ring‐opening polymerization

  • 文章类型: Journal Article
    过氧化物酶,像辣根过氧化物酶(HRP),是血红素金属酶,是各种氧化反应的强大生物催化剂。通过使用简单的嫁接方法,开环聚合(ROP),锰卟啉,成功制备了能够催化H2O2氧化反应的HRP星形多肽类似物。像他们的蛋白质模型一样,这些简化的类似物在氧化剂的mM范围内显示出有趣的Michaelis-Menten常数(KM)。有趣的是,聚合物结构对变性的抵抗力更强(热,蛋白水解和氧化剂浓度)比HRP,为它们在催化或生物传感设备中的使用开辟了有趣的前景。
    Peroxidases, like horseradish peroxidase (HRP), are heme metalloenzymes that are powerful biocatalysts for various oxidation reactions. By using simple grafting-from approach, ring-opening polymerization (ROP), and manganese porphyrins, star-shaped polypeptides analogues of HRP capable of catalyzing oxidation reactions with H2O2 is successfully prepared. Like their protein model, these simplified analogues show interesting Michaelis-Menten constant (KM) in the mM range for the oxidant. Interestingly, the polymer structures are more resistant to denaturation (heat, proteolysis and oxidant concentration) than HRP, opening up interesting prospects for their use in catalysis or in biosensing devices.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    具有明确结构的聚合物,通过金属催化过程合成,具有与骨架不同的极性和反应性的端基,在科学界和工业界都获得了相当大的关注。这些聚合物在创新功能材料的创建中显示出作为基本构件和添加剂的潜在应用。研究旨在通过结合稀土金属配合物介导的活性配位聚合和通过σ键复分解的C-H键活化反应来确定最佳和简单的合成方法。这种组合直接从单一前体产生具有不同官能团的催化剂,无需连续反应即可生产末端官能化聚合物,如终止反应。利用这种创新的方法可以精确控制端基功能,提供了一种通用的方法来定制所得聚合物的性能和应用。这个角度讨论的原则,挑战,以及与这种合成策略相关的潜在进步,强调其在推进金属有机化学界面方面的重要性,高分子化学,和材料科学。
    Polymers with well-defined structures, synthesized through metal-catalyzed processes, and having end groups exhibiting different polarity and reactivity than the backbone, are gaining considerable attention in both scientific and industrial communities. These polymers show potential applications as fundamental building blocks and additives in the creation of innovative functional materials. Investigations are directed toward identifying the most optimal and uncomplicated synthetic approach by employing a combination of living coordination polymerization mediated by rare-earth metal complexes and C-H bond activation reaction by σ-bond metathesis. This combination directly yields catalysts with diverse functional groups from a single precursor, enabling the production of terminal-functionalized polymers without the need for sequential reactions, such as termination reactions. The utilization of this innovative methodology allows for precise control over end-group functionalities, providing a versatile approach to tailor the properties and applications of the resulting polymers. This perspective discusses the principles, challenges, and potential advancements associated with this synthetic strategy, highlighting its significance in advancing the interface of metalorganic chemistry, polymer chemistry, and materials science.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    随着对可持续聚合物需求的增加,大多数研究工作都集中在聚酯上,可以是生物衍生的和可生物降解的。然而类似的聚硫酯,其中一个氧原子被硫原子取代,仍然是一个相对未开发的潜力来源。硫的掺入使聚合物表现出广泛的有利性能,如热电阻,降解性,和高折射率。聚硫酯合成代表了研究的前沿,承诺为传统聚酯的生态友好替代品铺平道路。此外,聚硫酯研究也可以为可持续和可回收材料的开发开辟道路。在过去的25年里,已经开发了许多合成聚硫酯的方法。然而,迄今为止,由于成本的挑战,尚未开发出聚硫酯的工业合成,产量,以及副产品的毒性。本文将总结聚硫酯合成的最新进展,涵盖逐步增长聚合,开环聚合(ROP),和生物合成。至关重要的是,将强调这些过程的好处和挑战,特别注意它们的可持续性,目的是鼓励对快速增长的聚硫酯领域进行进一步的探索和研究。本文受版权保护。保留所有权利。
