bluuebunny/crossref_metadata_2025_split huggingface dataset:
Terphen[n]arenes and Quaterphen[n]arenes (n=3–6): One‐Pot Synthesis, Self‐Assembly into Supramolecular Gels, and Iodine Capture
Authors: Li Bin , Wang Bin , Huang Xiayang , Dai Lu , Cui Lei , Li Jian , Jia Xueshun , Li Chunju 
Published: January 2019

AbstractHerein, two new classes of macrocyclic compounds, terphen[n]arenes (TPns) (n=3–6) and quaterphen[n]arenes (QPns) (n=3–6), were designed and synthesized by a one‐step condensation reaction in relatively high yields. They comprise 2,2′′‐dimethoxy terphenyl and 2,2′′′‐dimethoxy quaterphenyl monomers, respectively, linked by methylene bridges. Given their long and rigid monomers, TPns and QPns have much larger cavities and better self‐assembly properties than classic macrocycles. More interestingly, the cyclic pentamers and hexamers TP5, TP6, QP5, and QP6 formed supramolecular organogels, which were composed of interwoven fibers, nanosheets, or entangled macropore networks formed by multiple face‐to‐face and edge‐to‐face π⋅⋅⋅π stacking interactions. The xerogel materials effectively captured volatile iodine, not only in aqueous media but also in the gaseous state, and could be recycled multiple times without obvious loss in performance.
C−F Bond Activation by a Saturated N‐Heterocyclic Carbene: Mesoionic Compound Formation and Adduct Formation with B(C6F5)3
Authors: Pait Moumita , Kundu Gargi , Tothadi Srinu , Karak Suvendu , Jain Shailja , Vanka Kumar , Sen Sakya S. 
Published: January 2019

AbstractThe reaction of SIPr, [1,3‐bis(2,6‐diisopropylphenyl)‐imidazolin‐2‐ylidene] (1), with C6F6 led to the formation of an unprecedented mesoionic compound (2). The formation of 2 is made accessible by deprotonation of the SIPr backbone with simultaneous elimination of HF. The C−F bond para to the imidazolium ring in 2 is only of 1.258(4) Å, which is the one of the shortest structurally authenticated C−F bonds known to date. The liberation of HF during the reaction is unequivocally proved by the addition of one more equivalent of SIPr, which leads to the imidazolium salt with the HF2− anion. To functionalize 2, the latter reacted with B(C6F5)3 to give an unusual donor–acceptor compound, where the fluoride atom from the C6F5 moiety coordinates to B(C6F5)3 and the carbanion moiety remains unaffected. Such coordination susceptibility of the fluoride atom of a nonmetallic system to a main‐group Lewis acid (Fnon‐metal→BR3) is quite unprecedented.
Sulfilimines as Versatile Nitrene Transfer Reagents: Facile Access to Diverse Aza‐Heterocycles
Authors: Tian Xianhai , Song Lina , Rudolph Matthias , Rominger Frank , Oeser Thomas , Hashmi A. Stephen K. 
Published: January 2019

AbstractWe herein report the unprecedented synthesis of diverse biologically important aza‐heterocycles by employing sulfilimines as nitrene transfer reagents. This class of sulfur‐based aza‐ylides had not been successfully used for gold nitrene transfer before. This work contains an efficient generation of α‐imino gold carbenes by N−S cleavage of sulfilimines. These gold carbenes undergo C−H insertion, cyclopropanation, and nucleophilic attack to form indoles (44 examples), 3‐azabicyclo[3.1.0]hexan‐2‐imines (24 examples), and imidazoles (3 examples). Our study represents a unique gold‐catalyzed reaction between alkynes and sulfur ylides, and also includes the first aza‐heterocycle synthesis that proceeds by intermolecular nitrene transfer followed by cyclopropanation of the α‐imino gold carbenes. Moreover, an unexpected synthesis of 4‐acylquinolines (3 examples) from 2‐acylphenyl sulfilimines and propargylic silyl ether derivatives by a 1,2‐hydride shift onto the α‐imino gold carbene and a subsequent Mukaiyama aldol cyclization was discovered.
Influence of Hydronium Ions in Zeolites on Sorption
Authors: Eckstein Sebastian , Hintermeier Peter H. , Zhao Ruixue , Baráth Eszter , Shi Hui , Liu Yue , Lercher Johannes A. 
Published: January 2019

