Synthesis and characterization of T[Ni(CN)4]·2pyz with T=Fe, Ni; pyz=pyrazine: Formation of T–pyz–Ni bridges

✍ Scribed by A.A. Lemus-Santana; J. Rodríguez-Hernández; M. González; S. Demeshko; M. Ávila; M. Knobel; E. Reguera

• Book ID: 104030881
• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 729 KB
• Volume: 184
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2011.06.011

✦ Synopsis

The formation of T-pyz-Ni bridges (pyz ¼ pyrazine) in the T[Ni(CN) 4 ] Á 2pyz series is known for T ¼Mn, Zn, Cd and Co but not with T ¼ Fe, Ni. In this contribution the existence of such bridges also for T¼ Fe, Ni is discussed. The obtained pillared solids, T[Ni(CN) 4 ] Á 2pyz, were characterized from XRD, TG, UV-Vis, IR, Raman, M össbauer 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 ] Á 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 T[Ni(CN) 4 ] layer. In the paramagnetic region for Ni[Ni(CN) 4 ] Á 2pyz, a reversible temperature induced spin transition for the inner Ni atom was detected.