Controlling magnetic exchange coupling via coligands in three cyanide-bridged heterobimetallic complexes

Three one-dimensional (1D) cyanide-bridged heterobimetallic chains {[Fe-III(Tp)(CN)(3)](2)Co-II(mep)2}center dot 2CH(3)OH (1; Tp = hydrotris(pyrazolyl)borate, mep = 4- [(1E)-2-(4-Methylphenyl)ethenyl]pyridine), [Fe-III(Tp) (CN)(3)l(2)Co(II)(eep)(2)]center dot 2CH(3)OH (2; eep = 4- [(1E)-2-(4-Ethylphenyl)ethenyl]pyridine) and {[Fe-III(Tp) (CN)(3)](4)Co-2(II)(nep)(4)]center dot 3H(2)O center dot CH3OH (3; nep = 4-[(1E)-2-(2-Naphthalenyl)ethenyl]pyridine) have been synthesized via self-assembly of the same [Fe-III(Tp)(CN)(3)](-) unit and Con ion in the presence of different N-substituted pyridine ligands. Magnetic measurements reveal that complex 1 exhibits ferromagnetic interactions and a long-range magnetic ordering below 3.5 K. Complex 2 shows antiferromagnetic long-range ordering below 3.3 K, while complex 3 shows a typical ferrimagnetic coupling at low temperatures. These results highlight the significant influence of the coligands on their magnetic properties.