Katsuya INOUE and Hiizu IWAMURA (Kyushu Univ.)
[Mol. Clyst. Liq. Cryst. 286, 133 (1996)]
Manganese bis(hexafluoroacetylacetonate), Mn-(hfac)2, reacts with 1,3-bis-(N-oxy-tert-butylamino)benzene, 2, to give a 1:1 polymeric complex of formula [Mn(hfac)2·2]n. An X-ray crystal structure analysis reveals that the manganese(II) ion and the molecule of 1 makes one-dimensional chains by ligation of the latter serving as a bis(monodentate) ligand to the former. A crystalline sample of the complex undergoes transition to a metamagnet at 5.5 K. In the ordered phase, it exhibits a large uniaxial magnetic anisotropy with the uniaxial anisotropy constant, Ku1, of 8.3 * 106 J m-3 by single crystal magnetic measurements.
Figure 1. The angle dependence of the magnetization of a single crystal of this complex. Rotated along crystal a axis (circle).
Figure 2. The temperature dependencies of the magnetic susceptibility of a single crystal of [Mn(II)(hfac)2·2] along (circle) and perpendicular to (triangle) the crystal c axis measured in 5 Oe.
Figure 3. Field dependencies of the magnetization of a single crystal of [Mn(II)(hfac)2·2] with the field applied along (circle) and perpendicular to (triangle) the c axis at 1.8 K.
Figure 4. A schematic drawing of the magnetic structure of [Mn(II)(hfac)2·2]. Broken lines show the N(tert-Bu)O· - F - N(tert-Bu)O· antiferromagnetic interaction between the ferrimagnetic 1-D chains. Solid lines show the ferromagnetic interchain interaction through the ligands.