eligibility, 311 were randomized, of those 162 participants completed the 36‐month study, including 81 with 36‐month data eligible for efficacy analysis. Over 36 months, significant reductions in decline were observed for the NTB 5‐item composite (−60%; between‐group difference 0.212 [95% confidence interval: 0.044 to 0.380]; P = 0.014), Clinical Dementia Rating‐Sum of Boxes (−45%; P = 0.014), memory (−76%; P = 0.008), and brain atrophy measures; small to medium Cohen's d effect size (0.25–0.31) similar to established clinically relevant AD treatment.

Discussion

This multinutrient intervention slowed decline on clinical and other measures related to cognition, function, brain atrophy, and disease progression. These results indicate that intervention benefits increased with long‐term use.
A 30% incidence of renal cysts with varying sizes and densities in biomedical research swine is not associated with renal dysfunction
Authors: Gómez Belinda I. , Little Joshua S. , Leon Alisa J. , Stewart Ian J. , Burmeister David M.
Published: September 2020

Background

Renal cystic disease arising from various etiologies results in fluid‐filled cavities within the kidneys. Moreover, preexisting renal dysfunction has been shown to exacerbate multiple pathologies. While swine bred for biomedical research are often clinically inspected for illness/parasites, more advanced diagnostics may aid in uncovering underlying renal abnormalities.

Methods

Computed tomography was performed in 54 female prepubertal Yorkshire swine to characterize renal cysts; urine and blood chemistry, and histology of cysts were also performed.

Results

Digital reconstruction of right and left kidneys demonstrated that roughly one‐third of the animals (17/54; 31%) had one or more renal cyst. Circulating biomarkers of renal function were not different between animals that had cysts and those that did not. Alternatively, urinary glucose (P = .03) was higher and sodium (P = .07) tended to be lower in animals with cysts compared to animals without, with no differences in protein (P = .14) or potassium (P = .20). Aspiration of cystic fluid was feasible in two animals, which revealed that the cystic fluid urea nitrogen (97.6 ± 28.7 vs 911.3 ± 468.2 mg/dL), potassium (29.8 ± 14.4 vs 148.2 ± 24.85 mmol/L), uric acid (2.55 ± 1.35 vs 11.4 ± 5.65 mg/dL), and creatinine (60.34 ± 17.26 vs 268.99 ± 95.79 mg/dL) were much lower than in the urine. Histology demonstrated a cyst that markedly compresses the adjacent cortex and is lined by a single layer of flattened epithelium, bounded by fibrous connective tissue which extends into the parenchyma. There is tubular atrophy and loss in these areas.

Conclusion

This study provides valuable insight for future studies focusing on kidney function in swine bred for biomedical research.
Molekulares maschinelles Lernen: Die Zukunft der Synthesechemie?
Authors: Pflüger Philipp M. , Glorius Frank
Published: September 2020

Im letzten Jahrzehnt hat das moderne maschinelle Lernen Einzug in die Synthesechemie gehalten. Einige seit langem bestehende Herausforderungen, wie die computergestützte Syntheseplanung (Computer‐Aided Synthesis Planning, CASP), wurden erfolgreich angegangen, während andere Themen kaum berührt wurden. Dieser Standpunkt‐Beitrag wirft die Frage auf, ob aktuelle Trends langfristig bestehen können, und identifiziert Faktoren, die zu einer (un)produktiven Entwicklung führen werden. Dabei werden die spezifischen Risiken des molekularen maschinellen Lernens (MML) diskutiert. Ferner werden mögliche nachhaltige Entwicklungen, wie erklärbare künstliche Intelligenz (Explainable Artificial Intelligence, ExAI), für die Synthesechemie vorgeschlagen und Chancen für mögliche Neueinsteiger beleuchtet. Generell zielt dieser Standpunkt darauf ab, die wissenschaftliche Gemeinschaft in eine Diskussion über aktuelle wie auch zukünftige Trends zu führen.
Helicity Control of Polymeric Backbones with Alternating cis‐trans Double Bonds in Cyclopolymerized Dipropargyl Amides
Authors: Song Youngjun , Kang Sunyoung , Kang Sangyoon , Lee Yan
Published: September 2020

We report the synthesis of new helical polymeric structures having alternating cis and trans double bonds and chiral amino acid side chains by metathesis cyclopolymerization. The polymer helicity, which is generated by the interaction between fluorenylmethyloxycarbonyl (Fmoc) groups in the side chains, is dramatically affected by solvents. A thorough experimental and theoretical analysis including nuclear magnetic resonance, atomic force microscopy, and density functional theory and molecular mechanics calculations suggests that the helicity of both backbone and side chains are determined by anti‐syn rotation of the carbamate groups and by the different interactions of the Fmoc groups with solvents.
Selective Alkynylallylation of the C−C σ Bond of Cyclopropenes
Authors: Jiang Zeqi , Niu Sheng‐Li , Zeng Qiang , Ouyang Qin , Chen Ying‐Chun , Xiao Qing
Published: September 2020

