A new diphenylnaphthalene-based diamidine (1) having an N-ethyl-substituent to improve its solubility has been designed and synthesized for the recognition of dicarboxylic acids. The diamidine 1 forms 1:1 complexes with the α,ω-dicarboxylic acids in the competing protic solvent, MeOH, using the charge-assisted hydrogen bonding (i.e., formation of amidinium-carboxylate), and the formation of the complexes was determined by ¹H NMR and DOSY NMR spectroscopies in a high concentration (2.0 mM). However, at a low concentration (25 μM), the turn-on fluorescence detection of the dicarboxylic acids was not successful because the diamidine 1 emits in MeOH before recognizing the carboxylic acids. Interestingly, the diamidine 1 does not emit in 2-propanaol before recognizing the α,ω-dicarboxylic acids, and succeeded in the detection of a dicarboxylic acid (turn-on response) in the protic solvent, 2-propanol. The interesting tight binding of the diamidine 1 with α,ω-dicarboxylic acids was observed in 2-propanol-d₈ using ¹H NMR and the restriction of the rotation of the phenyl rings of the 1,8- diphenylnaphthalene unit was also observed. These fluorescence and binding characteristics of the N-ethyl-substituted diamidine 1 are applicable for the detection of carboxylic acids in a protic solvent.

设计并合成了一种新的二苯基萘基二脒 ( 1 )，其具有N-乙基取代基以提高其溶解度，用于识别二元羧酸。二脒1在竞争性质子溶剂 MeOH 中使用电荷辅助氢键（即形成脒-羧酸盐）与α , ω -二羧酸形成 1:1 复合物，复合物的形成由下式确定高浓度 (2.0 mM) 的¹ H NMR 和 DOSY NMR 光谱。然而，在低浓度（25  μ M）下，二元酸的开启荧光检测不成功，因为二脒1在识别羧酸之前在甲醇中发射。有趣的是，二脒1在识别α , ω -二羧酸之前不会在 2-丙醇中发射，并且成功地在质子溶剂 2-丙醇中检测到二羧酸（开启响应）。使用¹ H NMR在 2-丙醇-d _{8 中}观察到二脒1与α , ω -二羧酸的有趣紧密结合，并且还观察到 1,8-二苯基萘单元的苯环旋转受到限制。N-乙基取代的二脒的这些荧光和结合特性1适用于质子溶剂中羧酸的检测。