Synthesis of Polyarylated Carbazoles: Discovery toward Soluble Phenanthro- and Tetraceno-Fused Carbazole Derivatives

The successful iron chloride-catalyzed
Scholl reactions toward
a series of polyphenylated carbazole derivatives differing in their N-substitution are described. These reactions were found
to be compatible over a series of polyaryls possessing fluoro, methoxy,
and methyl functional groups, subsequently leading to the synthesis
of partially and completely annulated phenanthro- and tetracenocarbazoles
in excellent yields. One major consequence of nonsubstitution on carbazolyl-N and the unsymmetrical framework of some of the derivatives
is the low solubility of the product; thus, a change from NH- to N-decyl on the carbazole nucleus
was carried out. All newly developed derivatives were characterized
by spectroscopic techniques, while the chemical structures of fluorophenanthro-
and methoxytetracenocarbazoles were confirmed by single-crystal XRD
analyses. The present efforts may likely expand the family of growing
heteroarenes for future applications as semiconductors and electroluminescent
materials.