Abstract
The reaction of [Fe(bpca)2]·H2O with Fe(ClO4)3·6H2O in MeNO2-CHCl3 solution and MeNO2-CH2Cl2 solution afforded black crystals of a trinuclear complex, [Fe(H2O)2 {Fe(bpca)2}2](ClO4)4 (1), and a linear chain complex, catena-[Fe(ClO4)2 {Fe(bpca)2}]ClO4 (2), respectively (Hbpca = bis(2-pyridylcarbonyl)amine). In both complexes, iron atoms in {Fe(bpca)2}± units are in a low-spin 3± state, whereas irons coordinated by four carbonyl oxygen atoms and two axial oxygen atoms (from coordinated water molecules or perchlorate anions) take a high-spin 2± state. In both 1 and 2 antiferromagnetic interactions operated between high-spin Fe(II) and low-spin Fe(III) ions. 2 shows the ferrimagnetic ordering at 2.5 K. The plot of 1/χi m vs T above 50 K for 2 obeys the Curie-Weiss law with a negative Weiss constant of Θ = −15.3 K.

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