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

The interaction of mono- and tetranuclear hexafluoroacetylacetonates [M4(hfac)4(OMe)4(MeOH)4] (where М = Co, Ni) and [Cu4(hfac)4(OMe)4] with spin-labeled nitrophenols - nitronyl nitroxide 2-(2-hydroxy-5-nitrophenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (HL1) or with corresponding iminonitroxide (HL2) - is found to lead to the formation of solvates of binuclear complexes: [Co2(hfac)2(L2)2(H2O)2], [Ni2(hfac)2(L1)2(H2O)2], [Ni2(hfac)2(L2)2(H2O)], [Cu2(hfac)2(L1)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 L2 substitution for nitronyl nitroxide L1 changes the character of exchange interactions in the heterospin molecule to the ferromagnetic one. [ABSTRACT FROM AUTHOR]