A Pd‐catalyzed regio‐ and stereoselective alkynylallylation of a specific C−C σ bond in cyclopropenes, using allyl propiolates as both allylation and alkynylation reagents, has been achieved for the first time. By merging selective C(sp2)‐C(sp3) bond scission with conjunctive cross‐couplings, this decarboxylative reorganization reaction features fascinating atom and step economy and provides an efficient approach to highly functionalized dienynes from readily available substrates. Without further optimization, gram‐scale products can be easily obtained by such a simple, neutral, and low‐cost catalytic system with high TONs. DFT calculations afford a rationale toward the formation of the products and indicate that the selective insertion of the double bond of cyclopropenes into the C‐Pd bond of ambidentate Pd complex and the subsequent nonclassical β‐C elimination promoted by 1,4‐palladium migration are critical for the success of the reaction.
Synthesis of Discrete CHA Zeolite Nanocrystals without Organic Templates for Selective CO2 Capture
Authors: Debost Maxime , Klar Paul B. , Barrier Nicolas , Clatworthy Edwin B. , Grand Julien , Laine Fabien , Brázda Petr , Palatinus Lukas , Nesterenko Nikolai , Boullay Philippe , Mintova Svetlana
Published: September 2020

Small‐pore zeolites such as chabazite (CHA) are excellent candidates for the selective separation of CO2; however, the current synthesis involves several steps and the use of organic structure‐directing agent (OSDA), increasing their cost and energy requirements. We report the synthesis of small‐pore zeolite crystals (aluminosilicate) with CHA‐type framework structure by direct synthesis in a colloidal suspension containing a mixture of inorganic cations only (Na+, K+, and Cs+). The location of CO2 molecules in the host structure was revealed by 3D electron diffraction (3D ED). The high sorption capacity for CO2 (3.8 mmol g−1 at 121 kPa), structural stability and regenerability of the discreate CHA zeolite nanocrystals is maintained for 10 consecutive cycles without any visible degradation. The CHA zeolite (Si:Al=2) reaches an almost perfect CO2 storage capacity (8 CO2 per unit cell) and high selectivity (no CH4 was adsorbed).
Oxidative Addition of a Mechanically Entrapped C(sp)–C(sp) Bond to a Rhodium(I) Pincer Complex
Authors: Leforestier Baptiste , Gyton Matthew R. , Chaplin Adrian B.
Published: September 2020

By use of a macrocyclic phosphinite pincer ligand and bulky substrate substituents, we demonstrate how the mechanical bond can be leveraged to promote the oxidative addition of an interlocked 1,3‐diyne to a rhodium(I) center. The resulting rhodium(III) bis(alkynyl) product can be trapped out by reaction with carbon monoxide or intercepted through irreversible reaction with dihydrogen, resulting in selective hydrogenolysis of the C−C σ‐bond.
Highly Conducting Organic–Inorganic Hybrid Copper Sulfides CuxC6S6 (x=4 or 5.5): Ligand‐Based Oxidation‐Induced Chemical and Electronic Structure Modulation
Authors: Huang Xing , Qiu Yi , Wang Yishan , Liu Liyao , Wu Xiaoyu , Liang Yingying , Cui Yutao , Sun Yimeng , Zou Ye , Zhu Jia , Fang Weihai , Sun Junliang , Xu Wei , Zhu Daoben
Published: September 2020

Conductive coordination polymers (CPs) have potential in a wide range of applications because of their inherent structural and functional diversity. Three electrically conductive CPs (CuxC6S6, x=3, 4 or 5.5) derived from the same organic linker (benzenehexathiol) and metal node (copper(I)) were synthesized and studied. CuxC6S6 materials are organic–inorganic hybrid copper sulfides comprising a π‐π stacking structure and cooper sulfur networks. Charge‐transport pathways within the network facilitate conductivity and offer control of the Fermi level through modulation of the oxidation level of the non‐innocent redox‐active ligand. Two CuxC6S6 (x=4 or 5.5) CPs display high electrical conductivity and they feature a tunable structural topology and electronic structure. Cu4C6S6 and Cu5.5C6S6 act as degenerate semiconductors. Moreover, Cu5.5C6S6 is a p‐type thermoelectric material with a ZT value of 0.12 at 390 K, which is a record‐breaking performance for p‐type CPs.
A General Strategy for Development of Activatable NIR‐II Fluorescent Probes for In Vivo High‐Contrast Bioimaging
Authors: Ren Tian‐Bing , Wang Zhi‐Yao , Xiang Zhen , Lu Peng , Lai Huan‐Hua , Yuan Lin , Zhang Xiao‐Bing , Tan Weihong
Published: September 2020

Organic dye based NIR‐II fluorescent probes, owing to their high signal‐to‐background ratio and deeper penetration, are highly useful for deep‐tissue high‐contrast imaging in vivo. However, it is still a challenge to design activatable NIR‐II fluorescent probes. Here, a novel class of polymethine dyes (NIRII‐RTs), with bright (quantum yield up to 2.03 %), stable, and anti‐solvent quenching NIR‐II emission, together with large Stokes shifts, was designed. Significantly, the novel NIR‐II dyes NIRII‐RT3 and NIRII‐RT4, equipped with a carboxylic acid group, can serve as effective NIR‐II platforms for the design of activatable bioimaging probes with high contrast. As a proof of concept, a series of target‐activatable NIRII‐RT probes (NIRII‐RT‐pH, NIRII‐RT‐ATP and NIRII‐RT‐Hg) for pH, adenosine triphosphate (ATP), and metal‐ion detection, were synthesized. By applying the NIRII‐RT probe, the real‐time monitoring of drug‐induced hepatotoxicity was realized.
Biopolymer‐based Carriers for DNA Vaccine Design
Authors: Franck Christoph O. , Fanslau Luise , Bistrovic Popov Andrea , Tyagi Puneet , Fruk Ljiljana
Published: September 2020

