FIRST COMPARATIVE-STUDY OF THE STRUCTURE OF A 1,2-QUINONE MONOOXIME, ITS HYDROCHLORIDE SALT AND MAIN-GROUP METAL-COMPLEX

The synthesis of 5-ethylamino-4-methyl-1,2-benzoquinone-2-oxime (5-EtaqoH), its hydrochloride salt (5-EtaqoH(2)(+)Cl(-). H2O) and potassium complex K(5-Etaqo)(5-EtaqoH). 2H(2)O are described. The X-ray crystal structure of all three compounds are also reported. The neutral 5-EtaqoH was found to show largely quinone oxime rather than nitrosophenol character. The hydrochloride salt had essentially a 2,5-oxime imino structure with the acidic proton attached to the quinonoid carbonyl oxygen. The potassium atom in the complex K(5-Etaqo)(5-EtaqoH). 2H(2)O is coordinated to one neutral and one ionic ligand via the oxime nitrogens and the quinonoid carbonyl oxygen forming a five-membered chelate ring. The metal is therefore coordinated to seven donor atoms and is in a distorted pentagonal bipyramidal environment.