Ruthenium complexes of 3-hydroxy-4-pyranones and of 3-hydroxy-4-pyridinones

Abstract

Reactions of hydrated ruthenium chloride with 2-methyl-3-hydroxy-4-pyranone, ethylmaltol (etmaltH) and with 1,2-dimethyl-3-hydroxy-4-pyridinone (dmppH) are described. The former results in the formation of Ru(etmalt) 3 , but the course of the latter depends on conditions, producing the earlier-characterised Ru(dmmp) 3 Cl in ethanol-water solution, Ru(dmmp) 3 in aqueous solution under mild conditions, and Ru(dmpp) 2 (H 2 O) 2 after extended refluxing. EXAFS studies established ruthenium-oxygen distances in Ru(etmalt) 3 and in Ru(dmmp) 3 Á 6H 2 O. Solubilities of Ru(dmmp) 3 in methanol-water mixtures reveal greater solubility in methanol than in water, and indications of a modest solubility maximum, and thus synergic solvation, in methanol-rich mixtures.

Mannich products of kojic acid and N-heterocycles and their Ru(II)–arene complexes: Synthesis, characterization and stability

“…The chelating properties of such pyrones to transition metal ions, e.g., Ru(II/III), Fe(III), Cu(II), [27][28][29][30][31] make them interesting ligands. Complexes of pyrones with vanadium and zinc have already been developed as insulin mimics and vanadyl coordination compounds with maltol and ethylmaltol recently entered clinical trials [32][33][34][35][36].…”