We report here an iterative synthesis of long helical
perylene
diimide (hPDI[n]) nanoribbons with a
length up to 16 fused benzene rings. These contorted, ladder-type
conjugated, and atomically precise nanoribbons show great potential
as organic fast-charging and long-lifetime battery cathodes. By tuning
the length of the hPDI[n] oligomers,
we can simultaneously modulate the electrical conductivity and ionic
diffusivity of the material. The length of the ladders adjusts both
the conjugation for electron transport and the contortion for lithium-ion
transport. The longest oligomer, hPDI[6], when fabricated
as the cathode in lithium batteries, features both high electrical
conductivity and high ionic diffusivity. This electrode material exhibits
a high power density and can be charged in less than 1 min to 66%
of its maximum capacity. Remarkably, this material also has exceptional
cycling stability and can operate for up to 10,000 charging–discharging
cycles without any appreciable capacity decay. The design principles
described here chart a clear path for organic battery electrodes that
are sustainable, fast-charging, and long lasting.
Here
we show the access to single-handed helicene nanoribbons by
utilizing a [6]helicene building block to induce diastereoselective,
photochemical formation of [5]helicene units. Specifically, we have
synthesized nanoribbons P1 and P2 with different
ratios of [6]helicene “sergeants” to [5]helicene “soldiers”,
which on average consist of between ∼50 and 60 ortho-annulated benzene rings. These are the longest, optically active
helicene backbones that have been prepared to date. The chiroptic
properties of P1 and P2 reveal the transfer
of stereochemical information from “sergeants” to “soldiers”.
To gain further insight into the stereo-information relay, we apply
the same molecular design to discrete, model oligomers 1–5 and confirm that they also preferentially
adopt homochiral geometries.
We report a reliable way to manipulate
the dynamic, axial
chirality
in perylene diimide (PDI)-based twistacenes. Specifically, we reveal
how chiral substituents on the imide position induce the helicity
in a series of PDI-based twistacenes. We demonstrate that this remote
chirality is able to control the helicity of flexible [4]helicene
subunits by UV–vis, CD spectroscopy, X-ray crystallography,
and TDDFT calculations. Furthermore, we have discovered that both
the chiral substituent and the solvent each has a strong impact on
the sign and intensity of the CD signals, highlighting the control
of the dynamic helicity in this flexible system. DFT calculations
suggest that the steric interaction of the chiral substituents is
the important factor in how well a particular group is at inducing
a preferred helicity.
Redox-active two-dimensional polymers (RA-2DPs) are promising lithium battery organic cathode materials due to their regular porosities and high chemical stabilities.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.