Metal-free catalytic conversion of CO₂into methanol: local electrophilicity as a tunable property in the design and performance of aniline-derived aminoborane-based FLPs

Abstract

A deeper computational mechanistic study of a more environmentally friendly metal-free CO2 reduction process towards obtaining methanol is presented, employing a previously tested kind of intramolecular Frustrated Lewis Pair (2-[bis(R)boril]-N,N-dimethylaniline-based)...

New insights into H2activation by intramolecular frustrated Lewis pairs based on aminoboranes: the local electrophilicity index of boron as a suitable indicator to tune the reversibility of the process

“…Finally, the comparison between the Δ G H 2 ↔ ω B + relationship found in this work with that found in the previous work 33 to see differences when considering a larger set of reactions is discussed in more detail in the ESI †. Thus, it is recommended to use our new relationship between Δ G H 2 and ω B + , which is a more general expression since it takes into account a larger set of systems, being valid for a wide range of ω B + values.…”

“…Recently, it has been shown that the local electrophilicity condensed on the boron atom (u B + ) is inversely related to the Gibbs free energy of the H 2 activation using a 2-[bis(R)boryl]-N,Ndimethylaniline-based FLP, 33 i.e., the higher the u B + value, the more exergonic the process is, where u B + was then proposed as a measure of the Lewis acidity of the B atom. Note that in that study, the substitution of the N atom was not varied.…”

“…Consequently, in this work, we have centered our efforts on studying a broader set of systems in which both boron and nitrogen substituents have been modified to analyze how changes in boron acidity, nitrogen basicity, and the electronic nature of the linker affect the ω B + ↔ Δ G H 2 relationship recently found by us. 33 For this, a series of electron-withdrawing groups (EWGs) were employed in boron (X) and electron-donating groups (EDGs) in nitrogen (Y) to be changed systematically. As EWGs, trifluoromethyl ( CF 3 ), pentafluorophenyl ( C 6 F 5 ), nonafluoro- tert -butyl, also known as perfluoro- tert -butyl ( PF t B ), and 2,4,6-tris(trifluoromethyl)phenyl ( FMes ) were considered, whereas as EDGs, methyl ( CH 3 ), tert -butyl ( t -but ), phenyl ( Ph ), and mesityl ( Mes ) were studied.…”

Computational insights into CO2binding reactions by intramolecular geminal group-IV+/phosphorus- and zirconium+/group-15-based frustrated Lewis pairs

“…(5) Our ASM examinations indicate that the structural deformation energy of CO 2 is the primary factor influencing the activation barrier of the binding reaction between intramolecular geminal M + /G15-based FLP-type molecules and CO 2 . 117 (6) Our study of the CO 2 binding reaction using intramolecular geminal M + /P-based or Zr + /G15-based FLPs demonstrates that the presented computational results are consistent with the Hammond hypothesis, which states that an earlier transition state corresponds to a lower free energy barrier, while a later transition state corresponds to a higher free energy barrier.…”

“…(5) Our ASM examinations indicate that the structural deformation energy of CO 2 is the primary factor influencing the activation barrier of the binding reaction between intramolecular geminal M + /G15-based FLP-type molecules and CO 2 . 117…”