Repurposing Bial’s Reaction to Engender Donor–Acceptor Stenhouse Adducts: A Computational Investigation

Abstract

In pursuing novel photoresponsive materials, we computationally investigated a series of Bial’s reaction-derived Donor–Acceptor Stenhouse Adducts (BialDASAs), comparing them with a prototypical DASA compound, D1A1. We employed density functional theory to elucidate the electronic and geometric factors influencing their photochromic behaviour. Our study confirmed that BialDASA compounds display dual absorption peaks attributed to the π–π∗ transitions, distinct from the single peak of D1A1, reflecting the involvement of the acceptor group in their excited states. Moreover, minimal Bond Length Alternation (BLA) suggested a potential for extended conjugation, consistent across these compounds’ closed and open forms. Analysis of the Z to E isomerization in the excited state indicated a pathway for deactivation via conical intersection, hinting at efficient photoswitching capabilities. Furthermore, the thermodynamic profiles underscored feasible cyclization barrier heights in the ground state, augmented by solvent effects. These findings emphasis the promise of BialDASA molecules as photoswitchable entities and advance our understanding of photochemical mechanisms, providing a scaffold for further experimental validation and application development in molecular electronics and photonics.