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, RN=PPh2-NR-, and related chemistry

摘要

The reactions of phosphinohydrazines ArNH-N(Ar)-PPh2 {Ar = Ph (2a), p-Bu'-C6H4 (2b)} with metal silylamides M[N(Si-Me-3)(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 M[N(Ar)N(Ar)PPh2](n) {M = Li, Zn, Ge(II), Mn(II), Cr(III), Fe(H)). 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 (GeP)-P-... was found to be 2.563(1) Angstrom. 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-PPh2=NAr)(n) Complex Co[N(C6H4Bu')-PPh2==N-C6H4But](2) (11) was characterized by X-ray analysis. Nickel(I) silylamide, (Ph3P)(2)NiN(SiMe3)(2), being reacted with 2a yields azobenzene complex, (Ph3P)(2)Ni(PhN=NPh), while copper(I) silylamide originally forms (PhNH-NPh-PPh2)(2)CuN (SiMe3)(2) (18). Heating of the latter in toluene solution yields insoluble copper(I) diphenylphosphide, azobenzene, 2a and hexameth-yldisilazane. The reaction of hydrazobenzene with Ph2PCl (1:1) in methylene chloride for three days gives aminoiminophosphorane dihydrochloride [PhNH-PPh2==NPh] (.) 2HCl (3) inquantitative yield. (C) 2004 Elsevier B.V. All rights reserved.