Rhodamine-based "turn-on" fluorescent probe with high selectivity for Fe2+ imaging in living cells

A rhodamine-based "turn-on" fluorescent probe 1 was synthesized with high yield. The recognizing behavior displays high selectivity of 1 toward Fe2+ with a 2:1 complex, and 1 exhibits a stable response for Fe2+ over a concentration range from 2 mu M to 24 mu M. Most importantly, probe is hardly interfered by other transition metal ions. Their fluorescent enhancement is observed in the presence of Fe2+ because of the ring-open interactions of spirocyclic. All measurements are made in PBS buffer environments simulating biological conditions to make them suitable candidates for fluorescent labeling of biological systems. Confocal laser scanning microscopy experiments have proven that probe can be used to monitor Fe2+ in living cells. (c) 2013 Elsevier Inc. All rights reserved.