Structure copper(II) complexes with N-methylacetohydroxamic acid in crystal and solution

The structure of the dimeric complex [CuL2]2 (HL is N-methylacetohydroxamic acid) formed by two square-planar CuL2 moieties with the trans coordination of the ligands has been studied by X-ray crystallography. In methylene chloride at 297 K, the complex exists as two species, which are monomeric as probed by electron paramagnetic resonance. At 80 K, the dimeric and monomeric forms are identified. The relative concentrations of paramagnetic forms and their magnetic resonance parameters have been determined from simulation of EPR spectra.