Phosphinohydrazines and phosphinohydrazides M(-N(R)-N(R)-PPh2)n of some transition and main group metals: synthesis and characterization: Rearrangement of Ph2P-NR-NR- ligands into aminoiminophosphorane, RNPPh2-NR-, and related chemistry

The reactions of phosphinohydrazines ArNH-N(Ar)-PPh₂ {Ar = Ph (2a), p-Bu^t-C₆H₄- (2b)} with metal silylamides MN(SiMe₃)₂]_n, {M = Fe(II), Fe(III), Co(II), Ni(I), Cu(I)} or the reactions of lithium salts ArN(Li)-N(Ar)-PPh₂ with metal halides (GeCl₂, ZnCl₂, FeBr₂, CoCl₂, NiBr₂, CrCl₃, MnCl₂) are strongly dependent on nature of a metal and its ligand environment.Early transition metals or non-transition metals form stable phosphinohydrazides MN(Ar)N(Ar)PPh₂]_n {M = Li, Zn, Ge(II), Mn(II), Cr(III), Fe(II)}.Starting ligand 2a and germylene Ge(NPhNPhPPh₂)₂ (7) were characterized by X-ray analysis.Germanium is coordinated additionally with a phosphorus atom of one of the diphenylphosphine groups.The distance Ge?P was found to be 2.563(1) Å.This coordination leads to an appreciable increase in a pyramidal geometry of nitrogen atoms relatively to a non-coordinated fragment.Late transition metals (Co, Ni, Cu) and metals with enhanced oxidation state (Fe³⁺) cause transformation of a phosphinohydrazide ligand.For Co(II), Ni(II), Fe(III) this leads quantitatively to aminoiminophosphoranates M(NAr-PPh₂NAr)_n.Complex CoN(C₆H₄Bu^t)-PPh₂N-C₆H₄Bu^t]₂ (11) was characterized by X-ray analysis.Nickel(I) silylamide, (Ph₃P)₂NiN(SiMe₃)₂, being reacted with 2a yields azobenzene complex, (Ph₃P)₂Ni(PhNNPh), while copper(I) silylamide originally forms (PhNH-NPh-PPh₂)₂CuN(SiMe₃)₂ (18).Heating of the latter in toluene solution yields insoluble copper(I) diphenylphosphide, azobenzene, 2a and hexamethyldisilazane.The reaction of hydrazobenzene with Ph₂PCl (1:1) in methylene chloride for three days gives aminoiminophosphorane dihydrochloridePhNH-PPh₂NPh] · 2HCl (3) in quantitative yield.