AbstractIn the presence of sufficient concentrations of water, stable, hydrated hydronium ions are formed in the pores and at the surface of solid acids such as zeolites. For a medium‐pore zeolite, such as zeolite MFI, hydrated hydronium ions consist of eight water molecules and have an effective volume of 0.24 nm3. In their presence, larger organic molecules can only adsorb in the portions of the pore that are not occupied by hydronium ions. As a consequence, the available pore volume decreases proportionally to the concentration of the hydronium ions. The higher charge density (the increasing ionic strength) that accompanies an increasing concentration of hydronium ions leads to an increase in the activity coefficients of the adsorbed substrates, thus, weakening the interactions between the organic part of the molecules and the zeolite and favoring the interactions with polar groups. The quantitative understanding of these interactions makes it possible to link a collective property such as hydrophilicity and hydrophobicity of zeolites to specific interactions on molecular level.
Next‐Generation D2‐Symmetric Chiral Porphyrins for Cobalt(II)‐Based Metalloradical Catalysis: Catalyst Engineering by Distal Bridging
Authors: Hu Yang , Lang Kai , Tao Jingran , Marshall McKenzie K. , Cheng Qigan , Cui Xin , Wojtas Lukasz , Zhang X. Peter 
Published: January 2019

AbstractNovel D2‐symmetric chiral amidoporphyrins with alkyl bridges across two chiral amide units on both sides of the porphyrin plane (designated “HuPhyrin”) have been effectively constructed in a modular fashion to permit variation of the bridge length. The CoII complexes of HuPhyrin, [Co(HuPhyrin)], represent new‐generation metalloradical catalysts where the metal‐centered d‐radical is situated inside a cavity‐like ligand with a more rigid chiral environment and enhanced hydrogen‐bonding capability. As demonstrated with cyclopropanation and aziridination as model reactions, the bridged [Co(HuPhyrin)] functions notably different from the open catalysts, exhibiting significant enhancement in both reactivity and stereoselectivity. Furthermore, the length of the distal alkyl bridge can have a remarkable influence on the catalytic properties.
Nanostars on Nanopipette Tips: A Raman Probe for Quantifying Oxygen Levels in Hypoxic Single Cells and Tumours
Authors: Nguyen Thanh Danh , Song Min Seok , Ly Nguyễn Hoàng , Lee So Yeong , Joo Sang‐Woo 
Published: January 2019

AbstractMultiple sharp‐edged gold nanostars were efficiently assembled on nanopipette tips through electrostatic interactions for use as a potent intracellular hypoxia‐sensing Raman probe. Colloidal stability and surface immobilization were checked using scanning electron microscopy, light scattering, and zeta potential measurements. Site‐specific intracellular hypoxia levels can be estimated in vitro and in vivo using Raman lancets (RL). Distinct Raman spectral changes for the nitro‐(NO2) functional group of the redox marker 4‐nitrothiophenol (4NTP) can be quantified according to the intracellular oxygen (O2) content, ranging from 1 % to 10 %. Redox potential changes in mitochondrial respiration were also examined through serial injections of inhibitors. 3D‐cultured cells and in vivo tests were used to validate our method, and its application in the assessment of the aggressiveness of cancer cells by differentiating spectral changes between malignant and benign cells was demonstrated.
Direct Carbohydroxylation of Arylalkenes with Allylic Alcohols: Cooperative Catalysis of Copper, Silver, and a Brønsted Acid
Authors: Ahmed Waqar , Zhang Sheng , Yu Xiaoqiang , Feng Xiujuan , Yamamoto Yoshinori , Bao Ming 
Published: January 2019

