X-ray structure and fluxional behaviour of N,N '-di-p-fluorophenyltriazenido complex of nickel(II)

The Ni(II) triazenide complex, trans-(o-Tol)Ni(PEt3)(2)N3Ar2 (Ar = p-FC6H4) (1), was synthesized by the reaction of trans-(o-Tol)Ni(PEt3)(2)Br with Ar 2N3Na. The crystal structure as well as the H-1-, F-19- and -P-31-NMR spect ra in toluene-d(8) at different temperatures are reported. It was found tha t the triazenido group acts as a monodentate ligand. Complex 1 in solid sta te has a S-cis-structure with Ni-N(3) sigma-bond and exists as a 3:1 mixtur e of two isomers with cisoid or transoid orientation of the Me group of the o-tolyl ligand relative to the N(1)=N(2) bond. It was established that the N,N'-migration of (o-Tol)Ni(PEt3)(2) group occurs in a solution of I. The migration rate increases with the temperature increase in the range from -1 04 to -45 degrees C. However, a further increase in the temperature slows d own the process. (C) 2000 Elsevier Science S.A. All rights reserved.