Structure of Hydrates of Metal Complexes with Barbituric Acids

Golovnev, NN; Molokeev, MS; Lesnikov, MK JOURNAL OF SIBERIAN FEDERAL UNIVERSITY-CHEMISTRY, 10 (3):401-415; 10.17516/1998-2836-0036 2017

Data on the synthesis and structure of metal complexes with barbituric (H2ba), thiobarbituric (H2tba) and 1,3-diethyl-2-thiobarbituric (HDetba) acids, which include a different number of coordinated water molecules, are summarized. Depending on the conditions, compounds of the composition [M(H2O)n−kLm]0∙pH2O (Mm+ – metal ion; L− = Hba−, Htba− и Detba−; k≥0, p≥0) crystallize from the aqueous solution. The formation of neutral complexes of [M(H2O)n−kLm]0∙pH2O containing different amounts of coordinated water molecules (n-k) occurs in the case of L− ligands with potentially different dentateness and/or bridging coordination. Crystallization of several hydrates [M(H2O)n−kLm]0∙pH2O is also expected if water molecules can be both terminal and bridged ligands in them, and central ions, for example, of alkaline earth metals, easily form different coordination polyhedra. Synthesis of new hydrates can significantly expand the range of available compounds, including potentially useful functional properties