Preparation of stable imido(nitrene)-complexes of molybdenum and their conversion into nitrido-complexes

The reaction of [Mo(N2)2(dpe)2](dpe = Ph2-PCH2CH2PPh2) with trimethylsilyl azide gives the azido-nitrido-complex, [MoN(N3)(dpe)2], which is converted by hydrohalic acids HX (X Cl or Br) to the imido(nitrene)- complexes, [Mo(NH)X2(dpe)2]; these, on treatment with base, give the nitrido-complexes, [MoNX(dpe)2] which revert to the imido-complexes on treatment with acid.