Tri-, penta-, and hexa-phospha ruthenocenes

Reduction of tert-butylphosphaalkyne and trimethylsilylnitrile with magnesium(I) dimers

We report on the reactivity of magnesium(I) dimers, [Mg(nacnac)]₂ (nacnac = HC[C(Me)N(2,6-ⁱPr₂C₆H₃)]₂ ([^DippLMg]₂) and HC[C(Me)N(2,4,6-Me₃C₆H₂)]₂ ([^MesLMg]₂)), towards the phosphaalkyne ^tBuCP. The steric profile of the magnesium(I) dimer results in selectivity for different products. The larger diisopropylphenyl derivative yields exclusively the monomeric dimagnesiated phosphaalkene [^DippLMg]PC(^tBu)([^DippLMg]) (1), while the mesityl derivative facilitates reductive coupling of two phosphaalkyne equivalents to give access to the 1,3-diphosphacyclobutadienediide [^MesLMg]₂[(^tBu)₂C₂P₂](2). The reactivity differs in coordinating solvents such as THF, which allowed for the observation of C-P coupled products. For sake of comparison, reactions of magnesium(I) compounds with Me₃SiCN were carried out. In contrast to the reactions involving ^tBuCP, these afforded 1,3-diazabutadienediyl complexes via reductive coupling and silyl migration processes.

The "Hidden" Reductive [2+2+1]-Cycloaddition Chemistry of 2-Phosphaethynolate Revealed by Reduction of a Th-OCP Linkage

The reduction chemistry of the newly emerging 2‐phosphaethynolate (OCP)⁻ is not well explored, and many unanswered questions remain about this ligand in this context. We report that reduction of [Th(Tren^TIPS)(OCP)] (2, Tren^TIPS=[N(CH₂CH₂NSiPrⁱ₃)]³⁻), with RbC₈ via [2+2+1] cycloaddition, produces an unprecedented hexathorium complex [{Th(Tren^TIPS)}₆(μ‐OC₂P₃)₂(μ‐OC₂P₃H)₂Rb₄] (5) featuring four five‐membered [C₂P₃] phosphorus heterocycles, which can be converted to a rare oxo complex [{Th(Tren^TIPS)(μ‐ORb)}₂] (6) and the known cyclometallated complex [Th{N(CH₂CH₂NSiPrⁱ₃)₂(CH₂CH₂SiPrⁱ₂CHMeCH₂)}] (4) by thermolysis; thereby, providing an unprecedented example of reductive cycloaddition reactivity in the chemistry of 2‐phosphaethynolate. This has permitted us to isolate intermediates that might normally remain unseen. We have debunked an erroneous assumption of a concerted fragmentation process for (OCP)⁻, rather than cycloaddition products that then decompose with [Th(Tren^TIPS)O]⁻ essentially acting as a protecting then leaving group. In contrast, when KC₈ or CsC₈ were used the phosphinidiide C−H bond activation product [{Th(Tren^TIPS)}Th{N(CH₂CH₂NSiPrⁱ₃)₂[CH₂CH₂SiPrⁱ₂CH(Me)CH₂C(O)μ‐P]}] (3) and the oxo complex [{Th(Tren^TIPS)(μ‐OCs)}₂] (7) were isolated.

1,2,4-Triphospholyl anions - versatile building blocks for the formation of 1D, 2D and 3D assemblies

The potential of K[P₃C₂R₂] (R = ^tBu, Mes) as building blocks in metallo-supramolecular chemistry was investigated and self-assembly processes with Cu(i) halides resulted in the formation of a large variety of unprecedented one-, two- and even three-dimensional aggregates.

The potential of K[P₃C₂R₂] (R = ^tBu, Mes) as building blocks in metallo-supramolecular chemistry was investigated and self-assembly processes with Cu(i) halides resulted in the formation of a large variety of unprecedented one-, two- and even three-dimensional aggregates. The 3D networks showed an interesting topological similarity to allotropes of carbon: diamond and the theoretically proposed polybenzene. Furthermore, the negative charge of the phospholyl ligand favoured the generation of cationic Cu_aX_b (a > b, X = Cl, Br, I) assemblies, a challenging area within the well-studied coordination chemistry of CuX units. In addition, the 1D strands were also characterized in solution, revealing the presence of oligomeric units.

Unexpected fragmentations of triphosphaferrocene – formation of supramolecular assemblies containing the (1,2,4-P3C2Mes2)− ligand

An unusual fragmentation of a triphosphaferrocene is observed, when it is reacted with Cu(i) halides. As a result, a large variety of different monomeric, dimeric and 1D and 2D polymeric coordination compounds are formed.

A carbon-free sandwich complex [(P5)2Ti]2-

Reactions of highly reduced titanium complexes with white phosphorus, P4, at or below 25 degrees C yielded brown to deep red-brown salts of the first entirely inorganic metallocene, [(eta5-P5)2Ti](2-)(1). Like ferrocene and other carbon-based metallocenes, the structure of 1 has parallel and planar five-membered rings symmetrically positioned about the central metal atom. Despite its electron-deficient (16 electron) and formally zerovalent titanium character, salts of 1 are highly stable toward heat and air, both in solution and in the solid state. Computational studies show that the pentaphosphacyclopentadienyl unit, P5, functions as an unusually effective acceptor ligand, and this results in substantial stabilization of 1.