Tris(pentafluorophenyl)borane catalyzed Ferrier azaglycosylation with sulfonamides and carbamates

The reaction of tri-O-acetyl-d-glucal with different nitrogen nucleophiles was effectively promoted by a catalytic amount of tris(pentafluorophenyl)borane for the first time in acetonitrile at room temperature to produce a variety of azapseudoglycals via Ferrier rearrangement in good yields and preferential anomeric selectivity.     

Lewis-Pairing-Induced Electrochemiluminescence Enhancement from Electron Donor-Acceptor Diads Decorated with Tris(pentafluorophenyl)borane as an Electrochemical Protector

This study reports an effective peripheral decoration of organic donor-acceptor diads with B(C₆F₅)₃ for stabilizing electrogenerated radical ions. By employing a common p-type organic semiconductor benzothienobenzothiophene (BTBT) as the donor, tetracoordinate boron complexes showed improved solution electrochemiluminescence (ECL) intensity, reaching a 156-fold increase compared to that of the parent diad. The unprecedented Lewis-pairing-induced ECL enhancement is attributed to the multiple roles of B(C₆F₅)₃: 1) redistributing frontier orbitals, 2) facilitating electrochemical excitation, and 3) restricting molecular motions. Furthermore, B(C₆F₅)₃ converted the molecular arrangement of BTBT from conventional 2D herringbones into 1D π-stacks. This robust, highly ordered columnar nanostructure allowed red-shifting of the crystalline film ECL with electrochemical doping through the electronic coupling pathways of BTBT. Our approach will facilitate the development of elaborate metal-free ECL systems.     

Tris(pentafluorophenyl)borane: a special boron Lewis acid for special reactions

Tris(pentafluorophenyl)borane is best known for its role as an excellent activator component in homogeneous Ziegler-Natta chemistry. However, the special properties of B(C6F5)3 have made this strong boron Lewis acid an increasingly used catalyst or stoichiometric reagent in organic and organometallic chemistry. This includes catalytic hydrometallation reactions, alkylations and catalyzed aldol-type reactions. B(C6F5)3 catalyzes tautomerizations and can sometimes stabilize less favoured tautomeric forms by adduct formation. It induces some rather unusual reactions of early metal acetylide complexes and can help in stabilizing uncommon coordination geometries of carbon. The growing number of such examples indicates an increasing application potential of the useful Lewis acid B(C6F5)3 aside from its established role in olefin polymerization catalysis.     

Synthesis of Uniquely Branched Polyethylene by Anilinonaphthoquinone Ligated Nickel Complex Activated with Tris(pentafluorophenyl)borane

Summary: A novel nickel complex ligated with 2‐(2,6‐diisopropylanilino)‐1,4‐naphthoquinone ( 1 ) was synthesized. The molecular structure of 1 determined by X‐ray analysis was a square‐planar geometry. Complex 1 conducted ethylene polymerization at 40 °C in a low activity to give linear polyethylene. On the other hand, 1 activated with 4 eq. of B(C₆F₅)₃ was highly active for ethylene polymerization and gave a polymer possessing short chain branches of methyl, ethyl and propyl groups formed by a chain walking mechanism, as well as long chain branches, of which the content was almost the same as the total content of short chain branches. These results suggest that the macromonomer formed via β‐hydride elimination should have effectively copolymerized with ethylene to give the long chain branches in the B(C₆F₅)₃‐activated system.

     

1,2-Carbopentafluorophenylation of Alkynes: The Metallomimetic Pull-Push Reactivity of Tris(pentafluorophenyl)borane

We report the novel single-step 1,2-dicarbofunctionalization of an arylacetylene with an allylsilane and tris(pentafluorophenyl)borane [B(C₆F₅)₃] involving C−C bond formation with C−H bond scission at the β-position to the silicon atom of an allylsilane and B→C migration of a C₆F₅ group. The 1,2-carbopentafluorophenylation occurs smoothly without the requirement for a catalyst or heating. Mechanistic studies suggest that the metallomimetic “pull-push” reactivity of B(C₆F₅)₃ imparts consecutive electrophilic and nucleophilic characteristics to the benzylic carbon of the arylacetylene. Subsequent photochemical 6π-electrocyclization affords tetrafluoronaphthalenes, which are important in the pharmaceutical and materials sciences. Owing to the unique reactivity of B(C₆F₅)₃, the 1,2-carbopentafluorophenylation using 2-substituted furan proceeded with ring opening, and the reaction using silyl enolates formed a C−C bond with C−O bond scission at the silyloxy-substituted carbon.     

