Decafluorinated and\nPerfluorinated Warped Nanographenes:\nSynthesis, Structural Analysis, and Properties

Fluorination is a useful approach for tailoring the physicochemical\nproperties of nanocarbon materials. However, owing to the violent\nreactivity of fluorination, achieving edge-perfluorination of nanographene\nwhile maintaining its original π-conjugated structure is challenging.\nInstead of using traditional fluorination, here, we employed a bottom-up\nstrategy involving fluorine preinstallation and synthesized decafluorinated\nand perfluorinated warped nanographenes (<b>DFWNG</b> and <b>PFWNG</b>, respectively) through a 10-fold Suzuki–Miyaura\ncoupling followed by a harsh Scholl reaction, whereby precisely edge-perfluorinated\nnanographene with an intact π-conjugated structure was achieved\nfor the first time. X-ray crystallography confirmed the intact π-conjugated\nstructure and more twisted saddle-shaped geometry of <b>PFWNG</b> compared to that of <b>DFWNG</b>. Dynamic study revealed that\nthe 26-ring carbon framework of <b>PFWNG</b> is less flexible\nthan that of <b>DFWNG</b> and the pristine <b>WNG</b>,\nenabling chirality resolution of <b>PFWNG</b> and facilitating\nthe achievement of CD spectra at −10 °C. The edge-perfluorination\nof <b>PFWNG</b> resulted in improved solubility, lower lowest\nunoccupied molecular orbital, and a surface electrostatic potentials/dipole\nmoment direction opposite those of the pristine <b>WNG</b>.\nLikely owing to its intact π-conjugated structure, <b>PFWNG</b> exhibits comparable electron mobility with well-known PC<sub>61</sub>BM. Furthermore, perfluorination improves thermal stability and hydrophobicity,\nmaking <b>PFWNG</b> suitable for use as a thermostable/hydrophobic <i>n</i>-type semiconductor material. In the future, this fluorination\nstrategy can be used to synthesize other perfluorinated nanocarbon\nmaterials, such as perfluorinated graphene nanoribbons and porous\nnanocarbon.