|
ИСТИНА |
Войти в систему Регистрация |
ФНКЦ РР |
||
Difference between oxygen-containing groups on sp2 and sp3 carbons: deprotonationтезисы доклада
- Авторы: Vervald A.M., Kozhushnyi K.A., Dolenko T.A.
- Сборник: Book of Abstracts 15th International Conference “Advanced Carbon Nanostructures” ACNS’2021
- Тезисы
- Год издания: 2021
- Место издания: Saint-Petersburg, Russia
- Первая страница: 101
- Последняя страница: 101
- Номер статьи: O2-2-10
- Аннотация: The surface properties of carbon nanoparticles (CNPs) largely determine how nanoparticles interact with their environment. The colloidal stability of nanoparticles, their biocompatibility, adsorption properties, as well as surface photoluminescence all depend on composition of surface groups. Like that, oxidized surface provides high biocompatibility, dispersibility and intense photoluminescence for carbon dots and nanodiamonds. However, the question arises: are the same oxygen-containing functional groups on carbon in sp3 and sp2 hybridization on the surfaces of nanodiamonds and carbon dots truly the same or differ in their properties?In this study, quantum mechanical calculations were used to compare the properties of carboxyl and hydroxyl groups on sp2- and sp3-hybridized surface regions of carbon nanoparticles. It was found that with a change in the hybridization of the base, the binding strength of hydrogen to the group – the length of the O-H bond – changes. Based on the known relationship between the bond lengths of O-H groups and pKa for simple organic molecules, the pH ranges of deprotonation of -OH and -COOH groups on the CNP surfaces were calculated. It turned out that the deprotonation of the carboxyl group occurs in the pH range from 3 to 5 and only weakly depends on the hybridization of the base, while the deprotonation of the hydroxyl group depends strongly: for the sp2 base it occurs in the pH range from 8 to 11, for sp3 from 15 to 19 (Fig. 1). The group deprotonation was confirmed experimentally by a change in the zeta potential value with a change in pH for detonation nanodiamonds with a high content of sp2-hybridized carbon on the surface. This study has been performed at the expense of the grant of RFBR (project № 20-32-70150).
- Добавил в систему: Вервальд Алексей Михайлович