A New Family of High-Dimensional Molecular Magnets Built from the Manganese-Azido System. Syntheses, Structures, and Magnetic Characterization of Two New Ferro-Antiferromagnetic Two-Dimensional Complexes

Inorg Chem. 1997 Jul 30;36(16):3440-3446. doi: 10.1021/ic961476f.

Abstract

Two new compounds in the series of general formula [Mn(L)(2)(N(3))(2)](n)() in which L = 4-cyanopyridine (1) or 3-acetylpyridine (2) have been obtained and structurally and magnetically characterized. Both compounds crystallize in the monoclinic system, space group P2(1)/a, formula [C(12)H(8)MnN(10)] with a = 13.286(4) Å, b = 8.340(3) Å, c = 13.579(4) Å, beta = 90.55(2) degrees, and Z = 4 for compound 1 and space group P2(1)/c, formula [C(14)H(14)MnN(8)O(2)] with a = 11.843(4) Å, b = 9.550(3) Å, c = 14.998(5) Å, beta = 105.99(3) degrees, and Z = 4 for compound 2. The two compounds show a similar arrangement of alternating end-to-end and end-on azido bridges between the manganese atoms, giving magnetically alternated ferro-antiferromagnetic two-dimensional compounds. The pyridyl ligands coordinated to the axial sites stick out above and below the 2-D sheets, and intersheet pi-pi interactions are formed between the pyridyl ligands, playing a role in the structural differences. The low-temperature magnetic properties of 1 and 2, together with those of the previously reported compounds with L = pyridine (3), 4-acetylpyridine (4), and ethyl isonicotinate (5), are reported. Magnetic ordering and spontaneous magnetization is achieved at T(C) = 18, 16, 40, 28, and 16 K for 1-5, respectively.