2 research outputs found
Pentaleno[1,2‑<i>a</i>:4,5′]diacenaphthylenes: Uniquely Stabilized Pentalene Derivatives
We
demonstrate the preparation of diacenaphthoÂpentalene derivatives
via a palladium-catalyzed dimerization of 1-iodo-2-arylethynyl-acenaphthylenes.
The resulting 7,14-diarylÂpentalenoÂ[1,2-<i>a</i>:4,5<i>a</i>′]ÂdiaceÂnaphthylenes, which
contain four linearly fused five-membered rings, are benchtop stable
and behave as hole-transporting or ambipolar semiconductors in organic
field effect transistors. The X-ray crystal structure shows the important
role of the fused naphthalene unit that enforces a formal pentalene
subunit at the central five-membered rings and [5]-radialene-like
structures at the proximal five-membered rings. Nucleus-independent
chemical shift (NICS) calculations show the internal pentalene rings
are intermediate in antiaromaticity character between known pentalene
and dibenzoÂpentalenes derivatives. The diaceÂnaphthoÂpentalene
derivatives give high optical gap materials owing to a forbidden HOMO
to LUMO transition, yet have narrow electrochemical gaps and are reduced
at small negative potentials giving LUMO energy levels of −3.57
to −3.74 eV
Cobalt-Catalyzed Aerobic Cross-Dehydrogenative Coupling of C–H and Thiols in Water for C–S Formation
Organosulfides have great significance
and value in synthetic and
biological chemistry. To establish a versatile and green methodology
for C–S bond generation, we successfully developed a new aerobic
cross-dehydrogenative coupling of C–H and S–H to synthesize
aryl sulfides in water, utilizing CoPcS as the catalyst and O<sub>2</sub> as the oxidant. This protocol shows great tolerance of a
wide range of substrates. A large variety of organosulfur compounds
were produced in modest to excellent yields