Over the last 30 years, genetically engineered DNA has been tested as novel vaccination strategy against various diseases, including human immunodeficiency virus (HIV), hepatitis B, several parasites, and cancers. However, the clinical breakthrough of the technique is confined by the low transfection efficacy and immunogenicity of the employed vaccines. Therefore, carrier materials were designed to prevent the rapid degradation and systemic clearance of DNA in the body. In this context, biopolymers are a particularly promising DNA vaccine carrier platform due to their beneficial biochemical and physical characteristics, including biocompatibility, stability, and low toxicity. This article reviews the applications, fabrication, and modification of biopolymers as carrier medium for genetic vaccines.
Iron‐Catalyzed Radical Relay Enabling the Modular Synthesis of Fused Pyridines from Alkyne‐Tethered Oximes and Alkenes
Authors: Du Fei , Li Shi‐Jun , Jiang Kun , Zeng Rong , Pan Xi‐Chun , Lan Yu , Chen Ying‐Chun , Wei Ye
Published: September 2020

We have rationally designed a new class of alkyne‐tethered oximes and applied them in an unprecedented iron‐catalyzed radical relay protocol for the rapid assembly of a wide array of structurally new and interesting fused pyridines. This method shows broad substrate scope and good functional‐group tolerance and enabled the synthesis of several biologically active molecules. Furthermore, the fused pyridines could be diversely functionalized through various simple transformations, such as cyclization, C−H alkylation, and a click reaction. DFT calculation studies indicate that the reactions involve cascade 1,5‐hydrogen atom transfer, 5‐exo‐dig radical addition, and cyclization processes. Moreover, preliminary biological investigations suggest that some of the fused pyridines exhibit good anti‐inflammatory activity by restoring the imbalance of inflammatory homeostasis of macrophages in a lipopolysaccharide‐induced model.
Direkte β‐ und γ‐C(sp3)‐H Alkinylierung freier Carbonsäuren**
Authors: Ghiringhelli Francesca , Uttry Alexander , Ghosh Kiron Kumar , van Gemmeren Manuel
Published: September 2020

In dieser Studie berichten wir über die Identifizierung einer neuen Klasse von Liganden für die Palladium‐katalysierte C(sp3)‐H‐Aktivierung, welche die direkte Alkinylierung freier Carbonsäuren ermöglicht. Im Gegensatz zu früheren synthetischen Methoden ist keine Einführung/Entfernung einer exogenen dirigierenden Gruppe erforderlich. Als Substrate kann eine breite Palette von Säuren verwendet werden, darunter sowohl α‐quartäre als auch anspruchsvolle α‐nicht‐quartäre Substrate. Zusätzlich wird über die Alkinylierung in der entfernten γ‐Position berichtet. Schließlich beinhaltet diese Studie vorläufige Ergebnisse zu einer enantioselektiven Variante der Titelreaktion sowie zu synthetischen Anwendungen der erhaltenen Produkte.
Bindung von CO am FeV‐Cofaktor der CO‐reduzierenden Vanadium‐Nitrogenase bei atomarer Auflösung
Authors: Rohde Michael , Grunau Katharina , Einsle Oliver
Published: September 2020

Nitrogenasen reduzieren N2, das häufigste Element in der Erdatmosphäre, das aufgrund seiner Dreifachbindung chemisch nicht leicht zugänglich ist. Vanadium‐Nitrogenase zeichnet sich zudem durch die Fähigkeit aus, Kohlenmonoxid, einen bekannten Inhibitor für alle Substrate mit Ausnahme von H+, umzusetzen. Die Reduktion von CO führt zur Bildung von Kohlenwasserstoffprodukten, welche das Potential für biotechnologische Anwendungen in Analogie zum industriellen Fischer‐Tropsch‐Verfahren bergen. Hier berichten wir über die bisher detaillierteste Struktur der Vanadium Nitrogenase bei einer Auflösung von 1.0 Å, in welcher CO nach katalytischer Umsetzung an den Cofaktor des aktiven Zentrums gebunden ist. CO verbrückt dabei die Eisenionen Fe2 und Fe6 und ersetzt damit das Sulfid S2B in einem Bindungsmodus, der mit bisherigen Berichten des CO‐Komplexes der Molybdän‐Nitrogenase in Einklang ist. Wir erläutern zudem die strukturellen Konsequenzen fortlaufender katalytischer Umsetzung, wenn CO wieder entfernt wird. Diese umfassen den Austausch von CO, möglicherweise durch OH−, Bewegungen der Seitenketten Q176D und K361D, die Rückkehr des Sulfids und das Auftauchen zweier zusätzlicher Wassermoleküle, die im CO‐gebunden Zustand nicht vorhanden sind.
Visible‐Light‐Induced Vicinal Dichlorination of Alkenes through LMCT Excitation of CuCl2
Authors: Lian Pengcheng , Long Wenhao , Li Jingjing , Zheng Yonggao , Wan Xiaobing
Published: September 2020

