Design and synthesis of three new D-A multifunctional stimulus response compounds

Three new compounds {[(bcbpy)2]·10H2O}n (1), {[(H2bcbpy)(H2btec)(NaOH)(H2O)]·H2O}n (2), {Cd(bcbpy)0.5(btec)0.5(H2O)}n (3) were synthesized under hydrothermal conditions in the presence of viologen 1,1′-bis (3-carboxybenzyl)-4,4′-bipyridinium dichloride (H2bcbpy·2Cl), 1,2,4,5-Benzenetetracarboxylic acid (H4btec) and different metal salts. Interestingly, it has been found that the structure of the three compounds depends on metal salts. All three compounds exhibited photochromic properties under the irradiation of a 300 W xenon lamp, compound 1 changed from yellow to dark green, compound 2 changed from light yellow to blue, and compound 3 changed from light gray to blue. Due to the influence of intermolecular D-A distance, π-π interaction, intermolecular hydrogen bond and metal ions, there are sensing differences among the three compounds, and their light response rates are 1 > 2 > 3. It is worth noting that all three compounds produce color changes under ammonia vapor, and the fluorescence quenching effect of compound 1 can also be observed under the action of Cr2O72- anion.