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Published on: August 12, 2019
Catalytic Carbodiimide Guanylation by a Nucleophilic, High Spin Iron(II) Imido Complex
Yafei Gao1, Veronica Carta1, Maren Pink1
1Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States.
Abstract:
Reduction of the three-coordinate iron(III) imido [Ph2B(BuIm)2Fe═NDipp] (1) affords [Ph2B(BuIm)2Fe═NDipp][K(18-C-6)THF2] (2), a rare example of a high-spin (S = 2) iron(II) imido complex. Unusually for a late metal imido complex, the imido ligand in 2 has nucleophilic character, as demonstrated by the reaction with DippNH2, which establishes an equilibrium with the bis(anilido) complex [Ph2B(BuIm)2Fe(NHDipp)2][K(18-C-6)THF2] (3). In an unusual transformation, formal insertion of PrN═C═NPr into the Fe═N(imido) bond yields the guanidinate [Ph2B(BuIm)2Fe(PrN)2CNDipp][K(18-C-6)THF2] (4). Reaction of 4 with excess DippNH2 provides 3, along with the guanidine (PrNH)2C═NDipp. As suggested by these stoichiometric reactions, 2 is an efficient catalyst for the guanylation of carbodiimides, converting a wide range of aniline substrates under mild conditions.
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