Details

Autor(en) / Beteiligte

• Song, Chengling
• Hu, Jiayi
• Ling, Yajing
• Feng, YunLong
• Krishna, Rajamani
• Chen, De-li
• He, Yabing

Titel

The accessibility of nitrogen sites makes a difference in selective CO2 adsorption of a family of isostructural metal-organic frameworksElectronic supplementary information (ESI) available: PXRD patterns (Fig. S1-S3), TGA (Fig. S4), gas sorption isotherms (Fig. S5-S7), schematic of the breakthrough apparatus (Fig. S8), FTIR spectra (Fig. S9-S11), 1H and 13C NMR (Fig. S12), comparison of the textural properties of ZJNU-43a, ZJNU-44a and ZJNU-45 (Table S1), single-site Langmuir fit parameters (Tab

Erscheinungsjahr

2015-09

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• By using three rigid diisophthalate organic linkers incorporating different numbers and orientations of Lewis basic nitrogen atoms into the spacers between two terminal isophthalate moieties, namely, 5,5′-(quinoline-5,8-diyl)-diisophthalate, 5,5′-(isoquinoline-5,8-diyl)-diisophthalate, and 5,5′-(quinoxaline-5,8-diyl)-diisophthalate, a family of isostructural copper-based metal-organic frameworks, ZJNU-43 , ZJNU-44 and ZJNU-45 , were successfully solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction. The three MOFs, after activation, exhibited almost the same porosities but distinctly different CO 2 adsorption properties. At room temperature and 1 atm, the adsorption capacities for CO 2 reached 103, 116 and 107 cm 3 (STP) g −1 for ZJNU-43a , ZJNU-44a and ZJNU-45a , respectively. Furthermore, Ideal Adsorbed Solution Theory (IAST) and simulated breakthrough analyses indicated that ZJNU-44a bearing much more easily accessible nitrogen sites is the best among the three MOFs for the separation of the following two binary gas mixtures at 296 K, i.e. , 50/50 CO 2 /CH 4 and 15/85 CO 2 /N 2 gas mixtures, indicating that the accessibility of nitrogen sites plays a much more crucial role, which is further confirmed by comprehensive quantum chemical calculations. The work demonstrates that the CO 2 adsorption properties of MOFs depend not only on the number of Lewis basic nitrogen sites but also more importantly on their accessibility. Three isostructural metal-organic frameworks exhibit different CO 2 adsorption properties depending on the number and orientation of nitrogen sites in the frameworks, and the accessibility of nitrogen sites plays a much more crucial role in enhancing CO 2 adsorption.