Inclusion of Amine Isomers with Open-Chain Hosts Having a Partial Structure of Butylthiacalixarene.

Porous materials, which can capture a specific compound from a hard-to-separate molecular mixture, are strongly desired for practical separation and purification processes. Aiming to develop such materials, we have investigated the performance of our original host compounds, [3,3'-thiobis(5-butyl-2-hydroxybenzene)-1,1'-diyl]diacetic acid () and its monopropyl ester (), in discriminating among regio- or stereoisomers of three groups of amines, 2-, 3-, and 4-methylpyridine, 2-, 6-, and 8-methylquinoline, and and 4-cyclohexanamine. Diacid selectively included 4-methylpyridine in hexane and 3-methylpyridine in toluene in competitive inclusion among the three regioisomers.

Design and Synthesis of Open-Chain Hosts Having a Partial Structure of p-tert-Butylthiacalixarene.

The development of separation materials for hard-to-separate molecular mixtures is highly desired from environmental and economic perspectives. Although the crystal of p-tert-butylthiacalix[4]arene exhibits high guest selectivity in inclusion from a mixture of molecules with similar sizes and shapes, it cannot include molecules larger than its calix cavity. To extend its guest inclusivity, we designed and synthesized an open-chain host, [3,3'-thiobis(5-tert-butyl-2-hydroxybenzene)-1,1'-diyl]diacetic acid (4).