Carboxylate sensing solid-contact ion-selective electrodes (ISEs) were created to provide a proof-of-concept ISE development process covering all aspects from in silico ionophore design to functional sensor characterization. The biscarbazolylurea moiety was used to synthesize methylene-bridged macrocycles of different ring size aiming to fine tune selectivity towards different carboxylates. Cyclization was achieved with two separate strategies, using either amide synthesis to access up to –[CH₂]₁₀– macrocycles or acyl halides to access up to –[CH₂]₁₄– macrocycles. Seventy-five receptor–anion complexes were modelled and studied with COSMO-RS, in addition to all free host molecules. In order to predict initial selectivity towards carboxylates, ¹H NMR relative titrations were used to quantify binding in DMSO-d₆/H₂O solvent systems of two proportions – 99.5%:0.5% m/m and 90.0%:10.0% m/m, suggesting initial selectivity towards acetate. Three ionophores were selected for successful sensor prototype development and characterization. The constructed ion-selective electrodes showed higher selectivity towards benzoate than acetate, i.e., the selectivity patterns of the final sensors deviated from that predicted by the classic titration experiments. While the binding constants obtained by NMR titration in DMSO-d₆/H₂O solvent systems provided important guidance for sensor development, the results obtained in this work emphasize the importance of evaluating the binding behavior of receptors in real sensor membranes.

中文翻译：

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咔唑大环在阴离子传感器中的设计，合成和应用。

创建了羧酸盐感测固体接触离子选择电极（ISE），以提供概念验证的ISE开发过程，涵盖从硅离子载体设计到功能传感器表征的各个方面。biscarbazolylurea部分用于合成不同环尺寸的亚甲基桥环大环，旨在微调对不同羧酸盐的选择性。通过两种单独的策略实现环化，即使用酰胺合成方法最多可获得– [CH ₂ ] ₁₀ –大环，或使用酰基卤可以最多进行– [CH ₂ ] ₁₄–宏周期。除所有游离宿主分子外，还用COSMO-RS对75种受体-阴离子复合物进行了建模和研究。为了预测对羧酸盐的初始选择性，使用¹ H NMR相对滴定法定量DMSO- d ₆ / H _{2中的结合}两种比例的O溶剂系统– 99.5％：0.5％m / m和90.0％：10.0％m / m，表明对乙酸盐的初始选择性。选择了三个离子载体，以成功开发和表征传感器。所构建的离子选择电极对苯甲酸酯的选择性高于乙酸盐，即最终传感器的选择性模式与经典滴定实验所预测的不同。尽管在DMSO- d ₆ / H ₂ O溶剂系统中通过NMR滴定获得的结合常数为传感器开发提供了重要指导，但这项工作中获得的结果强调了评估受体在实际传感器膜中的结合行为的重要性。