Capturing snapshots of post-synthetic metallation chemistry in metal–organic frameworks

• Published in: Nature chemistry Vol. 6; no. 10; pp. 906 - 912
• Main Authors: Bloch, Witold M., Burgun, Alexandre, Coghlan, Campbell J., Lee, Richmond, Coote, Michelle L., Doonan, Christian J., Sumby, Christopher J.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.10.2014; Nature Publishing Group
• Subjects: 639/638/11/879; 639/638/263/911; 639/638/298/921; Analytical Chemistry; Biochemistry; Chemistry; Chemistry/Food Science; Crystal structure; Crystallinity; Crystals; Inorganic Chemistry; Ligands; Metal-organic frameworks; Metals; Organic Chemistry; Performance enhancement; Physical Chemistry; Pores; Pyrazole; Reaction products; Single crystals; X-ray diffraction; Australia
• ISSN: 1755-4330; 1755-4349
• DOI: 10.1038/nchem.2045

Post-synthetic metallation is employed strategically to imbue metal–organic frameworks (MOFs) with enhanced performance characteristics. However, obtaining precise structural information for metal-centred reactions that take place within the pores of these materials has remained an elusive goal, because of issues with high symmetry in certain MOFs, lower initial crystallinity for some chemically robust MOFs, and the reduction in crystallinity that can result from carrying out post-synthetic reactions on parent crystals. Here, we report a new three-dimensional MOF possessing pore cavities that are lined with vacant di-pyrazole groups poised for post-synthetic metallation. These metallations occur quantitatively without appreciable loss of crystallinity, thereby enabling examination of the products by single-crystal X-ray diffraction. To illustrate the potential of this platform to garner fundamental insight into metal-catalysed reactions in porous solids we use single-crystal X-ray diffraction studies to structurally elucidate the reaction products of consecutive oxidative addition and methyl migration steps that occur within the pores of the Rh-metallated MOF, 1·[Rh(CO) 2 ][Rh(CO) 2 Cl 2 ]. Obtaining precise structural information for metal-centred reactions that take place within the pores of metal–organic frameworks continues to be an elusive goal. Now, a flexible framework has been synthesized that enables the direct elucidation of the products of post-synthetic metallation reactions and subsequent chemical transformations by single-crystal X-ray crystallography. Camera image: © boyoglu/iStock/Thinkstock