Near-IR region absorbing 1,4-diaminoanthracene-9,10-dione motif based ratiometric chemosensors for Cu2+

1,4-Bis[2-aminoethylamino]anthracene-9,10-diones selectively bind with Cu2+ to form complexes with unusual selectivity under basic conditions. The deprotonation of the aryl amine NH in the case of these chemosensors causes a bathochromic shift in the absorption band from 585 nm and 635 nm to 725 nm and enables ratiometric estimation of Cu2+ between pH 8 and 12.