Dinuclear Cu(II) complexes based on two flexible Schiff-base ligands and one unusual in situ formed diphenolate 2,6-piperidin-4-one derivative.

A dinuclear Cu(ii) complex [Cu2(L3)2]·2H2O, having an unprecedented in situ formed diphenolate 2,6-piperidin-4-one derived ligand produced from the flexible Schiff-base ligand HL1, can be yielded as a side product in the presence of Cu(OAc)2·H2O-NH3·H2O dissolved in methanol and acetone in addition to the expected dinuclear Cu(ii) complex [Cu2(L1)4].