A new rhodamine-based chemosensor for Cu2+ and the study of its behaviour in living cells.

A new rhodamine-based chemosensor (L1) was synthesized, and it exhibits high sensitivity and selectivity for the copper cation over other commonly coexistent metal ions in aqueous solution. Upon the addition of Cu(2+), the spirolactam ring of L1 was opened and a 1 : 1 metal-ligand complex was formed. Fluorescent imaging of Cu(2+) in living cells is also successfully demonstrated.