Photoswitching of arylazopyrazoles upon S₁ (nπ*) excitation studied by transient absorption spectroscopy and ab initio molecular dynamics

Abstract

Arylazopyrazoles (AAPs) are an important class of molecular photoswitches with high photostationary states (PSS) and long thermal lifetimes. The ultrafast photoisomerization of four water-soluble arylazopyrazoles, all of them featuring an...

Structure, Dynamics, and Reactivity of Encapsulated Molecules in Restricted Spaces: Arylazoisoxazoles within an Octa Acid Capsule

“…To the best of our knowledge, there are only very few ultrafast timeresolved study on azoheteroarene, but none on arylazoisoxazoles. 30,85 These studies propose that the isomerization of the N�N bond occurs via a hula-twist of the phenyl part of the molecule. 86−91 Due to lack of further knowledge, we assume the same mechanism also holds during the photoisomerization of arylazoisoxazoles in solution and within an OA capsule.…”

“…Given the current surge in evidence in favor of hula-twist mechanism during cis−trans isomerization, this process cannot be ignored in arylazoisoxazoles. 80,85,87,89,90,92,93 Especially within the confined space of the OA capsule volume conserving hula-twist mechanism is likely. We are aware that only ultrafast time-resolved experiments and high-level computations can provide an in-depth and unequivocal understanding of the photoisomerization process in solution and within an OA capsule.…”