A ninhydrin based colorimetric molecular switch for Hg2+ and CH3COO−/F−

We have prepared a new ninhydrin-based colorimetric molecular switch (receptor 1) which gets ‘ON’ (blue) in the simultaneous presence of Hg2+ and CH3COO−/F− while the absence of any one among them leads the system ‘OFF’ (purple). The switching is highly specific in terms of its inputs as no other ion pairs were able to do the same. The corresponding UV–vis spectral changes involve a bathochromic shift in the charge transfer (CT) band of receptor 1 from 535 to 590 nm and get fitted to AND logic function. In the light of involvement of Hg(CH3COO)2 as a catalyst in a number of organic reactions, receptor 1 is quite promising.