Decafluorinated and Perfluorinated Warped Nanographenes: Synthesis, Structural Analysis, and Properties
Xuepeng Zhang, Si‐Wei Ying, Yilu Zhang, Wenxin Zhang, Wenjie Shi, Bin‐Wen Chen, Han‐Rui Tian, Gan Xu, Shanshan Wang, Qianyan Zhang, Su‐Yuan Xie, Lan‐Sun Zheng
Abstract
Fluorination is a useful approach for tailoring the physicochemical properties of nanocarbon materials. However, owing to the violent reactivity of fluorination, achieving edge-perfluorination of nanographene while maintaining its original π-conjugated structure is challenging. Instead of using traditional fluorination, here, we employed a bottom-up strategy involving fluorine preinstallation and synthesized decafluorinated and perfluorinated warped nanographenes ( DFWNG and PFWNG, respectively) through a 10-fold Suzuki–Miyaura coupling followed by a harsh Scholl reaction, whereby precisely edge-perfluorinated nanographene with an intact π-conjugated structure was achieved for the first time. X-ray crystallography confirmed the intact π-conjugated structure and more twisted saddle-shaped geometry of PFWNG compared to that of DFWNG . Dynamic study revealed that the 26-ring carbon framework of PFWNG is less flexible than that of DFWNG and the pristine WNG, enabling chirality resolution of PFWNG and facilitating the achievement of CD spectra at −10 °C. The edge-perfluorination of PFWNG resulted in improved solubility, lower lowest unoccupied molecular orbital, and a surface electrostatic potentials/dipole moment direction opposite those of the pristine WNG . Likely owing to its intact π-conjugated structure, PFWNG exhibits comparable electron mobility with well-known PC 61 BM. Furthermore, perfluorination improves thermal stability and hydrophobicity, making PFWNG suitable for use as a thermostable/hydrophobic n -type semiconductor material. In the future, this fluorination strategy can be used to synthesize other perfluorinated nanocarbon materials, such as perfluorinated graphene nanoribbons and porous nanocarbon.