Pillar(n)arenes: towards higher yielding synthetic routes
An efficient templated approach for the synthesis of pillar(n)arenses (P(n)) bearing different alkoxy substituent has been developed. P(6) was obtained in high yield up to 38% with higher selectivity than P(5) thank to the use of small organic cation binding P(6) better than P(5) as templates.
Pillararenes are a novel class of macrocyclic molecules made up of hydroquinone ether units linked by methylene bridges reported by Ogoshi’s group in 2008 (Figure 1).(1) In the past eight years, pillar(n)arenes (n = 5–15) have been studied extensively investigating in particular their synthesis, host-guest complexation and structural function up to self-assembly.
The introduction of this new host unit attracted the attention of the scientific community as shown from the number of annual publications, increased rapidly from around 20 in 2011 to nearly 90 in 2015.
Compared with other traditional macrocyclic hosts, pillar(n)arenes have several advantages: the easy and convenient synthesis and functionalization; their solubilization ability in solvent of different polarity including water, dichloromethane, and acetone after chemical modification; their rigid electron-rich cavity that make them good candidates to construct molecular aggregates based on host–guest complexation.
In fact, host–guest interactions of pillararene chemistry and their related applications have been extensively studied in diverse fields, including molecular recognition and sens ...