It was shown experimentally that interaction of polynuclear hexafluoroacetylacetonates [Cu₄(hfac)₄(MeO)₄] and [Cu₁₁(hfac)₁₀(OH)₈(O)₂]·2C₇H₈ with nitronyl nitroxide radicals as well as their recrystallization in the presence of acetone led to complexes containing tetranuclear fragment {Cu₄(hfac)₂(L^HF)_x(L^F)_2-x} (x = 0–2), where L^HF and L^F are triply charged anions of 2-methyl-4,6-bis(trifluoromethyl)tetrahydropyran-2,4,6-triol and 2,4,6-tris(trifluoromethyl)tetrahydropyran-2,4,6-triol, respectively. The main factors contributing to the formation of the 4-nuclear fragment and trioxanes L^HF and L^F were identified. It is established that self-assembly of {Cu₄(hfac)₂(L^HF)_x(L^F)_2-x} is observed only in the case of mono- and polynuclear Cu^II hexafluoroacetylacetonates. For Co^II and Ni^II compounds the formation of such a fragment is not registered.