B(C6F5)3在有机化学及高分子化学中的应用研究进展

B(C6F5)3与传统的Lewis酸相比,具有化学性质稳定、酸性强、使用方便等优点,被称为非传统的Lewis酸。B(C6F5)3的应用领域已经从最初的烯烃聚合共催化剂向有机化学及高分子化学的其它各个领域发展。B(C6F5)3催化的反应与传统Lewis酸催化的反应在反应机理及反应结果上均有很大的不同。本文主要综述B(C6F5)3近年来在有机化学及高分子化学中的应用研究成果。     

Carboboration Reactions of 1,2‐Bis[(diarylphosphino)ethynyl]benzenes with Tris(pentafluorophenyl)borane

The 1,2‐bis[(diarylphosphino)ethynyl]benzene derivatives 1a (R=Ph) and 1b (R=o‐tolyl) undergo 1,1‐carboboration at one of their acetylene units upon treatment with (C₆F₅)₃B at elevated temperature to give the products 5a and 5b , respectively. At room temperature, we observed the formation of the corresponding phosphireniumborate zwitterions, 7a and 7b , respectively, which may be intermediates of the 1,1‐carboboration reactions. The reaction of the more bulky 1,2‐bis[(dimesitylphosphino)ethynyl]benzene 1c with (C₆F₅)₃B takes a different course. At 110°, we observed the complete conversion to the benzopentafulvene derivative 8 which is probably formed in a typical carbocation rearrangement sequence after the initial (C₆F₅)₃B Lewis acid‐addition step. The compounds 5a, 5b, 7b , and 8 were characterized by X‐ray crystal‐structure analyses.     

Infrared Spectroscopy Evidence of Weak Interactions in Frustrated Lewis Pairs Formed by Tris(pentafluorophenyl)borane

Frustrated Lewis pairs (FLPs) have been widely investigated as promising catalysts due to their metal-free feature and ability to activate small molecules. Since their discovery, many works have been investigating how these Lewis pairs (intermolecular pairs) are held together in an encounter complex. This prompted several studies based on theoretical investigations, but experimental ones are limited yet. In this communication we show evidence of weak intermolecular interactions between Lewis acids and Lewis bases, distinguishing the Lewis adduct from FLPs, by probing fluorine-carbon vibrational modes using infrared spectroscopy. The main evidence is based on the band shifts occurring in FLPs due to weak hydrogen bonds between the hydrogen atoms of the Lewis base and the fluorine atoms of Lewis acid.     

Tris(pentafluorophenyl)borane: a mild and efficient catalyst for the chemoselective tritylation of alcohols

An efficient acid-catalyzed protection of alcohols as trityl ethers is described using triphenylmethanol in the presence of tris(pentafluorophenyl)borane (3 mol %) in dichloromethane at room temperature. The chemoselectivity of this protocol is demonstrated by studying the tritylation of a primary alcohol in the presence of a secondary alcohol and also the mildness of this catalyst was studied with substrates containing acid labile protecting groups.     

Semiconducting Polymers Based on Simple Electron-Deficient Cyanated trans-1,3-Butadienes for Organic Field-Effect Transistors

Developing high-performance but low-cost n-type polymers remains a significant challenge in the commercialization of organic field-effect transistors (OFETs). To achieve this objective, it is essential to design the key electron-deficient units with simple structures and facile preparation processes, which can facilitate the production of low-cost n-type polymers. Herein, by sequentially introducing fluorine and cyano functionalities onto trans-1,3-butadiene, we developed a series of structurally simple but highly electron-deficient building blocks, namely 1,4-dicyano-butadiene ( CNDE ), 3-fluoro-1,4-dicyano-butadiene ( CNFDE ), and 2,3-difluoro-1,4-dicyano-butadiene ( CNDFDE ), featuring a highly coplanar backbone and deep-positioned lowest unoccupied molecular orbital (LUMO) energy levels (−3.03–4.33 eV), which render them highly attractive for developing n-type semiconducting polymers. Notably, all these electron-deficient units can be easily accessed by a two-step high-yield synthetic procedure from low-cost raw materials, thus rendering them highly promising candidates for commercial applications. Upon polymerization with diketopyrrolopyrrole ( DPP ), three copolymers were developed that demonstrated unipolar n-type transport characteristics in OFETs with the highest electron mobility of >1 cm² V⁻¹ s⁻¹. Hence, CNDE , CNFDE , and CNDFDE represent a class of novel, simple, and efficient electron-deficient units for constructing low-cost n-type polymers, thereby providing valuable insight for OFET applications.     

Tris(pentafluorophenyl)borane catalyzed acylation of alcohols,phenols, amines,and thiophenols under solvent-free condition

The acylation of alcohols, phenols, amines, and thiophenols was accomplished with 0.5 mol % of tris(pentafluorophenyl)borane [B(C₆F₅)₃] at ambient temperature under solvent-free condition. Major advantages of this method include high yield, short reaction time, simple procedure, compatibility with sensitive protecting groups as well as other functional groups, absence of racemization of optical active compounds, and epimerization of sugars.     

