Электронный каталог

Книга (аналит. описание)

Lebedev, V.T.
Structuring of Endofullerenols with Lanthanides in Aqueous Solutions / V.T.Lebedev, M.V.Remizov, A.I.Kuklin, [a.o.] // Emerging Sustainable Nanomaterials for Biomedical Applications [Electronic resource] / Ed.: S.Garg, A.Chandra, S.Sagadevan. – Cham : Springer, 2024. – P. 89-116. – URL: https://doi.org/10.1007/978-3-031-63961-6_4. – Bibliogr.: 84.

Endofullerenols with lanthanides (Ln) being effective molecular magnets are attractive in biomedicine as spin labels and especially as magnetic contrast agents to increase the diagnostic capabilities of Magnetic Resonance Imaging. The magnetic fields of such molecules effectively accelerate surrounding proton spin relaxation in tissues without any significant risks of release of toxic heavy Ln atoms into biological environment. In total, these factors give endofullerenols really great advantages over traditional chelate compounds. Among various polydisperse carbon nanoparticles, the endofullerenols are exclusive molecular forms with a high excellence to be used in pharmaceuticals with strict requirements for the physicochemical certification of the substances used. However, there is a necessity to provide predictable behaviors of endofullerenols in biological media where they trend to be assembled due to specific interactions (dipole electric and magnetic, hydrophobic, via hydrogen bonding). Till now, the principal features of endofullerenols’ structuring remained not completely understood, and the mechanisms of their assembly, as dependent on the atomic number of the endohedral element, were not discovered. We have studied the regularities those determine a formation of supramolecular structures of endofullerenols, Ln@C82(OH)X (X = 38–40), with lanthanides (series from Pr to Tm) in aqueous solutions (20 °C) at a given concentration (1.5 wt%) by small-angle neutron scattering. The samples were characterized by X-ray fluorescence spectroscopy in the measurements of the secondary radiation from lanthanides, and in this way, we have evaluated the fraction of endohedral molecules (90 wt%) and empty fullerenol residual. In addition, we tested the solutions of endofullerenols by measuring their optical density at light wavelengths of 190–1100 nm. We used also the EXAFS method to determine the coordination of endohedral Ln ions with fullerene cage. Inside fullerenols containing the lanthanides with atomic numbers Z = 59–69, the distance between endohedral atom and the inner border of carbon cage increased approximately linearly due to progressive atomic contraction and electronegativity amplification. As a result, the electric dipole moment of fullerenols became greater that made stronger the attractive molecular forces provoked the association of fullerenols into primary groups assembled into massive chain-like fractal aggregates. The trends in molecular integration demonstrated a progressive strengthening with the growth of endohedral lanthanides atomic number. These findings allow predict the hydrodynamic behaviors of endofullerenols as dependent on the atomic numbers of captured atoms that is crucially important for biomedical applications of endofullerenols.



ОИЯИ = ОИЯИ (JINR)2024
Спец.(статьи,препринты) = С 350 - Приложения методов ядерной физики в смежных областях
Спец.(статьи,препринты) = С 325.7 - Фуллерены (Сn). Атомные кластеры
Спец.(статьи,препринты) = С 326.3 - Ферми-системы. Спиновые системы