ic5026153_si_005.cif (28.84 kB)
Carbon–Hydrogen Bond Activation, C–N Bond Coupling, and Cycloaddition Reactivity of a Three-Coordinate Nickel Complex Featuring a Terminal Imido Ligand
dataset
posted on 2015-12-17, 06:22 authored by Daniel J. Mindiola, Rory Waterman, Vlad M. Iluc, Thomas R. Cundari, Gregory L. HillhouseThe
three-coordinate imidos (dtbpe)NiNR (dtbpe = tBu2PCH2CH2PtBu2, R = 2,6-iPr2C6H3, 2,4,6-Me3C6H2 (Mes), and 1-adamantyl (Ad)), which contain
a legitimate Ni–N double bond as well as basic imido nitrogen
based on theoretical analysis, readily deprotonate HCCPh to
form the amide acetylide species (dtbpe)Ni{NH(Ar)}(CCPh).
In the case of R = 2,6-iPr2C6H3, reductive carbonylation results in formation
of the (dtbpe)Ni(CO)2 along with the N–C coupled
product keteneimine PhCHCN(2,6- iPr2C6H3). Given the ability
of the NiN bond to have biradical character as suggested by
theoretical analysis, H atom abstraction can also occur in (dtbpe)NiN{2,6-iPr2C6H3}
when this species is treated with HSn(nBu)3. Likewise, the microscopic reverse reactionconversion
of the Ni(I) anilide (dtbpe)Ni{NH(2,6-iPr2C6H3)} to the imido (dtbpe)NiN{2,6-iPr2C6H3}is
promoted when using the radical Mes*O• (Mes* = 2,4,6-tBu3C6H2).
Reactivity studies involving the imido complexes, in particular (dtbpe)NiN{2,6-iPr2C6H3},
are also reported with small, unsaturated molecules such as diphenylketene,
benzylisocyanate, benzaldehyde, and carbon dioxide, including the
formation of C–N and N–N bonds by coupling reactions.
In addition to NMR spectroscopic data and combustion analysis, we
also report structural studies for all the cycloaddition reactions
involving the imido (dtbpe)NiN{2,6-iPr2C6H3}.