Essential differences in the luminescence properties of dibenzoylmethanatoboron difluoride (1) bulk and microcrystals were detected. Analysis of the spectral data showed that in every case the fluorescence spectrum of 1 consisted of three components: monomer fluorescence, excimer fluorescence, and fluorescence related with interdimer interaction. Evolution of luminescence spectra observed with decrease of the crystal size are bound with decrease of monomer fluorescence intensity and considerable growth of intensity of fluorescence related to interdimer interaction. The presence of reversible luminescence thermochromism was discovered for 1: lowering the temperature from 300 to 77 K resulted in essential hypsochromic shift of the luminescence band maximum ( approximately 60 nm) connected with considerable decrease of the distances between the planes of the neighboring molecules ( approximately 0.1 Angstrom) that lead to the weakening of interdimer interaction and intensification of monomer luminescence.

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It is shown that the addition of precursor, tetrakis(2-hydroxyethyl) orthosilicate, that is absolutely soluble in water to a solution of cyclodextrins (CDs) leads to the formation of a hydrogel as a result of sol-gel processes. The synthesis is performed with neither a catalyst nor heating under the conditions that are inapplicable for traditionally employed precursors (tetraethoxy-and tetramethoxysilanes). The occurrence of sol-gel processes is due to the catalytic action of CDs. At the same time, their molecules act as matrix for precipitating polysilicic acids. As a result of hydrogel calcination, xerogels were prepared with micropores and microparticles dimensions of which were determined by the sizes of CD molecules.

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