SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF LITHIUM AND SODIUM COMPLEXES OF 5-ETHYLAMINO-4-METHYL-1,2-BENZOQUINONE 2-OXIME

Reactions of 5-ethylamino-4-methyl-1,2,benzoquinone 2-oxime (5-Et-4-Me qoH) with lithium and sodium hydroxide produce a series of complexes o f types [M(5-Et-4-Meqo)(5-Et-4-MeqoH)(n)] [n = 0, 1 when M = Na; n = 1 , 2 when M = Li]. All the compounds in this series have been character ized by elemental and spectroscopic analyses and the solid state struc tures of the complexes [Na(5-Et-4-Meqo)(5-Et-4-MeqoH)(H2O) . H2O] and [Li(5-Et-4-Meqo)(5-Et-4-MeqoH)(2) . 1 1/2 H-2] have been determined by a single-crystal X-ray diffraction analysis. In both the compounds, c onjugation involving the atoms N(7)-C(4)-C(3)-C(2)-O(2) is observed, t hus supporting the ligand configuration as being an intermediate betwe en the quinone oxime and imino oxime form. The H-1 NMR spectra of the tris-chelate [Li(5-Et-4-Meqo)(5-Et-4-MeqoH)(2) . 1 1/2 H2O] and the bi s-chelate [Na(5-Et-4-Meqo)(5-Et-4-MeqoH)(H2O) . H2O] are consistent wi th the solid state structures and establish that, even in solution, th e coordination generated around the metal ion remains unaltered.