AbstractThe cooperative catalysis of copper, silver, and Brønsted acid is presented as a new strategy for olefin functionalization. The catalytic direct carbohydroxylation of arylalkenes with allylic alcohols provided a straightforward and efficient approach for preparing 4,5‐unsaturated alcohols. Synthetically useful functional groups, such as Cl, Br, carbonyl, and chloromethyl, remained intact during the functionalization reaction.
Z‐Scheme 2D/2D Heterojunction of Black Phosphorus/Monolayer Bi2WO6 Nanosheets with Enhanced Photocatalytic Activities
Authors: Hu Jundie , Chen Dongyun , Mo Zhao , Li Najun , Xu Qingfeng , Li Hua , He Jinghui , Xu Hui , Lu Jianmei 
Published: January 2019

AbstractBlack phosphorus (BP), a star‐shaped two‐dimensional material, has attracted considerable attention owing to its unique chemical and physical properties. BP shows great potential in photocatalysis area because of its excellent optical properties; however, its applications in this field have been limited to date. Now, a Z‐scheme heterojunction of 2D/2D BP/monolayer Bi2WO6 (MBWO) is fabricated by a simple and effective method. The BP/MBWO heterojunction exhibits enhanced photocatalytic performance in photocatalytic water splitting to produce H2 and NO removal to purify air; the highest H2 evolution rate of BP/MBWO is 21042 μmol g−1, is 9.15 times that of pristine MBWO and the NO removal ratio was as high as 67 %. A Z‐scheme photocatalytic mechanism is proposed based on monitoring of .O2−, .OH, NO2, and NO3− species in the reaction. This work broadens applications of BP and highlights its promise in the treatment of environmental pollution and renewable energy issues.
Comparative Adsorption of Acetone on Water and Ice Surfaces
Authors: Cyran Jenée D. , Backus Ellen H. G. , van Zadel Marc‐Jan , Bonn Mischa 
Published: January 2019

AbstractSmall organic molecules on ice and water surfaces are ubiquitous in nature and play a crucial role in many environmentally relevant processes. Herein, we combine surface‐specific vibrational spectroscopy and a controllable flow cell apparatus to investigate the molecular adsorption of acetone onto the basal plane of single‐crystalline hexagonal ice with a large surface area. By comparing the adsorption of acetone on the ice/air and the water/air interface, we observed two different types of acetone adsorption, as apparent from the different responses of both the free O−H and the hydrogen‐bonded network vibrations for ice and liquid water. Adsorption on ice occurs preferentially through interactions with the free OH group, while the interaction of acetone with the surface of liquid water appears less specific.
Catalysis with Palladium Complexes Photoexcited by Visible Light
Authors: Chuentragool Padon , Kurandina Daria , Gevorgyan Vladimir 
Published: January 2019

AbstractPalladium catalysis induced by visible light is an emerging field of catalysis. In contrast to classical reactions catalyzed by Pd complexes in the ground state, which mostly proceed through two‐electron redox processes, the mechanisms of these new methods based on photoexcited Pd complexes usually operate through transfer of a single electron. Such processes lead to putative hybrid Pd/radical species, which exhibit both radical and classical Pd‐type reactivity. This Minireview highlights the recent progress in this rapidly growing area.
An Enantioselective CpxRh(III)‐Catalyzed C−H Functionalization/Ring‐Opening Route to Chiral Cyclopentenylamines
Authors: Wang Shou‐Guo , Cramer Nicolai 
Published: January 2019

AbstractA chiral CpxRhIII catalyst system in situ generated from a CpxRhI(cod) precatalyst and bis(o‐toluoyl) peroxide as activating oxidant was developed for a C−H activation/ring‐opening sequence between aryl ketoxime ethers and 2,3‐diazabicyclo[2.2.1]hept‐5‐enes. This transformation provides access to densely functionalized chiral cyclopentenylamines in excellent yields and enantioselectivities of up to 97:3 er. The reported method is also well suitable for asymmetric alkenyl C−H functionalizations of α,β‐unsaturated oxime ethers, furnishing skipped dienes with high levels of enantiocontrol.
Three‐in‐One Oxygen Vacancies: Whole Visible‐Spectrum Absorption, Efficient Charge Separation, and Surface Site Activation for Robust CO2 Photoreduction
Authors: Yu Hongjian , Li Jieyuan , Zhang Yihe , Yang Songqiu , Han Keli , Dong Fan , Ma Tianyi , Huang Hongwei 
Published: January 2019

