TY - JOUR
T1 - Unique coordination of pyrazine in T[Ni(CN)4]·2pyz with T=Mn, Zn, Cd
AU - Lemus-Santana, A. A.
AU - Rodríguez-Hernández, J.
AU - del Castillo, L. F.
AU - Basterrechea, M.
AU - Reguera, E.
N1 - Funding Information:
A.L. acknowledges the support provided by CONACyT (Mexico) for her PhD studies. The help of C.P. Krap, R.Y. Sato-Berrú and J. Ocotlan-Flores for the CO 2 and H 2 adsorption, Raman and IR data collection, respectively, is highly appreciated. The authors thank Dr. N. Barba-Behrens for the experimental facility for UV-Vis and magnetic data collection. This research was partially supported by the Projects SEP-2004-C01-47070, SEP-CONACyT-2007-61-541 and PAPIIT IN-119606. The authors thank E. Fregoso-Israel from IIM-UNAM for the DSC and TG data collection. Access to the LNLS synchrotron radiation facility (at Campinas, Brazil) is also acknowledged.
PY - 2009/4
Y1 - 2009/4
N2 - The materials under study, T[Ni(CN)4]·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 up to 140 °C. No CO2 and H2 adsorption was observed in the small free spaces of their frameworks.
AB - The materials under study, T[Ni(CN)4]·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 up to 140 °C. No CO2 and H2 adsorption was observed in the small free spaces of their frameworks.
KW - Crystal chemistry
KW - Layered compounds
KW - Pillared solids
KW - Structural studies
UR - http://www.scopus.com/inward/record.url?scp=62849105276&partnerID=8YFLogxK
U2 - 10.1016/j.jssc.2008.12.028
DO - 10.1016/j.jssc.2008.12.028
M3 - Artículo
SN - 0022-4596
VL - 182
SP - 757
EP - 766
JO - Journal of Solid State Chemistry
JF - Journal of Solid State Chemistry
IS - 4
ER -