Short-Range and Long-Range Magnetic Ordering, in Third Generation Brannerite Type Inorganic - Organic-Vanadates: [{Mn(Bpy)}(VO3)(2)]approximate to(H2O)(1.16) and [{Mn(Bpy)(0.5)}(VO3)(2)]approximate to(H2O)0.62

作者：de Luis Roberto Fernandez; Urtiaga M Karmele; Mesa Jose L; Vidal Karmele; Lezama Luis; Rojo Teofilo; Arriortua Maria I^*

来源：Chemistry of Materials, 2010, 22(19): 5543-5553.

DOI：10.1021/cm1015433

The three-dimensional [{Mn(BPY)}( VO3)(2)]approximate to(H2O)(1.16) and {Mn(Bpy)(0.5)}(VO3)(2)]approximate to(H2O)(0.62) inorganic organic compounds. where Bpy is 4,4'-bipyridine, (C10H8N2), have been synthesized using mild hydrothermal conditions under autogenous pressure at 170 degrees C during three days, obtaining single-crystals suitable for X-ray structure determination. The compounds crystallize in the monoclinic system, space group C2/m, with a = 16.706(5), b = 3.5245(4), c 11.558(5) angstrom, and beta = 100.77(5)degrees for 1, and a = 16.305(6), b = 3.5304(11), c = 17.788(6) angstrom, and beta = 116.87(4)degrees for 2. Single crystal X-ray diffraction reveals that both crystal structures are composed of inorganic layers pillared by organic ligands. However, 1 possesses simple layers, while 2 is constructed from double inorganic sheets. This structural organization gives rise to channels along the [010] direction, in which the crystallization water molecules are located. The thermogravimetry and thermodiffractometry experiments show that both crystal structures have a dynamical and reversible response to the removal and uptake of crystallization water molecules. Magnetic, ESR, specific heat, and neutron measurements indicate that both phases possess one-dimensional ferromagnetic coupling of the Mn(II) ions above the Neel temperature. Below 4 K for 1 and 7.5 K for 2, a three-dimensional antiferromagnetic order is established. The sigmoidal shape of the magnetization curves indicates that the three-dimensional antiferromagnetic order can be reverted by the application of higher magnetic fields.

• 出版日期2010-10-12