A NEW FAMILY OF HIGH-DIMENSIONAL MOLECULAR MAGNETS BUILT FROM THE MANGANESE-AZIDO SYSTEM - SYNTHESES, STRUCTURES, AND MAGNETIC CHARACTERIZATION OF 2 NEW FERRO-ANTIFERROMAGNETIC 2-DIMENSIONAL COMPLEXES

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 compoun ds crystallize in the monoclinic system, space group P2(1)/a, formula [C12H8MnN10] with a 13.286(4) Angstrom, b 8.340(3) Angstrom, c = 13.57 9(4) Angstrom, beta = 90.55(2)degrees 0, and Z = 4 for compound 1 and space group P2(1)/c, formula [C14H14MnN8O2] with a = 11.843(4) Angstro m, b = 9.550(3) Angstrom, c 14.998(5) Angstrom, beta = 105.99(3)degree s, and Z = 4 for compound 2. The two compounds show a similar arrangem ent of alternating end-to-end and end-on azido bridges between the man ganese atoms, giving magnetically alternated ferro-antiferromagnetic t wo-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 o f 1 and 2, together with those of the previously reported compounds wi th L = pyridine (3), 4-acetylpyridine (4), and ethyl isonicotinate (5) , are reported. Magnetic ordering and spontaneous magnetization is ach ieved at T-C = 18, 16, 40, 28, and 16 K for 1-5, respectively.