    As the demand for sustainable polymers increases, most research efforts have focused on polyesters, which can be bioderived and biodegradable. Yet analogous polythioesters, where one of the oxygen atoms has been replaced by a sulfur atom, remain a relatively untapped source of potential. The incorporation of sulfur allows the polymer to exhibit a wide range of favorable properties, such as thermal resistance, degradability, and high refractive index. Polythioester synthesis represents a frontier in research, holding the promise of paving the way for eco-friendly alternatives to conventional polyesters. Moreover, polythioester research can also open avenues to the development of sustainable and recyclable materials. In the last 25 years, many methods to synthesize polythioesters have been developed. However, to date no industrial synthesis of polythioesters has been developed due to challenges of costs, yields, and the toxicity of the by-products. This review will summarize the recent advances in polythioester synthesis, covering step-growth polymerization, ring-opening polymerization (ROP), and biosynthesis. Crucially, the benefits and challenges of the processes will be highlighted, paying particular attention to their sustainability, with the aim of encouraging further exploration and research into the fast-growing field of polythioesters.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    聚乳酸(PLA),一种生物相容性和生物可降解的聚合物,广泛用于各种生物医学应用。然而,将丙交酯转化为PLA的工业标准涉及有毒的锡(Sn)基催化剂。为了减少这些有害催化剂的使用,已经研究了用于有效丙交酯聚合的其他环境友好的含金属试剂,但是这些替代品受到复杂合成过程的阻碍,反应性问题,和选择性限制。为了克服这些缺点,我们探索了Cu-(Phe)2和Zn-(Phe)2金属-氨基酸共组装体作为丙交酯开环聚合(ROP)成PLA的潜在催化剂的催化活性。在不同的温度和溶剂下使用1H-NMR光谱监测组件的催化活性以确定催化参数。值得注意的是,Zn-(Phe)2在回流条件下在甲苯中12小时内实现了>99%的丙交酯转化为PLA,并且发现具有一级动力学,而Cu-(Phe)2表现出显著较低的催化活性。在Zn-(Phe)2介导的催化之后,所得PLA具有128kDa的平均分子量和通过凝胶渗透色谱法测定的1.25的分散指数。一起来看,我们的简约方法扩展了可用于丙交酯ROP的基于金属氨基酸的超分子催化纳米材料的领域。这一进步为工业和生物医学应用中的简化生物催化剂的未来设计显示了希望。
    Polylactide (PLA), a biocompatible and biodegradable polymer, is widely used in diverse biomedical applications. However, the industry standard for converting lactide into PLA involves toxic tin (Sn)-based catalysts. To mitigate the use of these harmful catalysts, other environmentally benign metal-containing agents for efficient lactide polymerization have been studied, but these alternatives are hindered by complex synthesis processes, reactivity issues, and selectivity limitations. To overcome these shortcomings, we explored the catalytic activity of Cu-(Phe)2 and Zn-(Phe)2 metal-amino acid co-assemblies as potential catalysts of the ring-opening polymerization (ROP) of lactide into PLA. Catalytic activity of the assemblies was monitored at different temperatures and solvents using 1H-NMR spectroscopy to determine the catalytic parameters. Notably, Zn-(Phe)2 achieved >99% conversion of lactide to PLA within 12 h in toluene under reflux conditions and was found to have first-order kinetics, whereas Cu-(Phe)2 exhibited significantly lower catalytic activity. Following Zn-(Phe)2-mediated catalysis, the resulting PLA had an average molecular weight of 128 kDa and a dispersity index of 1.25 as determined by gel permeation chromatography. Taken together, our minimalistic approach expands the realm of metal-amino acid-based supramolecular catalytic nanomaterials useful in the ROP of lactide. This advancement shows promise for the future design of simplified biocatalysts in both industrial and biomedical applications.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    在生物塑料中,天然聚(3-羟基丁酸酯)(PHB)具有完全生物相容性和可生物降解性,即使在海洋环境中,其高的全同立构规整度和结晶度限制了其机械性能和应用。PHB也可以通过β-丁内酯(BBL)的催化开环聚合(ROP)合成,为PHB具有更好的热机械性能和加工性能铺平了道路。在这项工作中,我们基于铝苯氧基-亚胺甲基催化剂[AlMeL2]扩展了我们的催化剂系列,这表明在BBL的ROP中有效,到卤素类似络合物[AlClL2]。同样,我们进一步探索了不同引发剂对ROP机理的影响,特别是在二甲基氨基吡啶(DMAP),一种几乎没有研究过的BBLROP引发剂。进行了彻底的机制研究,证明存在两种伴随的DMAP介导的机制,导致DMAP或巴豆酸酯封端基团。此外,为了增加PHB后聚合官能化的可能性,我们探索了侧链功能的引入,建立BBL与β-烯丙氧基亚甲基丙内酯(BPLOAll)的共聚,产生定义明确的P(BBL-co-BPLOAll)共聚物。本文受版权保护。保留所有权利。
