SYNTHESIS AND STRUCTURE OF THYLCYCLOPENTADIENYL-1,4-DIPHENYLTETRAAZABUTADIENE COMPLEXES OF RHODIUM AND IRIDIUM

Monomeric rhodium and iridium-diaryltetrazene complexes NN=NNR)(Cp=1, 2,3,4,5-pentamethylcyclopentadienyl; M=Rh, Ir; R=Ph, 4-tolyl) have bee n synthesized from [CpMCl2]2(M=Rh, Ir) and 2 equiv. of [Li(THF)x]2 (R N4R) in benzene. We have determined the crystal structure of eta5-pent amethylcyclopentadienyl)diphenyltetrazene iridium by using graphite-mo nochromated Mo-K(alpha)radiation. The compound was crystallized in the monoclinic space group P2(1)/c with a=13.781(3), b=9.035(l), c=17.699 (3) angstrom, and beta=111.93(1)degrees. An X-ray crystal structure of complex 1 showed a short N(2)-N(3) distance (1.265 angstrom) consiste nt with the valence tautomer A with Ir(III) rather than Ir(1). All com plexes are highly colored and decompose on irradiation at 254 run. Ele ctrochemical studies show that complex 1 displays a quasi-reversible r eduction.