Non-covalent Bonded 3D Supramolecular Architectures Based on Acid-base Adducts

Two novel acid-base adducts,[H2L1^2＋]（Hpbda）2（1,L1 = 1,4-di（lH-imidazol-4-yl）benzene,H2pbda = 1,4-benzenedicarboxylic acid） and[H2L2^2＋]（NO3）2（2,L2 = l,4-di（l-carboxymethyl-imidazol-4-yl）benzene）,have been prepared and characterized by single-crystal X-ray diffraction,IR spectroscopy and elemental analysis.Compound 1 crystallizes in monoclinic,space group P21/n with a = 5.3525（11）,b = 9.1471（19）,c = 19.314（4） ？,β = 92.342（3）°,V= 944.8（3） A°3,Z = 2,C16H16N6O（10）,Mr = 452.35,Dc = 1.590 g/cm^3,μ = 0.135 mm^-1,S = 1.058,F（000） = 468,the final R = 0.0661 and wR = 0.1887 for 2298 observed reflections（I〉 2σ（I））.Compound 2 crystallizes in monoclinic,space group P21/c with a = 9.6923（10）,b = 17.2950（17）,c = 7.1880（7） ？,β =94.801（2）°,V= 1200.7（2）A°3,Z = 2,C（28）H（22）N4O8,Mr = 542.50,Dc = 1.501 g/cm^3,μ = 0.112 mm^-1,S= 1.060,F（000） = 564,the final R = 0.0394 and wR = 0.1017 for 2768 observed reflections（I 〉2σ（I））.In the title compounds,both of L1 and L2 ligands act as weak base to accept protons to exhibit diprotonated H2L1^2＋ and H2L2^2＋ form,which can effectively employ as hydrogen bonding donors to combine anion moieties to form binary adducts respectively.In the crystal packing diagram of two polymers,there exist extensive noncovalent interactions including charge-transfer interactions,C（N）-H…π and N-H…O,C-H…O,O-H…O hydrogen bonding interactions between co-crystal moieties which consolidate the structures of supramolecular polymers,thus generating three-dimensional（3D） frameworks.

Highly efficient catalyst for 1,1,2-trichloroethane dehydrochlorination via BN_(3) frustrated Lewis acid-base pairs

In this study,a novel non-metallic carbon-based catalyst co-doped with boron and nitrogen(B,N)was successfully synthesized.By precisely controlling the carbonization temperature of a binary mixed ionic liquid,we selectively modified the doping site structure,ultimately constructing a B,N co-doped frustrated Lewis acid-base pair catalyst.This catalyst exhibited remarkable catalytic activity,selectivity,and stability in the dehydrochlorination reaction of 1,1,2-trichloroethane(TCE).Detailed characterization and theoretical calculations revealed that the primary active center of this catalyst was the BN_(3)configuration.Compared to conventional graphitic N structures,the BN_(3)structure had a higher p-band center,ensuring superior adsorption and activation capabilities for TCE during the reaction.Within the BN_(3)site,three negatively charged nitrogen atoms acted as Lewis bases,while positively charged boron atoms acted as Lewis acids.This synergistic interaction facilitated the specific dissociation of chlorine and hydrogen atoms from TCE,significantly enhancing the 1,1-dichloroethene selectivity.Through this research,we not only explored the active site structure and catalytic mechanism of B,N co-doped catalysts in depth but also provided an efficient,selective,and stable catalyst for the dehydrochlorination of TCE,contributing significantly to the development of non-metallic catalysts.

Efficient nitrite-to-ammonia electroreduction over Zr-Ni frustrated Lewis acid-base pairs

Electrochemical NO_(2)~--to-NH_(3) conversion(NO_(2)RR) offers a green route to NH_(3) electrosynthesis, while developing efficient NO_(2)RR catalysis systems at high current densities remains a grand challenge. Herein, we report an efficient Zr-NiO catalyst with atomically dispersed Zr-dopants incorporated in NiO lattice, delivering the exceptional NO_(2)RR performance with industriallevel current density(>0.2 A cm^(-2)). In situ spectroscopic measurements and theoretical simulations reveal the construction of ZrNi frustrated Lewis acid-base pairs(FLPs) on Zr-Ni O, which can substantially increase the number of absorbed nitrite(NO_(2)~-),promote the activation and protonation of NO_(2)~- and concurrently hamper the H coverage, boosting the activity and selectivity of Zr-NiO towards the NO_(2)RR. Remarkably, Zr-NiO exhibits the exceptional performance in a flow cell with high Faradaic efficiency for NH_(3) of 94.0% and NH_(3)yield rate of 1,394.1 μmol h^(-1)cm^(-2) at an industrial-level current density of 228.2 m A cm^(-2),placing it among the best NO_(2)RR electrocatalysts for NH_(3) production.

