Hans_Bauer96

Publication date: Available online 16 October 2024

Source: Chem

Author(s): Manjur O. Akram, Caleb D. Martin

The Front Cover shows a gull on a beautiful sunset flying with a series of smaller cartoonish gulls. In between these gulls, the ingredients for a novel reductive transmetalation route are provided: “AlCp*” and ZnR₂ (R=aryl), which selectively react to yield compounds of the generic formula [AlCp*R₂]. As an example, a crystal structure is shown that spreads its newly introduced aryl rings as wings to fly with the big gull. Corroborated by quantum chemical calculations, such compounds found application for selective CO₂ insertion in their AlCp* moieties to yield small inorganic rings. More information can be found in the Research Article by E. Hevia and F. M. Dankert.

As a new entry to low-valent phosphorous ligands, we introduce a naphthalene-supported phosphanyl phosphinidene. This represents a unique example of a bis(amino)phosphine-stabilised phosphinidene. Computational investigations suggest a high degree of P^I→arene delocalisation, lending this species its deep red-purple colouration, which is lost upon coordination to Cu^I.

Abstract

Extending the available intramolecularly-stabilised phosphinidene ligands, we report a novel naphthalene supported system derived from readily available starting materials. Specifically, 1,8-bis(diaminophosphino)naphthalene, naphth-1,8-{P(NEt₂)₂}₂ (1), reacts with ethereal HCl to form the mixed diphosphine naphth-1-(PCl₂)-8-{P(NEt₂)₂} 2 as a phosphoranide Zwitterion, which is readily reduced with elemental Mg in forming the target intramolecularly-stabilised phosphinidene 3. The electronic nature of this species is explored through computational DFT, NBO, and TD-DFT analyses, indicating a high electron density at the P^I centre, which delocalizes across the naphthalene ring lending this deep red-purple compound its colour. The coordination capacity of 3 is demonstrated through its reaction with excess CuCl, which surprisingly leads to exclusive formation of the 2 : 1 complex of 3 to Cu, giving initial insights into the coordination chemistry of this novel ligand.

Abstract

We present complexes of alkaline earth metal ions with the large cyclodimethylsiloxane D₇, D₈ and D₉. The compounds prepared are [Mg(D₇)(H₂O)₂][GaI₄]₂ (1⋅2H₂O), [Ca(D₈)][GaI₄]₂ (2), [Sr(D₈)][GaI₄]₂ (3), [Ba(D₈)][GaI₄]₂ (4), [Ca(D₉)][GaI₄]₂ (5), [Sr(D₉)][GaI₄]₂ (6) and [Ba(D₉)][GaI₄]₂ (7). Single-crystal X-ray diffraction and multinuclear NMR spectroscopy were used to analyze the prepared compounds and coordination modes in the solid state and in solution.

Abstract

A fluorenyl amido constrained geometry magnesium complex is described, which was obtained by deprotonation of the corresponding neutral ligand system with dibutyl magnesium. Its structure was determined by SC-XRD and it was shown to be a potent catalyst for amine-borane dehydrogenation/dehydrocoupling.

Several classes of bulky or multidentate ligands have been used to stabilise hydride complexes of divalent lanthanides. Recent developments regarding this field of chemistry are summarised. Structural aspects, reactivity and spectroscopic parameters are included in the review.

Abstract

Molecular hydride complexes have attracted recent attention, and divalent lanthanides as central atoms in particular are very interesting. They open up possibilities of combining hydride reactivity and lanthanide reactivity. To date, only Yb(II), Eu(II) and Sm(II) as well as a mixed-valent Dy(II)/Dy(III) hydride complexes have been isolated and characterised but the known examples are still low in numbers. In this contribution the development of divalent lanthanide chemistry is summarised, and structural features, reactivity patterns in stoichiometric and catalytic reactions as well as spectroscopic details are outlined.

Nature Chemistry, Published online: 23 October 2024; doi:10.1038/s41557-024-01657-z

Secondary aminophosphanes serve as a synthetic equivalent for iminophosphanes. Dehydrogenation in the presence of Cp₂Ti(C₂TMS₂) (TMS=SiMe₃) afforded titanocene iminophosphane complexes.

Abstract

Dehydrocoupling reactions represent a powerful tool for element-element bond formation upon H₂ elimination. It was shown that transition metals (in low oxidation states or in the form of hydrides) can be coupled with two equivalents of primary pnictanes (R–PnH₂; Pn=P, Sb) providing direct access to otherwise elusive η ² -dipnictene (R–Pn=Pn–R) complexes. Herein, we report on the reactivity of the common group IV metallocene precursors Cp₂Ti(btmsa) and Cp₂Zr(btmsa)(pyridine) (btmsa=C₂(SiMe₃)₂) towards primary pnictanes (R–PnH₂ (Pn=P or N) and secondary aminophosphanes (R'P(H)–N(H)R). We found that Cp₂Ti(btmsa) reacts with secondary aminophosphanes (R'P(H)–N(H)R) to give η ² -iminophosphane titanocene complexes. The molecular and electronic structure of the new compounds were thoroughly investigated spectroscopically, crystallographically and computationally.