A Lead(II) Substituted\nTriplet Carbene

Reaction of the pincer-type ligand L<sub>3</sub> supported\ncomplex\n[L<sub>3</sub>PbBr][BArF<sub>24</sub>] (<b>1</b>) with Li[(C(N<sub>2</sub>)TMS)] furnishes [L<sub>3</sub>Pb(C(N<sub>2</sub>)TMS)][BArF<sub>24</sub>] (<b>2</b>). Diazo-compound <b>2</b> eliminates\ndinitrogen upon irradiation affording formal plumba-alkyne <b>3</b>, which persists in cold fluoroarene solutions. Variable temperature\nUV/Vis and NMR spectroscopies in combination with quantum-chemical\ncalculations identify <b>3</b> as a metal-substituted triplet\ncarbene. In-crystallo irradiation of [L<sub>3</sub>Pb(C(N<sub>2</sub>)TMS)(tol)][BArF<sub>24</sub>] (<b>2</b>·tol) provides\na snapshot of intermolecular C–H bond insertion with toluene\n(<b>4</b>).