Cleavage of Hydrazine and 1,1-Dimethylhydrazine by Dinuclear Tantalum Hydrides: Formation of Imides, Nitrides, and <i>N</i>,<i>N</i>-Dimethylamine

The complexes (RPh[NPN]Ta)2(μ-H)4 (RPh[NPN] = RP(CH2SiMe2NPh)2) activate molecular nitrogen to give (RPh[NPN]Ta)2(μ-η-η-N2)(μ-H)2; however, addition of hydrazine to (CyPh[NPN]Ta)2(μ-H)4 promotes cleavage of the N−N bond and N−H activation to give the bridging bisimide complex (CyPh[NPN]Ta)2(μ-H)2(μ-NH)2. Substitution of the phosphine substituent from cyclohexyl to phenyl allows for characterization of (PhPh[NPN]Ta)2(μ-H)2(μ-NH)2 crystallographically. Addition of the substituted hydrazine Me2NNH2 results in formation of a mono(nitride) complex, (RPh[NPN]Ta)2(μ-H)3(μ-N). The N−N bond has again been cleaved, but the second nitrogen atom has been functionalized and ejected as Me2NH.