THE INTERACTION OF DIRHENIUM(III) CLUSTER COMPOUNDS WITH SUCCINIC ACID

Abstract

Complex compounds of dirhenium(III) with bridge carboxylates and halide ligands show various types of bioactivity, and the entry into the internal coordination sphere of the central “atom”- complexing the ligands that have their own physiological activity may extend the range of useful properties of dirhenium(III) complex compounds. From this perspective development the methods of synthesis of dirhenium(III) complex compounds with such ligands and determination of their structure are promising. In this work the interaction (NBu 4 ) 2 Re 2 Cl 8 with succinic acid under different conditions was investigated. As a result of these experiments, the method of synthesis of cis-tetrachlorodi-μ-ethane-1,2-dicarboxylates of dirhenium(III) (axial ligands are DMSO or DMF) in mixture of organic solvents with heating under inert atmosphere was developed. These compounds were synthesized and isolated in the individual state, their spectral properties were investigated. The composition and structure of synthesized compounds were confirmed by IR spectroscopy, NMR spectroscopy at 1Н, 13С and EAS. The single absorption maximum at 16 130 cm-1, which corresponds to the δ - δ* electron transition for cis-tetrachlorodi-μ-carboxylates of dirhenium(III), is present in the EAS visible region of the complex compounds solution. In the IR spectrum the intense, weakly split band at 1428 cm-1 is observed. This band corresponds to the stretching vibration νas(СО) of the coordinated carboxylate group and confirms the addition of succinic acid to the cluster fragment Re 2 6+ . Also, the reaction of the same starting compounds under melting condition and inert atmosphere lead to formation of dirhenim(III) tetra-μ-carboxylate with ethan-1,2-dicarboxylic acid. The complex compound was isolated in solid state, its composition and structure were proved. The interaction of Re 2 (HOOC(CH 2 ) 2 COO) 4 Cl 2 with 1-adamantanecarboxylic acid lead to the complete replacement of the equatorial ligands on adamantanecarboxylates groups with the preservation of the structural type of dirhenium(III) tetra-μ-carboxylate.