Potassium tetrakis(pentafluorophenyl)borate

Potassium tetrakis(pentafluorophenyl)borate (CAS 89171-23-3) is a weakly coordinating borate salt of formula C24BF20K, 718.1 g/mol.

A weakly coordinating anion: it is used as an electrolyte salt or as a phase-transfer counter-ion, not as a nucleophile. The salt form is chosen for handling and storage; the free base or free acid is generated in situ when the reaction needs it.

The formula C24BF20K resolves to 24 carbons with one boron, 20 fluorines and one potassium counter-ion. Long-chain entries of 24 carbons behave as oils or waxy solids and are warmed before packing so that the unit weight is accurate.

Where this entry sits in a route

Potassium tetrakis(pentafluorophenyl)borate is the potassium salt of a very weakly coordinating anion. It is bought for situations where a normal counter-ion would interfere: electrolyte formulations, catalyst activation where the anion has to stay innocent, and phase-transfer conditions where lipophilic cations are being moved into an organic phase.

What the analysis covers

The lot is checked for chloride and for the free borate acid, both of which change conductivity and catalyst behaviour. Water content is stated separately because the salt is hygroscopic.

Handling and storage

These salts are hygroscopic and are dried before use in an electrochemical or catalytic step.

Ordering

The unit weights held are 1kg / 25kg / 100kg. A split shipment across two of those sizes is treated as one lot and one certificate. Identity is confirmed by NMR and MS at release, and the assay value belongs to the lot rather than to the catalogue entry.