Binuclear Co(II), Ni(II), and Cu(II) Hexafluoroacetylacetonates with Spin-Labeled Nitrophenols

The interaction of mono- and tetranuclear hexafluoroacetylacetonates [M 4 (hfac) 4 (OMe) 4 (MeOH) 4 ] (where М = Co, Ni) and [Cu 4 (hfac) 4 (OMe) 4 ] with spin-labeled nitrophenols - nitronyl nitroxide 2-(2-hydroxy-5-nitrophenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1 H -imidazole-3-oxide-1-oxyl (HL 1 ) or with corresponding iminonitroxide (HL 2 ) - is found to lead to the formation of solvates of binuclear complexes: [Co 2 (hfac) 2 (L 2 ) 2 (H 2 O) 2 ], [Ni 2 (hfac) 2 (L 1 ) 2 (H 2 O) 2 ], [Ni 2 (hfac) 2 (L 2 ) 2 (H 2 O)], [Cu 2 (hfac) 2 (L 1 ) 2 ]. The magnetochemical analysis reveals that exchange interactions between metal ions and coordinated nitronyl nitroxides are strongly feroomagnetic and result in the compensation of spins. Imino nitroxide L 2 substitution for nitronyl nitroxide L 1 changes the character of exchange interactions in the heterospin molecule to the ferromagnetic one.