Norbornadiene Quadricyclane as Multimode Photoswitches: Synergistic Light and Protonation-Controlled Heat Release.

ABSTRACT: Two low molecular weight acceptor-acceptor norbornadiene (NBD) photoswitches functionalized with meta- and ortho-substituted pyridine and cyano groups are presented. These molecular systems can be converted between four states in response to light, acid, base, and heat. Quantitative conversion to higher energy metastable quadricyclane (QC) photoisomers is achieved upon UV irradiation, with photoisomerization quantum yields of 37% and 24% for NBD 1 and 2. The thermal half-lives, t_1/2, of 70 and 205 days greatly surpass those of previously reported pyridine-functionalized norbornadiene switches, as well as other acceptor-acceptor systems. In particular, the ortho-positioning of the pyridine has a profound effect on the half-life; QC 2 in its unprotonated form has the longest t

SUBMITTER: Aslam AS 

PROVIDER: S-EPMC12487741 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature