Design and synthesis of diphenyldiazomethanes possessing stable aminoxyl radicals: photolytic generation of quartet species and their reaction with C60
Design and synthesis of diphenyldiazomethanes possessing stable aminoxyl radicals: photolytic generation of quartet species and their reaction with C60
Compounds of formula (IIa):
are provided where:
X is a group capable of being cleaved from the α-carbon atom to form an ion of formula (I')
C is a carbon atom bearing a single positive charge or a single negative charge;
The invention further provides compounds of formula (IIb):
where:
X is a counter-ion to C.
The compounds of formula (IIa) and (IIb) may form ions of formula (I') by either cleaving the C-X bond between X and the α-carbon atoms in the case of the compounds of formula (IIa) or dissociating X in the case of compounds of formula (IIb).
A facile route has been developed for the preparation of a new family of contorted 1.2,3.4,7.8,9.10-tetrabenzocoronenes (TBCs). A two-step cyclization reaction, i.e., oxidative photocyclization followed by FeCl3-mediated intramolecular cyclodehydrogenation, was carried out on the olefin precursors to obtain the final TBC compounds. These new TBC molecules have contorted conformation due to steric overcrowding as disclosed by single-crystal crystallographic analysis. Nevertheless, they showed extended pi-conjugation compared with coronene and exhibited strong aggregation in solution. The thermal behavior and self-assembly of TBC-C8 in solid were studied by a combination of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM). Compound TBC-C8 showed very good thermal and photostability and exhibited long-range ordered pi-stacking in the bulk state. Moreover, uniform nanofibers with tens of micrometer length are formed in the drop-casted thin films. TBC-C8 also possesses a desirable HOMO energy level (-5.10 eV), which allows efficient charge injection from electrodes such as gold electrode. The charge carrier mobilities were determined by using the space-charge limited-current (SCLC) technique and high average hole mobility of 0.61 cm(2) V-1 s(-1) was obtained for TBC-C8.