FORMATION OF BRIDGING NITRIDE VERSUS TERMINAL OXOVANADIUM PROMOTED BYA VANADIUM(II) MACROCYCLIC COMPLEX

The reaction of [VCl2(tmeda)(2)] with the tetralithium salt of octaeth ylporphyrinogen (oepg)[Li(thf)](4) initially yielded a monomeric V-II complex [(oepg)VLi4Cl2(thf)(4)] (1). Treatment of this species with te tramethylethylenediamine afforded a mixture from which [(oepg)V(thf)(2 )][Li(tmeda)(2)]. 0.5 toluene (2a) (or 2b when ethyl is replaced by nP r) and the unprecedented nitrido-bridged dimeric species [{(oepg)V}(2) (mu-N)(mu-Li)(4)][Li(tmeda)(2)] (3) were isolated and characterized. T he bridging nitrogen atom probably originated from the cleavage of din itrogen, since the same reaction carried out under exclusion of N-2 ga ve [(oepg)VO][Li(tmeda)](2) (4), where the oxo atom probably originate d from deoxygenation of THE The connectivity of 1, 2b, 3, and 4 was de monstrated by X-ray analysis.