Arsinocarbyne reactivity

The reactivity of the tungsten diphenylarsinocarbyne [W(CAsPh₂)(CO)₂(Tp*)] (1; Tp* = hydrotris(dimethylpyrazolyl)borato) is described. The pyramidal arsenic coordinates to a selection of 5d metal centres, forming heterobi- or trimetallic complexes with osmium(II), iridium(III), platinum(II) and gold(I). In the latter case, the WC bond provides a competitive site for gold(I) coordination. Treatment with MeOSO₂CF₃ results in methylation at arsenic to give the first example of an arsoniocarbyne, [W(CAsPh₂CH₃)(CO)₂(Tp*)]O₃SCF₃, for which only the WC bond remains available for gold(I) coordination.

Heterocyclic arsinocarbynes via tandem transmetallation

Gold(i)-catalysed tandem transmetallation (Sn→Au→As) of the stannylcarbyne [W(≡CSnⁿBu₃)(CO)₂(Tp*)] (Tp* = hydrotris-(dimethylpyrazolyl)borate) with haloarsines gives direct access to a range of novel arsinocarbyne complexes, L_nM≡CAsR₂, including unusual heterocyclic phenarsazininyl and arsolyl examples.

Tetrel and pnictogen functionalised propargylidynes

The reaction of [W([triple bond, length as m-dash]CC[triple bond, length as m-dash]CSiMe₃)(CO)₂(Tp*)] (Tp* = tris(dimethylpyrazolyl)borate) with AgNO₃ affords {[W([triple bond, length as m-dash]CC[triple bond, length as m-dash]CAg)-(CO)₂(Tp*)][AgNO₃]}_n while [Hg{C[triple bond, length as m-dash]CC[triple bond, length as m-dash]W(CO)₂(Tp*)}₂] with ⁿBuLi affords [W([triple bond, length as m-dash]CC[triple bond, length as m-dash]CLi)(CO)₂(Tp*)]. These anhydrous reagents allow the installation of main group elements (e.g., Si, Sn, Pb, P, As) as propargylidyne termini.

A Terminal Chlorophosphinidene Complex

Terminal, electrophilic phosphinidene complexes (M=PR) are attractive platforms for PR-transfer to organic substrates. In contrast to aryl- or alkylphosphinidene complexes terminal chlorophosphinidenes (M=PCl) have only been proposed as transient intermediates but isolable example remain elusive. Here we present the transfer of PCl from chloro-substituted dibenzo-7λ3-phosphanorbornadiene to a square-planar osmium(II) PNP pincer complex to give the first isolable, terminal chlorophosphinidene complex with remarkable thermal stability. Os=P bonding was examined computationally giving rise to highly covalent {OsII=PICl} double bonding.

Metal coordination to bipyridyl carbynes

A new synthetic approach to hetero-aryl substituted carbyne complexes has allowed the synthesis of bipyridyl functionalised carbynes and bis(carbynes) with three potential sites for metal coordination to either the two pyridyl donors or the WC bond.

Tungsten–platinum μ-carbido and μ-methylidyne complexes

The lithiocarbyne [W]CLi ([W] = W(CO)₂(Tp*); Tp* = tris(dimethylpyrazolyl)borate) with divalent platinum complexes afford access to μ-carbido, μ-methylidyne and carbyne-based metallo-ligand complexes.