Synergism in host–guest selectivity of picolinium chlorides by triphenylsilanol and triphenylmethanol

Abstract

The host compound triphenylsilanol (TPS) has been employed in the separation of the isomers of picolinium chlorides (2PIC⁺, 3PIC⁺ and 4PIC⁺). By analogy with the Dutch resolution method, we employed triphenylmethanol (TPM) as an additive to TPS and thus changed the composition of the mother liquors in a systematic manner. The resulting crystals were analysed by NMR spectroscopy and X-ray diffraction. The selectivity results for TPS are 2PIC⁺ > 3PIC⁺ ≈ 4PIC⁺.