Isolation of bridging and terminal coinage metal-nitrene complexes

Transition metal complexes featuring a metal-nitrogen multiple bond have been widely studied due to their implication in dinitrogen fixation and catalytic nitrogen-carbon bond formation. Terminal copper- and silver-nitrene complexes have long been proposed to be the key intermediates in aziridination and amination reactions using azides as the nitrogen source. However, due to their high reactivity, these species have eluded isolation and spectroscopic characterization even at low temperatures. In this paper we report that a stable phosphinonitrene reacts with coinage metal trifluoromethanesulfonates, affording bridging and terminal copper- and silver-nitrene complexes, which are characterized by NMR spectroscopy and single crystal X-ray diffraction analysis.