Photoinduced tuning of (anti)aromaticity and associated molecular properties is currently
in the focus of attention for both tailoring photochemical reactivity and designing
new materials. Here, we report on the synthesis and spectroscopic characterization
of diarylethene-based molecular switches embedded in a biphenylene structure composed
of rings with different levels of local (anti)aromaticity. We show that it is possible
to modulate and control the (anti)aromatic character of each ring through reversible
photoswitching of the aryl units of the system between open and closed forms. Remarkably,
it is shown that the irreversible formation of an annulated bis(dihydro-thiopyran)
side-product that hampers the photoswitching can be efficiently suppressed when the
aryl core formed by thienyl groups in one switch is replaced by thiazolyl groups in
another.
