Department of Bioscience and Biotechnology, Fukui Prefectural University, Eiheiji, Fukui, 910-1195, Japan.
Department of Chemistry, Kobe University, Nada, Kobe, 657-8501, Japan.
Anal Sci. 2021 Oct 10;37(10):1379-1383. doi: 10.2116/analsci.21P041. Epub 2021 Mar 12.
This paper describes that fluorous ethers, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether and 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, can be used for a non-aqueous medium in electrochemistry at a liquid | liquid interface. These solvents dissolved a high concentration of tetraalkylammonium salts with highly-fluorinated anions, such as bis(nonafluorobutanesulfonyl)imide and tetrakis[3,5-bis(trifluoromethyl)phenyl]borate ions, and the solution had a high conductivity. The fluorous ether | water interfaces exhibited a substantial polarizable potential window, and various ions, including tetraphenylarsonium and tetraphenylborate ions, gave a reversible voltammetric wave due to their ion transfer across the interfaces. Using the tetraphenylarsonium-tetraphenylborate assumption, the formal potentials for the ion transfer and the formal Gibbs energies of ion transfer from the ethers to water were estimated. The Gibbs energies were close to those from a previously reported fluorous solvent, 1,1,1,2,3,4,4,5,5,5-decafluoropentane; the fluorous ethers also exhibited a higher affinity for fluorinated ions. Because of a lower volatility, the fluorous ethers would be more advantageously used in two-phase electrochemistry, particularly concerning analytical purposes.
本文描述了氟醚，即 1,1,2,2-四氟乙基-2,2,3,3-四氟丙基醚和 1H,1H,5H-八氟戊基-1,1,2,2-四氟乙基醚，可以在液-液界面的电化学中非水相中使用。这些溶剂溶解了高浓度的四烷基铵盐，具有高度氟化的阴离子，如双（全氟丁烷磺酰基）亚胺和四[3,5-双（三氟甲基）苯基]硼酸根离子，并且溶液具有高导电性。氟醚-水界面表现出相当大的可极化电势窗口，各种离子，包括四苯基鏻和四苯基硼酸根离子，由于它们在界面之间的离子转移而给出了可逆的伏安波。使用四苯基鏻-四苯基硼酸根的假设，估计了离子转移的形式电位和从醚到水的离子转移的形式吉布斯能量。吉布斯能量与先前报道的氟溶剂 1,1,1,2,3,4,4,5,5,5-十氟戊烷的吉布斯能量接近；氟醚对氟化离子也表现出更高的亲和力。由于挥发性较低，氟醚在两相电化学中，特别是在分析目的方面，将更有利地使用。
