Guest-Induced Modification of a Magnetically Active Ultramicroporous, Gismondine-like, Copper(II) Coordination Network
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- 作者：Jorge A. R. Navarro ; Elisa Barea ; Antonio Rodrí ; guez-Dié ; guez ; Juan M. Salas ; Conchi O. Ania ; José ; B. Parra ; Norberto Masciocchi ; Simona Galli ; Angelo Sironi
- 刊名：Journal of the American Chemical Society
- 出版年：2008
- 出版时间：March 26, 2008
- 年：2008
- 卷：130
- 期：12
- 页码：3978 - 3984
- 全文大小：350K
- 年卷期：v.130,no.12(March 26, 2008)
- ISSN：1520-5126
文摘
A novel ultramicroporous coordination polymer, namely [Cu(F-pymo)2(H2O)1.25]n (1, F-pymo =5-fluoropyrimidin-2-olate), has been prepared and structurally characterized. 1 displays a zeolitic gismondine(GIS) topology, with ca. 2.9 Å wide helical channels which, in the thermally activated counterpart (1'),account for a 13% void volume and are responsible for the observed selective solid-gas adsorptionproperties toward H2, N2, and CO2. At 77 K 1' behaves as a molecular sieve, selectively adsorbing H2 overN2, possibly due to size-exclusion reasons. At variance, although CO2 molecules are slightly larger thanthe pore size, they are readily incorporated by 1' at temperatures as high as 433 K. Variable-temperatureX-ray powder diffraction (TXRPD) studies, in the temperature range 303-473 K, show that dehydration isreversible and has almost negligible effects on the network. At variance, the uptake of CO2 occurs througha transient phase and channels expansion. While the gas storage capacity of 1' is not very high-H2, 0.56wt % and 0.010 kg H2/L at 90 K and 900 Torr, and CO2, 7.6 wt % at 273 K and 900 Torr-the guestmolecules achieve very high densities, comparable to that of the liquid for H2 (0.023 vs 0.021 moleculesÅ-3) and to that of the solid for CO2 (0.014 vs 0.022 molecules Å-3). In addition, we have also studied theeffect of the perturbation exerted by the guest molecules on its magnetic properties. The results show thatwhile dehydration of 1 has negligible effect on its spin-canted antiferromagnetic behavior, CO2 incorporationin the pores is responsible for an increment of the transition temperature at which the weak ferromagneticordering takes place from 22 to 29 K.