This work demonstrates photoredox vicinal dichlorination of alkenes, based on the homolysis of CuCl2 in response to irradiation with visible light. This catalysis proceeds via a ligand to metal charge transfer process and provides an exciting opportunity for the synthesis of 1,2‐dichloride compounds using an inexpensive, low‐molecular‐weight chlorine source. This new process exhibits a wide substrate scope, excellent functional group tolerance, extraordinarily mild conditions and does not require external ligands. Mechanistic studies show that the ready formation of chlorine atom radicals is responsible for the facile formation of C−Cl bonds in this synthetic process.
Ligand‐Controlled Regiodivergence in Nickel‐Catalyzed Hydroarylation and Hydroalkenylation of Alkenyl Carboxylic Acids**
Authors: Li Zi‐Qi , Fu Yue , Deng Ruohan , Tran Van T. , Gao Yang , Liu Peng , Engle Keary M.
Published: September 2020

A nickel‐catalyzed regiodivergent hydroarylation and hydroalkenylation of unactivated alkenyl carboxylic acids is reported, whereby the ligand environment around the metal center dictates the regiochemical outcome. Markovnikov hydrofunctionalization products are obtained under mild ligand‐free conditions, with up to 99 % yield and >20:1 selectivity. Alternatively, anti‐Markovnikov products can be accessed with a novel 4,4‐disubstituted Pyrox ligand in excellent yield and >20:1 selectivity. Both electronic and steric effects on the ligand contribute to the high yield and selectivity. Mechanistic studies suggest a change in the turnover‐limiting and selectivity‐determining step induced by the optimal ligand. DFT calculations reveal that in the anti‐Markovnikov pathway, repulsion between the ligand and the alkyl group is minimized (by virtue of it being 1° versus 2°) in the rate‐ and regioselectivity‐determining transmetalation transition state.
C−H Methylation of Iminoamido Heterocycles with Sulfur Ylides**
Authors: Ghosh Prithwish , Kwon Na Yeon , Kim Saegun , Han Sangil , Lee Suk Hun , An Won , Mishra Neeraj Kumar , Han Soo Bong , Kim In Su
Published: September 2020

The direct methylation of N‐heterocycles is an important transformation for the advancement of pharmaceuticals, agrochemicals, functional materials, and other chemical entities. Herein, the unprecedented C(sp2)‐H methylation of iminoamido heterocycles as nucleoside base analogues is described. Notably, trimethylsulfoxonium salt was employed as a methylating agent under aqueous conditions. A wide substrate scope and excellent level of functional‐group tolerance were attained. Moreover, this method can be readily applied to the site‐selective methylation of azauracil nucleosides. The feasibility of gram‐scale reactions and various transformations of the products highlight the synthetic potential of the developed method. Combined deuterium‐labeling experiments aided the elucidation of a plausible reaction mechanism.
Two Spectroscopies in One: Interference of Circular Dichroism and Raman Optical Activity
Authors: Wu Tao , Li Guojie , Kapitán Josef , Kessler Jiří , Xu Yunjie , Bouř Petr
Published: September 2020

Previously, we and other laboratories have reported an unusual and strong Raman optical activity (ROA) induced in solvents by chiral dyes. Various theories of the phenomenon appeared, but they were not capable of explaining fully the observed ROA band signs and intensities. In this work, an analysis based both on the light scattering theory and dedicated experiments provides a more complete understanding. For example, double‐cell magnetic circular dichroism and magnetic ROA experiments with copper‐porphyrin complex show that the induced chirality is observed without any contact of the solvents with the complex. The results thus indicate that a combination of electronic circular dichroism (ECD) with the polarized Raman scattering is responsible for the effect. The degree of circularity of solvent vibrational bands is a principal molecular property participating in the event. The insight and the possibility to predict the chirality transfer promise future applications in spectroscopy, chemical analysis and polarized imaging.
MOF‐Mediated Fabrication of a Porous 3D Superstructure of Carbon Nanosheets Decorated with Ultrafine Cobalt Phosphide Nanoparticles for Efficient Electrocatalysis and Zinc–Air Batteries
Authors: Hou Chun‐Chao , Zou Lianli , Wang Yu , Xu Qiang
Published: September 2020

