Synthesis and structure of bis(dialkylamino)carbeniumdithiocarboxylates

2-Chloro and 2-phenoxy substituted 1,1-bis(diethylamino)ethylenes ( 4a and 4c ) react with elemental sulfur at room temperature to give the inner salt, bis(diethylamino)carbeniumdithiocarboxylate ( 1a ), in excellent yields with extrusion of hydrogen chloride and phenol, respectively, thus providing a new and convenient synthesis of the structurally interesting inner salt. X-ray single crystal structure analysis of 1a reveals that the N C N and S C S planes are nearly vertical to each other with a dihedral angle of 82.0° and that the positive and negative charges are delocalized over the N C N and S C S moieties, respectively. Results of solid-state ¹³C NMR of 1a are also briefly described.