A Water‐Soluble [2]Biphenyl‐Extended Pillar[6]arene

The facile design and synthesis of a series of extended pillar[6]arene derivatives is described. In particular, the first water‐soluble version bearing eight pyridinium moieties (CWBpP6) showed strong binding capabilities towards certain guest compounds with sulfonate groups. Significantly, CWBpP6 could uptake 2,6‐naphthalene‐disulfonate from water due to the rapid precipitation upon host–guest complexation, which indicates the potential of CWBpP6 as a promising detection and separation agent for naphthalene sulfonate substrates in water. This provides a possibility for further development of extended pillararenes in selective cargo precipitation as well as sensing and detection of analytes. The facile synthesis of a diverse range of [2]biphenyl‐extended pillar[6]arenes is described. Among the compounds generated is the first water‐soluble version, bearing eight pyridinium moieties; this compound showed strong binding capabilities towards some sulfonate anion guests in aqueous solution and holds great potential for the detection or separation of anionic naphthalenesulfonates through rapid precipitation.