卤键在化学传感和分子识别中的应用

卤键是一种新的分子间非共价作用力,它存在于卤素原子(路易斯酸)和具有孤电子对的原子或π-电子体系(路易斯碱)之间,在超分子化学、材料科学、生物识别和药物设计等领域已经显示出独特的优势。本文主要从卤键的特征和在化学传感和分子识别中的应用以及发展前景等几方面进行了介绍,期望引起人们对卤键的更多关注。     

化学及生物体系中的分别识别*

分子识别的目标是研究分子间专一性地相互作用, 这在化学及生命过程中起着非常重要的作用。本文综述了分子识别的机制及其在化学、生命科学、材料、信息等有关学科中的应用。     

Supramolecular chemistry

The article discusses molecular recognition and overviews the key concepts -storage and retrieval of chemical information by molecular structures, supramolecular reagents and catalysts, molecular transport, semiochemistry and self assembly. The prospects of controlling supramolecular architecture through engineered molecular recognition and design of ‘programmed systems’ controlled by molecular information are also discussed.     

Molecular sensing using armchair graphene nanoribbon

In molecular electronics, the conductance strongly depends on the frontier energy levels and spatial orientations of molecules. Utilizing these features, we investigate the electron transport characteristics of conjugated molecules attached on an armchair graphene nanoribbon. The resulting sharp reduction in the transmission which represents molecular fingerprints and the change of the transmission depending on the molecular orientation, are examined in accordance with a unified picture of the Fano–Anderson model. These characteristics, being unique for each molecule, would be applicable to molecular recognition and configurational analysis. © 2014 Wiley Periodicals, Inc.     

分子钳人工受体研究进展

分子识别是生物体系的基本特征, 并在生命活动中起中心作用. 利用合成的人工受体与适当底物间的分子识别以建立化学模型或化学仿生体系对生命过程中的分子识别现象进行模拟研究是生物有机化学和超分子化学前沿富于挑战的课题之一. 按照不同的隔离基, 综述了分子钳人工受体的研究进展.     

Direct Observation of Kinetic Pathways of Biomolecular Recognition

The pathways of molecular recognition, which is a central event in all biological processes, belong to the most important subjects of contemporary research in biomolecular science. By using fluorescence spectroscopy in a microfluidics channel, it can be determined that molecular recognition of α‐chymotrypsin in hydrous surroundings at two different pH values (3.6 and 6.3) follows two distinctly different pathways. Whereas one corroborates an induced‐fit model (pH 3.6), the other one (pH 6.3) is consistent with the selected‐fit model of biomolecular recognition. The role of massive structural perturbations of differential recognition pathways could be ruled out by earlier XRD studies, rather was consistent with the femtosecond‐resolved observation of dynamic flexibility of the protein at different pH values. At low concentrations of ligands, the selected‐fit model dominates, whereas increasing the ligand concentration leads to the induced‐fit model. From molecular modelling and experimental results, the timescale associated with the conformational flexibility of the protein plays a key role in the selection of a pathway in biomolecular recognition.     

计算机分子模拟在分子印迹技术中的应用

传统的分子印迹技术对模板分子、功能单体、交联剂、致孔剂等的筛选往往依靠经验,常通过反复实验对合成条件进行优化,存在实验周期长、耗材量大等问题。计算机分子模拟技术的应用在实验过程中起到可预见性指导作用,可以实现精准识别位点的裁制、识别驱动力的设计,通过结合能等物化特征参数计算优化识别体系的稳定性,从而合理选择模板分子、功能单体、交联剂、致孔剂,优化聚合条件,以提高聚合物识别特异性和亲和力,缩短实验周期,更符合绿色化学的理念。本文简单介绍了计算机分子模拟技术,重点对其在分子印迹技术中的指导作用进行了综述,并对其在分子印迹技术中的应用进行了展望。     

Weak interactions and molecular recognition in systems involving electron transfer proteins

