Five New Manganese−μ-Azido 2D Compounds Synthesized in Aqueous Hydrazoic Acid from Pyrazine Derivatives

Abstract

The syntheses, structural characterization, and magnetic behavior of five new 2D manganese(II) complexes with empirical formulas [Mn(N(3))(2)(2,6-DiMepyz)(H(2)O)](n)() (1), [Mn(N(3))(2)(Etpyz)(H(2)O)](n)() (2), [Mn(N(3))(2)(H(2)O)(2)](n)()(2,3-DiMepyz)(n)() (3), [Mn(N(3))(2)(Clpyz)(2)](n)() (4), and [Mn(N(3))(2)(Ipyz)(2)](n)() (5) (pyz = pyrazine (1,4-diazine)) are reported. 1 crystallizes in the monoclinic system, space group P2(1)/c, with unit cell parameters a = 7.513(4) A, b = 17.438(7) A, c = 8.404(4) A, beta = 94.53(4) degrees , and Z = 4. 2 crystallizes in the triclinic system, space group P, with unit cell parameters a = 7.386(2) A, b = 8.434(2) A, c = 9.442(3) A, alpha = 71.82(2) degrees , beta = 72.08(2) degrees , gamma = 88.54(2) degrees , and Z = 2. 3 crystallizes in the monoclinic system, space group C2/c, with unit cell parameters a = 20.438(7) A, b = 7.711(2) A, c = 7.457(2) A, beta = 93.76(3) degrees , and Z = 4. 4 crystallizes in the orthorhombic system, space group Pbca, with unit cell parameters a = 8.600(2) A, b = 13.440(4) A, c = 24.083(7) A, and Z = 8. 5 crystallizes in the orthorhombic system, space group Pbca, with unit cell parameters a = 8.521(2) A, b = 13.787(3) A, c = 26.237(5) A, and Z = 8. The compounds 1-5 have only azido bridging ligands. In 1-3 each manganese atom is linked to the four nearest neighbors by only end-to-end azido bridges, forming square layers. 4 and 5 show alternating end-to-end and end-on azido bridges between manganese atoms. The magnetic properties of 1-5 are reported. At high temperatures the plots of chi(M) or chi(M)T vs T for the 1-3 compounds can be fitted as homogeneous 2D systems with J = -4.9, -4.4, and -3.9 cm(-)(1) for 1-3, respectively. For 1, 3, and 5 magnetic ordering and spontaneous magnetizations is achieved below T(c) = 35, 29, and 22 K, respectively, whereas 2 and 4 do not show spontaneous magnetization up to 2 K.