Syntheses and crystal structures of copper mixed-ligand complexes of multidentate enaminones and acetate anions

Reactions of ferrocenoylacetone with 2-(aminomethyl)pyridine and N-(2-hydroxyethyl)-1,2-diaminoethane afford the multidentate enaminones HL1 and H3L2, respectively. Reactions of copper acetate with the two enaminones generate the corresponding mixed-ligand complexes I and II, which are formulated as [CuL1(OAc)] and [Cu(H2L2)(OAc)], respectively. The structures of HL1, I and II have been determined by single-crystal X-ray crystallography. In complex I, HL1 acts as a monoanionic tridentate donor via the carbonyl oxygen, deprotonated enamine nitrogen and pyridyl nitrogen atoms, the acetate anion is monodentate and the coordination geometry of the central metal is square planar. In complex II, H3L2 is a monoanionic tetradentate ligand via the carbonyl oxygen, deprotonated enamine nitrogen, secondary amine nitrogen and hydroxy oxygen atoms, the acetate anion is monodentate and the coordination geometry of the central metal is a distorted trigonal bipyramid.

Graphical abstractReactions of ferrocenoylacetone with 2-(aminomethyl)pyridine and N-(2-hydroxyethyl)-1,2-diaminoethane afford the multidentate enaminones HL1 and H3L2, respectively. Reactions of copper acetate with the two enaminones generate the corresponding mixed-ligand complexes I and II, which are formulated as [CuL1(OAc)] and [Cu(H2L2)(OAc)], respectively. The structures of HL1, I and II have been determined by single-crystal X-ray crystallography. In complex I, HL1 acts as a monoanionic tridentate donor via the carbonyl oxygen, deprotonated enamine nitrogen and pyridyl nitrogen atoms, the acetate anion is monodentate and the coordination geometry of the central metal is square planar. In complex II, H3L2 is a monoanionic tetradentate ligand via the carbonyl oxygen, deprotonated enamine nitrogen, secondary amine nitrogen and hydroxy oxygen atoms, the acetate anion is monodentate and the coordination geometry of the central metal is a distorted trigonal bipyramid.Figure optionsDownload full-size imageDownload as PowerPoint slide