Spiropyran-Based Molecular Photoswitches

Spiropyran is one of the classic photochromic compounds, which undergoes photoisomerization under ultraviolet exposure with its structure transformed from a non-polar, closed and colorless spiro-form to a highly polar, open and colorful cyanine-form with extended π-electron delocalization.This has encourged researchers to employ this material with unique photochemical and photophysical properties as a molecular photoswitch in the field of optoelectronic devices, chemical biosensing, controlled release drug delivery and so on.In this review, noticeable designs, synthesis, properties of some spiropyran derivatives and their applications in relative fields are summarized.Finally, as a promising fluorescent probe, the future developing prospects in bioimaging are discussed and highlighted.