Formal Nickelate(−I) Complexes Supported by Group 13 Ions

Abstract

Formal nickelate(-I) complexes bearing Group 13 metalloligands (M=Al and Ga) were isolated. These 17 e complexes were synthesized by one-electron reduction of the corresponding Ni →M precursors, and were investigated by single-crystal X-ray diffraction, EPR spectroscopy, and quantum chemical calculations. Collectively, the experimental and computational data support: 1) the strengthening of the Ni-M bond upon one-electron reduction, and 2) the delocalization of the unpaired spin across the Ni and M atoms. An intriguing electronic configuration is revealed where three valence electrons occupy two σ-type bonding interactions: Ni(3dz2 ) →M and σ-(Ni-M) . The latter is an unusual Ni-M σ-bonding molecular orbital that comprises primarily the Ni 4p and M np /ns atomic orbitals.

Reductive Disproportionation of CO2 Mediated by Bimetallic Nickelate(–I)/Group 13 Complexes

“…Both 1 red and 2 red exhibit a reversible {NiM} 10 /{NiM} 11 redox couple at –2.82 V (vs. Fc + /Fc) and –2.48 V, respectively . These negative potentials should be suitable for reduction of CO 2 ( E°′ = –1.90 V vs. NHE for CO 2 + e – → CO 2 · – ) .…”

“…The synthesis and characterization of the formally nickelate(–I) compounds, [NiAlL] – ( 1 red ) and [NiGaL] – ( 2 red ), where L is {N[( o‐ C 6 H 4 )NCH 2 P i Pr 2 ] 3 } 3– were previously reported . Both 1 red and 2 red were obtained by reducing the neutral counterparts, NiAlL and NiGaL, respectively, with potassium graphite.…”

“…NMR shifts were referenced to the internal solvent residual signal (for 1 H spectra) or an external H 3 PO 4 reference (for 31 P spectra) . The neutral ligand {N[ o ‐(NHCH 2 P i Pr 2 )C 6 H 4 ] 3 } (H 3 L), bimetallic complexes NiML (M = Al, Ga, In), and the [K(crypt‐222)] salts of 1 red and 2 red were synthesized according to literature procedures , , . Elemental analyses were performed by Robertson Microlit Laboraties, Inc. (Ledgewood, NJ).…”

Zerovalent Rhodium and Iridium Silatranes Featuring Two‐Center, Three‐Electron Polar σ Bonds

“…Following the spectroscopic characterization of a boron–boron one‐electron σ‐bond (Figure b), our group later reported on a copper‐boratrane complex featuring a polar Cu−B 2c/1e − σ‐bond, the first of its type with a TM center (Figure b) . Herein, we describe the extension of this approach towards well‐defined 2c/3e − TM‐E σ‐half‐bonded complexes featuring a TM (Rh or Ir) and a main‐group element E (Si) . Specifically, we report the thorough characterization of zerovalent, d 9 Rh and Ir complexes [K(THF) 3 ][P 3 Si M] (M=Rh, Ir; P 3 Si =tris( o ‐diisopropylphosphinophenyl)silylide; Scheme ).…”

Formal Nickelate(−I) Complexes Supported by Group 13 Ions

“…b) Molecular structure of 1 red with ellipsoids set at 50 %p robability.C ountercation and hydrogen atoms are omitted for clarity. [20] Table 1: Geometrical parameters including bond lengths []and angles [8 8]f or 1 red and 1. [20] [NiAlL] À (1 red )N iAlL (1) NiÀAl 2.389(1) 2.450(1) r [a] 0.97 1.00 NiÀP [b] 2.136(1) 2.204(1) AlÀN eq [b] 1.904 (3) 1.876 (2) (1) 359.0(1) AE(]N eq -Al-N eq )3 47.7 (2) 354.5 (2)…”