四氟乙烯齐聚体的反应 四氟乙烯四、五聚体和芳香胺的反应

前已报道四氟乙烯四聚体(全氟-3,4-甲基己烯-3)(1)、五聚体(全氟-3,4-二甲基-4-乙基己烯-2)(2)和脂肪烷氧以及脂肪胺的亲核反应.本文报道化合物1,2和芳香胺如苯胺、β-萘胺的反应.由于烯烃1、2双键处于分子中间,因而当亲核试剂进攻时,双键容易发生重排,生成的末端基烯烃更具反应性,故导致一取代、二取代、三取代以及环化降解等复杂产物.     

Trichalcogenasumanene ortho‐Quinones: Synthesis,Properties, and Transformation into Various Heteropolycycles

The regioselective transformation of heterobuckybowl trichalcogenasumanenes 1 a , b at peripheral butoxy groups afforded trichalcogenasumanene ortho ‐quinones 2 a , b . Compounds 2 a , b are distinct from 1 a , b in terms of their molecular geometry and electronic state; that is, they have a shallower bowl depth and show absorbance in the NIR region. The reaction of 2 a , b with diamines resulted in a variety of heteropolycycles, including molecular spoon 3 a – 6 a , planar π‐systems 3 b – 6 b , and highly twisted [7‐6‐6]‐fused systems 7 a , b . These new heteropolycycles had different optical/electrical properties: 4 a,b showed hole mobility of approximately 0.002 cm² V⁻¹ s⁻¹, 6 a displayed red emission in both solution and the solid state, and 7 a , b formed tight stacks of the curved π‐surface.     

Photochromic reactions of diarylethenes in single crystals with intermolecular O--H...N hydrogen-bonding networks

The crystal structures and photochromic performance of a single crystal of a diarylethene derivative possessing carboxyl groups, 1,2-bis(5-carboxyl-2-methyl-3-thienyl)perfluorocyclopentene (1 a), and cocrystals of 1 a with 4,4'-, 2,4'-, and 2,2'-bipyridines were examined. In crystal 1 a, a discrete cyclic structure was observed, in which four 1 a molecules are linked through hydrogen bonds between the carboxyl groups. In the homocrystal, photoreactive and photoinactive conformers of 1 a exist in the ratio of 1:1. In the cocrystals of 1 a with bipyridines, O--HN-type hydrogen bonds between 1 a and pyridyl groups were formed, and all 1 a molecules are fixed in a photoreactive conformation. Both the homocrystal 1 a and the cocrystals showed photochromic performances, and color variation from bluish-violet to cyan was observed, depending on the conformation of the packed diarylethene molecules.     

Domino 6pi-electrocyclization/Diels-Alder reactions on 1,6-disubstituted (E,Z,E)-1,3,5-hexatrienes: versatile access to highly substituted tri- and tetracyclic systems

The (E,Z,E)-1,3,5-hexatrienes 1a, 2a,b and 3b undergo 6pi-electrocyclization within 15-30 min upon heating to 200-215 degrees C. While the cyclohexene-annelated products 8a,b were stable, the analogous cyclopentene- and cycloheptene-annelated derivatives 7a and 9b easily underwent dehydrogenation to the corresponding aromatic compounds 10a and 12b during the work-up. The cyclohexadiene derivatives 8a,b were employed in thermal Diels-Alder reactions with 4-phenyl-3H-1,2,4-triazoline-3,5-dione (PTAD) and tetracyanoethylene (TCNE) to give the expected [4+2] cycloadducts 13a and 14a in good yields (60 and 78%). The initially formed cycloadduct of 8a and dimethyl acetylenedicarboxylate (DMAD) underwent a subsequent retro-Diels-Alder reaction to give the tetrahydronaphthalene 11b (47%). Under high pressure (10 kbar), the cycloadduct 15a was formed at room temperature and could be isolated in 44% yield. TCNE and N-phenylmaleimide with 8a under high pressure also led to the [4+2] cycloadducts 14a and 16a in good yields (60 and 77%). The 6pi-electrocyclization and subsequent Diels-Alder reaction, when performed as a one-pot domino process, provided direct access to Diels-Alder products of intermediately formed 6pi-electrocyclization products, for example from the 1,3,5-hexatrienes 1a,b, 2a,b, 3b and TCNE to the corresponding tricyclic products 17a,b, 14a,b, 18b in moderate to good yields (27-80%) depending on the nature of the alkoxycarbonyl group. Such sequential reactions with N-phenylmaleimide, maleic anhydride, dimethyl maleate and fumarodinitrile, the latter two under high pressure (10 kbar), worked as well to yield 16b (70%), 19a,b (19, 32%) and 20b (39%) and 21b (76%), respectively. With PTAD, however, the hexatrienes 2a,b reacted at ambient temperature without 6pi-electrocyclization to give the formal [4+2] cycloadducts 27a,b (48 and 46%), most probably via zwitterionic intermediates 23a,b and 25a,b.     

