Discovery of EDA-Complex Photocatalyzed Reactions Using Multidimensional Image Processing: Iminophosphorane Synthesis as a Case Study

Herein, we report a multidimensional screening strategy for the discovery of EDA-complex photocatalyzed reactions using only photographic devices (webcam, cellphone) and TLC analysis. An algorithm was designed to identify automatically EDA-complex reactive mixtures in solution from digital image processing in a 96-wells microplate and by TLC-analysis. The code highlights the region of absorption of the mixture in the visible spectrum, and the quantity of the color change through grayscale values. Furthermore, the code identifies automatically the blurs on the TLC plate and classifies the mixture as colorimetric reactions, non-reactive or potentially reactive EDA mixtures. This strategy allowed us to discover and then optimize a new EDA-mediated approach for obtaining iminophosphoranes in up to 90% yield.

Extended Ensemble Molecular Dynamics Study of Cellulose I–Ethylenediamine Complex Crystal Models: Atomistic Picture of Desorption Behaviors of Ethylenediamine

Cellulose I crystals swell on exposure to ethylenediamine (EDA) molecules to form a cellulose I–EDA complex, and successive extraction of EDA molecules converts the complex crystalline phase to either original cellulose I or cellulose IIII, depending on the treatment procedure. The present study reports the extended ensemble molecular dynamics (MD) simulation of the cellulose I–EDA complex models. An accelerated MD simulation allows most of the EDA molecules to desorb from the crystal model through a hydrophilic channel between the piles of cellulose chains, one at a time. Migration of a single EDA molecule along the channel is simulated by the adopted steered MD method combined with the umbrella sampling method to evaluate the potential of mean force (PMF) or free energy change on its movement. The PMF continues to increase during the migration of an EDA molecule to give a final PMF value of more than 30 kcal/mol. The PMF profiles are largely lowered by the removal of EDA molecules in the neighboring channels and by the widening of the channel. The former suggests that the EDA desorption cooperates with that in the neighboring channels, and, in the latter case, an EDA migration is efficiently promoted by solvation with water molecules in the expanded channel. We conclude that the atomistic picture of the EDA desorption behaviors observed in the crystal models is applicable to the real crystalline phase.

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

The reversible, weak ground-state aggregate formed by dipole–dipole interactions between an electron donor and an electron acceptor is referred to as an electron-donor–acceptor (EDA) complex. Generally, upon light irradiation, the EDA complex turns into the excited state, causing an electron transfer to give radicals and to initiate subsequent reactions. Besides light as an external energy source, reactions involving the participation of EDA complexes are mild, obviating transition metal catalysts or photosensitizers in the majority of cases and are in line with the theme of green chemistry. This review discusses the synthetic reactions concerned with EDA complexes as well as the mechanisms that have been shown over the past five years.

Photoexcited Halogen Bonding EDA Complex of Thiophenolate Anion with Iodobenzene for C(sp3)–H Activation and Thiolation

The thiophenol was discovered to form an EDA complex with iodobenzene through halogen bonding interactions upon treatment with KOH. A direct photochemical thiolation of C(sp3)–H bonds containing etheric, allylic, and...

Visible-light-induced surfactant-promoted sulfonylation of alkenes and alkynes with sulfonyl chloride by the formation of EDA-complex with NaI in water at room temperature

A green and efficient visible-light-induced iodosulfonyl reaction of alkenes in water using EDA complex strategy at room temperature has been disclosed. The addition of anionic surfactant allows the formation of...

Correction: A photoexcited halogen-bonded EDA complex of the thiophenolate anion with iodobenzene for C(sp3)–H activation and thiolation

Correction for ‘A photoexcited halogen-bonded EDA complex of the thiophenolate anion with iodobenzene for C(sp3)–H activation and thiolation’ by Tao Li et al., Chem. Sci., 2021, DOI: 10.1039/d1sc03667j.

Direct excitation strategy for radical generation in organic synthesis

This tutorial review encompasses the radical generation based on classical methods and photoredox catalysis. It will also focus on radical generation only demanding visible-light, which involves EDA complex and direct photo-excitation strategy.