Synthesis, Structure, and Magnetic Properties of Heterospin Polymers MI[MII(Hfac)L2]

Heterospin polymeric complexes based on Ni(II) and Co(II) hexafluoroacetylacetonates and deprotonated iminonitroxide, 2-(2-hydroxy-5-nitrophenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-1-oxyl (HL), were synthesized. The [MII(Hfac)L2]– anions (Hfac = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate) in the complexes are linked into 1D–3D polymers by Na+, K+, Rb+, or Cs+ cations (I–V). An X-ray diffraction study of MI[MII(Hac)L2] ∙ n(Me2CO) (n = 0–2.5) demonstrated that the polymer structural motif is determined by alkali metal cation (CIF files CCDC nos. 1974139–1974143 for I–V). According to magnetic measurements, ferromagnetic interactions in the {LML} exchange clusters predominate in the solid phase, which gives rise to increase in the effective magnetic moment with decreasing temperature.