Trichalcogenasumanene ortho‐Quinones: Synthesis,Properties, and Transformation into Various Heteropolycycles

The regioselective transformation of heterobuckybowl trichalcogenasumanenes 1 a , b at peripheral butoxy groups afforded trichalcogenasumanene ortho ‐quinones 2 a , b . Compounds 2 a , b are distinct from 1 a , b in terms of their molecular geometry and electronic state; that is, they have a shallower bowl depth and show absorbance in the NIR region. The reaction of 2 a , b with diamines resulted in a variety of heteropolycycles, including molecular spoon 3 a – 6 a , planar π‐systems 3 b – 6 b , and highly twisted [7‐6‐6]‐fused systems 7 a , b . These new heteropolycycles had different optical/electrical properties: 4 a,b showed hole mobility of approximately 0.002 cm² V⁻¹ s⁻¹, 6 a displayed red emission in both solution and the solid state, and 7 a , b formed tight stacks of the curved π‐surface.     

Crystal engineering of photochromic diarylethene single crystals

Photochromic performance of diarylethene single crystals was controlled by crystal engineering using non-covalent aromatic-aromatic interactions as the directional intermolecular force. A diarylethene derivative with two pentafluorophenyl groups, 1,2-bis(2-methyl-5-pentafluorophenyl-3-thienyl)perfluorocyclopentene (1a), formed stoichiometric co-crystals with benzene (Bz) and naphthalene (Np) by aryl-perfluoroaryl interactions. Face-to-face pi-stacking interactions between the pentafluorophenyl groups of 1a and the aromatic molecules are responsible for 2:1 and 1:1 stoichiometric compositions in 1a/Bz and 1a/Np co-crystals, respectively. The diarylethene underwent thermally stable and photoreversible photochromic reactions in a homo-crystal of 1a and co-crystals 1a/Bz and 1a/Np. The absorption spectra of the photogenerated closed-ring isomers varied depending on the conformation of the diarylethene molecules packed in the crystals. The diarylethene 1a also formed 1:1 stoichiometric co-crystals with different kinds of diarylethenes, 1,2-bis(2-ethyl-5-phenyl-3-thienyl)perfluorocyclopentene (2a) and 1,2-bis[2-methyl-5-(1-naphthyl)-3-thienyl]perfluorocyclopentene (3a). Both co-crystals 1a/2a and 1a/3a showed photochromism. Although 1a, 2a, and 3a underwent efficient photocyclization reactions in their homo-crystals, highly selective photocyclization reactions of 2a or 3a were observed in the co-crystals. The selective reactions were confirmed by HPLC and X-ray crystallography. Excited energy transfers from 1a to 2a and from 1a to 3a are considered to occur and cause the selective reactions.     

