Complexes Based on Calix[4]arene Sulfonic Acid with Acetic Acid and Its Derivatives: NMR Analysis
- Авторы: Chernyak A.1,2, Slesarenko N.1, Volkov V.1
-
Учреждения:
- Institute of Problems of Chemical Physics RAS
- Science Center in Chernogolovka RAS
- Выпуск: Том 50, № 1-3 (2019)
- Страницы: 199-209
- Раздел: Original Paper
- URL: https://journals.rcsi.science/0937-9347/article/view/248228
- DOI: https://doi.org/10.1007/s00723-018-1063-5
- ID: 248228
Цитировать
Аннотация
Calix[4]arene sulfonic acid complexes with acetic acid CH3COOH and its derivatives CCl3COOH, CF3COOH were studied by nuclear magnetic resonance (NMR). The formation of guest–host type complexes was shown by magic angle spinning (MAS) NMR and high-resolution NMR techniques. Increase in calixarene molecule conformational flexibility with moisture content rising was observed by 13C MAS NMR. Consequently, CCl3COOH, CF3COOH molecules vacate calixarene cavity at relative humidity RH > 33%. While the complex with CH3COOH remains stable up to RH = 64%. The self-diffusion processes were investigated by 1H pulsed field gradient technique. Spin-echo attenuation curves show non-exponential shape indicating the occurrence of several phases with a different translational mobility. The existence CCl3COOH, CF3COOH acid molecules inside the calixarene cavity leads to average self-diffusion coefficient Dsaver reduction compared with pure calix[4]arene sulfonic acid. The values of Dsaver for the CH3COOH complex are close to average self-diffusion coefficient of calix[4]arene sulfonic acid. From Dsaver proton conductivities σcalc on the basis of the Nernst–Einstein equation were calculated. Calculated σcalc and experimental σexp conductivities are agreed well in the RH range from 33% to 75%. At low water content (RH = 10%) σexp is about one order of magnitude less compare with σcalc in calixarene and its complexes with CH3COOH and CCl3COOH. It may be explained by low conductivity boundary formation at these conditions between grains in process of target sample preparation for conductivity measurement.
Об авторах
A. Chernyak
Institute of Problems of Chemical Physics RAS; Science Center in Chernogolovka RAS
Автор, ответственный за переписку.
Email: sasha_cherniak@mail.ru
Россия, Chernogolovka, Moscow Region; Chernogolovka, Moscow Region
N. Slesarenko
Institute of Problems of Chemical Physics RAS
Email: sasha_cherniak@mail.ru
Россия, Chernogolovka, Moscow Region
V. Volkov
Institute of Problems of Chemical Physics RAS
Email: sasha_cherniak@mail.ru
Россия, Chernogolovka, Moscow Region