Use of 5,10‐Disubstituted Dibenzoazaborines and Dibenzophosphaborines as Cyclic Supports of Frustrated Lewis Pairs for the Capture of CO₂

Abstract

The reactivity of 5,10-disubstituted dibenzoazaborines and dibenzophosphaborines towards carbon dioxide was studied at the DFT, M06-2X/def2-TZVP, computational level. The profile of this reaction comprises of three stationary points: the prereactive complex and adduct minima and the transition state(TS) linking both minima. Initial results show that dibenzoazaborines derivatives are less suitable to form adducts with CO 2 than dibenzophosphaborine systems. The influence of the basicity on the P atom and the acidity on the B center of the dibenzophosphaborine in the reaction with CO 2 was also explored. Thus, an equation was developed relating the properties (acidity, basicity and boron hybridization) of the isolated dibenzophosphaborine derivatives with the adduct energy. We found that modulation of the boron acidity allows to obtain more stable adducts than the pre-reactive complexes and isolated monomers.[a] M.

Reactivity of a model of B3P3-doped nanographene with up to three CO2 molecules

“…respectively. As observed in the case of the dibenzophosphaborine 39 , CO 2 is tilted toward the central phenyl ring, due to a π-π stacking between the π-system of the B 3 P 3 -NG and the C=O double bond. The IGMPlot software was used to characterize the interaction between the B 3 P 3 -NG and the CO 2 molecules The transformation of the first pre-reactive complex into the adduct proceeds through a TS with an energy barrier of + 40.2 kJ mol −1 (Fig.…”

“…It is more stable than the entrance channel (B 3 P 3 -NG + CO 2 ) but less stable than the complex. This behavior is common in the interaction between CO 2 and FLPs 31,39,58 .…”

“…4 , the successive fixation of CO 2 molecules is accompanied by a decrease of the activation barrier. In a previous paper, we observed that during the capture of CO 2 by a P/B cyclic FLP, the energy of the TS can be influenced by the basicity of the phosphorus atom 39 . In order to see if the differences in activation energy are related to the increase of phosphorus basicity, we computed Electron Density Shift (EDS) plots of the 1CO 2 -(B 3 P 3 -NG) and 2CO 2 -(B 3 P 3 -NG) adducts, as shown in Fig.…”

“…The potential interaction and activation of carbon dioxide by 5,10-disubstituted dibenzoazaborinines and dibenzophosphaborines intramolecular-FLP was investigated by us recently 39 . It was observed that both were able to interact with CO 2 due to their FLP features.…”

A multi-FLP approach for CO2 capture: investigating nitrogen, boron, phosphorus and aluminium doped nanographenes and the influence of a sodium cation

“…In order to obtain more accurate enthalpies, the electronic energy at the M06-2X/6-311++G(3df,3pd)//M06-2X/6-31+G(d) level was corrected with the thermodynamic terms calculated at the M06-2X/6-31+G(d) level. As proven in previous papers, [65][66][67] these evaluations allow for a better understanding of the acidic and basic properties of the compounds and their interactions with CO 2 .…”