By combining the versatile electrochemical behavior of cobalt-based metallacarboranes with the excellent emission properties of perylenediimides, new fluorescent molecular switches were prepared that respond to redox stimuli. These systems not only surpass the performance of previous switches based on other metal complexes, but also allow the preparation ofsupramolecular fluorescent gels by taking advantage of the self-assembly capabilities of their constituting units.

The cover illustrates a "switch" and its two states: ON (fluorescent state) and OFF (non-fluorescent state), which is related to the Cobalt oxidation state. 

Read more:

More information can be found in the Full Paper by R. Núñez, J. Hernando, et al.:

Reversibly switchable fluorescent molecular systems based on metallacarborane‐perylenediimide conjugates
Laura Parejo, Mahdi Chaari, Sara Santiago, Gonzalo Guirado, Francesc Teixidor, Rosario Núñez, Jordi Hernando
Chemistry A European Journal, 2020
Article: DOI: 10.1002/chem.202002419
Cover: DOI: 10.1002/chem.202003598

Or you can read the press release "Smart fluorescent molecular switches based on boron-based compounds" published in our website (Oct 2020).