Development of Functional Powdered Materials via Selective Molecular Recognition Premised on Non-porous Organic Molecules

Abstract

Since certain organic molecules were reported to exhibit porous material-like sorption behaviors in the crystalline state, many groups have studied the sorption behaviors of small organic molecules such as calix[n]arene, cucurbit[n]uril, and pillar[n]arene, to name just a few. Our group has demonstrated that tris(phenylisoxazolyl)benzene derivatives possessing long alkyl chains in their periphery form stacking constructs in solution. In order to extend the solution phase chemistry of the tris(phenylisoxazolyl)benzene derivatives to the crystalline state, we have here newly designed a tris(phenylisoxazolyl)benzene derivative, namely tris(methoxyphenylisoxazolyl)benzene, which possesses methoxy chains and exhibits good crystallinity. The crystal structure of the solvent-free powder of tris(methoxyphenylisoxazolyl)benzene clearly displayed a densely packed structure with no apparent pores. The solvent-free powder was exposed to a vapor mixture of cis- and trans-decalin, resulting in cis-decalin encapsulated tris(methoxyphenylisoxazolyl)benzene. These results demonstrate the feasibility of producing separation materials based on tris(phenylisoxazolyl)benzene derivatives.