Synthesis and characterization of tetraphenylammonium salts.

The phenyl (Ph) group is a representative substituent in the field of organic chemistry as benzene (the parent molecule) is of fundamental importance. Simple Ph-substituted compounds of common chemical elements are well known. However, extensive structural characterization of tetraphenylammonium (Ph4N+) salts has not been reported. Herein, the synthesis of Ph4N+ salts and their characterization data including the 1H and 13C nuclear magnetic resonance (NMR) spectra and the single-crystal X-ray structure have been presented. An intermolecular radical coupling reaction between an aryl radical and a triarylammoniumyl radical cation was conducted to synthesize the target moieties. The Ph4N+ salts described herein are the simplest tetraarylammonium (Ar4N+) salts known. The results reported herein can potentially help access the otherwise inaccessible non-bridged Ar4N+ salts, a new class of rigid and sterically hindered organic cations.