A novel fused bi-macrocyclic host for sensitive detection of Cr2O72− based on enrichment effect

Improving the highly selective and sensitive binding of chemosensor to target guest is always very challenging. In order to solve this issue, herein, the enrichment effect was introduced into the design of chemosensor molecule. A novel bi-fused-macrocyclic host molecule BPN1 was synthesized by bridging a pillar[5]arene and a naphthalene diimide (NDI) group through hydrogen-bond-rich chain. In the BPN1, the naphthalimide side ring is outside the cavity of the pillar[5]arene. In addition, Cr(VI) greatly threat human health and the environment due to its severe toxicity, and it is very important to develop effective chemosensor for sensitive and selective detection of Cr2O72− or its ion pairs. In this paper, the novel bi-fused-macrocyclic host molecule BPN1 can recognize Cr2O72− with high selectivity and sensitivity. The mechanism of BPN1 recognition of Cr2O72− was studied through experiments and density functional theory (DFT), the results show that BPN1 could supply enrichment effect to bind Cr2O72− through multiple weak interactions such as hydrogen bonds and anion-π, and achieve highly sensitive and selective detection of Cr2O72−. It's a significant and feasible strategy for improve high selectivity and sensitivity of host to specific objects by using the enrichment effect of fused bi-macrocyclic.