Unique coordination of pyrazine in T[Ni(CN)(4)] center dot 2pyz with T = Mn, Zn, Cd

作者：Lemus Santana A A; Rodriguez Hernandez J; del Castillo L F^*; Basterrechea M; Reguera E

来源：Journal of Solid State Chemistry, 2009, 182(4): 757-766.

DOI：10.1016/j.jssc.2008.12.028

• Crystal chemistry
• Structural studies
• Layered compounds
• Pillared solids

The materials under study, T[Ni(CN)(4)] center dot 2pyz with T = Mn, Zn, Cd, were prepared by separation of T[Ni(CN)(4)] layers in citrate aqueous solution to allow the intercalation of the pyrazine molecules. The obtained solids were characterized from chemical analyses, X-ray diffraction, infrared, Raman, thermogravimetry, UV-Vis, magnetic and adsorption data. Their crystal structure was solved from ab initio using direct methods and then refined by the Rietveld method. A unique coordination for pyrazine to metal centers at neighboring layers was observed. The pyrazine molecule is found forming a bridge between Ni and T atoms, quite different from the proposed structures for T = Fe, Ni where it remains coordinated to two T atoms to form a vertical pillar between neighboring layers. The coordination of pyrazine to both Ni and T atoms minimizes the material free volume and leads to form a hydrophobic framework. On heating the solids remain stable LIP to 140 degrees C. No CO2 and H-2 adsorption was observed in the small free spaces of their frameworks.

• 出版日期2009-4