Zinc Porphyrin/Imidazolium Integrated Multivariate Zirconium Metal–Organic Frameworks for Transformation of CO₂ into Cyclic Carbonates

Abstract

The design and synthesis of metal-organic frameworks (MOFs) enclosed with multiple catalytic active sites is favorable for cooperative catalysis, but is is still challenging. Herein, we developed a sequential postsynthetic ionization and metalation strategy to prepare bifunctional multivariate Zr-MOFs incorporating zinc porphyrin and imidazolium functionalities. Using this facile strategy, tetratopic [5,10,15,20-tetrakis(4-carboxyphenyl)porphyrinato]zinc(II) (ZnTCPP) ligands were successfully installed into the cationic Zr-MOF to obtain ZnTCPP⊂(Br)Etim-UiO-66. These MTV-MOFs, including TCPP⊂Im-UiO-66, TCPP⊂(Br)Etim-UiO-66, and ZnTCPP⊂(Br)Etim-UiO-66, were well characterized and used in CO capture and conversion into cyclic carbonate from allyl glycidyl ether and CO under cocatalyst-free and 1 bar CO pressure conditions. It was found that the structural features and CO affinity properties of these MTV-MOFs can be tuned by introducing imidazolium groups or doping zinc sites. Additionally, ZnTCPP⊂(Br)Etim-UiO-66 exhibited enhanced catalytic activities compared to other MTV-MOFs herein for obtaining the 3-allyloxy-1,2-proplyene carbonate product, which was attributed to the cooperative effect of Zn sites and Br ions in this microporous ionic MTV-MOF. ZnTCPP⊂(Br)Etim-UiO-66 can be recycled easily and used at least three times.

Highly Porous Metalloporphyrin Covalent Ionic Frameworks with Well‐Defined Cooperative Functional Groups as Excellent Catalysts for CO2 Cycloaddition

“…This peak confirmed the formation of azo‐linked aromatic carbon atoms, as previously reported in the literature . Peaks related to methyl and methylene groups were also observed for CIF1‐C 2 H 5 , CIF2‐C 2 H 5 , and CIF2‐C 2 H 4 at 11, 45.4, and 49 ppm …”

“…[17] Peaks relatedt om ethyl and methylene groups were also observed for CIF1-C 2 H 5 ,C IF2-C 2 H 5 ,a nd CIF2-C 2 H 4 at 11,4 5.4, and 49 ppm. [19] Figure 2. TGA of metalloporphyrinC o-CIF1-C 2 H 5 ,Z n-CIF1-C 2 H 5 ,Zn-CIF2-C 2 H 5 , and Zn-CIF2-C 2 H 4 under N 2 atmosphere up to 800 8Cataheating rate of 10 8Cmin À1 .…”

Hybrid Catalysts for CO2 Conversion into Cyclic Carbonates

“…The proposed reaction mechanism for the reaction catalyzed by UiO-OH involves a synergic activation of the epoxide via coordination of the oxygen of the threemembered ring with the Zr center, together with the formation of a hydrogen bond with the -OH group in close spatial proximity, as reported in Scheme 18. Other more complex MOF structures prepared employing Zr-based SBUs and displaying both Zn porphyrin (having four carboxyphenyl extremities) and imidazolium moieties incorporated in the structure were obtained by Huang, Cao, and co-workers (Scheme 19) [74]. While the importance of having imidazolium functionalities in the structure is clear, the incorporation of Zn porphyrin as an additional source of Lewis acid (together with the Zr clusters) may be questionable.…”

“…Other more complex MOF structures prepared employing Zr-based SBUs and displaying both Zn porphyrin (having four carboxyphenyl extremities) and imidazolium moieties incorporated in the structure were obtained by Huang, Cao, and co-workers (Scheme 19) [74]. While the importance of having imidazolium functionalities in the structure is clear, the incorporation of Zn porphyrin as an additional source of Lewis acid (together with the Zr clusters) may be questionable.…”

Sustainable Heterogeneous Catalysts for CO2 Utilization by Using Dual Ligand ZnII/CdII Metal–Organic Frameworks

“…[61][62][63][64][65][66][67][68] In addition to the mentioned applications, MOFs as ah eterogeneous catalyst forC O 2 conversion at ambient reaction conditions is aprime area of research contributing towardsa cademic interest and industrial application. [69][70][71][72][73][74][75][76][77] The field of MOFs as heterogeneous catalysts for chemical fixation of CO 2 has remained largely untapped and still there is scope for improvement. However,alimited number of MOFs are known for efficient conversion of CO 2 under ambient reaction conditions such as atmospheric pressure, low loading of catalyst/co-catalyst, and room temperature.…”