An Hg2+-gated chiral molecular switch created by using binaphthalene molecules with two anthracene units and two 1,3-dithiole-2-thione (1,3-dithiole-2-one) units.

By integrating the features of anthracene, 1,3-dithiole-2-thione, and binaphthalene units, (S)-1 and its analogue (S)-2, which contains two 1,3-dithiole-2-one units instead of 1,3-dithiole-2-thione, were studied for creating a new molecular regulation system and building a gated chiral molecular switch. The results show that the photodimerization is controlled by the remote functional-group transformation of C=S into C=O, thus providing an elegant example of molecular regulation. The photodimerization of two anthracene units induces circular dichroism (CD) spectral variation. Overall, the CD spectrum can be remotely modulated by Hg2+ in (S)-1, which leads to an Hg2+-gated chiral molecular switch.