Cubane-like tetranuclear Cu(ii) complexes bearing a CuO core: crystal structure, magnetic properties, DFT calculations and phenoxazinone synthase like activity.

In the present work, two new copper complexes 3a and 3b with a CuO cubane core are reported. Both complexes are obtained by means of the in situ conversion of the imine functionality of Schiff's base ligands 1a [(E)-4-chloro-2-((thiazol-2-ylimino)methyl)phenol] and 1b [(E)-4-bromo-2-((thiazol-2-ylimino)methyl)phenol] into amino alcohols 2a (4-chloro-2-(hydroxy(thiazol-2-ylamino)methyl)phenol) and 2b (4-bromo-2-(hydroxy(thiazol-2-ylamino)methyl)phenol), respectively. The ligand transformation may be metal assisted and the generated ligands show an interesting mode of coordination in which the alkoxo-O atom binds in a μ-manner connecting simultaneously three copper centers and forming a CuO cubane core.