The binuclear copper(II) complex based on N,N’-bis(3-formyl-5-tert-butylsalicylidene)-1.3-diaminopropanol-2 with acetate exogenous bridge (1) as well as its DMSOsolvate derivative (2) were synthesized for the first time. The DMSO molecule acts as the additional bridging ligand. It was shown that the DMSO molecule’s bridging coordination leads to change of sign of exchange interaction between copper(II) atoms. The value of exchange parameter is –94.8 см-1 for complex 1 and + 121 см–1 for complex 2. Some lowering of μef at the temperature below 30 K for type 2 complex can be attributed to intermolecular exchange coupling; zJ' = –0.2 см–1 . It should be noted that all binuclear copper(II) complexes with 1.3-diaminopropanol-2 derivatives described both in literature and by our research group exhibit antiferromagnetic character of exchange interaction.figureThe quantum-chemical calculations based on “broken symmetry” approach have been carried out in order to evaluate the theoretical exchange parameters for 1 and 2 complexes taking into account fixed (from the X-ray analysis data) as well as optimized geometry. It was shown that the calculation’s results for the fixed geometry are better fitted with the experimental data. It was concluded that the ferromagnetic character of exchange interaction in complex 2 is caused by the realization of “distorted” conformation of coordinated diaminopropanol ligand. The role of DMSO molecule as "switch" of exchange interaction’s character consists exclusively in stabilization of “distorted” metallocycle conformation, rather than in forming the additional exchange channels