Triple-Bond Reactivity of an AsP Complex Intermediate: Synthesis Stemming from Molecular Arsenic, As₄

Abstract

While P(4) is the stable molecular form of phosphorus, a recent study illustrated the possibility of P(2) generation for reactions in organic media under mild conditions. The heavier group 15 element arsenic can exist as As(4) molecules, but As(4) cannot be stored as a pure substance because it is both light-sensitive and reverts thermally to its stable, metallic gray form. Herein we report As(4) activation giving rise to a mu-As(2) diniobium complex, serving in turn as precursor to a terminal arsenide anion complex of niobium. Functionalization of the latter provides the new AsPNMes* ligand, which when complexed with tungsten pentacarbonyl elicits extrusion of the (AsP)W(CO)(5) molecule as a reactive intermediate. Trapping reactions of the latter with organic dienes are found to furnish double Diels-Alder adducts in which the AsP unit is embedded in a polycyclic organic framework. Thermal generation of (AsP)W(CO)(5) in the presence of the neutral terminal phosphide complex P identical withMo(N[(i)Pr]Ar)(3) leads to the cyclo-AsP(2) complex (OC)(5)W(cyclo-AsP(2))Mo(N[(i)Pr]Ar)(3). The (AsP)W(CO)(5) trapping products were crystallized and characterized by X-ray diffraction methods, and computational methods were applied for analysis of the As-As and As-P bonds in the complexes.

Triamidoamine uranium(IV)–arsenic complexes containing one-, two- and threefold U–As bonding interactions

“…The bond topology analysis suggests that the U-As bonds are polarized, and in agreement with DFT and NBO analyses, confirms the presence of σ 2 , σ 2 π 2 and σ 2 π 4 U-As bonding interactions in 2c, 3c and 4′. Although it should be recognized that dipolar U n+ -As n− resonance forms will contribute to the electronic structure of these U-As linkages, the ellipticity values for σ 2 2c and σ 2 π 4 4′ are similar to those of ethane (0.0) and acetylene (0.0), whereas that of 3c lies between those of benzene (0.23) and ethylene (0.45) and exceeds the calculated value for the parent E-diarsene HAs=AsH (0.33) 63,74 .…”

“…More surprising than the mono-deprotonation of 2c is that double deprotonation can be effected to access the arsenido complex 4, adding to a class of metal-ligand multiple bonds previously limited to the d-block [62][63][64] . Uranium(IV) generally forms more polarized multiple bonds with ligands than uranium(V) or (VI), so any uranium(IV)-ligand multiple bond would be expected to be reactive and weak.…”

“…Reports of a terminal M=AsH unit in the p-block are restricted to one example in a silylidenearsane/arsasilene with a HSi=AsH subunit 61 . The (As) 3− arsenido is rare in a molecular context and only four terminal arsenidos with group 5 and 6 d-block metals are known [62][63][64] . AsH n fragments are key intermediates in metal organic chemical vapour deposition materials processes, so studying metal derivatives is germane to understanding their properties.…”

The shortest Th–Th distance from a new type of quadruple bond

“…While there are numerous examples of compounds with metal-metal bonds built from main group and d transition elements, 2,3 only a very few actinideactinide bonds are known, in systems stabilised by noble gas matrices. 4 The nature of the bonds formed between actinide metals is of fundamental importance in deepening our understanding of chemical bonding in general, 5 and more specifically of the electronic structure and the coordinative diversity of the 5f elements, 6 where differences exist from their main group, d block and lanthanide counterparts.…”

Molecular Pnictogen Activation by Rare Earth and Actinide Complexes

“…Reaction of the thorium butadiene complex (η In contrast, activation of molecular arsenic by homogeneous transition metal complexes is considerably more diverse; formation of cyclo-Asn ligands (n = 3-6, 8) [54,148], metal arsenic clusters [149], coordination of intact As4 tetrahedra to metal ions [133,150,151], fragmentation into As2 and other As4 ligands [152][153][154], catenation to As10 and As12 ligands [155], reactions to form PnAsm ligands [156], and full As4 fragmentation resulting in terminal M≡As arsenide bonds [157] have all been reported.…”