Biosensors Based on Ion-Sensitive Field-Effect Transistors for HLA and MICA Antibody Detection in Kidney Transplantation

This work demonstrates the ability of the Ion-Sensitive Field-Effect Transistor (ISFET)-based immunosensor to detect antibodies against the human leukocyte antigen (HLA) and the major histocompatibility complex class-I-related chain A (MICA). The sensing membrane of the ISFET devices was modified and functionalized using an APTES-GA strategy. Surface properties, including wettability, surface thickness, and surface topology, were assessed in each module of the modification process. The optimal concentrations of HLA and MICA proteins for the immobilization were 10 and 50 μg/mL. The dose-response curve showed a detection range of 1.98–40 µg/mL for anti-HLA and 5.17–40 µg/mL for anti-MICA. The analytical precision (%CV) was found to be 10.69% and 8.92% for anti-HLA and -MICA, respectively. Moreover, the electrical signal obtained from the irrelevant antibody was considerably different from that of the specific antibodies, indicating the specific binding of the relevant antibodies without noise interference. The sensitivity and specificity in the experimental setting were established for both antibodies (anti-HLA: sensitivity = 80.00%, specificity = 86.36%; anti-MICA: sensitivity = 86.67%, specificity = 88.89%). Our data reveal the potential of applying the ISFET-based immunosensor to the detection of relevant anti-HLA and -MICA antibodies, especially in the field of kidney transplantation.     

Dioxygen Reactivity with a Ferrocene–Lewis Acid Pairing: Reduction to a Boron Peroxide in the Presence of Tris(pentafluorophenyl)borane

Ferrocenes, which are typically air‐stable outer‐sphere single‐electron transfer reagents, were found to react with dioxygen in the presence of B(C₆F₅)₃, a Lewis acid unreactive to O₂, to generate bis(borane) peroxide. Although several Group 13 peroxides have been reported, boron‐supported peroxides are rare, with no structurally characterized examples of the BO₂B moiety. The synthesis of a bis(borane)‐supported peroxide anion and its structural and electrochemical characterization are described.     

基于等离子激元耦合效应的高灵敏汞离子传感器

提出了一种基于单颗粒光谱技术,能够高灵敏检测汞离子的新方法,原理是基于汞离子诱导的纳米金自组装过程.在两种不同大小的纳米金表面分别修饰两段富含T碱基的DNA序列,当Hg²⁺存在时,两段DNA序列自发形成双链结构,导致小金球能够在大金球表面自组装成核-卫星纳米金结构,这一过程伴随着纳米颗粒散射光颜色和散射峰位置的变化,变化的程度与Hg²⁺浓度具有相关性,依托单颗粒光谱技术极高的检测灵敏度,该方法可以实现pmol/L级的检测.     

Meniscus-Assisted Solution Printing Enables Cocrystallization in Poly(3-alkylthiophene)-based Blends for Field-Effect Transistors

The formation of cocrystallization in two various conjugated components may endow the newly formed conjugated cocrystals with multiple functionalities and improved charge transport properties. However, compared to conjugated small molecules, this strategy is rather limitedly realized in conjugated polymers. Herein, a simple meniscus-assisted solution printing(MASP) strategy is utilized to achieve the cocrystallization in the blends of two conjugated polymers, i.e., poly(3-hexylthiophene)(P3HT) a...     

Microwave Irradiation as a Powerful Tool for the Preparation of n-Type Benzotriazole Semiconductors with Applications in Organic Field-Effect Transistors

In this work, as an equivocal proof of the potential of microwave irradiation in organic synthesis, a complex pyrazine-decorated benzotriazole derivative that is challenging to prepare under conventional conditions has been obtained upon microwave irradiation, thus efficiently improving the process and yields, dramatically decreasing the reaction times and resulting in an environmentally friendly synthetic procedure. In addition, this useful derivative could be applied in organic electronics, specifically in organic field-effect transistors (OFETs), exhibiting the highest electron mobilities reported to date for benzotriazole discrete molecules, of around 10⁻² cm²V⁻¹s⁻¹.     

Metal and solvent‐free cyanosilylation of carbonyl compounds with tris(pentafluorophenyl)borane

A highly effective method of the cynaosilylation of aldehydes and ketones with TMSCN in the presence of catalytic amount of B(C₆F₅)₃ [tris(pentafluorophenyl)borane] has been developed. Cyano transfer from TMSCN to carbonyl group proceeds at room temperature under solvent‐free conditions. Various alehydes and ketones have been converted into the corresponding trimethylsilylether within short reaction times with excellent yield under mild conditions. Copyright © 2008 John Wiley & Sons, Ltd.