Gold(III)-Substituted Carbenes

The Au(III)-substituted diazo compounds (N^C^C)AuC(N₂)R (R = Dmp = 2,6-dimesitylphenyl and SiMe₃) <b>1</b> and <b>6</b> were synthesized by reacting the (N^C^C)AuCl precursor with the corresponding lithiated diazo compounds. Dinitrogen extrusion was then promoted by UV-vis irradiation. The (N^C^C)Au-C-Dmp carbene <b>3</b> undergoes intramolecular C-H insertion followed by β-H elimination, affording a phenanthrene derivative and the Au(III) hydride complex (N^C^C)AuH. Steric shielding prevents intermolecular carbene trapping. The related (N^C^C)Au-C-SiMe₃ carbene <b>7</b> was generated and characterized by <i>in crystallo</i> photolysis. In solution, it displays intermolecular reactivity typical for triplet as well as singlet carbenes, such as H atom abstraction and carbene-type couplings with isocyanides. DFT calculations shed light on the structure, bonding, and reactivity of these Au(III)-substituted carbenes.