Tanabe Kristine K, Wang Zhenqiang, Cohen Seth M
Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, USA.
J Am Chem Soc. 2008 Jul 2;130(26):8508-17. doi: 10.1021/ja801848j. Epub 2008 Jun 10.
The pendant amino groups in isoreticular metal-organic framework-3 (IRMOF-3) were subjected to postsynthetic modification with 10 linear alkyl anhydrides (O(CO(CH2)nCH3)2 (where n = 1 to 18) and the extent of conversion, thermal and structural stability, and Brunauer-Emmett-Teller (BET) surface areas of the resulting materials were probed. (1)H NMR of digested samples showed that longer alkyl chain anhydrides resulted in lower conversions of IRMOF-3 to the corresponding amide framework (designated as IRMOF-3-AM2 to IRMOF-3-AM19). Percent conversions ranged from essentially quantitative (approximately 99%, -AM2) to approximately 7% (-AM19) with IRMOF-3 samples. Modified samples were thermally stable up to approximately 430 degrees C and remained crystalline based on powder X-ray diffraction (PXRD) measurements. Under specific reaction conditions, significant conversions were obtained with complete retention of crystallinity, as verified by single-crystal X-ray diffraction experiments. Single crystals of modified IRMOF-3 samples all showed that the F-centered cubic framework was preserved. All single crystals used for X-ray diffraction were analyzed by electrospray ionization mass spectrometry (ESI-MS) to confirm that these frameworks contained the modified 1,4-benzenedicarboxylate ligand. Single crystals of each modified IRMOF-3 were further characterized by measuring the dinitrogen gas sorption of each framework to determine the effects of modification on the porosity of the MOF. BET surface areas (m(2)/g) confirmed that all modified IRMOF-3 samples maintained microporosity regardless of the extent of modification. The surface area of modified MOFs was found to correlate to the size and number of substituents added to the framework.
对同构金属有机骨架-3（IRMOF-3）中的 pendant 氨基进行了用 10 种线性烷基酸酐（O(CO(CH2)nCH3)2，其中 n = 1 至 18）的后合成修饰，并对所得材料的转化程度、热稳定性和结构稳定性以及布鲁诺尔-埃米特-泰勒（BET）表面积进行了探究。消化后样品的（1）H NMR 表明，较长链烷基酸酐导致 IRMOF-3 向相应酰胺骨架（命名为 IRMOF-3-AM2 至 IRMOF-3-AM19）的转化率较低。IRMOF-3 样品的转化率范围从基本定量（约 99%，-AM2）到约 7%（-AM19）。基于粉末 X 射线衍射（PXRD）测量，修饰后的样品在高达约 430℃时热稳定且保持结晶性。在特定反应条件下，通过单晶 X 射线衍射实验验证，获得了显著的转化率且结晶性完全保留。修饰后的 IRMOF-3 样品的单晶均表明 F 心立方骨架得以保留。对所有用于 X 射线衍射的单晶进行电喷雾电离质谱（ESI-MS）分析，以确认这些骨架包含修饰后的 1,4-苯二甲酸配体。通过测量每个骨架的氮气吸附对每个修饰后的 IRMOF-3 单晶进行进一步表征，以确定修饰对 MOF 孔隙率的影响。BET 表面积（m²/g）证实，所有修饰后的 IRMOF-3 样品无论修饰程度如何均保持微孔性。发现修饰后 MOF 的表面积与添加到骨架上的取代基的大小和数量相关。
