A series of novel coronands having a 2n-crown- n topology based on trioxane (6-crown-3) derivatives are designed and characterized. These neutral hosts can sense anions through pure aliphatic C?H hydrogen bonding (HB) in condensed phases due to the unusual topology of 2n-crown-n. C?H bonds are strongly polarized by two adjacent oxygen atoms in this scaffold. These hosts provide a rare opportunity to modulate anion binding strength by changing the electronic nature of aliphatic C?H bonds and offer ease of synthesis.
Reference: Shi, G. et al. Org. Lett. 2014, 16(2), 334-337.