New alternating ferro- and antiferromagnetic, one-dimensional manganese(II) azide complex, [Mn(dpa)(N-3)(2)] - Crystal structure and spectroscopic and magnetic properties
M. Villanueva et al., New alternating ferro- and antiferromagnetic, one-dimensional manganese(II) azide complex, [Mn(dpa)(N-3)(2)] - Crystal structure and spectroscopic and magnetic properties, EUR J INORG, (6), 2001, pp. 1581-1586
The synthesis, crystal structure, and spectroscopic and magnetic properties
of a new alternating ferro- and antiferromagnetic, one-dimensional mangane
se(II) azide complex, [Mn(dpa)(N-3)(2)] (where dpa is the 2,2'-dipyridylami
ne ligand), are reported. The compound's crystal structure has been resolve
d at room temperature. The complex crystallizes in the monoclinic P2(1)/c s
pace group, with a = 7.089(2), b = 19.090(4), and c = 9.682(4) Angstrom, be
ta = 104.61(2) degrees, and Z = 4. The structure consists of neutral chains
in which each Mn-II cation is alternatively bridged by two end-on and two
end-to-end azido bridges. The octahedral coordination of the metallic catio
n is completed by two dpa ligand nitrogen atoms. Reflectance measurements c
onfirm the hexacoordination of the Mn-II ions in the complex. The ESR spect
ra at room temperature and at 4.2 K are isotropic, with a mean g-value of 2
.010(1). Magnetic data were analyzed on the basis of an alternating ferro-
and antiferromagnetic Heisenberg chain of Mn-II ions. The J-exchange parame
ters found are 64.3 and -75.7 K. A spin canting phenomenon has been observe
d in this compound, with a remnant magnetization which vanishes above 15 K.
Magnetostructural correlations in manganese(II) systems of alternating mag
netic sign are discussed.