pK_a tuning of Brønsted acids in synthetic nano-materials is of great importance for the design of ion exchange and bio-/molecular-separation media and polymer catalysis. It has been reported that hydrogel nanoparticles with carboxylic acids that show large and reversible pK_a shifts in response to thermal stimuli can be prepared by copolymerization of N-isopropylacrylamide (NIPAm), acrylic acids (AAc) and N,N′-methylene bisacrylamide (BIS) via the proton imprinting polymerization process. However, the reported range of pK_a shifts is limited to the range of 5.3 to 7.5. In this study, we report a procedure to prepare proton imprinted NPs that show pK_a shifts in the tuned pK_a range and demonstrate applications of the NPs. pK_a values ranging from 4.3 to 8.7 were achieved by designing the structure of monomers containing carboxylic acids and applying the proton imprinting procedure. It was demonstrated that proton-imprinted NPs with different pK_a values could be used for the reversible and selective protonation of target molecules which have specific pK_a values. Our results establish the generality of the proton imprinting procedure and provide a guide for designing stable and inexpensive materials for sophisticated purification processes.

中文翻译：

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宽范围p ķ_一个质子印迹纳米颗粒用于目标分子的可逆的质子化调谐经由热刺激

p ķ_一个布朗斯台德的调谐合成纳米材料是酸的离子交换的设计和生物/分子分离介质和聚合物催化非常重要的。据报道，可以通过使N-异丙基丙烯酰胺（NIPAm），丙烯酸（AAc）与N，N′-亚甲基双丙烯酰胺共聚来制备_具有响应于热刺激而显示出大且可逆的p K _a位移的羧酸的水凝胶纳米颗粒。（BIS）通过质子印迹聚合过程。但是，报告的p K _a范围移位限制在5.3到7.5的范围内。在这项研究中，我们报告了一种制备质子印迹NP的程序，该程序显示了p K _a在调整的p K _a范围内的变化并证明了NP的应用。通过设计包含羧酸的单体的结构并应用质子压印程序，可实现4.3到8.7的p K _a值。已证明具有不同p K _a值的质子印迹NP可用于具有特定p K _a的靶分子的可逆和选择性质子化价值观。我们的结果建立了质子印迹程序的一般性，并为设计用于复杂纯化过程的稳定且廉价的材料提供了指南。