Comparative analysis of two aqueous-colloidal solutions of C60 fullerene with help of FTIR reflectance and UV–Vis spectroscopy

Two types of fullerene–water colloidal systems: molecular-colloidal C60 solution in water (C60FWS) and typical monodisperse C60 hydrosol are compared in this work. It was confirmed that C60FWS consists of isolated C60 molecules in hydrated state, C60@{H2O}n, and of their small spherical C60 clusters of different sizes. It was shown that C60FWS simultaneously has the properties of both true solutions and colloidal systems. The origin of supramolecular complexes C60@{H2O}n stabilization is explained both by the weak donor–acceptor interactions of unpaired electrons of H2O oxygen atoms with fullerene molecule and by formation of ordered, H-bounded and sphere-like hydrated shells around the fullerene. Spectra of surface enhanced infrared absorption (SEIRA) of C60 on gold substrate were recorded in FTIR reflectance mode. In the 400–900 cm−1 region some additional vibration bands of C60, which are forbidden in IR spectra, have been registered. Earlier the similar bands had been observed in inelastic neutron scattering.