Crystallographic evidence of metal scrambling in an N4O2-tetraiminodiphenolate macrocyclic complex

• Heterodinuclear CuZn and CuMn Robson-type complexes.
• Metal scrambling lead to co-crystallization of homonuclear CuCu, ZnZn and MnMn complexes.
• EPR prior to metal scrambling shows only the spectral features of decoupled heterodinuclear species in solution.

Heterodinuclear complexes [CuZn(tidf)(H2O)2(ClO4)2] and [CuMn(tidf)(H2O)2(ClO4)2] undergo intermolecular metal scrambling in water and water/acetonitrile solutions. X-ray diffraction, EPR and molecular magnetism unambiguously established the prominent species in solution and in the solid state. Spectroscopy properties in solution were in accordance with the presence of heterodinuclear complexes, while single-crystal determination revealed co-crystallization of homometallic CuIICuII and MIIMII (MZn or Mn) macrocyclic complexes.