title: Towards better understanding of C60 organosols.
abstract: It is of common knowledge that fullerenes form colloids in polar solvents. However, the coagulation via electrolytes and the origin of the negative charge of species are still unexplored. Using a 'radical scavenger' and electrospray ionization spectroscopy (ESI), we proved the formation of ion-radical C60˙(-) and its (probable) transformation into C60(2-) or (C60)2(2-). The coagulation of C60 organosols by NaClO4 and other perchlorates and nitrates in acetonitrile and its mixture with benzene obeys the Schulze-Hardy rule. At higher Ca(ClO4)2 and La(ClO4)3 concentrations, instead of coagulation, stable re-charged colloidal particles appeared, up to a zeta-potential of +(20-42) mV, as compared with -(33-35) mV of the initial organosols. The influence of both HClO4 and CF3SO3H was similar. This phenomenon is attributed to poor solvation of inorganic cations in cationo- and protophobic acetonitrile, which was proven using [2.2.2] cryptand. Further increasing the concentration of Ca(ClO4)2 led again to coagulation, thus demonstrating a novel type of 'coagulation zones'.
authors.affiliation: Department of Physical Chemistry, V. N. Karazin National University, 61022, Kharkov, Ukraine. mchedlov@yandex.ru.
authors.forename: Nikolay O
authors.initials: NO
authors.lastname: Mchedlov-Petrossyan
authors.affiliation: Department of Physical Chemistry, V. N. Karazin National University, 61022, Kharkov, Ukraine. mchedlov@yandex.ru.
authors.forename: Nika N
authors.initials: NN
authors.lastname: Kamneva
authors.affiliation: Department of Physical Chemistry, V. N. Karazin National University, 61022, Kharkov, Ukraine. mchedlov@yandex.ru.
authors.forename: Younis T M
authors.initials: YT
authors.lastname: Al-Shuuchi
authors.affiliation: National University of Food Technologies, Volodymyrska, 68, Kiev, 01601, Ukraine.
authors.forename: Andriy I
authors.initials: AI
authors.lastname: Marynin
authors.affiliation: Friedrich-Alexander University, Department of Chemistry and Pharmacy, Erlangen-Nürnberg, Germany.
authors.forename: Olexii S
authors.initials: OS
authors.lastname: Zozulia
authors.affiliation: Department of Physics and Technology, V. N. Karazin National University, Kharkov, 61022, Ukraine.
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Kryshtal
authors.affiliation: Institute for Scintillation Materials NAS of Ukraine, 61001 Kharkov, Ukraine.
authors.forename: Vladimir K
authors.initials: VK
authors.lastname: Klochkov
authors.affiliation: Department of Physical Chemistry, V. N. Karazin National University, 61022, Kharkov, Ukraine. mchedlov@yandex.ru.
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Shekhovtsov