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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-10
H-phenothiazine-3-car
baldehyde. The formed intermediary3,3'-(1
E,1'
E)-2,2'-(2,5-diiodo-1,4-phenylene)
bis(ethene-2,1-diyl)
bis(10-hexyl-10
H-phenothiazine) wasreacted with several different aromatic alkynes (1-
tert-
butyl-4-ethynyl
benzene,
N,
N-di
butyl-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 a
bsorption when exposed to magnesium triflate orzinc triflate. In the case of magnesium triflate, a
blue shift in emission was o
bserved; 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 or
bitals, 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.