64 research outputs found
Molecular Complexes Featuring Unsupported Dispersion-Enhanced AluminumâCopper and GalliumâCopper Bonds
The reaction of the copper(I) ÎČ-diketiminate copper complex {(Cu(BDIMes))2(ÎŒ-C6H6)} (BDIMes = N,NâČ-bis(2,4,6-trimethylphenyl)pentane-2,4-diiminate) with the low-valent group 13 metal ÎČ-diketiminates M(BDIDip) (M = Al or Ga; BDIDip = N,NâČ-bis(2,6-diisopropylphenyl)pentane-2,4-diiminate) in toluene afforded the complexes {(BDIMes)CuAl(BDIDip)} and {(BDIMes)CuGa(BDIDip)}. These feature unsupported copperâaluminum or copperâgallium bonds with short metalâmetal distances, CuâAl = 2.3010(6) Ă
and CuâGa = 2.2916(5) Ă
. Density functional theory (DFT) calculations showed that approximately half of the calculated association enthalpies can be attributed to London dispersion forces.peerReviewe
Synthesis of a Carbene-Stabilized (Diphospha)aminyl Radical and Its One Electron Oxidation and Reduction to Nonclassical Nitrenium and Amide Species
Herein,
we report the synthesis of an acyclic carbene-stabilized
diphospha(aminyl) PNP radical CAACMePNPCAACMe 4 (CAACMe = 1-[2,6-bis(isopropyl)phenyl]-3,3,5,5-tetramethyl-2-pyrrolidinylidene)
by a facile one-pot, seven-electron reduction of hexachlorophosphazene
chloride [Cl3PNPCl3][Cl]. The PNP radical 4 features a conjugated framework with spin density primarily
localized on the central nitrogen atom as well as the flanking carbenes.
Unlike other tripnictogen radicals, 4 undergoes facile
one-electron oxidation and reduction to yield nonclassical nitrenium
and amide species [5]+ and [6]â, respectively. The cation [5]+ exhibits conformational flexibility in the solution state
between the expected W-shaped geometry [5b]+ and a previously unobserved linear heteroallene-type
structure [5a]+, which
was characterized in the solid state. The equilibrium was explored
both computationally and experimentally, showing that [5a]+ is favored over [5b]+ both enthalpically (ÎH = â2.9 Ă 103 ± 80 J molâ1) and entropically (ÎS = 4.2
± 0.25 J molâ1 Kâ1). The
formal amide [6]â displays remarkable
flexibility in its coordination chemistry due to the presence of multiple
Lewis basic centers, as evidenced by the structure of its potassium
complex K262, which exhibits ÎŒ, Îș-P, Îș-P,
and η3-PNP coordination modes. Protonation of [6]â leads to the formation of an amine 7, which features a trigonal planar geometry around nitrogen
Synthesis of a Carbene-Stabilized (Diphospha)aminyl Radical and Its One Electron Oxidation and Reduction to Nonclassical Nitrenium and Amide Species
Herein,
we report the synthesis of an acyclic carbene-stabilized
diphospha(aminyl) PNP radical CAACMePNPCAACMe 4 (CAACMe = 1-[2,6-bis(isopropyl)phenyl]-3,3,5,5-tetramethyl-2-pyrrolidinylidene)
by a facile one-pot, seven-electron reduction of hexachlorophosphazene
chloride [Cl3PNPCl3][Cl]. The PNP radical 4 features a conjugated framework with spin density primarily
localized on the central nitrogen atom as well as the flanking carbenes.
Unlike other tripnictogen radicals, 4 undergoes facile
one-electron oxidation and reduction to yield nonclassical nitrenium
and amide species [5]+ and [6]â, respectively. The cation [5]+ exhibits conformational flexibility in the solution state
between the expected W-shaped geometry [5b]+ and a previously unobserved linear heteroallene-type
structure [5a]+, which
was characterized in the solid state. The equilibrium was explored
both computationally and experimentally, showing that [5a]+ is favored over [5b]+ both enthalpically (ÎH = â2.9 Ă 103 ± 80 J molâ1) and entropically (ÎS = 4.2
± 0.25 J molâ1 Kâ1). The
formal amide [6]â displays remarkable
flexibility in its coordination chemistry due to the presence of multiple
Lewis basic centers, as evidenced by the structure of its potassium
complex K262, which exhibits ÎŒ, Îș-P, Îș-P,
and η3-PNP coordination modes. Protonation of [6]â leads to the formation of an amine 7, which features a trigonal planar geometry around nitrogen
Nickel as a Lewis Base in a TâShaped Nickel(0) Germylene Complex Incorporating a Flexible Bis(NHC) Ligand
Flexible, chelating bis(NHC) ligand 2, able to accommodate both cis- and trans-coordination modes, was used to synthesize (2)Ni(η 2 -cod), 3. In reaction with GeCl2, this produced (2)NiGeCl2, 4, featuring a T-shaped Ni(0) and a pyramidal Ge center. Complex 4 could also be prepared from [(2)GeCl]Cl, 5, and Ni(cod)2, in a reaction that formally involved Ni-Ge transmetalation, followed by coordination of the extruded GeCl2 moiety to Ni. A computational analysis showed that 4 possesses considerable multiconfigurational character and the NiâGe bond is formed through Ï-donation from the Ni 4s, 4p, and 3d orbitals to Ge. (NHC)2Ni(cod) complexes 9 and 10, as well as (NHC)2GeCl2 derivative 11, incorporating ligands that cannot accommodate a wide bite angle, failed to produce isolable Ni-Ge complexes. The isolation of (2)Ni(η 2 -Py), 12, provides further evidence for the reluctance of the (2)Ni(0) fragment to act as a ÏLewis acid.peerReviewe
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