Structural and photophysical studies on a linear trinuclear zinc complex of 2-[(2-hydroxyethylimino)methyl]quinolin-8-ol

A linear trinuclear zinc complex was obtained when after refluxing 8-hydroxyquinoline-2-carboxaldehyde and 2-aminoethanol (in a 1:1 molar ratio) until the formation of the H2L ligand, a methanol solution of zinc acetate dihydrate was added. Reaction between Zn(OAc)2·2H2O and H2L, both in 3:2 or 4:2 ratios, yielded Zn3(HL)2(OAc)4. This latter could be crystallographically characterised, and rather surprisingly, the potentially tetradentate HL− is only acting as an O,N-donor, while two phenolate and four acetate bridges hold together the three zinc ions. A study of the luminescence properties in methanol solution showed that the quantum yield of Zn3(HL)2(OAc)4 (ΦF = 0.07) is slightly higher than that of 8-hydroxyquinoline-2-carboxaldehyde (ΦF = 0.06).

Single crystal X-ray diffraction studies on Zn3(HL)2(OAc)4 evidence that HL− is acting as an O,N-donor. A study of the luminescence properties in methanol solution showed that the quantum yield of Zn3(HL)2(OAc)4 is slightly higher than that of 8-hydroxyquinoline-2-carboxaldehyde.Figure optionsDownload as PowerPoint slide