Buchko O. Different types of homo- and heterometallic (citrato)germanates (stannates). Synthesis, structures and properties

A new approach in the synthesis of different types of coordination supramolecular structures, that crystalize from the systems GeO2 –citric acid-nitrogen-containing organic molecules and GeO2/SnCl4 – citric acid – 3d metal salt – 1,10-phenanthroline/2,2`-bipyridine. The stepwise interaction of individual components between each other creates conditions for existence of special blocks that become the basis for formation of homo- and heterometallic citratogermanates(stannates) with ion-ionic, covalent, donor-acceptor and hydrogen bonds. Optimal synthesis methods have been developed and allowed to obtain 27 new coordination compounds including supramolecular salts with citratogermanate anions and protonated nitrogen-containing organic molecules as cations and different-metal mixed-ligand complexes of Germanium(IV)/Tin(IV) and 3d-metals with citric acid and heterocyclic amines. They have been fully characterized with elemental analysis, IR-, Diffuse reflection spectroscopy, thermogravimetry, mas-spectroscopy, X-Ray. An ability of existing in the solution citratogermanate acid to form supramolecular salts with the protonated nitrogen-containing organic molecules was proved and different-metal complexes of dissimilar types (cation-anionic or heteronuclear) depending from the anion of 3d-metal salt. It has been established that all citratostannates are compounds of cation-anionic type with complex anion in which coordination polyhedron of tin is distorted octahedron formed by three pairs of oxygen atoms of two monoprotonated citric ligands, similar to the ones that exist in the citratogermanate complexes. An ability of citratogermanates to increase the activity of α-L-rhamnosidase Bacillus sp. 19, C. albidus, E. еrubescens and P. Tardum, their anticonvulsant activity with antagonism to corazol and modifying properties in the production of polymeric materials have been studied.