关于frustrated Lewis pair的中文名

frustrated Lewis pair(FLP)是一个最近出现的新名词,指分子内或混合体系中同时具有路易斯酸和路易斯碱两个位点,由于空间位阻较大而使得这两个位点不能结合形成路易斯酸碱加合物,从而具有独特的反应活性。建议译为"受阻路易斯酸碱对"。

Probing the Impact of Solvent on the Strength of Lewis Acids via Fluorescent Lewis Adducts

Various methods have been developed to measure the strength of a Lewis acid.A major challenge for these measurements lies in the complexity that arises from variable solvent interactions and perturbations of Lewis acids as their reaction environment changes.Herein,we investigate the impact of solvent effects on Lewis acids for the first time as measured by the fluorescent Lewis adduct(FLA)method.The binding of a Lewis acid in various solvents reveals a measurable dichotomy between both polarity and donor ability of the solvent.While not strictly separable,we observe that the influence of solvent polarity on Lewis acid unit(LAU)values is distinctly opposite to the influence of donor ability.This dichotomy was confirmed by titration data,illustrating that solvation effects can be appropriately and precisely gauged by the FLA method.

Lewis base-CO2 adducts as organocatalysts for CO2 transformation

In the recent decade, the development and application of organocatalysis for CO_2 transformation into useful chemicals have attracted much attention. Among these organocatalysts, Lewis base-CO_2 adducts(LB-CO_2) were found to be more efficient.The used Lewis base has great effect on the catalytic activity of its CO_2 adduct. This review reports the recent progress in LB-CO_2 adducts catalyzed the cyclization of CO_2 with epoxides or aziridines to afford cyclic carbonates or oxazolidinones,the carboxylation of CO_2 with propargylic alcohols to α-alkylidene cyclic carbonates, and the reduction of CO_2 to methanol,formamides and methylamines, with the focus on the catalytic mechanism.

Synergistic Lewis acid-base sites of ultrathin porous Co_(3)O_(4)nanosheets with enhanced peroxidase-like activity

Surface Lewis acid-base sites in crystal structure may influence the physicochemical properties and the catalytic performances in nanozymes.Understanding the synergistic effect mechanism of Co_(3)O_(4)nanozymes towards substances(3,3’,5,5’-tetramethylbenzidine(TMB)and hydrogen peroxide(H2O2))induced by surface Lewis acid-base sites is important to enhance the efficiency for peroxidase-like reaction.Herein,ultrathin porous Co_(3)O_(4)nanosheets with abundant Lewis acid-base sites were prepared by sodium borohydride(NaBH4)reduction treatment,which exhibited high-efficiency peroxidase-like activity compared with original Co_(3)O_(4)nanosheets.The Lewis acid-base sites for ultrathin porous Co_(3)O_(4)nanosheets nanozyme were owing to the coordination unsaturation of Co ions and the formation of defect structure.Ultrathin porous Co_(3)O_(4)nanosheets had 18.26-fold higher catalytic efficiency(1.27×10^(-2)s^(-1)·mM^(-1))than that of original Co_(3)O_(4)(6.95×10^(-4)s^(-1)·mM^(-1))in oxidizing TMB substrate.The synergistic effect of surface acid and base sites can enhance the interfacial electron transfer process of Co_(3)O_(4)nanosheets,which can be a favor of absorption substrates and the generation of reactive intermediates such as radicals.Furthermore,the limit of detection of hydroquinol was 0.58μM for ultrathin porous Co_(3)O_(4)nanosheets,965-fold lower than original Co_(3)O_(4)(560μM).Besides,the linear range of ultrathin porous Co_(3)O_(4)nanosheets was widely with the concentration of 5.0-1,000μM.Colorimetric detection of hydroquinol by agarose-based hydrogel membrane was provided based on excellent peroxidase-like properties.This study provided insights into designing high-performance nanozymes for peroxidase-like catalysis via a strategy of solid surface acid-base sites engineering.

Writing and Erasing Encryption Information Based on Frustrated Lewis Pair Chemistry

Lewis acid−base adducts resulting from instantaneous interactions provide a cost-effective strategy for color tuning and anticounterfeiting information.Herein,we report the construction of luminescent Lewis acid−base adducts via inkjet printing.Due to the unique weak coordination bond of B→N,it is feasible to construct anticounterfeiting information that is easy to erase.The in situ postsynthesis of the luminescent quick response codes via inkjet printing facilitates precision chemistry control to change the emission ranging from deep-blue(peaking at 407 nm)to orange-red(peaking at 597 nm).The encrypted information can be quickly erased either by modulating the temperature to dissociate the weak coordination or strong Lewis base to promote a neutralization reaction.

