Two-Photon-Induced [2 + 2] Cycloaddition of Bis-thymines: A Biocompatible and Reversible Approach

Abstract

Despite having great value across a wide variety of scientific fields, two-photon polymerizations currently suffer from two significant problems: the need for photoinitiators, which generate toxic side products, and the irreversibility of the process. Hence, the design of a versatile approach that circumvents these issues represents a major scientific challenge. Herein, we report a two-photon absorption strategy where reversible [2 + 2] cycloaddition of bis-thymines was achieved without the need for any photoinitiator. The cycloaddition and cycloreversion reactions could be induced by simply changing the irradiation wavelength, and repeated writing and erasing cycles were performed. The simplicity, reversibility, and biocompatibility of this strategy open up a whole new toolbox for applications across a wide variety of scientific fields.

Beyond the Conventional Limitation of Photocycloaddition Reaction in the Roomy Nanospace of a Metal–Organic Framework

“…[2+2] photocycloaddition is a representative dimerization reaction in which the influence of the reactants’ spatial location on the reactivity in the solid state has been well studied. ,,− It forms a cyclobutane ring between two carbon–carbon double bonds upon photoirradiation. In the liquid phase, a mixture of four regio- and stereospecific cyclization products ( syn -HH, anti -HH, syn -HT, and anti -HT) are often produced .…”