Cyaphide

Cyaphide, P≡C⁻, is the phosphorus analogue of cyanide. It is not known as a discrete salt; however, in silico measurements reveal that the −1 charge in this ion is located mainly on carbon (0.65), as opposed to phosphorus.

Structure of the first transition metal cyaphide complex, RuH(dppe)₂(CP)

The word "cyaphide" was first coined in 1992, by analogy with cyanide.^[1]

Preparation

Organometallic complexes of cyaphide were first reported in 1992.^[2] More recent preparations use two other routes:

From SiR₃-functionalised phosphaalkynes

Treatment of the η¹-coordinated phosphaalkyne complex trans–[RuH(P≡CSiPh₃)(dppe)₂]⁺ with an alkoxide resulted in desilylation, followed by subsequent rearrangement to the corresponding carbon-bound cyaphide complex.^[3] Cyaphide-alkynyl complexes are prepared similarly.^[4]

From 2-phosphaethynolate anion (⁻OC≡P)

An actinide cyaphide complex can be prepared by C−O bond cleavage of the phosphaethynolate anion, the phosphorus analogue of cyanate.^[5] Reaction of the uranium complex [((^Ad,MeArO)₃N)U^III(DME)] with [Na(OCP)(dioxane)
_2.5] in the presence of 2.2.2-cryptand results in the formation of a dinuclear, oxo-bridged uranium complex featuring a C≡P ligand.

See also

• phosphaalkyne (P≡CR)
• Methylidynephosphane
• Cyaarside

References

1. Jun, Hyoung; Young, Victor G.; Angelici, Robert J. (1992). "A phosphorus analog (C≡P⁻) of a bridging cyanide (C≡N⁻) ligand: synthesis and structure of (Cl)(PEt₃)₂Pt(μ-C≡P)Pt(PEt₃)₂". Journal of the American Chemical Society. 114 (25): 10064–10065. doi:10.1021/ja00051a050. ISSN 0002-7863.
2. Robert J. Angelici (2007). "Cyaphide (C≡P⁻): The Phosphorus Analogue of Cyanide (C≡N⁻)". Angew. Chem. Int. Ed. 46 (3): 330–332. doi:10.1002/anie.200603724. PMID 17154215.
3. Cordaro; et al. (2006). "Making the True "CP" Ligand". Angewandte Chemie International Edition. 45 (37): 6159–6162. doi:10.1002/anie.200602499. PMID 16937421.
4. Trathen; et al. (2014). "Synthesis and electronic structure of the first cyaphide-alkynyl complexes" (PDF). Dalton Transactions. 43 (24): 9004–9007. doi:10.1039/C4DT01108B. PMID 24867599.
5. Christopher J. Hoerger, Frank W. Heinemann, Elisa Louyriac, Laurent Maron, Hansjörg Grützmacher, Karsten Meyer (2017). "Formation of a Uranium-Bound η¹-Cyaphide Ligand via Activation and C−O Bond Cleavage of Phosphaethynolate". Organometallics. 36: 4351–4354. doi:10.1021/acs.organomet.7b00590.{{cite journal}}: CS1 maint: multiple names: authors list (link)