Nanographenes are emerging as a distinctive class of functional materials for electronic and optical devices. It is of remarkable significance to enrich the precise synthetic chemistry for these molecules. Herein, we develop a facile strategy to recompose helicenes into chiral nanographenes through a unique oxidative cyclo-rearrangement reaction. Helicenes with 7~9 ortho-fused aromatic rings are firstly oxidized and cyclized, and subsequently rearranged into nanographenes with an unsymmetrical helicoid shape through sequential 1,2-migrations. Such skeletal reconstruction is virtually driven by the gradual release of the strain of the highly distorted helicene skeleton. Importantly, the chirality of the helicene precursor can be integrally inherited by the resulting nanographene. Thus, a series of chiral nanographenes are prepared from a variety of carbohelicenes and heterohelicenes. Moreover, such cyclo-rearrangement reaction can be sequentially or simultaneously associated with conventional oxidative cyclization reactions to ulteriorly enrich the geometry diversity of nanographenes, aiming at innovative properties.

Helicene-AIE conjugates with tailored marriage of helicenes and AIE luminophores show prominent fluorescence in the aggregated state with colour varying from blue to green, quantum yield up to 37.0%, and |glum| value up to 0.015.

Synthetic innovation for constructing sophisticated nanographenes is of fundamental significance for a variety of advanced applications. Herein, we report a distinctive method to prepare π-extended chiral nanographenes with 29 benzenoid rings and two helical breaches from a highly crowded perylene-cored oligoarylene precursor. Under Scholl's conditions, the reaction predominantly involves the regioselective and sequential cyclization in the peri-and bay regions of the perylene core, and the complanation of the 1-phenyl-[5]helicene intermediate module via 1,2-phenyl migration. The resulting chiral nanographenes are configurationally stable at 180 °C due to the high diastereomerization barriers of ca. 45 kcal mol À 1 . These molecules also possess globally delocalized π-systems with low HOMO/LUMO gaps, leading to nearly panchromatic absorption, intensive electronic circular dichroism signals and deep-red circularly polarized luminescence.

In this study, we prepared paclitaxel/chitosan (PTX/CS) nanosuspensions (NSs) with different mass ratios of PTX and CS (1.5:2, 2:2, and 2.5:2), for controlled drug delivery purposes. For attachment and dispersion in water medium, a simple ultrasonic disruption technique was employed. The water-dispersed PTX/CS NSs exhibited a rod-shape morphology with an average diameter of 170-210 nm and average length of about 1-10 µm. Transmission electron microscopy, differential scanning calorimetry and X-ray diffraction indicated that the obtained PTX/CS NSs contain a nanocrystalline PTX phase. It was also inferred that presence of CS can promotes the crystalline nature of PTX up to 80%. In addition, efficiency of PTX loading reached over 85% in freeze-dried PTX/CS NSs, showing a slow rate of drug release in vitro for 8 days. The MTT and LDH assessments revealed that PTX/CS NSs significantly inhibit the growth of tumor cells (HeLa), while it is slightly toxic for the normal cells (NIH/3T3). Therefore, PTX/CS NSs is suggested as a potential nanodrug delivery system for cancer therapy.