Step Forward to Stronger Neutral Organic Superbases: Fused Troponimines

作者：Kayvan Saadat, Ali Shiri, Borislav Kovačević · 发表于：The Journal of Organic Chemistry · 年份：2020 · DOI：10.1021/acs.joc.0c01466 · 被引用次数：16 · 研究领域：Coordination Chemistry and Organometallics、N-Heterocyclic Carbenes in Organic and Inorganic Chemistry、Chemical Reaction Mechanisms

In this study, using a computational approach, we are pursuing to find a proper answer about the possible application of fused TIs as superbases through the calculation and discussion of standard thermochemistry parameters, like gas-phase basicity (GB) and proton affinity (PA). In some studied cases, the role of aromaticity/antiaromaticity fluctuations supposed to be more important than mesomeric effects. In this sense, nucleus-independent chemical shift (NICS) and anisotropy of the induced current density (ACID) were utilized in this study to probe into the aromaticity-related parameters of the proposed molecules. Results revealed the highest GB/PA values for the molecules having cyclobutadiene in between two troponimines. Additional investigation was performed into the other candidates of cyclobutadiene-fused troponimines by substituting several electron donors along with the changing position of donors. Some novel superbases offered record-holding GB/PA values so that PA magnitudes higher than 300 kcal mol –1 are now feasible for nonphosphorous neutral organic superbases (NOS).