Electrostatic interactions and other weak interactions between amino acid side chains on protein surfaces play important roles in molecular recognition, and the mechanism of their intermolecular interactions has gained much interest. We established that charged peptides are useful for investigating the molecular recognition character of proteins and their molecular interaction induced structural changes. Positively charged lysine peptides competitively inhibited electron transfer from reduced cytochrome f (cyt f or cytochrome c (cyt c) to oxidized plastocyanin (PC), due to neutralization of the negatively charged site of PC by formation of PC-lysine peptide complexes. Lysine peptides also inhibited electron transfer from cyt c to cytochrome c peroxidase. Likewise, negatively charged aspartic acid peptides interacted with the positively charged sites of cytfand cyt c, and competitively inhibited electron transfer from reduced cytfor cyt c to oxidized PC and from [Fe(CN)6]4- to oxidized cyt c. Changes in the geometry and a shift to a higher redox potential of the active site Cu of PC on oligolysine binding were detected by spectroscopic and electrochemical measurements, owing to the absence of absorption in the visible region for lysine peptides. Structural and redox potential changes were also observed for cyt f and cyt c by interaction with aspartic acid peptides.     

芳杂环类多重氢键分子钳人工受体对中性分子的识别性能研究

根据多点氢键识别原理,设计合成了新的分子钳受体1～6。研究了其对巴比妥 、尿素、二苯甲酮、戊二酰亚胺等中性分子的识别性能。用差紫外光谱法测定了结 合常数和自由能变化（ΔG）。结果表明,所有分子钳受体与所考察的客体分子均 形成1：1型超分子配合物,识别作用的推动力主要为多重氢键的协同作用。讨论了 主客体间尺寸/形状、几何互补等因素对形成超分子配合物的影响。并利用~1H NMR、计算机模拟作辅助手段对实验结果和现象进行了解释。     

分子印迹技术用于蛋白质的识别

分子印迹技术是一种新型的高效分离技术。合成含识别蛋白质的分子印迹聚合物具有极大的应用价值,又极具挑战性,已成为许多分子识别领域工作者的研究热点。本文总结了近10年来该领域的研究进展,讨论了已有不同方法的发展状况以及相对优缺点,阐明了其可能发展的方向和前景。     

Ternary choline chloride/caffeic acid/ethylene glycol deep eutectic solvent as both a monomer and template in a molecularly imprinted polymer

A molecularly imprinted polymer based on a ternary deep eutectic solvent comprised of choline chloride/caffeic acid/ethylene glycol was prepared. The caffeic acid in the ternary deep eutectic solvent was used as both a monomer and template. The molecularly imprinted polymer based on the ternary deep eutectic solvent was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, field‐emission scanning electron microscopy, Brunauer–Emmett–Teller surface area analysis, atomic force microscopy, and elemental analysis. A series of molecularly imprinted polymers based on choline chloride/caffeic acid/ethylene glycol with different molar ratios was prepared and applied to the molecular recognition of polyphenols. A comparison of the recognition ability of molecularly imprinted polymers to polyphenols revealed that the choline chloride/caffeic acid/ethylene glycol (1:0.4:1, molar ratio) molecularly imprinted polymer had the best molecular recognition effect with 132 μg/g of protocatechuic acid, 104 μg/g of catechins, 80 μg/g of epicatechin, and 123 μg/g of caffeic acid in 6 h, as well as good molecular recognition ability for polyphenols from a Radix Asteris sample. These results show that the ternary deep eutectic solvent based molecularly imprinted polymer is a potential medium that can be applied to drug purification, drug delivery, and drug analysis.     

葫环联脲新进展

葫环联脲这类新型主体分子正受到化学家们的广泛关注,并逐渐成为超分子化学研究领域中的一个热点.本文综述了近两-来葫环联脲同系物、衍生物的合成及其在分子识别、分子催化、分子组装等方面的研究进展,并对该领域的研究前景作一展望.     