Superstructures have attracted great interest owing to their potential applications. Herein, we report the first scalable preparation of a porous nickel‐foam‐templated superstructure of carbon nanosheets decorated with ultrafine cobalt phosphide nanoparticles. Uniform two‐dimensional (2D) Co‐metal organic framework (MOF) nanosheets (Co‐MNS) grow on nickel foam, followed by a MOF‐mediated tandem (carbonization/phosphidation) pyrolysis. The resulting superstructure has a porous 3D interconnected network with well‐arranged 2D carbon nanosheets on it, in which ultrafine cobalt phosphide nanoparticles are tightly immobilized. A single piece of this superstructure can be directly used as a self‐supported electrode for electrocatalysis without any binders. This “one‐piece” porous superstructure with excellent mass transport and electron transport properties, and catalytically active cobalt phosphide nanoparticles with ultrasmall size (3–4 nm), shows excellent trifunctional electrocatalytic activities for oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR), achieving great performances in water splitting and Zn–air batteries.
Self‐Waveguide Single‐Benzene Organic Crystal with Ultralow‐Temperature Elasticity as a Potential Flexible Material
Authors: Liu Bin , Lu Zhuoqun , Tang Baolei , Liu Hao , Liu Huapeng , Zhang Zuolun , Ye Kaiqi , Zhang Hongyu
Published: September 2020

With the increasing popularity and burgeoning progress of space technology, the development of ultralow‐temperature flexible functional materials is a great challenge. Herein, we report a highly emissive organic crystal combining ultralow‐temperature elasticity and self‐waveguide properties (when a crystal is excited, it emits light from itself, which travels through the crystal to the other end) based on a simple single‐benzene emitter. This crystal displayed excellent elastic bending ability in liquid nitrogen (LN). Preliminary experiments on optical waveguiding in the bent crystal demonstrated that the light generated by the crystal itself could be confined and propagated within the crystal body between 170 and −196 °C. These results not only suggest a guideline for designing functional organic crystals with ultralow‐temperature elasticity but also expand the application region of flexible materials to extreme environments, such as space technology.
Photochemical In Situ Exfoliation of Metal–Organic Frameworks for Enhanced Visible‐Light‐Driven CO2 Reduction
Authors: Zheng Hui‐Li , Huang Shan‐Lin , Luo Ming‐Bu , Wei Qin , Chen Er‐Xia , He Liang , Lin Qipu
Published: September 2020

Two novel two‐dimensional metal–organic frameworks (2D MOFs), 2D‐M2TCPE (M=Co or Ni, TCPE=1,1,2,2‐tetra(4‐carboxylphenyl)ethylene), which are composed of staggered (4,4)‐grid layers based on paddlewheel‐shaped dimers, serve as heterogeneous photocatalysts for efficient reduction of CO2 to CO. During the visible‐light‐driven catalysis, these structures undergo in situ exfoliation to form nanosheets, which exhibit excellent stability and improved catalytic activity. The exfoliated 2D‐M2TCPE nanosheets display a high CO evolution rate of 4174 μmol g−1 h−1 and high selectivity of 97.3 % for M=Co and Ni, and thus are superior to most reported MOFs. The performance differences and photocatalytic mechanisms have been studied with theoretical calculations and photoelectric experiments. This study provides new insight for the controllable synthesis of effective crystalline photocatalysts based on structural and morphological coregulation.
Facile Dinitrogen and Dioxygen Cleavage by a Uranium(III) Complex: Cooperativity Between the Non‐Innocent Ligand and the Uranium Center
Authors: Wang Penglong , Douair Iskander , Zhao Yue , Wang Shuao , Zhu Jun , Maron Laurent , Zhu Congqing
Published: September 2020

Activation of dinitrogen (N2, 78 %) and dioxygen (O2, 21 %) has fascinated chemists and biochemists for decades. The industrial conversion of N2 into ammonia requires extremely high temperatures and pressures. Herein we report the first example of N2 and O2 cleavage by a uranium complex, [N(CH2CH2NPiPr2)3U]2(TMEDA), under ambient conditions without an external reducing agent. The N2 triple bond breaking implies a UIII–PIII six‐electron reduction. The hydrolysis of the N2 reduction product allows the formation of ammonia or nitrogen‐containing organic compounds. The interaction between UIII and PIII in this molecule allows an eight‐electron reduction of two O2 molecules. This study establishes that the combination of uranium and a low‐valent nonmetal is a promising strategy to achieve a full N2 and O2 cleavage under ambient conditions, which may aid the design of new systems for small molecules activation.
α‐Functionalisation of Ketones Through Metal‐Free Electrophilic Activation
Authors: Zawodny Wojciech , Teskey Christopher J. , Mishevska Magdalena , Völkl Martin , Maryasin Boris , González Leticia , Maulide Nuno
Published: September 2020

Triflic anhydride mediated activation of acetophenones leads to highly electrophilic intermediates that can undergo a variety of transformations when treated with nucleophiles. This electrophilic ketone activation gives access to α‐arylated and α‐oxyaminated acetophenones under metal‐free conditions in moderate to excellent yields and enables extension to the synthesis of arylated morpholines via generation of vinylsulfonium salts. Computational investigations confirmed the transient existence of intermediates derived from vinyl triflates and the role of the oxygen atoms at the para position of aromatic ring in facilitating their stabilisation.
Frustrated Lewis Pairs Comprising Nitrogen Lewis Acids for Si–H Bond Activation
Authors: Avigdori Idan , Pogoreltsev Alla , Kaushanski Alexander , Fridman Natalia , Gandelman Mark
Published: September 2020

