Reaction of [σ:η⁵-(C₉H₆)C₂B₉H₁₀]Zr(NMe₂)(DME) with Guanidines: Metallacarborane-Mediated C−N Bond Cleavage and 1,5-Sigmatropic Rearrangement

Treatment of [σ:η5-(C9H6)C2B9H10]Zr(NMe2)(DME) with 2 equiv of guanidines iPrNHC(NR2)NiPr (R = Me, Et) in refluxing toluene gave unprecedented complexes [η:σ:η5-{2-[CNiPr(NHiPr)]C9H5}C2B9H10]Zr[η-(iPrN)2C(NR2)] (R = Me, Et). This communication describes the mechanism by which they are formed. Experimental results show that guanidinates are not inert ligands in the present cases that can undergo C−N bond cleavage to generate amido and carbodiimide that subsequently insert into the Zr−C bond to form the final product via 1,5-sigmatropic shift.