    Within bioplastics, natural poly(3-hydroxybutyrate) (PHB) stands out as fully biocompatible and biodegradable, even in marine environments; however, its high isotacticity and crystallinity limits its mechanical properties and hence its applications. PHB can also be synthesized with different tacticities via a catalytic ring-opening polymerization (ROP) of rac-β-butyrolactone (BBL), paving the way to PHB with better thermomechanical and processability properties. In this work, the catalyst family is extended based on aluminum phenoxy-imine methyl catalyst [AlMeL2], that reveals efficient in the ROP of BBL, to the halogeno analogous complex [AlClL2]. As well, the impact on the ROP mechanism of different initiators is further explored with a particular focus in dimethylaminopyridine (DMAP), a hardly studied initiator for the ROP of BBL. A thorough mechanistic study is performed that evidences the presence of two concomitant DMAP-mediated mechanisms, that lead to either a DMAP or a crotonate end-capping group. Besides, in order to increase the possibilities of PHB post-polymerization functionalization, the introduction of a side-chain functionality is explored, establishing the copolymerization of BBL with β-allyloxymethylene propiolactone (BPLOAll), resulting in well-defined P(BBL-co-BPLOAll) copolymers.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    仅由CO2和本体烯烃合成单体可回收聚酯在显著减少CO2排放和解决塑料污染问题方面具有巨大潜力。由于与本体烯烃的均聚相比,CO2和本体烯烃直接共聚的动力学缺点,通过六元二取代内酯中间体的开环聚合(ROP)合成聚酯的研究得到了广泛的关注,1,2-亚乙基-6-乙烯基-四氢-2H-吡喃-2-酮(?-L),从CO2和1,3-丁二烯的调聚反应中获得。然而,α-L六元环上的共轭烯烃导致严重的Michael加成副反应。因此,选择性ROP?-L,它可以精确控制用于生产聚酯的重复单元,这些聚酯可能适合于有效的单体回收,仍然是一个尚未解决的挑战。在这里,我们报告了使用有机碱基和N的组合对?-L进行选择性ROP的第一个例子,N'-双[3,5-双(三氟甲基)苯基]脲作为催化体系。脲取代基的系统修饰表明,缺电子的3,5-双(三氟甲基)-苯基的存在是相对于迈克尔加成的非凡开环选择性的关键。在温和的催化条件下,还可以实现低聚(α-L)的有效单体回收。本文受版权保护。保留所有权利。
    Synthesis of monomer-recyclable polyesters solely from CO2 and bulk olefins holds great potential in significantly reducing CO2 emissions and addressing the issue of plastic pollution. Due to the kinetic disadvantage of direct copolymerization of CO2 and bulk olefins compared to homopolymerization of bulk olefins, considerable research attention has been devoted to synthesis of polyester via the ring-opening polymerization (ROP) of a six-membered disubstituted lactone intermediate, 1,2-ethylidene-6-vinyl-tetrahydro-2H-pyran-2-one (𝜹-L), obtained from telomerization of CO2 and 1,3-butadiene. However, the conjugate olefin on the six-membered ring of 𝜹-L leads to serious Michael addition side reactions. Thus, the selective ROP of 𝜹-L, which can precisely control the repeating unit for the production of polyesters potentially amenable to efficient monomer recycling, remains an unresolved challenge. Herein, the first example of selective ROP of 𝜹-L is reported using a combination of organobase and N,N\'-Bis[3,5-bis(trifluoromethyl)phenyl]urea as the catalytic system. Systematic modifications of the substituent of the urea show that the presence of electron-deficient 3,5-bis(trifluoromethyl)-phenyl groups is the key to the extraordinary selectivity of ring opening over Michael addition. Efficient monomer recovery of oligo(𝜹-L) is also achieved under mild catalytic conditions.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    蛋白质-聚合物缀合物和聚合物纳米材料在许多应用中具有巨大的前景,包括生物材料,医学或纳米电子学。在这项工作中,我们提出了第一种在水性介质中进行的PISA(聚合诱导的自组装)方法,通过使用开环聚合(ROP)实现蛋白质-聚合物缀合物和完全由氨基酸组成的纳米颗粒。我们确实表明,水性ROPISA可以与蛋白质或肽大分子引发剂一起使用,而无需事先进行化学修饰,并且可以简单地制备具有蛋白质样性质的纳米材料,例如在药物递送中实现仿生热响应性。本文受版权保护。保留所有权利。