N‐heterocyclic nitrogen Lewis acids are a recent addition to the field of organic chemistry. Based on nitrenium cations, these acids where previously shown to generate Lewis adducts when combined with the appropriate Lewis bases. Herein, a triazinium‐based Lewis acid was combined with tBu3P to generate a frustrated Lewis pair (FLP) capable of cleaving, for the first time, Si−H bonds in silanes. Whereas low yields were initially encountered owing to insufficient Lewis acidity, a new nitrenium‐based Lewis acid was synthesized, and its superior Lewis acidity was experimentally and computationally confirmed. A FLP based on this acid cleaved the Si−H bond in PhSiH3, generating the triazane product in a quantitative yield. This unprecedented N−H triazane was fully characterized by multinuclear NMR techniques and single‐crystal X‐ray crystallography. A new class of compounds, N‐H triazanes display the potential capacity to participate in hydride transfer reactions.
Synthesis ofi‐Corona[6]arenes for Selective Anion Binding: Interdependent and Synergistic Anion–π and Hydrogen‐Bond Interactions
Authors: Zhuang Sheng‐Yi , Cheng Ying , Zhang Qian , Tong Shuo , Wang Mei‐Xiang
Published: September 2020

i‐Corona[3]arene[3]tetrazines were synthesized from the nucleophilic aromatic substitution reaction of resorcinol and its derivatives with 3,6‐dichlorotetrazine in a one‐pot fashion under mild conditions. All of the resulting macrocycles adopted 1,3,5‐alternate conformation irrespective of the nature of the substituents on both upper‐ and lower‐rims. i‐Corona[3]arene[3]tetrazine was found to self‐regulate its macrocyclic conformation and cavity to recognize anions with binding constants spanning from 26 M−1to 2.2×103 M−1depending on the structure of the anions. The selective binding resulted from a significant interdependent and synergistic effect between multiple tetrazine π/anion and Caryl–H/anion hydrogen bond interactions. Taking advantage of synergistic effect revealed, a cyanobenzene‐embedded i‐corona[3]arene[3]tetrazine was designedly synthesized and highly selective and very strong affinity toward nitrate with a binding constant of 2.2×105 M−1was achieved.
Double Histidine Based EPR Measurements at Physiological Temperatures Permit Site‐Specific Elucidation of Hidden Dynamics in Enzymes
Authors: Singewald Kevin , Bogetti Xiaowei , Sinha Kaustubh , Rule Gordon S , Saxena Sunil
Published: September 2020

Protein dynamics is at the heart of all cellular processes. Here, we utilize the dHis‐CuIINTA label to obtain site‐specific information on dynamics for both an α‐helix and β‐sheet site of GB1, the immunoglobulin binding domain of protein G. Spectral features found in our CW‐EPR measurements were consistent with the overall rigid nature of GB1 and with predictions from molecular dynamics simulations. Using this information, we show the potential of this approach to elucidate the role of dynamics in substrate binding of a functionally necessary α‐helix in human glutathione transferase A1‐1 (hGSTA1‐1). We observe two dynamical modes for the helix. The addition of the inhibitor GS‐Met and GS‐Hex resulted in hGSTA1‐1 to favor the more rigid active state conformation, while the faster mode potentially aids the search for substrates. Together the results illustrate the remarkable potential of the dHis‐based labelling approach to measure site‐specific dynamics using room temperature lineshape analysis.
Hydrogen Purification through a Highly Stable Dual‐Phase Oxygen‐Permeable Membrane
Authors: Jia Lujian , He Guanghu , Zhang Yan , Caro Jürgen , Jiang Heqing
Published: September 2020

Using oxygen permeable membranes (OPMs) to upgrade low‐purity hydrogen is a promising concept for high‐purity H2 production. At high temperatures, water dissociates into hydrogen and oxygen. The oxygen permeates through OPM and oxidizes hydrogen in a waste stream on the other side of the membrane. Pure hydrogen can be obtained on the water‐splitting side after condensation. However, the existing Co‐ and Fe‐based OPMs are chemically instable as a result of the over‐reduction of Co and Fe ions under reducing atmospheres. Herein, a dual‐phase membrane Ce0.9Pr0.1O2−δ‐Pr0.1Sr0.9Mg0.1Ti0.9O3−δ (CPO‐PSM‐Ti) with excellent chemical stability and mixed oxygen ionic‐electronic conductivity under reducing atmospheres was developed for H2 purification. An acceptable H2 production rate of 0.52 mL min−1 cm−2 is achieved at 940 °C. No obvious degradation during 180 h of operation indicates the robust stability of CPO‐PSM‐Ti membrane. The proven mixed conductivity and excellent stability of CPO‐PSM‐Ti give prospective advantages over existing OPMs for upgrading low‐purity hydrogen.
A Concise Enantioselective Total Synthesis of (−)‐Deoxoapodine
Authors: Yoshida Kei , Okada Kosuke , Ueda Hirofumi , Tokuyama Hidetoshi
Published: September 2020

