TRISPHAT

Tributylammonium TRISPHAT is the an organic salt with the formula [(C₄H₉)₃NH]+[P(O₂C₆Cl₄)^3-]. The anion features phosphorus(V) bonded to three tetrachlorocatecholate (C₆Cl₄O₂^2-) ligands. This anion can be resolved into the enantiomers, which are optically stable (the picture shows the Δ enantiomer).

Additional recommended knowledge

Better weighing performance in 6 easy steps

Daily Visual Balance Check

How to quickly check pipettes?

The TRISPHAT anion has been used as a “chiral shift reagent” for cations. It improves the resolution of ¹H NMR spectra by forming diastereomeric ion pairs.

Preparation

The anion is prepared by treatment of phosphorus pentachloride with tetrachlorocatechol followed by a tertiary amine gives the anion:

PCl₅ + 3 C₆Cl₄(OH)₂ → H[P(O₂C₆Cl₄)₃] + 5 HCl

H[P(O₂C₆Cl₄)₃] + Bu₃N Bu₃NH⁺ [P(O₂C₆Cl₄)₃]^- Using a chiral amine, the anion can be readily resolved.^[1]

References

1. ^ F. Favarger, C. Goujon-Ginglinger, D. Monchaud, J. Lacour “Large-Scale Synthesis and Resolution of TRISPHAT [Tris(tetrachlorobenzenediolato) Phosphate(V)] Anion” Journal of Organic Chemistry, 2004, volume 69, pp. 8521 -8524, 2004. DOI: 10.1021/jo048641q.