A red fluorescence 'off-on' molecular switch for selective detection of Al3+, Fe3+ and Cr3+: experimental and theoretical studies along with living cell imaging

A spirobenzopyran-quinoline (SBPQ) based sensor was synthesized which selectively detects trivalent ions viz. Al3+, Fe3+ and Cr3+ through a fluorescence turn on signal in the red region (similar to 675 nm) with the detection limit in the order of 10(-8) M. The potentiality of the probe was confirmed by employing it for fluorescence bio-imaging with Al3+ in three different types of live-cells.