| Abstract
| - We report the synthesis and characterization of five novel phenothiazine-containing cruciforms (5−9).The targets were prepared by a NaH-promoted Horner reaction of tetraethyl(2,5-diiodo-1,4-phenylene)bis(methylene)diphosphonate with 10-hexyl-10H-phenothiazine-3-carbaldehyde. The formed intermediary3,3‘-(1E,1‘E)-2,2‘-(2,5-diiodo-1,4-phenylene)bis(ethene-2,1-diyl)bis(10-hexyl-10H-phenothiazine) wasreacted with several different aromatic alkynes (1-tert-butyl-4-ethynylbenzene, N,N-dibutyl-4-ethynylaniline, 1-ethynyl-3-(trifluoromethyl)benzene, and 1-ethynyl-3,5-bis(trifluoromethyl)benzene) to give thecorresponding cruciform fluororphores (XF). The XFs were fully characterized by NMR and IRspectroscopy and then exposed to trifluoroacetic acid as well as to several metal triflates. The XFs showdramatic shifts in emission and to a lesser extent in absorption when exposed to magnesium triflate orzinc triflate. In the case of magnesium triflate, a blue shift in emission was observed; in contrast, additionof zinc triflate results in either quenching or a red-shifted emission. Due to the electronic situation, theseXFs display spatially separated frontier molecular orbitals, allowing the HOMO or the LUMO of theXFs to be addressed independently by addition of zinc or magnesium ions. Phenothiazine XFs may havepotential in array-type sensory applications for metal cations.
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