Activation of Ammonia by a Carbene-Stabilized Dithiolene Zwitterion

A carbene-stabilized dithiolene zwitterion ( 3 ) activates ammonia, affording 4 • and 5, through both single-electron transfer (SET) and hydrogen atom transfer (HAT). Reaction products were characterized spectroscopically and by single-crystal X-ray diffraction. The mechanism of the formation of 4 • and 5 was probed by experimental and computational methods. This discovery is the first example of metal-free ammonia activation via HAT.