Reversible colorimetric switching of thiophene hydrazone based on complementary IMP/INH logic functions

We have synthesized a thiophene hydrazone (receptor 1) that acts as a colorimetric receptor showing a reversible color switching (ON and OFF) function induced by anion and cation recognition. This remarkable color switching is based on two-input complementary IMP/INH logic functions. The (ON and OFF) process of this molecular switch is triggered by an anion (CH3COO-, C6H5COO-, HCOO-, H2PO4- or F-), while it is quenched by any one M-II ion of 3d (d(5)-d(10)) as well as Cd-II and Hg-II. A DMSO solution of receptor 1 underwent a bathochromic shift from 407 to 505 nm upon adding any one of the above-mentioned anions, while switch OFF was achieved by the addition of any one of the above-mentioned cations to regenerate a band at 407 nm.