Design of Borole- and Silylene-Based Frustrated Lewis Pairs for Dinitrogen Activation Promoted by Aromaticity: A Combined DFT and Machine Learning Study

In recent years, while main-group elements from the <i>s</i>- and <i>p</i>-block have emerged in the field of N₂ activation, silylenes─despite their remarkable successes in the activation of diverse small molecules─remain unreported for N₂ activation. Herein, we design "silylene-borole" frustrated Lewis pairs (FLPs) by combining silylene moieties with boron components and conduct comprehensive density functional theory (DFT) calculations to thoroughly investigate their potential for N₂ activation. Screening silylene moieties via machine learning suggests that a smaller Δ<i>E</i>_ST value will benefit N₂ activation thermodynamically. Interestingly, all these designed novel FLPs were found to be kinetically and thermodynamically favorable for N₂ activation, exhibiting low reaction barriers (ranging from 16.9 to 22.5 kcal/mol) and significant exergonicity, with Δ<i>G</i> values ranging from -32.3 to -36.7 kcal/mol. The notable thermodynamic stability of the products, enhanced by aromaticity, coupled with low activation barriers, represents a pivotal advancement in the development of FLP-chemistry for metal-free N₂ activation.