We have established a highly convergent 10‐step route for the total synthesis of (−)‐deoxoapodine, which is a hexacyclic aspidosperma alkaloid. The quaternary C5 center of the characteristic tetrahydrofuran ring was constructed by a chiral‐phosphoric‐acid‐catalyzed enantioselective bromocycloetherification in a 5‐endo fashion and subsequent allylation by using the Keck protocol. Construction of the aspidosperma skeleton features the formation of a nine‐membered lactam by a catalytic C−H palladation/alkylation cascade at the indole 2‐position and an iron‐catalyzed oxidative transannular reaction at a late‐stage of the synthesis.
Molecular Zinc Hydride Cations [ZnH]+: Synthesis, Structure, and CO2 Hydrosilylation Catalysis
Authors: Ritter Florian , Spaniol Thomas P. , Douair Iskander , Maron Laurent , Okuda Jun
Published: September 2020

Protonolysis of [ZnH2]n with the conjugated Brønsted acid of the bidentate diamine TMEDA (N,N,N′,N′‐tetramethylethane‐1,2‐diamine) and TEEDA (N,N,N′,N′‐tetraethylethane‐1,2‐diamine) gave the zinc hydride cation [(L2)ZnH]+, isolable either as the mononuclear THF adduct [(L2)ZnH(thf)]+[BArF4]− (L2=TMEDA; BArF4−=[B(3,5‐(CF3)2‐C6H3)4]−) or as the dimer [{(L2)Zn)}2(μ‐H)2]2+[BArF4]−2 (L2=TEEDA). In contrast to [ZnH2]n, the cationic zinc hydrides are thermally stable and soluble in THF. [(L2)ZnH]+ was also shown to form di‐ and trinuclear adducts of the elusive neutral [(L2)ZnH2]. All hydride‐containing cations readily inserted CO2 to give the corresponding formate complexes. [(TMEDA)ZnH]+[BArF4]− catalyzed the hydrosilylation of CO2 with tertiary hydrosilanes to give stepwise formoxy silane, methyl formate, and methoxy silane. The unexpected formation of methyl formate was shown to result from the zinc‐catalyzed transesterification of methoxy silane with formoxy silane, which was eventually converted into methoxy silane as well.
Isotope Effects in Plasmonic Photosynthesis
Authors: Yu Sungju , Jain Prashant K.
Published: September 2020

The photoexcitation of plasmonic nanoparticles has been shown to drive multistep, multicarrier transformations, such as the conversion of CO2 into hydrocarbons. But for such plasmon‐driven chemistry to be precisely understood and modeled, the critical photoinitiation step in the reaction cascade must be identified. We meet this goal by measuring H/D and 12C/13C kinetic isotope effects (KIEs) in plasmonic photosynthesis. In particular, we found that the substitution of H2O with D2O slows hydrocarbon production by a factor of 5–8. This primary H/D KIE leads to the inference that hole‐driven scission of the O−H bond in H2O is a critical, limiting step in plasmonic photosynthesis. This study advances mechanistic understanding of light‐driven chemical reactions on plasmonic nanoparticles.
The preparation of new palladium (II) complexes with Schiff base type ligands and its impregnated Al2O3 materials: As the catalysts for degradation/reduction of organic dyes
Authors: Selvi Gizem , Tercan Melek , Özdemir Namık , Dayan Osman
Published: September 2020

The removal of organic dyes used in many sectors such as textile, paper, leather, and packaging from water sources is very important in terms of preventing the spread of industrial pollutants to the environment. Transition metal complexes supported to an inorganic solid material are frequently used for the degradation/reduction of organic dyes causing this pollution. In this study, new Pd (II) complexes with Schiff base ligands were synthesized and structurally characterized by nuclear magnetic resonance (NMR), Fourier‐transform infrared spectroscopy (FT‐IR), mass spectrometry (MS), and single‐crystal X‐ray diffraction (sc‐XRD) spectroscopic methods. Then, the Al2O3‐impregnated materials of these Pd (II) complexes were prepared and characterized by scanning electron microscopy with energy dispersive X‐ray analysis (SEM‐EDX), FT‐IR, and thermogravimetry (TG) techniques. The catalytic activities of the synthesized Pd (II) complexes and their Al2O3‐impregnated materials were comparatively analyzed to investigate the degradation/reduction of organic dyes (2‐nitroaniline, 4‐nitroaniline, 4‐nitrophenol, eosin yellow, and methylene blue). The catalytic results indicate that Al2O3‐impregnated materials are very active catalysts for the degradation/reduction of organic dyes under those circumstances. Conversions of up to 98% for all substrates were obtained after 5 min at ambient temperature.
Copper(II) complex intercalated graphene oxide nanocomposites as versatile, reusable catalysts for click reaction
Authors: Samuel Angel Green , Nagarajan Karthikeyan , Cidhuraj Karthick , Gopal Bhalerao , Chakravarty Sujay , Selvaraj Varadharajaperumal , Lourdusamy Emmanuvel , Bhagavathsingh Jebasingh
Published: September 2020