AbstractA facile and controllable in situ reduction strategy is used to create surface oxygen vacancies (OVs) on Aurivillius‐phase Sr2Bi2Nb2TiO12 nanosheets, which were prepared by a mineralizer‐assisted soft‐chemical method. Introduction of OVs on the surface of Sr2Bi2Nb2TiO12 extends photoresponse to cover the whole visible region and also tremendously promotes separation of photoinduced charge carriers. Adsorption and activation of CO2 molecules on the surface of the catalyst are greatly enhanced. In the gas‐solid reaction system without co‐catalysts or sacrificial agents, OVs‐abundant Sr2Bi2Nb2TiO12 nanosheets show outstanding CO2 photoreduction activity, producing CO with a rate of 17.11 μmol g−1 h−1, about 58 times higher than that of the bulk counterpart, surpassing most previously reported state‐of‐the‐art photocatalysts. Our study provides a three‐in‐one integrated solution to advance the performance of photocatalysts for solar‐energy conversion and generation of renewable energy.
Improved line weighting reduces seabird bycatch without affecting fish catch in the Brazilian pelagic longline fishery
Authors: Santos Rodrigo C. , Silva‐Costa Augusto , Sant'Ana Rodrigo , Gianuca Dimas , Yates Oliver , Marques Caio , Neves Tatiana 
Published: January 2019

Abstract

Increasing the sink rate of baited hooks by adding weights in close proximity to the hook is crucial to reduce seabird mortality in pelagic longline fisheries. However, weights placed next to the hook are a cause for concern for fishing crew because they can fly back in the event of a line break, injuring deck crew.
Lumo Leads, an alternative weight system designed to slide in the event of a line break, and therefore prevent accidents, were trialled in pelagic longline fisheries off southern Brazil. Four fishing trips were conducted and 26,377 hooks sampled to compare sink rates, seabird bycatch rates and catch rates of target species between three treatments: (1) 60 g Lumo Lead attached at 1.0 m from the hook; (2) 60 g Lumo Lead at 3.5 m; and (3) 60 g leaded swivels at 3.5 m from the hook.
A Lumo Lead placed at 1.0 m from the hook resulted in a faster sink rate and caught fewer seabirds (0.11 birds per unit of effort [BPUE]) when compared with a Lumo Lead (0.33 BPUE) or weighted swivel (0.85 BPUE) placed at 3.5 m. The bycatch with Lumo Lead placed at 1.0 m from the hook was 90% lower than the bycatch of Lumo Lead or weighted swivel placed at 3.5 m combined. There was no difference in the catch rates of target species between the three treatments.
These findings support a growing body of evidence that placing weights close to the hook reduces seabird bycatch without affecting the catchability of the target species. The high seabird bycatch rates recorded despite night setting and recommended line weighting regimes reinforces the need of simultaneous deployment of a toriline with these other two mitigation measures to reduce seabird bycatch to negligible levels in the south‐west Atlantic.
Efficient synthesis of meso‐substituted porphyrins and molecular docking as potential new antioxidant and cytotoxicity agents
Authors: Abu‐Melha Sraa 
Published: January 2019

AbstractAn improved methodology is reported for the synthesis of new series of mesotetrakis[aryl]‐21H,23H‐porphyrin derivatives 2a–h and was considered as a model to study their antioxidant and cytotoxic activities. The structures of the novel compounds were determined in 1H and 13C NMR, UV‐Vis, and elemental analyses. Among the derivatives, compounds 2c, 2d, and 2h showed strongest radical‐scavenging activity. Moreover, according to our results, compounds 2c, 2d, 2g, and 2h have very strong activity against the HepG2 hepatoma cell line, with IC50 values from 9 to 25 μg/mL. Molecular docking was performed to investigate the binding between the most active porphyrin derivatives 2c, 2d, 2g, 2h and the two molecular targets Bcl‐2 and caspase‐3. Compounds 2c and 2d seem to have better affinities to both proteins than 2g and 2h.
Aminopyrazole‐substituted metallophthalocyanines: Preparation, aggregation behavior, and investigation of metabolic enzymes inhibition properties
Authors: Güzel Emre , Koçyiğit Ümit M. , Arslan Barış S. , Ataş Mehmet , Taslimi Parham , Gökalp Faik , Nebioğlu Mehmet , Şişman İlkay , Gulçin İlhami 
Published: January 2019

