Y–H bond functionalization has always been the focus of research interest in the area of organic synthesis. Direct hydrogen atom transfer (HAT) from the Y–H bond is one of the most efficient and practical methods to activate the Y–H bond. Recently, nitrogen centered radical cations were broadly utilized as H-abstraction catalysts to activate Y–H bonds via the HAT process. As a type of HAT catalyst, the H-affinity of nitrogen centered radical cations is a significant thermodynamic parameter to quantitatively evaluate the thermodynamic H-abstraction potentials of nitrogen centered radical cations. In this work, the pK_a values of 120 protonated N-containing compounds in acetonitrile (AN) are predicted, and the H-affinities of 120 nitrogen centered radical cations in AN are derived from the reduction potentials of nitrogen centered radical cations and pK_a of protonated N-containing compounds using Hess’ law. This work focuses on the H-abstraction abilities of 120 nitrogen centered radical cations in AN to enrich the molecule library of novel HAT catalysts or H-abstractors and provides valuable thermodynamic guidelines for the application of nitrogen centered radical cations in Y–H bond functionalization.

Dipines are a type of important antihypertensive drug as L-calcium channel blockers, whose core skeleton is the 1,4-dihydropyridine structure. Since the dihydropyridine ring is a key structural factor for biological activity, the thermodynamics of the aromatization dihydropyridine ring is a significant feature parameter for understanding the mechanism and pathways of dipine metabolism in vivo. Herein, 4-substituted-phenyl-2,6-dimethyl-3,5-diethyl-formate-1,4-dihydropyridines are refined as the structurally closest dipine models to investigate the thermodynamic potential of dipine oxidative metabolism. In this work, the thermodynamic cards of dipine models’ aromatization on 21 potential elementary steps in acetonitrile have been established. Based on the thermodynamic cards, the thermodynamic properties of dipine models and related intermediates acting as electrons, hydrides, hydrogen atoms, protons, and two hydrogen ions (atoms) donors are discussed. Moreover, the thermodynamic cards are applied to evaluate the redox properties, and judge or reveal the possible oxidative mechanism of dipine models.

Thermodynamic cards of three classic NADH models (XH), namely 1-benzyl-1,4-dihydronicotinamide (BNAH), Hantzsch ester (HEH), and 10-methyl-9,10-dihydroacridine (AcrH), as well as their photoexcited states (XH*: BNAH*, HEH*, AcrH*) releasing hydrides in nine elementary steps in acetonitrile are established. According to these thermodynamic cards, the thermodynamic reducing abilities of XH* are remarkably enhanced upon photoexcitation, rendering them thermodynamically highly potent electron, hydrogen atom, and hydride donors. The application of these thermodynamic cards to imine reduction is demonstrated in detail, revealing that photoexcitation enables XH* to act as better hydride donors, transforming the hydride transfer process from thermodynamically unfeasible to feasible. Most intriguingly, AcrH* is identified as the most thermodynamically favorable electron, hydride, and hydrogen atom donor among the three classic NADH models and their photoexcited states. The exceptional thermodynamic properties of XH* in hydride release inspire further investigation into the excited wavelengths, excited potentials, and excited state stabilities of more organic hydrides, as well as the discovery of novel and highly effective photoexcited organic hydride reductants.

Traditionally employed as hydrogenation reagents, benzothiazolines have emerged as versatile carbanion and radical transfer reagents, playing a vital role in the construction of various carbon–carbon bonds. The cutting-edge progress in photochemistry and radical chemistry have prompted the study of visible light-driven radical reactions, bringing benzothiazolines into a vibrant focus. Their chemical processes have been uncovered to encompass a variety of activation mechanisms, with five distinct modes having been identified. This work reviews the innovative applications of benzothiazolines as donors of alkyl or acyl groups, achieving hydroalkylation or hydroacylation and alkyl or acyl substitution. By examining their diverse activation mechanisms, this review highlights the potential of benzothiazolines serving as alkyl and acyl groups for further research and development. Moreover, this review will offer exemplary applications and inspiration to synthetic chemists, contributing to the ongoing evolution of benzothiazolines utility in organic synthesis.