TRANSITION-METAL COMPLEXES OF DIAZENES .27. IRON CARBONYL INDUCED ORTHO-SEMIDINE REARRANGEMENT OF 1-ALKYL-2-ARYLDIAZENES

Irradiation of pentacarbonyl iron in the presence of Me3C - N = N - Ar (Ar = phenyl, p-tolyl, p-CH3OC6H4) produces in the first step ortho-metallated complexes of the type Me3C - Activated N - N(H)RC6H3Fe(CO)3Fe(CO)3 (2a-c, R = H, Me, MeO). In a thermal consecutive step these intermediates undergo an o-semidine rearrangement to Me3C - Activated NFe(CO)3 - Fe(CO)3N(H)RC6H3 (1a- c). The structure of 1a has been elucidated by X-ray structure analysis. Dynamic C-13-NMR spectra indicate restricted rotation of the Me3C group and hindered carbonyl scrambling for the latter and former complexes, respectively.