AbstractThe synthesis, characterization, aggregation behavior, theoretical studies, and investigation of antimicrobial, antidiabetic, and anticholinergic properties of 4‐(2‐(5‐amino‐4‐(4‐bromophenyl)‐3‐methyl‐1H‐pyrazol‐1‐yl)ethoxy)phthalonitrile (2) and its soluble aminopyrazole‐substituted peripheral metallo (Mn, Co, and Ni)‐phthalocyanine complexes (3–5) are reported for the first time. The synthesized compounds and phthalocyanine complexes were characterized spectroscopically. The new phthalonitrile derivative (2) and its peripheral metallophthalocyanine complexes (3–5) were found to be effective inhibitors of α‐glycosidase, acetylcholinesterase (AChE), human carbonic anhydrase I and II isoforms (hCA I and II), and butyrylcholinesterase (BChE) with Ki values in the range of 1.55 ± 0.47 to 10.85 ± 3.43 nM for α‐glycosidase, 8.44 ± 0.32 to 21.31 ± 7.91 nM for hCA I, 11.73 ± 2.82 to 31.03 ± 4.81 nM for hCA II, 101.62 ± 26.58 to 326.54 ± 89.67 nM for AChE, and 68.68 ± 11.15 to 109.53 ± 19.55 nM for BChE. This is the first study of peripherally substituted phthalocyanines containing an aminopyrazole group as potential carbonic anhydrase enzyme inhibitor. Also, the antimicrobial activities of the synthesized compounds were evaluated against six microorganisms (four bacteria and two Candida species) using the broth microdilution method. The gram‐positive bacteria were detected to be more sensitive than gram‐negative bacteria and yeasts in the synthesized compounds.
Synthesis, crystal structure, and biological evaluation of optically active 2‐amino‐4‐aryl‐7,7‐dimethyl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐3‐carbonitriles: Antiepileptic, antidiabetic, and anticholinergics potentials
Authors: Maharramov Abel , Kaya Ruya , Taslimi Parham , Kurbanova Malahat , Sadigova Arzu , Farzaliyev Vagif , Sujayev Afsun , Gulçin İlhami 
Published: January 2019

AbstractIn the presence of chiral organic catalysts, the optically active 4H‐chromine was synthesized from the multicomponent condensation of 5,5‐dimethylcyclohexane‐1,3‐dione with malononitrile and methylene‐active compound, and the specific angle of rotation of the compounds was determined in the AUTOPOL‐III polarimeter and their structures were confirmed by the X‐ray spectroscopic analysis method. These optically active 2‐amino‐4‐aryl‐7,7‐dimethyl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐3‐carbonitriles were effective inhibitors of α‐glycosidase, the cytosolic carbonic anhydrase I and II isoforms (hCA I and II), and acetylcholinesterase (AChE) enzymes with Ki values in the range of 21.33 ± 1.11 to 40.24 ± 10.78 μM for hCA I, 28.91 ± 6.51 to 59.97 ± 15.62 μM for hCA II, 18.16 ± 3.18 to 66.57 ± 1.36 μM for α‐glycosidase, and 8.68 ± 0.93 to 102.61 ± 24.96 μM for AChE.
A Heterobimetallic AuIII‐PtII Photocatalyst for Water Reduction to Hydrogen
Authors: Su Yi‐Bing , Yuan Yong‐Jun , Liu Xiao‐Le , Chen Guang‐Hui , Chen Xin , Yu Zhen‐Tao , Zou Zhi‐Gang 
Published: January 2019

AbstractA supramolecular complex, [Au(C^N^C)(C≡CC6H4C≡C)Pt(terpy)]+, has been synthesized as a photocatalyst for water reduction. This compound consists of a cyclometalated alkyne‐gold(III) photosensitizer and a platinum(II) terpyridine complex bridged through a central phenylethynyl group.
Oligo(ethylene glycol)/alkyl‐modified Chromophore Assemblies for Photon Upconversion in Water
Authors: Haruki Rena , Kouno Hironori , Hosoyamada Masanori , Ogawa Taku , Yanai Nobuhiro , Kimizuka Nobuo 
Published: January 2019

