A Water‐Soluble Perylene Bisimide Cyclophane as a Molecular Probe for the Recognition of Aromatic Alkaloids

Abstract

Herein, we report a water‐soluble macrocyclic host based on perylene bisimide (PBI) chromophores that recognizes natural aromatic alkaloids in aqueous media by intercalating them into its hydrophobic cavity. The host–guest binding properties of our newly designed receptor with several alkaloids were studied by UV/Vis and fluorescence titration experiments as the optical properties of the chromophoric host change significantly upon complexation of guests. Structural information on the host–guest complexes was obtained by 1D and 2D NMR spectroscopy and molecular modelling. Our studies reveal a structure–binding property relationship for a series of structurally diverse aromatic alkaloids with the new receptor and higher binding affinity for the class of harmala alkaloids. To our knowledge, this is the first example of a chromophoric macrocyclic host employed as a molecular probe for the recognition of aromatic alkaloids.

Deracemization of Carbohelicenes by a Chiral Perylene Bisimide Cyclophane Template Catalyst

“…As a consequence of their large π‐surfaces, PBIs bridged with para ‐xylylene spacer units proved to be excellent hosts with high binding affinities for polycyclic aromatic hydrocarbons[ 14 , 15 ] and even some alkaloids. [16] Furthermore, similar to previously described examples,[ 8 , 9 ] chirality transfer from chiral guest molecules to achiral PBI cyclophanes could be observed by CD spectroscopy. [17] Inspired by this work, we have now designed the first example of an inherently chiral PBI cyclophane host.…”

Deracemization of Carbohelicenes by a Chiral Perylene Bisimide Cyclophane Template Catalyst

“…As a consequence of their large p-surfaces, PBIs bridged with para-xylylene spacer units proved to be excellent hosts with high binding affinities for polycyclic aromatic hydrocarbons [14,15] and even some alkaloids. [16] Furthermore, similar to previously described examples, [8,9] chirality transfer from chiral guest molecules to achiral PBI cyclophanes could be observed by CD spectroscopy. [17] Inspired by this work, we have now designed the first example of an inherently chiral PBI cyclophane host.…”

Perylene Bisimide and Naphthyl‐Based Molecular Dyads: Hydrogen Bonds Driving Co‐planarization and Anomalous Temperature‐Response Fluorescence

“…In this study, strategically, the naphthyl moiety with an ortho ‐methoxy group (NM) and perylene bisimide (PBI) units were chosen as a donor and an acceptor, respectively, which are separated by an alkynyl linker, rendering a D‐A system, PBI‐2NM (Figure ). PBI was selected because of its advantages of low LUMO level, intense emission, and excellent photostability . 1 H NMR studies revealed that the oxygen atom in the ortho ‐methoxy group of the NM moiety and an aromatic hydrogen atom (H a , see Figure ) of the PBI core could form a weak but effective H‐bond (Ar−H⋅⋅⋅O, where Ar stands for an aromatic ring), allowing stabilization of a π‐conjugated configuration owing to blocking of the free rotation of the linker.…”