Reaction of [Re(O)X3(PPh3)2] (X = Cl or Br) with thiosemicarbazides RNHCSNHNH2 (R = Me or Ph) in ethanol under reflux in the presence of aqueous HX and PPh3 gave the rhenium(V) S,N-chelated thiosemicarbazide(3-) complexes [ReX 2(NNCSNHR) (PPh3)2]. On extended reflux for X = Cl the purple imide-hydrazide [ReCl2(NH)(NHNH2) (PPh 3)2] was formed, and a crystal structure determination showed a pseudo-octahedral geometry with trans PPh3 and nitrogen ligands and a significantly bent M-N-N system (145.5°). Further reflux gave the known nitride complex [Re(N)Cl2(PPh3)2] in good yield.