Modulated molecular recognition by a temperature‐sensitive molecularly‐imprinted polymer

Modulated molecular recognition was achieved in a temperature‐sensitive molecularly‐imprinted polymer. Using PNIPA as the temperature‐sensitive element, the adenine‐imprinted polymer (i.e., MIP‐S) was prepared and characterized. The MIP‐S exhibited a temperature‐responsive molecular recognition behavior because of the thermal phase‐transition within the MIP‐S network. Specifically, below the transition temperature (e.g., 20 °C), the MIP‐S showed a highly specific recognition for the imprint species (adenine). However, the MIP‐S did not show any significant resolution for the imprint species (adenine) and its analogue (1‐methyladenine) above the transition temperature (e.g., 40 °C). Such temperature‐regulated recognition is comparable to a switch‐on and switch‐off process, thereby making tunable molecular recognition feasible. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2352–2360, 2009     

A Chiral Molecular Cage Comprising Diethynylallenes and N-Heterotriangulenes for Enantioselective Recognition

Chirality, a characteristic tool of molecular recognition in nature, is often a complement of redox active systems. Scientists, in their eagerness to mimic such sophistication, have designed numerous chiral systems based on molecular entities with cavities, such as macrocycles and cages. In an attempt to combine chirality and redox-active species, in this contribution we report the synthesis and detailed characterization of a chiral shape-persistent molecular cage based on the combination of enantiopure diethynylallenes and electron-rich bridged triarylamines, also known as N-heterotriangulenes. Its ability for chiral recognition in solution was revealed through UV/vis titrations with enantiopure helicenes.     

Molecular recognition of aminoglycoside antibiotics by bacterial defence proteins: NMR study of the structural and conformational features of streptomycin inactivation by Bacillus subtilis aminoglycoside-6-adenyl transferase

The molecular recognition of streptomycin by Bacillus subtilis aminoglycoside-6-adenyl transferase has been analysed by a combination of NMR techniques and molecular dynamic simulations. This protein inactivates streptomycin by transferring an adenyl group to position six of the streptidine moiety. Our combined approach provides valuable information about the bioactive conformation for both the antibiotic and ATP and shows that the molecular recognition process for streptomycin involves a conformational selection phenomenon. The binding epitope for both ligands has also been analysed by 1D-STD experiments. Finally, the specificity of the recognition process with respect to the aminoglycoside and to the nucleotide has been studied.     

“分子钳”人工受体的研究进展

本文综述了分子钳人工受体近年来在分子识别领域中的新进展     

二聚雌二醇受体的设计合成

设计、合成了一类新型的“钳形”二聚雌二醇受体，其结构经MS、IR、^1H NMR及元素分析确证，并进行了识别性能研究。     

Molecular Tweezers: Concepts and Applications

Taken to the molecular level, the concept of “tweezers” opens a rich and fascinating field at the convergence of molecular recognition, biomimetic chemistry and nanomachines. Composed of a spacer bridging two interaction sites, the behaviour of molecular tweezers is strongly influenced by the flexibility of their spacer. Operating through an “induced‐fit” recognition mechanism, flexible molecular tweezers select the conformation(s) most appropriate for substrate binding. Their adaptability allows them to be used in a variety of binding modes and they have found applications in chirality signalling. Rigid spacers, on the contrary, display a limited number of binding states, which lead to selective and strong substrate binding following a “lock and key” model. Exquisite selectivity may be expressed with substrates as varied as C₆₀, nanotubes and natural cofactors, and applications to molecular electronics and enzyme inhibition are emerging. At the crossroad between flexible and rigid spacers, stimulus‐responsive molecular tweezers controlled by ionic, redox or light triggers belong to the realm of molecular machines, and, applied to molecular tweezing, open doors to the selective binding, transport and release of their cargo. Applications to controlled drug delivery are already appearing. The past 30 years have seen the birth of molecular tweezers; the next many years to come will surely see them blooming in exciting applications.     

Green polymers from Geobacillus thermodenitrificans DSM465--candidates for molecularly imprinted materials

Novel molecular recognition materials were prepared from water soluble proteins from thermophile G. thermodenitrificans DSM465 by an alternative molecular imprinting method. Water soluble proteins from G. thermodenitrificans DSM465 were converted into the molecularly imprinted materials by adopting 9-EA as a print molecule. The molecularly imprinted protein membranes recognized As in preference to Gs. The adsorption isotherms led to the conclusion that molecular recognition sites toward As were constructed by the presence of 9-EA during the membrane preparation process. The affinity constant between As and the molecular recognition site thus constructed was determined to be 1.75 x 10(5) mol(-1) dm(3). The results obtained in the present study suggest that water soluble proteins from G. thermodenitrificans DSM465 is one of environmentally-friendly 'green' polymers to be converted into molecular recognition materials by applying an alternative molecular imprinting method.