Artículos de revistas
Synthesis and characterization of T[Ni(CN)(4)] center dot 2pyz with T=Fe, Ni, pyz=pyrazine: Formation of T-pyz-Ni bridges
Journal Of Solid State Chemistry. Academic Press Inc Elsevier Science, v. 184, n. 8, n. 2124, n. 2130, 2011.
The formation of T-pyz-Ni bridges (pyz= pyrazine) in the T[Ni(CN)(4)] center dot 2pyz series is known for T=Mn, Zn, Cd and Co but not with T=Fe, Ni. In this contribution the existence of such bridges also for T=Fe, Ni is discussed. The obtained pillared solids, T[Ni(CN)(4)] center dot 2pyz, were characterized from XRD, TG, UV-Vis, IR, Raman, Mossbauer and magnetic data. Their crystal structures were refined in the orthorhombic Pmna space group from XRD powder patterns. The structural behavior of these solids on cooling down to 77 K was also studied. In the 180-200 K temperature range the occurrence of a structural transition to a monoclinic structure (P2(1)/c space group) was observed. No temperature induced spin transition was observed for Fe[Ni(cN)(4)]. 2pyz. The iron (II) was found to be in high spin electronic state and this configuration is preserved on cooling down to 2 K. The magnetic data indicate the occurrence of a low temperature weak anti-ferromagnetic interaction between T metal centers within the TINi(CN)(4)] layer. In the paramagnetic region for Ni[Ni(CN)4] center dot 2pyz, a reversible temperature induced spin transition for the inner Ni atom was detected. (C) 2011 Elsevier Inc. All rights reserved.184821242130[SEP-CONACyT-2009-01-129048][SEP-CONACyT-2009-01-129048]