Synthesis of Some New Fused/Spiroheterocyclic Compounds Incorporating Quinone Compounds

A series of fused and spiro pyrazolones, isoxazolines, pyrimidines, β‐lactams, and thiazolidinones incorporating 4‐amino‐2‐methyl‐5,10‐dioxo‐1,5,10,11‐tetrahydrobenz[g]quinoline 3‐carbonitrile 1 and 4‐amino‐2‐methyl‐5,6,11‐trioxo‐1,4,4a,5,6,11,12,12a‐octahydro‐1,12‐diazanaphthacene 3‐carbonitrile 2. 7,8a‐c, 15,16a‐c, 19,20a‐d, 21,22a‐d , have been synthesised by cyclocondensation addition reaction and cycloaddition reaction of hydrazines, hydroxylamine, urea, thiourea, monochloroacetyl chloride and mercaptoacetic acid with the synthesised 15,16a‐c and 17,18a‐c .     

Palladium‐Catalyzed Reductive Coupling Reaction of Terminal Alkynes with Aryl Iodides Utilizing Hafnocene Difluoride as a Hafnium Hydride Precursor Leading to trans‐Alkenes

Herein, we describe a reductive cross‐coupling of alkynes and aryl iodides by using a novel catalytic system composed of a catalytic amount of palladium dichloride and a promoter precursor, hafnocene difluoride (Cp₂HfF₂, Cp=cyclopentadienyl anion), in the presence of a mild reducing reagent, a hydrosilane, leading to a one‐pot preparation of trans‐alkenes. In this process, a series of coupling reactions efficiently proceeds through the following three steps: (i) an initial formation of hafnocene hydride from hafnocene difluoride and the hydrosilane, (ii) a subsequent hydrohafnation toward alkynes, and (iii) a final transmetalation of the alkenyl hafnium species to a palladium complex. This reductive coupling could be chemoselectively applied to the preparation of trans‐alkenes with various functional groups, such as an alkyl group, a halogen, an ester, a nitro group, a heterocycle, a boronic ester, and an internal alkyne.     

O‐Glycosylation/Alkylation and Antimicrobial Activity of 4,6‐Diaryl‐2‐Oxonicotinonitrile Derivatives

A series of glycosylation and alkylation reactions of 6‐phenanthernyl‐2‐pyridone derivatives 1a , 1b containing electron withdrawing and electron donating substituents at 4‐position is reported. Regioselective 2‐O‐ alkylated/glycosylated products were obtained exclusively, irrespective of the electronic nature of alkylating or the glycosyling agent. Glycosylation of 1a , 1b with glucosyl/galactosyl and lactosyl bromides afforded 2a , 2b ; 4a , 4b ; and 6a , respectively. Alkylation of 1a , 1b with epichlorohydrin, propargyl, allyl bromides, and 3‐chloropropanol resulted in compounds 8 , 9 , 10 and 13 , respectively. Deprotection of O‐glycosylated products under conventional conditions provided the free glycosides 3a , 3b ; 5a , 5b ; 7a , 12 ; and 13 , respectively. The minimal inhibitory concentration for some of the newly synthesized compounds showed high significant activity against Gram (+ve) and Gram (−ve) and antifungal activities. Among the screened compounds, the 4‐trifluromethyl phenyl derivatives 2a , 3a , 4a , 8a , and 11a exhibited strong antimicrobial activity.     

A novel method that improves sensitivity of protein detection in PAGE and Western blot

We have developed a simple and inexpensive method that improves sensitivity of protein and antigen detection in standard PAGE procedures. Our technique uses a sample microloader device with a funnel‐like structure, filled with a 4% stacking gel. When attach to the top of a polyacrylamide slab gel, the proteins in a sample are concentrated by electrophoresis into a small volume as they emerge from the device's narrow outlet. Our microloader has several advantages over previous devices, including simple assembly, high versatility, and absence of cross‐contamination between lanes. Addition of this device to a slab gel results in a fivefold increase in the sensitivity of antigen detection in a Western blot. As a result, less protein is required for loading and signal detection. Our protocol is a straightforward modification of a standard experimental technique, and is especially useful when only limited sample quantities are available.     

