Two cobalt(III) mono-dimethylglyoximates isolated from one reaction

Abstract

The reaction of cobalt(II) nitrate hexahydrate with dimethylglyoxime (DMGH(2)) and 1,10-phenanthroline (phen) in a 1:1:2 molar ratio results in two Co(III) mono-dimethylglyoximates having two chelating phen ligands in cis positions and the Co(III) atom coordinated by six N atoms in a distorted octahedral coordination geometry. The isolated products differ in the deprotonation state of the DMGH(2) ligand. In [mu-hydrogen bis(N,N'-dioxidobutane-2,3-diimine)]tetrakis(1,10-phenanthroline)cobalt(III) trinitrate ethanol disolvate 1.87-hydrate, [Co(2)(C(4)H(6)N(2)O(2))(C(4)H(7)N(2)O(2))(C(12)H(8)N(2))(4)](NO(3))(3).2C(2)H(6)O.1.87H(2)O, (I), the C(2)-symmetric cation is formed with the coordination [Co(DMG)(phen)(2)](+) cations aggregating via a very strong O(-)...H(+)...O(-) hydrogen bond with an O...O distance of 2.409 (4) A. Crystals of (I) exhibit extensive disorder of the solvent molecules, the nitrate anions and one of the phen ligands. Compound (I) is a kinetic product, not isolated previously from similar systems, that transforms slowly into (N-hydroxy-N'-oxidobutane-2,3-diimine)bis(1,10-phenanthroline)cobalt(III) dinitrate ethanol monosolvate 0.4-hydrate, [Co(C(4)H(7)N(2)O(2))(C(12)H(8)N(2))(2)](NO(3))(2).C(2)H(6)O.0.40H(2)O, (II), with the DMGH(-) ligand hydrogen bonded to one of the nitrate anions. In (II), the solvent molecules and one of the nitrate anions are disordered.