Molecules that respond to input stimulations to produce detectable outputs can be exploited to mimic Boolean logic operators and reproduce basic arithmetic functions. We have designed a two-state fluorescent probe with tunable emission wavelength for the construction of a molecular logic gate with reconfigurable single-or dual-output capability. The system is based on a BODIPY skeleton coupled with 4-(dimethylamino)benzaldehyde. The behavior of the molecular logic gate can be easily investigated in solution with fluorescence spectroscopy, and the optical readout (fluorescence) can be monitored in one (green) or two (green and red) channels. Depending on the solvent of choice, single INHIBIT or dual INHIBIT/IMPLY logic functions can be achieved using chemical inputs (acid and base). Reconfiguration from single-to dual-output is thus made possible by operating the system in acetonitrile (single output) or toluene (dual output), respectively. The logic gate can be switched by manipulating the fluorescence emission via protonation or deprotonation, even when immobilized onto a glass substrate. At the solid state, the resulting output can be stored for extended periods of time. This feature provides two added benefits: (i) memory function and (ii) "set/reset" capability of the logic gate. Our design thus provides a proof-of-concept interface between the molecular and electronic domains.

Photochemical reactions that produce a detectable change in the spectroscopic properties of organic chromophores can be exploited to harness the principles of Boolean algebra and design molecule-based logic circuits. Moreover,...

The design and synthesis of a microporous construct based on the entrapment of an emissive fluorescein derivative in a zinc 2-methylimidazolate (ZIF-8) metal-organic framework (MOF) is detailed. Synthesis of the MOF in the presence of a fluorophore enables the capture and dispersal of dye molecules within the ZIF-8 framework. Within the resulting supramolecular assemblies, the fluorophore components show excellent photophysical properties such as high emission and increased fluorescence lifetime, despite the tendency of the dye to undergo aggregation-caused quenching in the solid-state, as well as a 4-fold enhancement of the fluorophore’s photostability. The demonstration that supramolecular events can be invoked to construct solid fluorescent systems from separate components is realized. The encapsulation of the fluorescein in an enclosed subunit of the ZIF-8 framework was modelled using the density-functional tight-binding method. Furthermore, the fluorophore@MOF composite can be internalized by mammalian macrophage cells and transported to lysosomes without disrupting cell viability. In principle, this simple protocol can evolve into a general strategy for intracellular delivery of functional molecular components for targeted bioimaging or theranostic applications.

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