Polyquinolines have been studied
since the early 1970s due to their
favorable chemical, optical, electrical, and mechanical properties.
However, surprisingly few synthetic strategies have been developed
for the preparation of these polymers. Herein, we demonstrate the
application of the aza-Diels–Alder (Povarov) reaction for the
synthesis of soluble polyquinolines from a bifunctional monomer. Our
approach furnishes polyquinolines with a unique architecture and connectivity
in only two synthetic steps from inexpensive, commercially available
reagents. The reported strategy may therefore represent a welcome
addition to the polymer chemist’s toolkit by providing ready
access to a diverse library of polyquinoline-type materials.
Graphene nanoribbons (GNRs) represent promising materials for the next generation of nanoscale electronics. However, despite substantial progress towards the bottom-up synthesis of chemically and structurally well-defined all-carbon GNRs, strategies for the preparation of their nitrogen-doped analogs remain at a nascent stage. This scarce literature precedent is surprising given the established use of substitutional doping for tuning the properties of electronic materials. Herein, we report the synthesis of a previously unknown class of polybenzoquinoline-based materials, which have potential as GNR precursors. Our scalable and facile approach employs few synthetic steps, inexpensive commercial starting materials, and straightforward reaction conditions. Moreover, due to the importance of quinoline derivatives for a variety of applications, the reported findings may hold implications across a diverse range of chemical and physical disciplines.
Carbon-based materials, such as acenes, fullerenes, and graphene nanoribbons, are viewed as the potential successors to silicon in the next generation of electronics. Although a number of methodologies provide access to these materials' all-carbon variants, relatively fewer strategies readily furnish their nitrogen-doped analogues. Herein, we report the rational design, preparation, and characterization of nitrogen-containing rubicenes and tetrabenzopentacenes, which can be viewed either as acene derivatives or as molecular fragments of fullerenes and graphene nanoribbons. The reported findings may prove valuable for the development of electron transporting organic semiconductors and for the eventual construction of larger carbonaceous systems.
The chemoselectivity of molecular catalysts underpins much of modern synthetic organic chemistry. However, little is known about the selectivity of individual catalysts because this single-catalyst-level behavior is hidden by the bulk catalytic behavior. Here, for the first time, the selectivity of individual molecular catalysts for two different reactions is imaged in real time at the single-catalyst level. This imaging is achieved through fluorescence microscopy paired with spectral probes that produce a snapshot of the instantaneous chemoselectivity of a single catalyst for either a single-chainelongation or a single-chain-termination event during ruthenium-catalyzed polymerization. Superresolution imaging of multiple selectivity events, each at a different single-molecular ruthenium catalyst, indicates that catalyst selectivity may be unexpectedly spatially and time-variable.
Graphene nanoribbons (GNRs) are promising candidate materials for the next generation of nanoscale electronics. Described herein is the synthesis of 2,4,6-substituted benzoquinolines, which constitute building blocks for nitrogen-doped GNRs. The presented facile and modular aza-Diels-Alder chemistry accommodates the installation of diverse functionalities at the crowded benzoquinolines' 2 positions. Given the general utility of the benzoquinoline motif, these findings hold relevance not only for carbon-based electronics but also for a range of chemical disciplines.
This study describes the synthesis of modular diquinolineanthracene and polydiquinolineanthracene derivatives. The reported facile and scalable aza-Diels-Alder-based approach requires mild conditions, proceeds in two steps, uses commercially available starting materials, and accommodates varying functionalities. Given the known utility of the acene and quinoline motifs, the synthesized molecules and polymers hold promise for organic electronics applications.
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