A Rapid and Efficient Way to Dynamic Creation of Cross‐Reactive Sensor Arrays Based on Ionic Liquids

Based on the simple counterion exchange of ionic liquids, a rapid, facile, and efficient strategy to create a cross‐reactive sensor array with a dynamic tunable feature was developed, and exemplified by the construction of a sensor array for the identification and classification of nitroaromatics and explosives mimics. To achieve a good sensing system with fast response, good sensitivity, and low detection limit, the synthesized ionic liquid receptors were tethered onto a silica matrix with a macro‐mesoporous hierarchical structure. Through the facile anion exchange approach, abundant ionic‐liquid‐based individual receptors with diversiform properties, such as different micro‐environments, diverse molecular interactions, and distinctive physico‐chemical properties, were easily and quickly synthesized to generate a distinct fingerprint of explosives for pattern recognition. The reversible anion exchange ability further endowed the sensor array with a dynamic tunable feature as well as good controllability and practicality for real‐world application. With the assistance of statistical analysis, such as principal component analysis (PCA) and linear discrimination analysis (LDA), an optimized‐size array with a good resolution was rationally established from a large number of IL‐based receptors. The performed experiments suggested that the ionic‐liquid‐based sensing protocol is a general and powerful strategy for creating a cross‐reactive sensor array that could find a wide range of applications for sensing various analytes or complex mixtures.     

Application of Phase Transfer Catalysis in Heterocyclic Synthesis: Synthesis of Some New Polyfunctional Thiophenes,Thiopyrans, Pyridines and Oxazines

The reaction of compound 1 with CS 2 and different active halo compounds gave the corresponding thiophene derivatives 2a,b-4a,b , whereas treatment of compound 1 with CS 2 and active methylene compounds afforded the corresponding thiopyran derivatives 5a,b , 6a,b , 7 , and 8 . Also, 1,3-thioxane derivatives 9 and 10 were obtained by reacting compound 1 with CS 2 and different cycloalkanones. Thiophene and pyrrolidene derivatives 11 , 12a,b , and 13a,b were obtained by reacting compound 1 with phenyl isothiocyanate and different halo compounds. The active methylene compounds and/or cycloalkanones were treated with compound 1 in the presence of phenyl isothiocyanate to give pyridines, thiopyran and oxazine derivatives 14a,b-16a,b , 17a-19a , and 19b , respectively.     

Photocatalytic Z-scheme Overall Water Splitting: Insight into Different Optimization Strategies for Powder Suspension and Particulate Sheet Systems

Achieving solar light-driven photocatalytic overall water splitting is the ideal and ultimate goal for solving energy and environment issues. Photocatalytic Z-scheme overall water splitting has undergone considerable development in recent years; specific approaches include a powder suspension Z-scheme system with a redox shuttle and a particulate sheet Z-scheme system. Of these, a particulate sheet has achieved a benchmark solar-to-hydrogen efficiency exceeding 1.1 %. Nevertheless, owing to intrinsic differences in the components, structure, operating environment, and charge transfer mechanism, there are several differences between the optimization strategies for a powder suspension and particulate sheet Z-scheme. Unlike a powder suspension Z-scheme with a redox shuttle, the particulate sheet Z-scheme system is more like a miniaturized and parallel p/n photoelectrochemical cell. In this review, we summarize the optimization strategies for a powder suspension Z-scheme with a redox shuttle and particulate sheet Z-scheme. In particular, attention has been focused on choosing appropriate redox shuttle and electron mediator, facilitating the redox shuttle cycle, avoiding redox mediator-induced side reactions, and constructing a particulate sheet. Challenges and prospects in the development of efficient Z-scheme overall water splitting are also briefly discussed.     

Boron/nitrogen substitution of the central carbon atoms of the biphenalenyl diradical π dimer: a novel 2e-12c bond and large NLO responses