In this work, we report the efficient, high stable copper(II) complexes intercalated graphene oxide (GO) used as green catalysts for copper(II) complex mediated click reaction. Copper(II) Bis(2,2′‐bipyridine) [CuII (bpy)2] (C1) and Copper(II) Bis(1,10‐phenanthroline) [CuII (phen)2] (C2) have synthesized for the intercalation of corresponding nanocomposites with GO, [GO@CuII (bpy)2] (GO‐C1) and [GO@CuII (phen)2] (GO‐C2). The noncovalent interaction of complexes supported on the surface of the GO nanosheets proves as an evident active site to facilitate the enhanced catalytic activity of copper‐catalyzed alkyne azide cycloaddition (CuIIAAC) reaction for the isolation of 1,4‐disubstituted‐1,2,3‐triazoles as click products in shorter reaction time with 80%–91% yield (five examples). The X‐ray diffraction (XRD) pattern of these composites shows the enhanced interlayers d‐spacing range of 1.01–1.12 nm due to the intercalation of copper(II) complexes in between the GO basal planes and characterized by X‐ray photoelectron spectroscopy (XPS), Fourier‐transform infrared spectroscopy (FT‐IR), Raman, UV, scanning electron microscope (SEM), and thermogravimetric analysis (TGA). The as‐prepared nanocomposites were employed for the typical click reactions using the substrates of azide and acetylene. These classes of composite materials can be referred to recyclable, heterogeneous, green catalysts with high atom economy and could also be used for the isolation of click products in biomolecules.
Peripheral or nonperipheral tetra‐[4‐(9H‐carbazol‐9‐yl)phenoxy] substituted cobalt(II), manganese(III) phthalocyanines: Synthesis, acetylcholinesterase, butyrylcholinesterase, and α‐glucosidase inhibitory effects and anticancer activities
Authors: Barut Burak , Keleş Turgut , Biyiklioglu Zekeriya , Yalçın Can Özgür
Published: September 2020

In this work, peripheral or nonperipheral tetra‐[4‐(9H‐carbazol‐9‐yl)phenoxy] substituted cobalt(II), manganese (III) phthalocyanines were synthesized for the first time. Their acetylcholinesterase from Electrophorus electricus (AChE), butyrylcholinesterase equine serum (BuChE), and α‐glucosidase Saccharomyces cerevisiae inhibition were investigated spectrophotometrically. Finally, in vitro cytotoxicities of the compounds were investigated on human neuroblastoma (SH‐SY5Y) cell line using MTT cell viability assay. The compounds inhibited to enzymes in the range of 7.39 ± 0.25–35.29 ± 2.49 μM with IC50 values for AChE and 14.38 ± 0.66–58.02 ± 4.94 μM for BuChE as compared with galantamine, which used as a positive control. For α‐glucosidase, all compounds had stronger inhibition action than acarbose according to the IC50 values. The IC50 values of NCo and NMn were found to be 3.05 ± 0.10 and 15.82 ± 1.85 μM, respectively. The results of cytotoxicity showed that the IC50 values were above 100 μM showing the compounds had low cytotoxic action against SH‐SY5Y cell line for 24 h. Overall, carbazole substituted nonperipheral compounds can be considered as a potential agent for the treatment of Alzheimer's diseases and diabetes mellitus.
Cold Plasma Treatment of Soybean Oil with Hydrogen Gas
Authors: Yepez Ximena V. , Baykara Haci , Xu Lei , Keener Kevin M.
Published: September 2020

High‐voltage atmospheric cold plasma (HVACP) treatment generates reactive gas species that induce inter‐ and intramolecular reactions in soybean oil. The goal of this study is to analyze the effect of HVACP treatment on the chemical structure of soybean oil in a hydrogen gas environment at atmospheric pressure. HVACP was used to treat soybean oil (15 g) for up to 6 hours by triplicate. Plasma‐generated reactive gas species interact with the sample, producing three distinct fractions identified as a liquid, gel, and solid. Fatty acid profile, Fourier‐transform infrared spectroscopy, proton and carbon nuclear magnetic resonance, size‐exclusion chromatography, thermal properties, and peroxide value were used to characterize the chemical structure. Results indicated a lower content of polyunsaturated fatty acids, increased content of saturated fatty acids, and the presence of isomers. An insoluble portion was observed in the solid fraction and increased with treatment time up to 42% in the 6‐h treated samples. Plasma species may cause two main reactions: polymerization and hydrogenation.
Accurate Prediction of Kinematic Viscosity of Biodiesels and their Blends with Diesel Fuels
Authors: Mehrizadeh Masoud , Nikbin‐Fashkacheh Hadi , Zand Nima , Najafi‐Marghmaleki Adel
Published: September 2020

Viscosity of mixtures of biodiesels (admixtures) and mixtures of biodiesel/diesel (blends) is a important parameter for determining their combustion behavior. There is no universal and general model for prediction of viscosity of these systems at different conditions. Hence, developing simple, accurate, and general models for prediction of viscosity of these systems is of great importance. In this work, three computer‐based models named multilayer perceptron neural network (MLP‐NN), radial basis function optimized by particle swarm optimization (PSO‐RBF), and adaptive neuro fuzzy inference system optimized by hybrid approach (Hybrid‐ANFIS) were developed for prediction of viscosity of blends and admixtures. A number of 966 experimental data covering wide ranges of influencing parameters were utilized to develop the models. The accuracy of predictions of the developed models was examined by using different statistical quality measure approaches as well as comparing their results with the predictions of literature models. Results showed that the developed models present accurate predictions and are superior to the literature models. The predictions of PSO‐RBF model were also better than Hybrid‐ANFIS and MLP‐NN models.