A zinc porphyrin polymer as efficient bifunctional catalyst for conversion of CO₂ to cyclic carbonates

Abstract

The design and synthesis of efficient heterogeneous catalysts for catalytic conversion of CO2 are an important challenge. The novel zinc porphyrin polymer reported herein, [ZnPy+CPP‐BTA]I−, is synthesized from trans‐A2B2 porphyrin precursor 5,15‐(4‐carboxyphenyl)‐10,20‐(pyridyl)‐porphyrin (PyCPP) and 1,2,4,5‐benzenetetramine tetrahydrochloride (BTA), employing a sequential post‐synthetic methylation and metalation strategy. The newly synthesized zinc porphyrin polymer was well characterized by Fourier transform infrared spectroscopy (FT‐IR), Ultraviolet–visible spectroscopy (UV–vis), scanning electron microscope (SEM), transmission electron microscope (TEM), thermal gravimetric analysis (TGA), and X‐ray photoelectron spectroscopy (XPS). As bifunctional heterogeneous catalyst incorporated zinc porphyrin and nucleophile I−, [ZnPy+CPP‐BTA]I− shows good catalytic activity and recyclability for the cycloaddition reactions of epoxides and CO2 under lower CO2 initial pressure and cocatalyst‐free conditions.

Ammonium zincates as suitable catalyst for the room temperature cycloaddition of CO2 to epoxides

“…Remarkably, quantitative conversion of terminal epoxides with full selectivity towards the cyclic carbonate have been obtained at low temperature (T = 30 °C) and under just 0.2 MPa of CO 2 pressure. Reactions occur smoothly also at room temperature and under atmospheric CO 2 , at a big difference from most recently reported homogeneous (Tong et al, 2022) and heterogeneous (Nguyen et al, 2022;Su et al, 2022) systems operating without any co-catalyst added and in solvent free conditions, that normally are reported to be most performing at T 80-120 °C.…”

“…It is worth to note that in past literature, when a combination of a Lewis acid (catalyst) and a Lewis base (co-catalyst) have been used to promote the coupling reaction between CO 2 and epoxides, TOF values have been calculated only considering the amount of added catalyst, neglecting the role played by the sole Lewis base (Campisciano et al, 2020). In the search of more efficient catalysts, many recent efforts have been done in the design of materials embedding both Lewis acidic and basic catalytic sites, for the CO 2 cycloaddition reaction under milder reaction conditions, without the addition of any co-catalyst and both homogeneous (Tong et al, 2022) and heterogeneous catalysts (Nguyen et al, 2022;Su et al, 2022) have been reported especially in the last years. It should be noted that most of these catalysts work under solvent-free and ambient pressure CO 2 reaction conditions, however the temperatures required to observe good conversion of the starting epoxide are in the range 80-120 °C.…”

Palladium nanospheres-embedded metal–organic frameworks to enhance the ECL efficiency of 2,6-dimethyl-8-(3-carboxyphenyl)4,4′-difluoroboradiazene in aqueous solution for ultrasensitive Cu2+ detection

“…, AuCl 4 − , Pd 2+ and Pt 2+ ). 25,26 The delocalized π-orbitals and conjugated structure of BTA can be applied to stabilize the total structure or further link with some organic molecules. 27,28 What's more, the BTA-derived MOFs have the ability to link with active Pd 2+ units, which display excellent catalytic activity towards reactive oxygen species (ROS) during the ECL process for advanced emitters.…”

Syntheses, characterizations and catalytic properties of three zinc complexes and one lithium compound chelated by β-diketiminate ligands

“…A number of zinc complexes based on b-diketiminates have been prepared, 29,30 and some of them were active initiators for the ring-opening polymerization of lactide. [31][32][33][34][35] Currently, we discovered that zinc compounds supported by b-diketiminate ligands were active catalysts for the borylation of aryl iodides with B 2 Pin 2 (B 2 Pin 2 = 4,4,4 0 ,4 0 ,5,5,5 0 , 5 0 -octamethyl-2,2 0 -bis(1,3,2-dioxa-borolane)), affording a variety of aryl borates. However, the yields of the coupling reactions for some substrates are not ideal, 12,13 and the factors that influence the catalytic behaviours of the zinc complexes are not very clear.…”