Solvent-assisted linker exchange (SALE) and post-assembly metallation in porphyrinic metal–organic framework materials

Abstract

Using recently reported robust porphyrinic metal-organic framework (RPM) materials, we have examined the systematic exchange of pillaring linkers/struts as a means of accessing new versions of these materials.Dipyridyl-porphyrin Zn(II) (Zn-dipy) struts were successfully replaced by M 2 -dipy (M 2 ¼ 2H(+), Al(III), Sn(IV)), forming crystalline solid solutions of Zn(Zn 1Àx M x )-RPM in variable ratios. In addition, post-synthetic metallation was demonstrated using Zn2H-RPM, again with retention of crystallinity. We examined catalytic activity for an epoxide ring-opening reaction with a series of ZnM 2 -RPMs. The catalytic activity depends strongly on the identity of the metal ion present in the dipyridyl-porphyrin unit.Scheme 1 Synthesis of M 1 M 2 -RPM materials from M 1 -tetraacid, M 2 -dipy and Zn(NO 3 ) 2 $6H 2 O. Crystallography derived stick representations of the unit cells of RPM (yellow ¼ Zn, red ¼ O, green ¼ F, blue ¼ N, gray ¼ C). Hydrogen atoms and disordered solvent molecules have been omitted for clarity.

Strategies for Improving the Functionality of Zeolitic Imidazolate Frameworks: Tailoring Nanoarchitectures for Functional Applications

“… ii) The size of the MOF crystals . Smaller crystal sizes enable a faster rate of ligand exchange compared to larger crystals due to the faster diffusion rate iii) The choice of solvent .…”

Postsynthetic ligand exchange for the synthesis of benzotriazole-containing zeolitic imidazolate framework

“…10b,13 Recently, the replacement of the structure-building organic linkers has been utilized in the synthesis or functionalization of MOFs, including ZIFs, UiO and bio-MOFs. 10b, [12][13][14] Here, we report the use of ZIF-7 as the template to synthesize benzotriazole-containing ZIF (ZIF-7-M) without changing the framework via a PSE approach (Scheme 1). However, introducing new ligands with more coordinative atoms is challenging.…”

Tuning the crystal size and morphology of the substituted imidazole material, SIM-1

“…Li et al [43], reported the synthesis of new metal organic polyhedral (MOPs) from the replacement of organic linkers in three different Cu based MOPs thus allowing the as synthesized structure to take on new pore sizes/shapes and functionalities. Burnett et al [22], also reported linker exchange reactions in multidimensional materials, 2-D and 3-D MOFs, while Takaishu et al [44], reported new porphyrininic MOFs by exchanging the pillaring linkers. Mesoporous MOFs were also investigated for linker exchange; Li et al [45] demonstrated the exchange of dicarboxylate linkers from mesoporous bio-MOF-100, generating isoreticular bio-MOF analogs 101-103.…”