    Protein-polymer conjugates and polymeric nanomaterials hold great promise in many applications including biomaterials, medicine, or nanoelectronics. In this work, the first polymerization-induced self-assembly (PISA) approach performed in aqueous medium enabling protein-polymer conjugates and nanoparticles entirely composed of amino acids is presented by using ring-opening polymerization (ROP). It is indeed shown that aqueous ring-opening polymerization-induced self-assembly (ROPISA) can be used with protein or peptidic macroinitiators without prior chemical modification and afford the simple preparation of nanomaterials with protein-like property, for example, to implement biomimetic thermoresponsivity in drug delivery.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    将聚合物纳米载体用于生物医学应用的主要瓶颈,特别是那些基于自分解性聚(氨基酯)(PAE)的,在于它们在达到预期目标之前在生理pH下不受控制的自动降解。这里,一种优雅的三嵌段共聚物策略旨在通过生理pH(pH7.4)下的两性离子相互作用稳定不稳定的PAE链,并精确地编程它们的酶响应性生物降解,特别是在细胞内区室,确保有针对性地交付货物。为了实现这一目标,选择可生物降解的聚己内酯(PCL)平台,并对几种二嵌段和三嵌段结构进行结构改造,以达到精确的大分子几何形状。外围的疏水PCL核心和亲水阴离子PCL嵌段屏蔽了PAE的自动降解,从而确保在PBS中生理pH下的稳定性,FBS,细胞培养基和血流.临床抗癌药物阿霉素和深层组织可穿透的近红外IR-780生物标志物被封装,以通过体外活癌细胞和活体动物体内生物成像研究其生物学作用。这些两性离子是生物相容的,非溶血,和实时体外活细胞共聚焦研究已经证实了它们在内溶酶体区室中的内化和酶促生物降解以递送有效载荷。体内生物成像建立了超过72小时的延长血液循环,生物分布分析显示纳米颗粒主要在排泄器官中积累。本文受版权保护。保留所有权利。
    The major bottleneck in using polymer nanovectors for biomedical application, particularly those based on self-immolative poly(amino ester) (PAE), lies in their uncontrolled autodegradation at physiological pH before they can reach the intended target. Here, an elegant triblock-copolymer strategy is designed to stabilize the unstable PAE chains via zwitterionic interactions under physiological pH (pH 7.4) and precisely program their enzyme-responsive biodegradation specifically within the intracellular compartments, ensuring targeted delivery of the cargoes. To achieve this goal, biodegradable polycaprolactone (PCL) platform is chosen, and structure-engineered several di- and triblock architectures to arrive the precise macromolecular geometry. The hydrophobic-PCL core and hydrophilic anionic-PCL block at the periphery shield PAEs against autodegradation, thereby ensuring stability under physiological pH in PBS, FBS, cell culture medium and bloodstream. The clinical anticancer drug doxorubicin and deep-tissue penetrable near-infrared IR-780 biomarker is encapsulated to study their biological actions by in vitro live cancer cells and in vivo bioimaging in live animals. These zwitterions are biocompatible, nonhemolytic, and real-time in vitro live-cell confocal studies have confirmed their internalization and enzymatic biodegradation in the endo-lysosomal compartments to deliver the payload. In vivo bioimaging establishes their prolonged blood circulation for over 72 h, and the biodistribution analysis reveals the accumulation of nanoparticles predominantly in the excretory organs.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    两性离子环膨胀聚合(ZREP)是通过两性离子中间体将环状单体转化为环状聚合物的聚合方法。在这次审查中,我们探索了各种环状聚合物的ZREP,以及质谱如何帮助识别产品结构和理解其复杂的反应机理。对于大多数聚合物(从几千到几百万Da),基质辅助激光解吸/电离飞行时间质谱是确定所得产物的真实分子量(MW)的最有效的质谱技术,但仅当分散性较低(约低于1.2)时。本研究涵盖的关键主题是环状聚酯的ZREP,环状聚酰胺,和环醚。此外,这项研究还涉及许多其他初步主题,包括环状聚碳酸酯的ZREP,环状聚硅氧烷,和环状聚(亚烷基磷酸酯)。这些合成的纯度和效率很大程度上取决于催化剂。在几种催化剂中,N-杂环卡宾在环状聚酯和聚酰胺的合成中表现出很高的效率,而三(五氟苯基)硼烷[B(C6F5)3]是环聚醚合成的最佳催化剂。
