Golub O. . Structural features of complex formation at surface.

The thesis is devoted to investigation of anchoring to surface, ligands layer and surface structure influence on protolytic and complex formation equilibrium so as on formed coordination compounds structure. By means of formal thermodynamics it is shown that the reactions of the complex formation, which proceed on a silica surface have a number of distinctive features in comparison with similar reactions in solutions. Among them we can mention (i) the simultaneous formation of several kinds of superficial compounds, (ii) the lowering of basicity of immobilised ligands in comparing with free ones, (iii) the dependence of the stability of complexes on the degree of completeness of the reaction, as well as on the topology of immobilized ligands, (iv) the influence of excess of free electrostatic energy of a surface as a result of electric double layer formation and so on. One of the main factors, influencing complex formation is the structure of ligand cover, namely, arrangement and donor centers structu ral features. It is shown that major and frequently unique information may give molecular modeling (MM) of superficial ligands and their complexes. In difference from similar systems in solutions the application of theoretical methods for studying of coordination compounds at the solid surface seems to be especially attractive because of the rigidity of the support for this reduce the number of freedom degrees of the molecules and the number of spatial configurations to be analyzed. In thesis by meens of MM is shown an impossibility of hydrogen bonding formation between amino groups themselves and amino groups and silanols at plane regular aminopropylaerosil surface. In frames of simple geometrical model the peculiarities of chemosorbed molecules concentration dependence from their size, specific surface area and spacer length have been determined. Obtained analytical correlation permit to forecast a nonlinearity in the dependence between adsorbed molecules concentration and specific surface area which can e xceed 20% at 1.7 times surface area changing, and allow ligands effective size to be estimated from experimental data for similar molecules at adsorbent surfaces of different surface area. In thesis the possibilities of mathematical statistic methods for prediction of adsorption properties of complexing sorbents is discussed. As shown by the computational methods at the surface of nonporous silica metal-ions can bind only one structural silanol group. The complexes are bond with isolated silanols irrespective of the way of synthesis, - as in the case of ion exchange, by reaction of impregnation with salt solutions and the subsequent thermal decomposition. The formation regularity of metal oxide surface layer at aerosil is analysed. For silica, containing anchored phosphate or tiophosphate groups connected with a surface through silanols, molecular mechanic and the quantum chemistry predict primary stability of complexes of a structure 1:1 in the case of bidentate linkage with a metal.