Mixed-ligand complexes of osmium(III/IV)8-quinolinolates with one ketoximate ligand

Abstract

of osmium(III/IV)8-quinolinolates with Summary A group of mixed-tris chelates of type [OsAQ2 ] [A=isonitrosoacetophenonate (A ~) and isonitrosopropiophenonate (A2); Q = deprotonated 8-quinolinol (QI) and 2-methyl-8-quinolinol (Q2)] have been prepared by two distinct synthetic approaches. [OsAQ2] +, obtained by Ce Iv oxidation of [OsAQ2], can be regenerated by hydrazine hydrate reduction of the former. The complexes, characterized by physico-chemical, magnetic and spectroscopic methods, exhibit several spin-allowed and spin-forbidden charge transfer transitions in their electronic spectra. In MeCN solution the OsN30 3 unit displays a nearly-reversible OsW-Os m change and an Osm-Os" couple in the ca. -1.0-+0.3 V range versus s.c.e. The stability of the metal oxidation levels is discussed in terms of the chemical and electrochemical results.

Mixed-Ligand Complexes of Some Divalent Transition Metal Ions with Dicarboxylic Amino Acids and 8-Hydroxyquinoline

“…An EtOH solution of 8-hydroxyquinoline containing 5 mmol was added to the above mixture dropwise with constant stirring. For each an accurate mass corresponding to the (5 mmol) concentration was dissolved in 10 cm 3 EtOH. The mixture was refluxed for 2 h, evaporated, and cooled; the solid ternary complex precipitated out.…”

“…In recent years metal complexes of 8-hydroxyquinoline derivatives (Basudhar et al, 1996;Ibrahim et al, 1992Islam et al, 1995) and N-(2-acetamido)iminodiacetic acid (H 2 ADA) (Hamed et al, 1994;Mahmoud et al, 1996;Ahmed et al, 1996Ahmed et al, , 1997 have been studied because of their established biological activity. However, a survey of the literature reveals that studies of systems containing the two ligands H 2 ADA and 8-hydroxyquinoline have not been carried out.…”