Tuning the porosity of triangular supramolecular adsorbents for superior haloalkane isomer separations

Bin Hua, Yanjun Ding, Lukman Olawale Alimi, Basem Moosa, Gengwu Zhang, Walaa S. Baslyman, Jonathan L. Sessler, Niveen M. Khashab

Research output: Contribution to journalArticlepeer-review

Abstract

Distillation-free separations of haloalkane isomers represents a persistent challenge for the chemical industry. Several classic molecular sorbents show high selectivity in the context of such separations; however, most suffer from limited tunability or poor stability. Herein, we report the results of a comparative study involving three trianglamine and trianglimine macrocycles as supramolecular adsorbents for the selective separation of halobutane isomers. Methylene-bridged trianglamine, TA, was found to capture preferentially 1-chlorobutane (1-CBU) from a mixture of 1-CBU and 2-chlorobutane (2-CBU) with a purity of 98.1%. It also separates 1-bromobutane (1-BBU) from a mixture of 1-BBU and 2-bromobutane (2-BBU) with a purity of 96.4%. The observed selectivity is ascribed to the thermodynamic stability of the TA-based host–guest complexes. Based on single crystal X-ray diffraction analyses, a [3]pseudorotaxane structure (2TA⊃1-CBU) is formed between TA and 1-CBU that is characterized by an increased level of noncovalent interactions compared to the corresponding [2]pseudorotaxane structure seen for TA⊃2-CBU. We believe that molecular sorbents that rely on specific molecular recognition events, such as the triangular pores detailed here, will prove useful as next generation sorbents in energy-efficient separations.
Original languageEnglish (US)
JournalChemical Science
DOIs
StatePublished - Aug 16 2021

ASJC Scopus subject areas

  • Chemistry(all)

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