A quasi-tetrahedral tetracopper cluster with syn-anti bridging carboxylate groups: crystal and molecular structure and magnetic properties

The complex [Cu 4 (L) 3 (LH)(NO 3 )(H 2 O)]•2H 2 O, L and LH representing the dideprotonated and the monodeprotonated forms, respectively, of 6-amino- 1,3-dimethyl-5-((2-carboxyphenyl) azo) uracil, has been prepared, investigated by single-crystal X-ray analysis, and characterized through magnetic susceptibility and spectroscopic measurements. It crystallizes in the monoclinic space group P2 1 /c