1D and 2D End-to-End Azide-Bridged Cobalt(II) Complexes: Syntheses, Crystal Structures, and Magnetic Properties

Two new polynuclear azido-bridged Co(II) compounds with formulas catena-[Co(μ1,3-N3)(N3)(py)2(H2O)]n (1) and
[Co(μ1,3-N3)2(4-acpy)2]n (2) (py = pyridine, 4-acpy = 4-acetylpyridine) have been structurally and magnetically
characterized. Compound 1 crystallizes in the orthorhombic system Fddd space group and consists of a single
end-to-end azido-bridged chain with the Co(II) atoms in a CoN5O slightly distorted octahedron. Compound 2 crystallizes
in the monoclinic system P21/a space group and shows 2D sheets built up through end-to-end azido bridges with
the Co(II) atoms in a CoN6 environment. The magnetic properties of 1 and 2 are reported. In the high-temperature
region, the plots of χM or χMT vs T for 1 and 2 compounds can be fitted by using the Curie−Weiss law, and the
best-fit ϑ values are −69.1 and −22.6 K, respectively. For 2 magnetic ordering and spontaneous magnetization
is achieved below Tc = 25 K.