The first fully connected aromatic
carbaporphyrin dimer (6) and its bis-Pd complex (6-Pd
2
) that bear a rigid naphthalene
motif as an internal strap
were synthesized. These dimers consisted of two aromatic carbaporphyrins
that shared a naphthalene motif. The π-electron conjugation
of the obtained macrocycles was proposed to have two separated local
22 π-electron pathways and a 34 π-electron pathway. Their
weak aromaticity was fully supported by 1H NMR spectroscopy,
NICS values, ACID calculations, and ICSS plots.
Allyliporphyrin is a carbaporphyrin that has replaced one pyrrole with an allyl group. Dynamic behavior (bond rotation) was observed by variable temperature H NMR and 2D-NOESY NMR spectroscopy and theoretically examined by DFT calculations. These studies revealed that well-defined bond rotation was first observed in the limited space of the carbaporphyrin from 2 through cis-2 and the calculated rotational barrier was low enough, with the relative energy level of cis-2 only 0.65 kcal mol higher than 2. The synthesized allyliporphyrin (2) is a strongly aromatic macrocycle as indicated by the chemical shifts of its inner NH and CH signals. However, its palladium complex displayed reduced aromaticity due to the tilted thiophene of Pd-2.
The first aromatic benzicorrole termed naphthicorrole
was synthesized
with a carbon donor containing more than six members. Its oxidized
(enedione-embedded) porphyrinoid was also obtained using different
meso-aryl substitutions under sequential oxidation conditions. The
resulting enedione motif of the nonaromatic porphyrinoid was regioselective
to the C2 position for S or N nucleophiles. Thus, the oxidized porphyrinoid
was tested as a built-in linker for biomolecules. The progress of
the reaction was visually monitored due to their different conjugation
pathways.
A tolan derivative was synthesized as a fluorescent and cooperative ion pair receptor. As both Na and HSO ions were complexed to the receptor, only substantial fluorescence was quenched. Thus, it also acts as a logic AND gate.
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