Cyaphide Explained

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.

Preparation

Organometallic complexes of cyaphide were first reported in 1992.^[1] More recent preparations use two other routes:

From SiR₃-functionalised phosphaalkynes

Treatment of the η¹-coordinated phosphaalkyne complex trans - with an alkoxide resulted in desilylation, followed by subsequent rearrangement to the corresponding carbon-bound cyaphide complex.^[2] Cyaphide-alkynyl complexes are prepared similarly.^[3]

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.^[4] Reaction of the uranium complex [{{chem2|((^{Ad,Me}ArO)3N)U^{III}(DME)}}] with [{{chem|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

Notes and References

1. Robert Angelici. Robert J. Angelici. 2007. Cyaphide (C≡P⁻): The Phosphorus Analogue of Cyanide (C≡N⁻). Angew. Chem. Int. Ed.. 46. 3. 330–332. 10.1002/anie.200603724. 17154215. free.
2. Cordaro. etal. 2006. Making the True "CP" Ligand. Angewandte Chemie International Edition. 45. 37. 6159–6162. 10.1002/anie.200602499. 16937421. free.
3. Synthesis and electronic structure of the first cyaphide-alkynyl complexes . Trathen . etal . Dalton Transactions . 2014 . 43 . 24 . 9004–9007 . 10.1039/C4DT01108B. 24867599 .
4. 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. 10.1021/acs.organomet.7b00590.