Synthesis, Solid-State Crystal Structure, and Reactivity of a Monomeric Copper(I) Anilido Complex

Synthesis and isolation of the Cu(I) amido complex (dtbpe)Cu(NHPh) (dtbpe = 1,2-bis(di-tert-butylphosphino)ethane) is accomplished upon reaction of [(dtbpe)Cu(μ-Cl)]2 with LiNHPh. The anilido
complex has been fully characterized by IR spectroscopy and multinuclear NMR spectroscopy as well as
by single-crystal X-ray diffraction study. Salient features of the solid-state structure include an amido
orientation that allows π-interaction of the nitrogen-based lone pair with both the empty copper p-orbital
and the π*-system of the phenyl substituent. A solid-state X-ray diffraction study of [(dtbpe)Cu(NH2Ph)][BF4] has allowed a direct comparison of the structural features upon conversion of the amine ligand to an
amido. The reactivity of the amido ligand of (dtbpe)Cu(NHPh) is consistent with nucleophilic character. For
example, the formation of Ph3CNHPh is observed upon treatment with [Ph3C][BF4], and reaction at room
temperature with EtX (X = Br or I) yields N-ethylaniline. The reactivity of (dtbpe)Cu(NHPh) is compared to
that of the octahedral and d6 complex TpRu(PMe3)2(NHPh) (Tp = hydridotris(pyrazolyl)borate).