Baso-chromic Spiro pyrrolizine: the spiro-merocyanine isomerization and alkaline detection

Abstract A novel baso-chromic spiropyrrolizine displaying isomerization between the spiro and the merocyanine isomer have been designed. The baso-chromic behavior shows that the baso-cyclization is induced by organic/inorgainc base, affording the ring-closed isomer. In this process, base condition not only controls the formation of spiroisomer, but also it induces dramatic changes in both absorption and emission. It was evidenced by 1H NMR and DFT calculation to show the present of pyrrolizine.