glyoxime

Glyoxime is the di-oxime derivative of glyoxal (ethanedial). Its most common representation is the symmetrical structure HO-N=CH-CH=N-OH, arising from the reaction of glyoxal with hydroxylamine. The molecule contains two oxime functional groups and can exhibit tautomerism and geometric isomerism around the C=N bonds, giving rise to different isomeric forms.

Preparation and structure

Glyoxime is typically prepared by treating glyoxal with hydroxylamine under appropriate conditions. The resulting di-oxime retains the adjacent carbon framework of glyoxal, with each aldehydic carbon converted to an oxime moiety. In solution, the compound may exist in equilibrium with alternative tautomers or related nitroso/hydroxylamine forms, depending on pH and solvent.

Coordination chemistry

Glyoxime is valued in inorganic and coordination chemistry as a multidentate ligand. In its neutral form it can bind metal centers through the oxime nitrogen and oxygen atoms of both oxime groups. Upon deprotonation of the oxime hydroxyls, the ligand becomes more strongly dentate, often behaving as a tetradentate ligand that can chelate metals via two N and two O donors. Glyoxime and its metal complexes have been investigated for their structural, magnetic, and catalytic properties, with applications in catalyst design and fundamental studies of metal–ligand interactions.

Applications and context

As a building block and ligand, glyoxime serves primarily in chemical research, notably within coordination chemistry and catalysis. It is related to other oxime chemistry involving glyoxal and hydroxylamine, and it helps illustrate principles of multidentate ligand binding and chelate formation.

Safety and handling

Glyoxime should be handled with standard laboratory precautions appropriate for reactive organic compounds, including proper storage away from oxidants and use of appropriate personal protective equipment.