La Cognata Sonia, Mobili Riccardo, Merlo Francesca, Speltini Andrea, Boiocchi Massimo, Recca Teresa, Maher Louis J, Amendola Valeria
Department of Chemistry, Università degli Studi di Pavia, v.le T. Taramelli 12, Pavia 27100, Italy.
Department of Drug Sciences, Università degli Studi di Pavia,via Taramelli 12, Pavia 27100, Italy.
ACS Omega. 2020 Oct 7;5(41):26573-26582. doi: 10.1021/acsomega.0c03337. eCollection 2020 Oct 20.
We report the investigation of dicopper(II) bistren cryptate, containing naphthyl spacers between the subunits, as a receptor for polycarboxylates in neutral aqueous solution. An indicator displacement assay for dicarboxylates was also developed by mixing the azacryptate with the fluorescent indicator 5-carboxyfluorescein in a 50:1 molar ratio. Fluorimetric studies showed a significant restoration of fluorophore emission upon addition of fumarate anions followed by succinate and isophthalate. The introduction of hexyl chains on the naphthalene groups created a novel hydrophobic cage; the corresponding dicopper complex was investigated as an extractant for dicarboxylates from neutral water into dichloromethane. The liquid-liquid extraction of succinate-as a model anion-was successfully achieved by exploiting the high affinity of this anionic guest for the azacryptate cavity. Extraction was monitored through the changes in the UV-visible spectrum of the dicopper complex in dichloromethane and by measuring the residual concentration of succinate in the aqueous phase by HPLC-UV. The successful extraction was also confirmed by H-NMR spectroscopy. Considering the relevance of polycarboxylates in biochemistry and in the environmental field, e.g., as waste products of industrial processes, our results open new perspectives for research in all contexts where recognition, sensing, or extraction of polycarboxylates is required.
我们报道了对含有萘基间隔基的二铜（II）双三乙撑四胺穴合物作为中性水溶液中多羧酸盐受体的研究。通过将氮杂穴合物与荧光指示剂5-羧基荧光素按50:1的摩尔比混合，还开发了一种用于二羧酸盐的指示剂置换测定法。荧光研究表明，加入富马酸根阴离子后，接着加入琥珀酸根和间苯二甲酸根，荧光团发射显著恢复。在萘基上引入己基链形成了一种新型疏水笼；对相应的二铜配合物作为从中性水到二氯甲烷中提取二羧酸盐的萃取剂进行了研究。通过利用这种阴离子客体对氮杂穴合物空腔的高亲和力，成功实现了作为模型阴离子的琥珀酸根的液液萃取。通过监测二氯甲烷中二铜配合物紫外可见光谱的变化以及通过高效液相色谱-紫外法测量水相中琥珀酸根的残留浓度来监测萃取过程。核磁共振光谱也证实了成功萃取。考虑到多羧酸盐在生物化学和环境领域中的相关性，例如作为工业过程的废物，我们的结果为在需要识别、传感或萃取多羧酸盐的所有情况下的研究开辟了新的前景。