    Zwitterionic ring-expansion polymerization (ZREP) is a polymerization method in which a cyclic monomer is converted into a cyclic polymer through a zwitterionic intermediate. In this review, we explored the ZREP of various cyclic polymers and how mass spectrometry assists in identifying the product architectures and understanding their intricate reaction mechanism. For the majority of polymers (from a few thousand to a few million Da) matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is the most effective mass spectrometry technique to determine the true molecular weight (MW) of the resultant product, but only when the dispersity is low (approximately below 1.2). The key topics covered in this study were the ZREP of cyclic polyesters, cyclic polyamides, and cyclic ethers. In addition, this study also addresses a number of other preliminary topics, including the ZREP of cyclic polycarbonates, cyclic polysiloxanes, and cyclic poly(alkylene phosphates). The purity and efficiency of those syntheses largely depend on the catalyst. Among several catalysts, N-heterocyclic carbenes have exhibited high efficiency in the synthesis of cyclic polyesters and polyamides, whereas tris(pentafluorophenyl)borane [B(C6F5)3] is the most optimal catalyst for cyclic polyether synthesis.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    聚合诱导自组装(PISA)已成为制备嵌段共聚物(BCP)纳米颗粒的可扩展一锅法技术。最近,PISA程序,这导致聚(1-丙交酯)-b-聚(乙二醇)BCP纳米颗粒形成开环聚合(ROP)诱导的结晶驱动的自组装(ROPI-CDSA),已开发。所得的纳米棒表现出强烈的聚集倾向,导致2D图纸和3D网络的形成。本文报道了聚(N,ROPI-CDSA制备的N-二甲基丙烯酰胺)-b-聚(I)-丙交酯BCP纳米颗粒,用两步,一锅法。首先将双官能化光引发剂用于丙烯酰胺基单体的受控自由基聚合,并且所得聚合物用作有机催化的ROP的大分子引发剂以形成疏溶剂性聚酯嵌段。所得纳米棒是高度稳定的,并且在比先前报道更高的分子量(>12kDa)和浓度(>20%固体)下显示各向异性。这一发展扩展了ROPI-CDSABCP的化学范围,并提供了由生物相容性材料制成的易于获得的纳米棒。
    Polymerization-induced self-assembly (PISA) has emerged as a scalable one-pot technique to prepare block copolymer (BCP) nanoparticles. Recently, a PISA process, that results in poly(l-lactide)-b-poly(ethylene glycol) BCP nanoparticles coined ring-opening polymerization (ROP)-induced crystallization-driven self-assembly (ROPI-CDSA), was developed. The resulting nanorods demonstrate a strong propensity for aggregation, resulting in the formation of 2D sheets and 3D networks. This article reports the synthesis of poly(N,N-dimethyl acrylamide)-b-poly(l)-lactide BCP nanoparticles by ROPI-CDSA, utilizing a two-step, one-pot approach. A dual-functionalized photoiniferter is first used for controlled radical polymerization of the acrylamido-based monomer, and the resulting polymer serves as a macroinitiator for organocatalyzed ROP to form the solvophobic polyester block. The resulting nanorods are highly stable and display anisotropy at higher molecular weights (>12k Da) and concentrations (>20% solids) than the previous report. This development expands the chemical scope of ROPI-CDSA BCPs and provides readily accessible nanorods made with biocompatible materials.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

公众号