This work describes the synthesis and characterization of a series of arenephosphonic acid salts for use as water soluble down-converters in optogenetic assays.
Two phosphonate salts based on anthracene and naphthalene were synthesized through
cleavage of phosphonate esters. A third amphiphilic salt, developed from a long-alkylchain modified naphthalene, was produced in the same manner to demonstrate micelle
formation. Two techniques were used to determine if any of the salts showed micelle
behavior: 31P NMR and fluorescence spectroscopy. Interestingly, all three compounds
exhibited micelle formation in water. UV-induced fluorescence of NapPONa and
AntPONa revealed a secondary emission profile with maximum excitation wavelengths
that lie on top of the primary emission profile. This secondary emission can be attributed
to the emission of the micellular structure based on solid-state fluorescence experiments.
Moderate x-ray induced radioluminescence was observed in the solid forms of each
compound. A solution of amphiphilic NapPONa demonstrated both concentrationdependent and micelle-dependent radioluminescence, indicating the positioning of
aromatic rings in a micelle is inducive to a radioluminescent response. Furthermore, the
emission wavelength of this compounds lies on top of the excitation wavelength of
channelrhodopsin-2, a well-studied optogenetic target.
InstitutionUniversity of Alabama at Birmingham
ORCID For Submitting Author0000-0002-3147-5872
Declaration of Conflict of InterestNo Conflicts of Interest