On the basis of the famous staggered biphenalenyl diradical π dimer 1, the eclipsed biphenalenyl (1a), with no centrosymmetry, was obtained by rotating a layer of 1 by 60° around its central axis. Furthermore, the central carbon atoms of 1 and 1a were substituted by boron and nitrogen atoms to form 2 and 2a with a novel 2e-12c bond. We found that the novel 2e-12c bond is formed by the electron pair of the occupied orbital of the phenalenyl monomer substituted by the nitrogen atom and the unoccupied orbital of the phenalenyl monomer substituted by the boron atom. As a result of the novel 2e-12c bond, 2 and 2a exhibit a fascinating interlayer charge-transfer transition character, which results in a significant difference in the dipole moments (Δμ) between the ground state and the crucial excited state. The values of Δμ for 2 and 2a are 6.4315 and 6.9253 Debye, clearly larger than the values of 0 and 0.0015 Debye for 1 and 1a. Significantly, the boron/nitrogen substitution effect can greatly enhance the first hyperpolarizabilities (β(0) ) of 2 and 2a with a novel 2e-12c bond compared with 1 and 1a with a traditional 2e-12c bond: 0 and 19 a.u. for 1 and 1a are much lower than 3516 and 12272 a.u. for 2 and 2a. Furthermore, the interaction energies (E(int) )of 2 and 2a are larger than those of 1 and 1a, which could be considered as a signature of reliability for the newly designed dimers. Our present work will be beneficial for further theoretical and experimental studies on the properties of molecules with the novel 2e-12c bond.     

Triarylborane-Appended Anils and Boranils: Solid-State Emission,Mechanofluorochromism, and Phosphorescence

Herein, the design, synthesis, optical properties, and mechanofluorochromism characteristics of a series of conjugates having covalently linked triarylborane (TAB) and anil/boranil units (TAB-anil: 1 a – 3 a and TAB-boranil: 1 – 3 ) are reported. The electronic interactions between TAB and anil/boranil in 1 a – 3 a and 1 – 3 were fine-tuned by changing the boryl moiety's position on the phenyl spacer connecting the BMes₂ (Mes=mesityl) and anil/boranil units. A boryl moiety at the meta position ( 1 a ) of the phenyl spacer stabilizes the enolic form (E-OH), whereas a boryl moiety at the para position ( 2 a and 3 a ) stabilizes the keto form (Z-NH) in the solid state. However, in solution 1 a , 2 a , and 3 a exhibit keto–enol tautomerism in both ground and excited states. Compounds 1 a – 3 a and 1 – 3 show red-shifted absorption compared with 4 a and 4 , which are devoid of TAB moieties, which indicate effective participation of an empty p orbital on the boron center in 1 a – 3 a and 1 – 3 . Compounds 1 and 2 showed fluorescence variations in response to external stimuli such as mechanical grinding. Long phosphorescence lifetimes of 18–46 ms were observed for compounds 1 – 3 . The observed optical properties of 1 a – 3 a and 1 – 3 are rationalized in the context of quantum mechanical calculations.     

The Synthesis of New Spiro β-Lactam and Thiazolidinone Compounds Incorporating Quinones and Their Biological Activity

A series of some fused and spiro heterocyclic compounds such as pyrazolines, isoxazolines, pyrimidines, β-lactams, and thiazolidinone derivatives incorporating compounds 3, 6a–d, 7a–d, 9a–c, 10a–c, 11a–c, 12a–c, and 13a–c have been synthesized by a cycloaddition and cyclocondensation reaction of monochloroacetyl chloride, mercaptoacetic acid, hydrazines, hydroxylamine, urea, and thiourea with the prepared 5a–d and 8a–c.     

Peptide Self-Assembly into Amyloid Fibrils at Hard and Soft Interfaces—From Corona Formation to Membrane Activity

Peptides and proteins are exposed to a variety of interfaces in a physiological environment, such as cell membranes, protein nanoparticles (NPs), or viruses. These interfaces have a significant impact on the interaction, self-assembly, and aggregation mechanisms of biomolecular systems. Peptide self-assembly, particularly amyloid fibril formation, is associated with a wide range of functions; however, there is a link with neurodegenerative diseases, such as Alzheimer's disease. This review highlights how interfaces affect peptide structure and the kinetics of aggregation leading to fibril formation. In nature, many surfaces are nanostructures, such as liposomes, viruses, or synthetic NPs. Once exposed to a biological medium, nanostructures are coated with a corona, which then determines their activity. Both accelerating and inhibiting effects on peptide self-assembly have been observed. When amyloid peptides adsorb to a surface, they typically concentrate locally, which promotes aggregation into insoluble fibrils. Starting from a combined experimental and theoretical approach, models that allow for a better understanding of peptide self-assembly near hard and soft matter interfaces are introduced and reviewed. Research results from recent years are presented and relationships between biological interfaces, such as membranes and viruses, and amyloid fibril formation are proposed.     

