Helical conformation of alkanes in a hydrophobic cavitand.
Alkanes adopt extended conformations in solution that minimize steric interactions and maximize surface area. Folding can reduce the amount of hydrophobic surface exposed to solvent, but sterically unfavorable gauche interactions result. However, we found that the alkyl chains of two common surfactants in aqueous solution adopt helical conformations when bound within a synthetic receptor. The receptor recognizes the helical alkane better than the extended conformation, even though 2 to 3 kilocalories per mole of strain is introduced. The proper filling of space and burial of hydrophobic surface drive the molecular recognition between the receptor and the coiled alkane.
Trembleau
Laurent
L
Skaggs Institute for Chemical Biology and Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Rebek
Julius
J
D000473:Alkanes / Q000737:chemistry*; D001562:Benzimidazoles / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D012996:Solutions; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
D000473:Alkanes; D001562:Benzimidazoles; D012996:Solutions; D013501:Surface-Active Agents; D010767:Phosphorylcholine; D012967:Sodium Dodecyl Sulfate; C028810:dodecylphosphocholine