球形氯化镁载体

概述了用于丙烯聚合的球形Ziegler-Natta催化剂的重要组分球形氯化镁载体以及氯化镁载体在该催化剂中的作用,讨论了球形氯化镁醇加合物的结构、制备方法,回顾了其它不同形式的氯化镁载体。

平衡Lewis酸碱催化剂催化乙醇转化形成C–C键的最新进展（英文）

乙醇是生物质转化过程中重要的平台分子,可以通过ABE(丙酮-丁醇-乙醇)发酵过程大量获得.近几十年来,人们一直致力于将乙醇升级为高附加值化学品.通过C–C键生成过程,选择性地生成了1-丁醇和一系列高附加值产品.本文总结了近年来在平衡Lewis酸碱催化剂上选择性生成C–C键的研究进展,包括金属氧化物催化剂、混合金属氧化物催化剂、羟基磷灰石和沸石分子筛限域过渡金属氧化物催化剂.其中Pd-Mg AlO_x和Sr基羟基磷灰石催化剂对应1-丁醇的选择性>70%, Zn_xZr_yO_z和Ta-Si BEA沸石对异丁烯和丁二烯的选择性>80%.本文详细介绍了各反应体系中C–C键形成的机理和反应路径,并讨论了C–C键生成与催化剂表面Lewis酸、碱强度的关系.

Atomically Dispersed Manganese Lewis Acid Sites Catalyze Electrohydrogenation of Nitrogen to Ammonia

Ambient electrochemical nitrogen fixation is a promising and environmentally benign route for producing sustainable ammonia,but has been limited by the poor performance of existing catalysts that promote the balanced chemisorption of N2 and subsequent electrochemical activation and hydrogenation.Herein,we describe the highly selective and efficient electrohydrogenation of nitrogen to ammonia using a hollow nanorod-based hierarchically graphitic carbon electrocatalyst with abundant atomically dispersed Mn sites.We discovered that the electron interactions strengthen the interfacial binding between nitrogen and active Mn Lewis acidic hotspots.The Lewis acid-base interactions promote the chemisorption and lock up nitrogen on the active sites and suppress proton adsorption.The proton-coupled electron transfer cleavage of the nitrogen triple bond through an associative mechanism was confirmed under lower overpotential,which delivered high ammonia yield of 67.5μg h−1 mgcat.−1 and Faradaic efficiency of 13.7% at−0.25 V versus the reversible hydrogen electrode,along with∼100% selectivity and significantly enhanced electrochemical stability(about 88.8% current retention over 50 h potentiostatic test)under mild conditions.Our strategy is versatile to tailor the nitrogen fixation performance of single-atom catalysts with atomic accuracy.

Strategies and methods for fabricating high quality metal halide perovskite thin films for solar cells

With the development of human society,the problems of environmental deterioration and energy shortage have become increasingly prominent.In order to solve these problems,metal halide perovskite solar cells(PSCs)stand out because of their excellent properties(i.e.,high optical absorption coefficient,long carrier lifetime and carrier diffusion length,adjustable band gap)and have been widely studied.PSCs with low cost,high power conversion efficiency and high stability are the future development trend.The quality of perovskite film is essential for fabricating PSCs with high performance.To provide a full picture of realizing high performance PSCs,this review focuses on the strategies for preparing high quality perovskite films(including antisolvent,Lewis acid-base,additive engineering,scaleable fabrication,strain engineering and band gap adjustment),and therefore to fabricate high performance PSCs and to accelerate the commercialization.

Electrocatalytic and stoichiometric reactivity of 2D layered siloxene for high-energy-dense lithium-sulfur batteries

Lithium-sulfur batteries(LSBs)have emerged as promising power sources for high-performance devices such as electric vehicles.However,the poor energy density of LSBs owing to polysulfide shuttling and passivation has limited their further market penetration.To mitigate this challenge,two-dimensional(2D)siloxene(2DSi),a Si-based analog of graphene,is utilized as an additive for sulfur cathodes.The 2DSi is fabricated on a large scale by simple solvent extraction of calcium disilicide to form a thin-layered structure of Si planes functionalized with vertically aligned hydroxyl groups in the 2DSi.The stoichiometric reaction of 2DSi with polysulfides generates a thiosulfate redox mediator,secures the intercalation pathway,and reveals Lewis acidic sites within the siloxene galleries.The 2DSi utilizes the corresponding in-situ-formed electrocatalyst,the 2D confinement effect of the layered structure,and the surface affinity based on Lewis acid-base interaction to improve the energy density of 2DSi-based LSB cells.Combined with the commercial carbon-based current collector,2DSi-based LSB cells achieve a volumetric energy density of 612 Wh Lcell^(−1) at 1 mA cm^(−2) with minor degradation of 0.17%per cycle,which rivals those of state-of-the-art LSBs.This study presents a method for the industrial production of high-energy-dense LSBs.