Lasso Proteins: Modular Design,Cellular Synthesis,and Topological Transformation

Entangled proteins have attracted significant research interest. Herein, we report the first rationally designed lasso proteins, or protein [1]rotaxanes, by using a p53dim-entwined dimer for intramolecular entanglement and a SpyTag-SpyCatcher reaction for side-chain ring closure. The lasso structures were confirmed by proteolytic digestion, mutation, NMR spectrometry, and controlled ligation. Their dynamic properties were probed by experiments such as end-capping, proteolytic digestion, and heating/cooling. As a versatile topological intermediate, a lasso protein could be converted to a rotaxane, a heterocatenane, and a “slide-ring” network. Being entirely genetically encoded, this robust and modular lasso-protein motif is a valuable addition to the topological protein repertoire and a promising candidate for protein-based biomaterials.     

Reactions of Ruthenium–Allenylidene Complexes Tethering a Cyclopropyl Group

Two cyclopropyl allenylidene complexes [Ru]=CCC(R)(C₃H₅) ([Ru]=[RuCp(PPh₃)₂], Cp=Cyclopentadienyl; R=thiophene ( 2a ) and R=Ph ( 2b )) are prepared from the reactions of [Ru]Cl with the corresponding 1‐cyclopropyl‐2‐propyn‐1‐ol in the presence of KPF₆. Thermal treatment, halide‐anion addition, and palladium‐catalyzed reactions of 2a and 2b all lead to a ring expansion of the cyclopropyl group, giving the vinylidene complexes 4a and 4b , respectively, each with a five‐membered ring. This ring expansion proceeds by C C bond formation between Cβ of the cumulative double bond and a methylene group of the cyclopropyl ring. In the reaction of 2a with pyrrole, consecutive formation of two C C bonds, one between C‐2 of pyrrole and Cγ of 2a and the other between C‐3 of pyrrole and Cα, results in the formation of 6a . The reaction proceeds by addition of pyrrole and 1,3‐proton shifts. The hydrogenation of 2a by NaBH₄ is carried out in different solvents. The cumulative double bonds are reduced regioselectively to give a mixture of 7a and 8a . Interestingly, use of different solvents leads to different ratios of 7a and 8a . Presence of a protic solvent like methanol in dichloromethane or chloroform solution increases the yield of 8a , thus revealing that both the rates of hydroboration and deboronation increase. The structures of two new complexes 4a and 6a have been firmly established by X‐ray diffraction analysis.     

New Method for Obtaining a Bioactive Essence Extracted from Iberian Ham Fat Rich in MUFA and Antioxidants

Iberian ham is one of the most representative Spanish products and presents an excellent nutritional and sensory quality. Iberian ham trimming fat is considered a by-product and to give a new use to this remaining part could represent a healthy and innovative option for obtaining sustainable foods. The purpose of this work was to obtain a new bioactive ingredient from Iberian ham trimming fat with the highest amount of antioxidants and monounsaturated fatty acids (MUFA), using a new non-invasive solvent-free method. To obtain the essence, two different extraction procedures were carried out. After fatty acid characterization, degree of acidity, peroxide index and a basic sensory analysis were performed. Antioxidant in vitro activity and total phenolic compounds (TPC) were also determined. This new ingredient showed a better sensory profile than raw ham fat, a lower degree of acidity, a higher content of MUFAs, and also showed a higher antioxidant capacity and an increase in phenolic compounds compared to the raw material. This bioactive essence could be used as a food, a cosmetic or a nutraceutical ingredient to prevent certain diseases related to oxidative stress and could also contribute to the maintenance of the circular economy.