Two-Coordinate, Late First-Row Transition Metal Amido Derivatives of the Bulky Ligand -N(SiPrⁱ₃)Dipp (Dipp = 2,6-diisopropylphenyl): Effects of the Ligand on the Stability of Two-Coordinate Copper(II) Complexes

Abstract

The synthesis and spectroscopic, structural, and magnetic characterization of the quasi-linear metal­(II) bis­(amides) M­{N­(SiPr i 3)­Dipp}2 [Dipp = C6H3-2,6-Pr i 3; M = Fe (1), Co (2), or Zn (3)] are described. The magnetic data demonstrate the impact of metal ligand π-interactions on the magnetic properties of these two-coordinate transition metal amides. Disproportionation of the copper­(I) amide species featuring the ligand -N­(SiPr i 3)­Dipp resulted in the decomposition product [(Pr i 3Si)­N­(c-C6H2-2,6-Pr i 2)]2 (4). The electron paramagnetic resonance spectrum of the unstable two-coordinate Cu­{N­(SiPr i 3)­Dipp}2 displays significantly less Cu–N bond covalency than the stable two-coordinate copper­(II) species Cu­{N­(SiMe3)­Dipp}2. The testing of -N­(SiPr i 3)­Dipp and a range of other, related bulky amide ligands with their copper derivatives highlights the peculiar combination of steric and electronic properties of the Wigley ligand -N­(SiMe3)­Dipp that enable it to stabilize the unique two-coordinate copper­(II) complex Cu­{N­(SiMe3)­Dipp}2.

Quasilinear 3d-metal(i) complexes [KM(N(Dipp)SiR3)2] (M = Cr–Co) – structural diversity, solution state behaviour and reactivity

“…The impact of attracting intramolecular dispersion interactions is further discussed to influence M-N distances. 12,22 However, the cobalt complexes 4 (M = Fe (8), Co (9), L 2 = N(Dipp)SiMe 3 ).…”

Towards Heteroleptic Dicoordinate CuII Complexes

“…The Power group reported on another attempt to generate dicoordinate Cu II complexes in 2019 when they employed modified variants of the aryl(silyl)amide of the 2016 study [21] . However, while for both Cu{N(Si i Pr 3 ) 2 Dipp} 2 ( C ) and Cu{N(Si i Pr 3 )Dipp‐4‐Ad} 2 ( D ) unambiguous EPR spectra were obtained and the characteristic blue colour of the dicoordinate Cu II complexes was observed, the isolation of the complexes was not possible due to their thermal instability.…”

Synthesis, Characterization, and Reactivity of Low-Coordinate Titanium(III) Amido Complexes

“…Recently, this research group demonstrated the versatility of the amido ligand [N­(Si i Pr 3 )­DIPP] (DIPP = 2,6-di- iso -propylphenyl) in supporting two-coordinate chromium complexes in the +1, +2, and +3 oxidation states, as well as the two-coordinate vanadium­(II) complex D (Scheme ). Other groups have used this amido ligand with yttrium, alkaline earth metals, − and several late transition metals . Further investigations of this bulky amido ligand in allowing access to low-valent early transition metal complexes are described here, involving the synthesis, characterization, and reactivity of a family of low-coordinate, heteroleptic complexes of titanium­(III) supported by the [N­(Si i Pr 3 )­DIPP] ligand.…”

“…20 Other groups have used this amido ligand with yttrium, 21 alkaline earth metals, 22−24 and several late transition metals. 25 Further investigations of this bulky amido ligand in allowing access to low-valent early transition metal complexes are described here, involving the synthesis, characterization, and reactivity of a family of low-coordinate, heteroleptic complexes of titanium-(III) supported by the [N(Si i Pr 3 )DIPP] ligand.…”