The fixation of CO₂ by epoxides over nickel-pyrazolate-based metal–organic frameworks

Abstract

CO2 emission reduction is one of the major concerns of human beings. The cycloaddition of CO2 and epoxide into cyclic carbonate is a promising reaction for reducing atmospheric CO2 meanwhile...

Ionothermal Synthesis of Metal‐Organic Frameworks Using Low‐Melting Metal Salt Precursors**

“…Encouraged by the successful synthesis of several triazolate frameworks under ionothermal conditions, we next investigated the generality of this strategy towards the synthesis of frameworks constructed from more basic pyrazolate linkers. One such framework of interest is Ni 3 (btp) 2 (btp 3− =4,4′,4′′‐(benzene‐1,3,5‐triyl)tris(pyrazolate)), which is a thermally and chemically robust MOF bearing coordinatively unsaturated square planar Ni II centers that is capable of catalyzing the solvent‐free cycloaddition of CO 2 and epoxides to form cyclic carbonates (Figure 3, see Supporting Information Section 6 for details) [11, 52] . The traditional solvothermal synthesis of Ni 3 (btp) 2 employs Ni(OAc) 2 ⋅4H 2 O as the metal precursor and is carried out in dilute DMF (0.05 M) [11] .…”

Ionothermal Synthesis of Metal‐Organic Frameworks Using Low‐Melting Metal Salt Precursors**

“…(btp 3À = 4,4',4''-(benzene-1,3,5triyl)tris(pyrazolate)), which is a thermally and chemically robust MOF bearing coordinatively unsaturated square planar Ni II centers that is capable of catalyzing the solventfree cycloaddition of CO 2 and epoxides to form cyclic carbonates (Figure 3, see Supporting Information Section 6 for details). [11,52] The traditional solvothermal synthesis of Ni 3 (btp) 2 employs Ni(OAc) 2 •4H 2 O as the metal precursor and is carried out in dilute DMF (0.05 M). [11] Switching from Ni(OAc) 2 •4H 2 O, which decomposes upon heating, to NiCl 2 •6H 2 O as the metal precursor and reaction medium enabled the ionothermal synthesis of Ni 3 (btp) 2 -IT under the same conditions employed to prepare Ni 2 Cl 2 (btdd)-IT (Figure 3).…”

Nickel Supported on Mesoporous Organosilica Nanoparticles Incorporating Pyridine-Based SNS Ligand as an Efficient Recoverable Catalyst for Chemical Fixation of CO2

“…39 Despite the amount of catalyst loading was not reported, a well-defined homogeneous molecular Ni(salphen) catalyst incorporated into a MOF structure, was found to be an efficient and recyclable heterogeneous catalyst for the synthesis of styrene carbonate in 80% yield in the presence of 3 mol % TBAB, 20 bar CO 2 at 80 °C within a short reaction time of 4 h. 40 He et al reported that the Ni(II)-based coordinated frameworks efficiently catalyzed the cycloaddition of CO 2 with styrene oxide with S/C of 300 in the presence of 5 mol % tetrabutylammonium bromide (TBAB) as a cocatalyst at 40 °C within 40 h. 41 By using 8.5 mol % TBAB and 5 bar CO 2 at 80 °C, Wang et al described that a Ni-pyrazolate-based metal−organic framework could effectively catalyze cycloaddition of carbon dioxide and styrene oxide with S/C of 200. 42 The propylene carbonate in excellent yield could be obtained by using NiO supported on the modified-TiO 2 nanoparticles with a S/C of 250 when 4 mol % TBAI as cocatalyst under solvent-free conditions under 10 bar CO 2 at 100 °C within 5 h were adopted. 43 Ni(acac) 2 chemically bonded to amine-modified starch displayed excellent activity when a S/C of 100, 1 mol % TBAB, 10 bar CO 2 at 50 °C within the short reaction time of 1.5 h were operated as the reaction conditions.…”

“…He et al reported that the Ni­(II)-based coordinated frameworks efficiently catalyzed the cycloaddition of CO 2 with styrene oxide with S/C of 300 in the presence of 5 mol % tetrabutylammonium bromide (TBAB) as a cocatalyst at 40 °C within 40 h . By using 8.5 mol % TBAB and 5 bar CO 2 at 80 °C, Wang et al described that a Ni-pyrazolate-based metal–organic framework could effectively catalyze cycloaddition of carbon dioxide and styrene oxide with S/C of 200 . The propylene carbonate in excellent yield could be obtained by using NiO supported on the modified-TiO 2 nanoparticles with a S/C of 250 when 4 mol % TBAI as cocatalyst under solvent-free conditions under 10 bar CO 2 at 100 °C within 5 h were adopted .…”