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

Abstract

The Ni(II) triazenide complex, trans-( o-Tol)Ni(PEt 3) 2N 3Ar 2 (Ar= p-FC 6H 4) ( 1), was synthesized by the reaction of trans-( o-Tol)Ni(PEt 3) 2Br with Ar 2N 3Na. The crystal structure as well as the 1H-, 19F- and 31P-NMR spectra in toluene- d 8 at different temperatures are reported. It was found that the triazenido group acts as a monodentate ligand. Complex 1 in solid state has a S- cis-structure with NiN(3) σ-bond and exists as a 3:1 mixture 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(PEt 3) 2 group occurs in a solution of 1. The migration rate increases with the temperature increase in the range from −104 to −45°C. However, a further increase in the temperature slows down the process.