Intramolecular Hydrogen Bonds Enhance Disparity in Reactivity between Isomers of Photoswitchable Sorbents and CO₂: A Computational Study

Abstract

Reducing the emission of greenhouse gases, such as CO2 , requires efficient and reusable capture materials. The energy for regenerating sorbents is critical to the cost of CO2 capture. Here, we design a series of photoswitchable CO2 capture molecules by grafting Lewis bases, which can covalently bond CO2 , to azo-based backbones that can switch configurations upon light stimulation. The first-principles calculations demonstrate that intramolecular hydrogen bonds are crucial for enlarging the difference of CO2 binding strengths to the cis and trans isomers. As a result, the CO2 -sorbent interaction can be light-adjusted from strong chemical bonding in one configuration to weak bonding in the other, which may lead to a great energy reduction in sorbent regeneration.

Size effect on the adsorption and dissociation of CO2 on Co nanoclusters

“…In recent years, in addition to the capture and storage technology [1][2][3][4][5][6][7], the recycling technology for CO2, a major greenhouse gas, has attracted considerable interest. A promising route for relieving the greenhouse effect is to convert CO2 into CO, which has been widely investigated in the recycling technology.…”

Cation-assisted interactions between N-heterocycles and CO2

“…[16][17][18][19][20] It is well-known that anionic NHCs (non-carbenes) dominate the reactions with CO 2 , while the charge balancing cations only exhibit limited secondary effects. 4,15,[21][22][23][24][25][26][27] However, in some cases, the cation effects are indispensable. Very recent experiments by He and Dai groups have revealed that the weakly basic salts composed of lithium or potassium and organic bases can nearly 1 : 1 stoichiometrically react with CO 2 by forming stable zwitterionic carbamate adducts through multidentate coordination between the metal cation and organic base.…”

Molecularly engineered switchable photo-responsive membrane in gas separation for environmental protection

“…For an example, Tang et al [70] had utilised AZB as the base in the backbones in conjunction with Lewis bases by covalently bonding them to design novel photo-switchable sorbents for CO 2 capture. Results demonstrated that the difference in binding strength between the designed molecules and CO 2 was hardly affected by electronic and steric effects.…”