Hans_Bauer96

Nature Chemistry, Published online: 05 December 2023; doi:10.1038/s41557-023-01380-1

Alkoxyphosphoranes, Ph₂P(OR)(O₂C₆Cl₄) and the metal chlorides generate corresponding phosphate-catecholate chelated Nd(III), Zr(IV) and Al(III) chlorides via ethyl chloride elimination. These monometallic and bimetallic metal complexes are stabilized by chelating P−O and catecholate-O donors.

Abstract

Metal phosphates are important catalysts and materials in synthesis chemistry. Herein, we describe the synthesis and characterization of phosphate-catecholate chelated Nd(III), Zr(IV) and Al(III) chlorides (2–5). These species are achieved via ethyl chloride elimination reaction of oxophosphoranes with corresponding metal chlorides. The product 2–5 represent a new serial of monometallic and bimetallic phosphate-catecholate chelated metal complexes stabilized by both P−O and catecholate-O donors. These findings pave the way for future explorations of such species in catalysis.

Mono-boryl complexes: The synthesis of the first terminal mono-boryl complexes of nickel, which are not stabilized by a pincer ligand, is reported.

Abstract

The synthesis of the first terminal mono-boryl complexes of nickel, which are not stabilized by a pincer ligand, is reported. The reaction of the nickel bis-boryl complex cis-[Ni( ⁱ Pr₂Im^Me)₂(Bcat)₂] 1 (cat=1,2-O₂C₆H₄) with the small donor ligand PMe₃ led to a complete ligand exchange at nickel with reductive elimination of B₂cat₂ and formation of the bis-NHC adduct [B₂cat₂ ⋅ ( ⁱ Pr₂Im^Me)₂] 3 and [Ni(PMe₃)₄] 2 as the metal-containing species. Electrophilic attack of MeI on complex 1 or ligand dismutation of 1 with trans-[Ni( ⁱ Pr₂Im^Me)₂Br₂] led to loss of only one boryl ligand of 1 and afforded the nickel mono-boryl complexes trans-[Ni( ⁱ Pr₂Im^Me)₂(Bcat)Br] 4 a and trans-[Ni( ⁱ Pr₂Im^Me)₂(Bcat)I] 4 b.

“The interplay between the exceptional π-acceptor and σ-donor properties of the pyridyl-mesoionic carbene is fascinating for the design of new potential photo- and electrocatalysts.” This and more about the story behind the front cover can be found in the article at 10.1002/chem.202301205).

Abstract

Invited for the cover of this issue are Biprajit Sarkar and co-workers at the University of Stuttgart and University of Freiburg. In the image, the solar flare represents the non-innocence (fluorine-specific interactions) of the counterion, and the black hole at the metal center illustrates the oxidation/electron deficiency of the Cr-center, while the electron “gets lost” in the space (oxidation agent). Read the full text of the article at 10.1002/chem.202301205.

Reduction of a bulky magnesium(II) diamide with 5 % w/w K/KI under an N₂ atmosphere has given a complex between magnesium and doubly reduced dinitrogen, N₂ ²⁻. The reaction has been calculated to proceed via an anionic magnesium(I) radical, and the final product shown to act as a masked dimagnesium(I) diradical in reactions with CO, H₂ and C₂H₄.

Abstract

The activation of dinitrogen (N₂) by transition metals is central to the highly energy intensive, heterogeneous Haber–Bosch process. Considerable progress has been made towards more sustainable homogeneous activations of N₂ with d- and f-block metals, though little success has been had with main group metals. Here we report that the reduction of a bulky magnesium(II) amide [(^TCHPNON)Mg] (^TCHPNON=4,5-bis(2,4,6-tricyclohexylanilido)-2,7-diethyl-9,9-dimethyl-xanthene) with 5 % w/w K/KI yields the magnesium-N₂ complex [{K(^TCHPNON)Mg}₂(μ-N₂)]. DFT calculations and experimental data show that the dinitrogen unit in the complex has been reduced to the N₂ ²⁻ dianion, via a transient anionic magnesium(I) radical. The compound readily reductively activates CO, H₂ and C₂H₄, in reactions in which it acts as a masked dimagnesium(I) diradical.