The 85th Meeting of the Israel Chemical Society

Invited
Pillar[n]arenes: From inhibitors of biofilm formation to supramolecular organogels and boxes

Yoram Cohen
School of Chemistry, Tel Aviv University, Tel Aviv, Israel

Pillar[n]arenes have been used, since their first synthesis in 2008, in many fields and in different applications.1,2 The development of anti-biofilm agents is of importance since bacteria in biofilm are generally much more resistant to antibiotics. In the lecture we will describe the ability of polycationic pillar[n]arenes to serve as potent, non-antimicrobial, anti-biofilm agents.3 The essential structural requirements needed for observing this anti-biofilm activity will be presented.

Supramolecular gels are intriguing class of stimuli-responsive soft materials. In the lecture we will demonstrate that per-carboxylato- and per-amino-pillar[5]arenes form two-components thixotropic and thermally stable supramolecular organogels in different alcoholic and chlorinated solvents.4a We will show that the respective pillar[6]arenes derivatives also form such two-component supramolecular organogels despite being significantly more flexible.4b These organogels are generally more fragile and form only in chlorinated solvents and not in alcohols. With these precursors in hands we will discuss the relative importance of shape-complementarity, multivalency and self-sorting in the self-assembly processes of such organogels.

Molecular containers, which can isolate molecular species from the bulk, may, in principle, be used as nano-flasks and as drug delivery systems. In the lecture we will show that per-diethyl-amino-pillar[6]arene forms with mellitic acid supramolecular hexagonal boxes (SHBs).5 These water-soluble SHBs, which are based on charge assist-hydrogen bonds, were characterized by NMR, DOSY, MS and computational methods. We will demonstrate, in the lecture, that these SHBs are pH-responsive.

  1. T. Ogoshi, et al., J. Am. Chem. Soc., 2008, 130, 5022-5023.

  2. T. Ogoshi, et al., Chem. Rev., 2016, 116, 7937–8002.

  3. a) R. Joseph, et al., J. Am. Chem. Soc., 2016, 138, 745-757. b) R. Joseph, et al., Chem. Commun., 2016, 52, 10656-10659.

  4. a) Y. Zafrani, et al., Chem. Eur. J., 2018, 25, 15750-15755. b) D. Kaizerman-Kane, et al., Org. Chem. Front., 2019, 6, 3348-3354.

  5. D. Kaizerman-Kane, et al., Angew. Chem. Int. Ed., 2019, 58, 5302-5306.









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