Pnictogen-functionalised isocyanide ligands

The reactions of a range of cyanometallate salts with ClAtBu2 (A = P, As, Sb, A ≠ Bi) afford the new phosphino, arsino and stibino-isonitrile complexes [M(CNAtBu2)(CO)5] (M = W, A = P, As, Sb) and [MLn(CNPtBu2)] [MLn = Cr(CO)5, Mo(CO)5, Mn(CO)2(η5-C5H5), Re(CO)2(η5-C5H5), Fe(CO)4, Fe(CO)3(PPh3)] allowing crystallographic spectroscopic and computational interrogation of isonitrile compexes functionalised by the heavier pnictogens.

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.

Heterobimetallic μ2-Halocarbyne complexes

The halocarbyne complexes [M(≡CX)(CO)2(Tp*)] (M = Mo, W; X = Cl, Br; Tp* = hydrotris(dimethylpyrazolyl)borate) react with [AuCl(SMe2)], [Pt(-H2C=CH2)(PPh3)2] or [Pt(nbe)3] (nbe = norbornene) to furnish rare examples of μ2-halocarbyne...

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.

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.

The significance of phosphoniocarbynes in halocarbyne cross-coupling reactions

Competent intermediates as well as productive and non-productive tangents have been identified in the catalytic cycle for palladium(0)–copper(i) mediated synthesis of propargylidynes via cross coupling reactions of bromocarbyne complexes with alkynes.

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.

Auriferous alkynylselenolatoalkylidynes

Gold plating carbynes – The incorporation of gold(i) centres, either terminal or bridging, into alkynylselenolatocarbynes provides models for how such metallated carbon-wires might bind to metal surfaces.

Alkynylselenolatoalkylidynes (LnMC–Se–CCR) as building blocks for mixed metal/main-group extended frameworks

The reactions of [W(CBr)(CO)₂(Tp*)] (Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate) with lithium alkynylselenolates LiSeCCR (R = SiMe₃, SiⁱPr₃, ⁿBu, ^tBu, Ph, p-tolyl) afford the alkynylselenolatoalkylidyne complexes [W(CSeCCR)(CO)₂(Tp*)].

Phosphaisonitrile umpolung – synthesis and reactivity of chloro aminophosphino carbynes

The synthesis of the first P-halo-aminophosphinocarbyne complex is described in addition to exploration of its ligand-based reactivity towards nucleophilic substitution and P-halide abstraction processes as a possible route to cationic aminophosphaisonitrile derivatives.

Alkynylbis(alkylidynyl)phosphines: {LnMC}2PCCR

Synthetic strategies are presented for the formation of alkynylbis(alkylidynyl)phosphines which represent promising building blocks for unsaturated 2- and 3-dimensional assemblies. Parent ethynyl derivatives provide a means for installing further donor functionalities, e.g., AsPh₂ as shown.