Highly Emissive Perylene Diimide-Based Metallacages and Their Host–Guest Chemistry for Information Encryption

Here
we report two highly emissive perylene diimide (PDI)-based
metallacages and explore their complexation with polycyclic aromatic
hydrocarbons, such as pyrene, triphenylene, and perylene. The fluorescence
quantum yields of metallacages exceed 90% and their binding constants
with perylene can reach as high as 2.41 × 104 M–1 in acetonitrile. These features enable further tuning
of the emission of the host–guest complexes to obtain white-light
emission based on the complementary orange emission of the metallacages
and the blue emission of perylene. Moreover, owing to the huge differences
of their quantum yields in solution and in the solid state, the host–guest
complexes are successfully employed for information encryption. This
study offers a general approach for the construction of emissive metallacages
and explores their application for information encryption.