For ratiometric "naked eye" detection of CN(-), an ESIPT exhibiting benzothiazole receptor (BHI) is designed having one aldehyde group ortho and the other aldehyde para to the OH group respectively. Due to RAHBs, the ortho aldehyde group is highly reactive undergoing nucleophilic cyanide addition selectively, which hampered ESIPT. This is also supported by DFT and TD-DFT calculations.

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Our designed chemosensor, rhodamine-HBT-dyad (RHD), selectively detects two biologically important ions (Al3+ and Zn2+) at two different wavelengths (red and green, respectively) through FRET and ESIPT in vitro and in vivo.

In this study, we have synthesized a simple Schiff base type isophthaloyl salicylaldehyde hydrazone (ISH) moiety which selectively detects Al(III) and PPi with a fluorescence enhancement at two different wavelengths in aqueous solution. The sensing phenomenon is also reversible and thus the sensor beautifully mimics logic gates (INHIBIT and EXOR gates).

The de-diaminomaleonitrile reaction in a simple carbazole diaminomaleonitrile hybrid (CDH) was promoted by OCl(-) which disrupted the ICT mechanism by breaking the donor and acceptor linkage. This system utilized an irreversible OCl(-) promoted oxidation reaction and it responded instantaneously at room temperature. The chemosensor also showed excellent performance in tap water and the "dip-stick" method.

A new pyrene based fluorescence probe has been synthesized for fluorogenic detection of Cu(2+) in acetonitrile-aqueous media (7 : 3 CH3CN-HEPES buffer, v/v, at pH 7.5) with bioimaging in both prokaryotic (Candida albicans cells) and eukaryotic (Tecoma stans pollen cells) living cells. The anion recognition properties of the sensor have also been studied in acetonitrile by fluorescence methods which show remarkable sensitivity toward fluoride over other anions examined.

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A multifunctional fluorescent chemosensor (PMN) for Al 3+ and Zn 2+ has been developed, which displays a dual-mode and "off-on" fluorescence response upon addition of Al 3+ or Zn 2+ at two different wavelengths.This was possibly due to the inhibition of PET and C]N isomerism, and the activation of chelationenhanced fluorescence (CHEF). Moreover, PMN exhibited a preferential second mode of selectivity for Al 3+ as it ratiometrically displaces Zn 2+ from the [PMN + Zn 2+ ] complex. Such fluorescence modulation behavior mimics the performance of an "OR" logic gate. It also shows an excellent performance in the "dipstick" method.