Framework Isomerism in Vanadium Metal鈥揙rganic Frameworks: MIL-88B(V) and MIL-101(V)

详细信息    查看全文

• 作者：Fabian Carson ; Jie Su ; Ana E. Platero-Prats ; Wei Wan ; Yifeng Yun ; Louise Samain ; Xiaodong Zou
• 刊名：Crystal Growth & Design
• 出版年：2013
• 出版时间：November 6, 2013
• 年：2013
• 卷：13
• 期：11
• 页码：5036-5044
• 全文大小：541K
• 年卷期：v.13,no.11(November 6, 2013)
• ISSN：1528-7505

文摘

Two families of metal鈥搊rganic frameworks (MOFs), MIL-88 and MIL-101 built by trinuclear transition metal (TM) clusters (TM = Cr, Fe, or Sc), have been known for several years, but their syntheses are often reported separately. In fact, these MOFs are polymorphs, or framework isomers: they are assembled from the same metal secondary building units and organic linkers, but the connectivity of these components differs. Here we report for the first time the synthesis of the vanadium MOF MIL-88B(V) and compare its synthesis parameters to those of MIL-47(V) and the recently reported MIL-101(V). The properties of MIL-88B(V) and MIL-101(V) are remarkably different. MIL-88B(V) can 鈥渂reathe鈥?and is responsive to different solvents, while MIL-101(V) is rigid and contains mesoporous cages. MIL-101(V) exhibits the highest specific surface area among vanadium MOFs discovered so far. In addition, both MIL-88B(V) and MIL-101(V) transform to MIL-47 at higher temperatures. We have also identified the key synthesis parameters that control the formation of MIL-88B(V), MIL-101(V), and MIL-47: temperature, time, and pH. This relates to the rate of reaction between the metal and linkers, which has been monitored by ex situ X-ray powder diffraction and V K-edge X-ray absorption spectroscopy during MOF synthesis. It is therefore important to fully study the synthesis conditions to improve our understanding of framework isomerism in MOFs.