Synthesis and reactivity of ruthenium(II) complexes with 1,5-cyclooctadiene and pyridine-2,6-dicarboxylato ligands

• Ruthenium(II) complexes with pyridine-2,6-dicarboxylato ligands were synthesized.
• The synthesized complexes were characterized by single-crystal X-ray diffraction.
• Easy substitution reactions occurred by N-donors on coordinated water molecule.

Reaction of [Ru(COD)Cl2]x (COD = 1,5-cyclooctadiene) with pyridine-2,6-dicarboxylic acid (dipicH2) in the presence of Et3N afforded an anionic complex [Et3NH][(dipic)(COD)RuCl] (1) with a κ3-dipic coordination mode. Treatment of 1 with AgNO3 in MeOH/H2O afforded a neutral complex [(dipic)(COD)Ru(H2O)] (2) in a high yield. Reaction of 2 with 1 equiv. of L gave the according adducts [(dipic)(COD)Ru(L)] (L = py (py = pyridine, 3), 4-t-Bupy (4), NH3 (5), t-BuNH2 (6), PhCH2NH2 (7), and MeCN (8)), while the similar reaction with 0.5 equiv. of 4,4′-bipyridine afforded a binuclear complex [{(dipic)(COD)Ru}2(μ-bipy)] (bipy = 4,4′-bipyridine, 9). All complexes have been spectroscopically characterized along with the electrochemical analyses, and the structures of complexes 1–4, 7·MeOH and 9·2H2O have been also determined by single-crystal X-ray diffraction.

Treatment of AgNO3 with the anionic complex [Et3NH][(dipic)(COD)RuCl] afforded a neutral aqua complex [(dipic)(COD)Ru(H2O)], which reacted easily with various N-donor ligands to yield the corresponding mono- and bi-nuclear ruthenium complexes by way of the typical substitution reactions.Figure optionsDownload as PowerPoint slide