Khavryuchenko O. Composites of fullerene and highly dispersed silica with luminescent properties

Українська версія

Thesis for the degree of Candidate of Sciences (CSc)

State registration number

0406U001665

Applicant for

Specialization

  • 02.00.01 - Неорганічна хімія

17-04-2006

Specialized Academic Board

Д26.001.03

Essay

Ten new composites of C60 fullerene and colloid water solution of the fullerene with highly dispersed silica: polyhydridesiloxane, silicon monoxide, fumed silica and fumed silica modified with hydrocarbon radicals - have been synthesised. The fumed silica, modified with unsaturated hydrocarbon radicals, has been firstly prepared by a high temperature treatment in the vacuum (carbonization) of samples, modified with aliphatic groups. The presence and the form of the fullerene on the surfaces of the supports have been determined by mass-spectrometry, diffusion reflectance and transmission Fourier transformation infrared spectroscopy. The concentrations of the carbonic component of the composites have been estimated by the differential thermogravimetry. The spectroscopic and quantum chemical examination of the commercial powder and synthesized film of silicon monoxide give an evidence to the existence of the silicon clusters, surrounded by the intermediate SiOx layer inside the SiO bulk. It has been shownthat the sorption of the fullerene on the surface of the silicon monoxide and polyhydridesiloxane is reversible and does not lead to the formation of stable composites, contrary to the sorption on the surface of modified fumed silica. The efficiency of the fullerene sorption on the fumed silica, modified with alkyl groups, increases upon the growth of the grafted chain length. The composites of the C60 with the silica, modified with saturated hydrocarbon radicals, contain the admixtures of the fullerene oxide C60O and, sometimes, the dimer of the partially destroyed fullerene C112. The mechanisms of the fullerene sorption on the silicon monoxide clusters, on the dehydroxylated areas of the fumed silica surface and on the carbonized samples of the modified fumed silica have been ascertained by the complex spectral and quantum chemical study. The formation of the covalent bonds between fullerene and the groups of the dehydroxylated area of the fumed silica has been shown. A formation of the covalent bond between the fullerene and dehydrogenized alkyl radicals, grafted on the fumed silica surface, has been observed. It has been shown that the intensity of the valent vibration of the conjugated C=C bond in the IR spectra of the fullerene composites with the carbonized modified silica increases due to the kinematic effect. This might be used for the identification of the fullerene bonding in the composite. It has been shown that a C60-(H2O)60 system is the most energetically stable clathrate formation of the fullerene and water. The water-fullerene clathrates appear to be quantitatively sorbed on the surface of the fumed silica, resulting in a composite formation, contrary to the toluene solutions. The photoluminescence of the synthesized composites has been studied. The impact of the silica surface, modified with the alkyl groups, is slight, while the emission spectra of the composites with the silica, modified by unsaturated hydrocarbon radicals, are significantly blue shifted and the intensity of the emission increases.

Files

Similar theses