U‐Shaped Conformation of Alkyl Chains Bound to a Synthetic Host

Abstract

Taking it in turn: Despite the high internal strain, the long aliphatic chains of alkyltrimethylammonium ions buried deeply inside the cucurbit[8]uril (CB[8]) cavity adopt a U-shaped conformation (see X-ray structure), which is stabilized by electrostatic and van der Waals interactions with the carbonyl-laced portal and hydrophobic cavity of CB[8]. This conformation is similar to that of fatty acids bound to fatty acid binding proteins.