Construction And Transportation Of Artificial Transmembrane Channel Based On Column

The new generation of macrocycles has received great attention for their unique tubular structure and excellent molecular recognition properties. Pillararene is a symmetrical pillar architecture in that hydroquinones are connected by methylene bridges. We are interested in building of single-molecular transmembrane channels from pillararenes to mimick the function of channel proteins.In the first part, peptide-appended pillar[n]arene (n=5,6) derivatives have been synthesized.1H NMR and IR studies revealed that the molecules adopt a tubular conformation in solution and lipid bilayer membranes. Kinetic measurements using the fluorescent labeling method with lipid vesicles revealed that these molecules can efficiently mediate the transport of amino acids across lipid membranes at a very low channel-to-lipid ratio (EC50=0.002mol%). In several cases, chiral selectivity for amino acid enantiomers was achieved, which is one of the key functions of natural amino acid channels. And the applications of artificial channels have a good prospect in the separation and purification of amino acids.In the second part, pillar[5]arenes with introverted amino groups were produced through aminolysis. X-ray analysis demonstrated that the intramolecular hydrogen bonding induced the amino group toward the inner space of the cavity. The kinetic studies and molecular modelings revealed that the hydrogen bonding also contributed to the acceleration of the aminolysis through stabilizing the intermediate. Arranging a functional group inward of pillar[5]arene might generate a new kind of functional group introverted cavity. With this structure, we can design the regulated artificial channel, which is under investigation.