A rare case of solution and solid state inter-conversion of two copper(II) dimers and a copper(II) chain

► Synthesis and crystal structure of three μ-1,1-azido bridged Cu(II) complexes with a NNO donor Schiff base ligand. ► A non-centrosymmetric Cu(II) dimer with a double μ-1,1-azido bridge and a Schiff base ligand undergoes solid state crystal transformation to a centrosymmetric one. ► The magnetic properties of compounds 1, 2 and 3 show weak antiferromagnetic exchange interactions mediated by 1,1-N3 azido bridges (J = −2.59(4), −0.10(1) cm−1 and J = −0.010(4) cm−1, respectively).