AbstractMolecular self‐assembly is a powerful means to construct nanoscale materials with advanced photophysical properties. Although the protection of the photo‐excited states from oxygen quenching is a critical issue, it still has been in an early phase of development. In this work, we demonstrate that a simple and typical molecular design for aqueous supramolecular assembly, modification of the chromophoric unit with hydrophilic oligo(ethylene glycol) chains and hydrophobic alkyl chains, is effective to avoid oxygen quenching of triplet–triplet annihilation‐based photon upconversion (TTA‐UC). While a TTA‐UC emission is completely quenched when the donor and acceptor are molecularly dispersed in chloroform, their aqueous co‐assemblies exhibit a clear upconverted emission in air‐saturated water even under extremely low chromophore concentrations down to 40 μm. The generalization of this nano‐encapsulation approach offers new functions and applications using oxygen‐sensitive species for supramolecular chemistry.
A Photostable AIEgen for Specific and Real‐time Monitoring of Lysosomal Processes
Authors: Zhang Weijie , Zhou Fan , Wang Zhiming , Zhao Zujin , Qin Anjun , Tang Ben Zhong 
Published: January 2019

AbstractLysosomes are recognized as advanced organelles involved in many cellular processes and are also considered as crucial regulators of cell homeostasis. The current strategies for monitoring activities of lysosomes exhibit some limitations. Herein, we synthesized a novel fluorescent probe named 2M‐DPAS with AIE characteristics, which was proved to have significant advantages of good biocompatibility, high selectivity, bright emission and excellent photostability. Based on those, 2M‐DPAS can be used to continuously monitor the dynamic changes of lysosomes, including autophagy and mitophagy, as well as to track the process of endocytosis of macromolecules in lysosomes, which are of benefit to better know about the lysosomes‐related diseases.
Impact of FRET between Molecular Aggregates and Quantum Dots
Authors: Maity Partha , Gayathri Thumuganti , Singh Surya Prakash , Ghosh Hirendra N. 
Published: January 2019

AbstractEnergy transfer has been employed in third‐generation solar cells for the conversion of light into electrical energy. Long‐range nonradiative energy transfer from semiconductor quantum dots (QDs) to fluorophores has been demonstrated by using CdS QDs and thiophene−BODIPY (boron dipyrromethene, abbreviated as TG2). TG2 shows a broad photoluminescence (PL) spectrum, which varies with concentration. At very low concentrations, monomeric units are present; then, upon increasing the concentration, these monomers form a mixed (J‐/H‐)aggregated state. Energy transfer between the CdS QDs and TG2 was confirmed by separately investigating the interactions between CdS and the monomer of TG2 and between CdS and the aggregated states of TG2. Size‐dependent PL quenching confirmed that nonradiative Förster resonance energy transfer (FRET) from photoexcited CdS QDs to the J‐aggregate state of TG2 was the major energy‐relaxation channel, which occurred on the timescale of hundreds of fs. These results have broad applications in the field of light harvesting based on the assembly of molecular aggregates.
An A‐D‐A′‐D‐A Conjugated Molecule Entailing Diazapentalene Unit for an n‐Type Organic Semiconductor
Authors: Lin Gaobo , Wang Lingna , Yang Yizhou , Liu Zitong , Zhang Guanxin , Zhang Deqing 
Published: January 2019

AbstractConjugated molecules with low lying LUMO levels are demanding for the development of air stable n‐type organic semiconductors. In this paper, we report a new A‐D‐A′‐D‐A conjugated molecule (DAPDCV) entailing diazapentalene (DAP) and dicyanovinylene groups as electron accepting units. Both theoretical and electrochemical studies manifest that the incorporation of DAP unit in the conjugated molecule can effectively lower the LUMO energy level. Accordingly, thin film of DAPDCV shows n‐type semiconducting behavior with electron mobility up to 0.16 cm2⋅V−1⋅s−1 after thermal annealing under N2 atmosphere. Moreover, thin film of DAPDCV also shows stable n‐type transporting property in air with mobility reaching 0.078 cm2⋅V−1⋅s−1.