A Stochastic Study on the Wicking Phenomena

A stochastic approach based on a 3D 3-state Potts model combined with Monte Carlo simulation was used to study the equilibrium wicking height of liquids in vertical cylindrical capillaries. The Lifshitz-van der Waals and Lewis acid-base theories were adopted to characterize the apolar and polar interactions in the spin system. The evolution of the spin system was driven by the difference in total energy for two successive states. To verify the model, equilibrium wicking height of water, formamide, heptane, and octane in capillaries of different radii were examined and the corresponding computer simulations were implemented. Good agreement was obtained between the simulation and experimental results. It shows the potential of the proposed approach to be applied in this area.

Electrochemical behaviors of novel composite polymer electrolytes for lithium batteries

A novel composite polymer electrolyte was prepared by blending an appropriateamount of LiClO_4 and 10 percent (mass fraction) fumed SiO_2 with the block copolymer of poly(ethylene oxide) (PEO) synthesized by poly (ethylene glycol) (PEG) 400 and CH_2C1_2 The ionicconductivity, electrochemical stability, interfacial characteristic and thermal behavior of thecomposite polymer electrolyte were studied by the measurements of AC impedance spectroscopy, linearsweep voltammetry and differential scanning calorimetry (DSC), respectively. The glass transitiontemperature acts as a function of salt concentration, which increases with the LiClO_4 content.Lewis acid-base model interaction mechanism was introduced to interpret the interactive relationbetween the filled fumed SiO_2 and the lithium salt in the composite polymer electrolyte. Over thesalt concentration range and the measured temperature, the maximum ionic conductivity of thecomposite polymer electrolyte (10^(-4.41) S/cm) appeared at EO/Li=25 (mole ratio) and 30 deg C, andthe beginning oxidative degradation potential versus Li beyond 5 V.

Recent advances in the coupling of CO2 and epoxides into cyclic carbonates under halogen-free condition

The chemical transformation of CO2 and epoxides into cyclic carbonates has been receiving much attention and is one of the successful examples for CO2 utilization as carbon resource.Many catalysts containing halide anions have been explored and exhibit excellent catalytic activity.However,halogen salt is generally toxic and corrosive to reactors.From a green chemistry perspective,it is more attractive to develop a halogen-free catalyst with excellent performance.Herein,a review of recent research progress of halogen-free catalysts in the cycloaddition of CO2 and epoxide is presented.According to previous experimental and theoretical works,two possible strategies for achieving the halogen-free process were summarized.The relationship between catalytic activity and catalyst structure,the mechanism of CO2 activation should be both studied deeply combined with experimental results and DFT calculation,which can guide the design of new catalysts and realize halogen-free process under mild reaction conditions.

“受阻路易斯酸碱对”催化的2,3-二取代2H-1,4-苯并噁嗪氢化反应机理研究

在受阻路易斯酸碱对(FLPs)催化的2,3-二取代2H-1,4-苯并噁嗪氢化反应中,3号位取代基不同会导致反应效率极大改变,因此我们选取反应活性具有较大差别的三种底物作为模型化合物对其反应机理进行了研究,建立了氢化反应势能面.发现当B(C6F5)3与2,3-二苯基2H-1,4-苯并噁嗪或2-甲基-3-苯基2H-1,4-苯并噁嗪混合后,会形成FLPs与路易斯酸碱加合物的混合物.而将B(C6F5)3与2,3-二甲基2H-1,4-苯并噁嗪混合后主要形成没有催化活性的路易斯酸碱加合物,因其能量低于FLPs,在催化体系中不容易转化为FLPs,这导致三种模型化合物在FLPs催化的氢化反应中效率不同.进一步的取代基电子效应及位阻效应计算表明:B(C6F5)3与2-甲基-3-取代2H-1,4-苯并噁嗪混合后形成的路易斯酸碱加合物和FLPs化合物之间稳定性差别源于3位取代基空间位阻不同.