quinolinolates

Quinolinolates are anions derived from quinolinol, which is a hydroxyquinoline molecule. Hydroxyquinolines are a class of organic compounds characterized by a quinoline ring system with one or more hydroxyl (-OH) groups attached. When a quinolinol loses a proton from its hydroxyl group, it forms a quinolinolate anion. These anions can then form salts with various cations, or they can act as ligands in coordination chemistry.

The most well-known and studied quinolinolate is 8-hydroxyquinolinate, also known as oxinate. This specific anion, derived from 8-hydroxyquinoline, is a bidentate ligand, meaning it can bind to a metal ion through two points of attachment. This chelating ability makes 8-hydroxyquinolinate particularly important in analytical chemistry for the gravimetric and spectrophotometric determination of many metal ions. It forms stable, often colored complexes with a wide range of metals, including aluminum, magnesium, zinc, and copper. The insolubility of many of these metal oxinate complexes in water allows for their quantitative precipitation and subsequent analysis.

Beyond analytical applications, quinolinolates have been explored for their biological activities. Some metal complexes of quinolinolates exhibit antimicrobial, antifungal, and even antineoplastic properties. The specific activity often depends on the metal ion coordinated and the substitution pattern on the quinoline ring. Research continues to explore the potential therapeutic uses of these compounds, as well as their roles in material science and catalysis due to their coordination properties.