Hydrogen
bonds not only play a crucial role in the life sciences
but also endow molecules with fantastic physical and chemical properties,
which help in the realization of their high-tech applications. This
work presents an efficient strategy for achieving highly efficient
solid-state dual-emission blue emitters with mechanical force-induced
enhanced emission properties via intermolecular hydrogen bonds via
novel pyrene-based intermediates, namely, 1,3,6,8-tetrabromo-2,7-dihydroxypyrene
(1) and 1,3,6,8-tetrabromo-2-hydroxypyrene (2), prepared via hydroxylation and bromination of pyrene in high yields.
Moreover, further use of a classical Pd-catalyzed coupling reaction
affords new pyrene-based luminescent materials 3–5, which display high thermal stability (in range of 336–447
°C), blue emission (<463 nm), and high quantum yields in solution.
Interestingly, with the monosubstituted hydroxyl (OH) or methoxy (OMe)
group located at position 2 of pyrene, compounds 4a and 5 display exciting dual emission with mechanical force-induced
enhanced emission properties, due to the presence of several hydrogen-bond
interactions. Moreover, this series of compounds exhibits numerous
advantages, for example, deeper blue emission with a narrower full
width at half-maximum, a stronger steric effect, and higher hydrophilicity.
Thus, these novel bromopyrene intermediates and related pyrene-based
luminescent materials will pave the way for further exploration of
novel organic solid-state luminescent materials for potential application
in organic electronics, bioimaging, chemosensors, etc.