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