Optical Sensing of Aromatic Amino Acids and Dipeptides by a Crown‐Ether‐Functionalized Perylene Bisimide Fluorophore

Abstract

The host-guest binding properties of a fluorescent perylene bisimide (PBI) receptor equipped with crown ether were studied in detail with a series of aromatic amino acids and dipeptides by UV/Vis, fluorescence and NMR spectroscopy. Fluorescence titration experiments showed that electron-rich aromatic amino acids and dipeptides strongly quench the fluorescence of the electron-poor PBI host molecule. Benesi-Hildebrand plots of fluorescence titration data confirmed the formation of host-guest complexes with 1:2 stoichiometry. Binding constants determined by global analysis of UV/Vis and fluorescence titration experiments revealed values between 10 m and 10 m in acetonitrile/methanol (9:1) at 23 °C. These data showed that amino acid l-Trp having an indole group and dipeptides containing this amino acid bind to the PBI receptor more strongly than other amino acids and dipeptides investigated here. For dipeptides containing l-Trp or l-Tyr, the binding strength is dependent on the distance between the ammonium group and the aromatic unit of the amino acids and dipeptides leading to a strong sensitivity for Ala-Trp dipeptide. 1D and 2D NMR experiments also corroborated 1:2 host-guest complexation and indicated formation of two diastereomeric species of host-guest complexes. The studies have shown that a properly functionalized PBI fluorophore functions as a molecular probe for the optical sensing of aromatic amino acids and dipeptides.

Selection of Planar Chiral Conformations between Pillar[5,6]arenes Induced by Amino Acid Derivatives in Aqueous Media

“…The intrinsic chirality of α‐amino acids and abundant hydrogen‐bonding sites afford diversified chiral structures at the nano‐, micro‐, and macroscale, [8–10] and this widely facilitates the development of chiroptical materials [11, 12] . Hitherto, chiral recognition of α‐amino acids has mainly focused on the determination of l / d enantiomers by observing circular dichroism (CD) spectra or fluorescence changes [13–17] . So, more strategies should be provided to detect the chirality of α‐amino acids even those that are CD‐silent or without fluorescence changes.…”

“…[11,12] Hitherto, chiral recognition of a-amino acids has mainly focused on the determination of l/d enantiomers by observing circular dichroism (CD) spectra or fluorescence changes. [13][14][15][16][17] So, more strategies should be provided to detectt he chirality of a-aminoa cids even those that are CDsilent or withoutf luorescence changes. Furthermore, to the best of our knowledge, little attention has been paid to competitive selection of chiral regions of as ingle chiral a-amino acid molecule.…”

Luminescent Rhenium(I)–Polypyridine Complexes Appended with a Perylene Diimide or Benzoperylene Monoimide Moiety: Photophysics, Intracellular Sensing, and Photocytotoxic Activity

“…The utilization of perylene derivatives in biological studies has been accomplished by using different strategies, such as the introduction of hydrophilic or charged groups at the imide positions or in the bay regions . For example, a crown ether modified PDI derivative has been designed as a sensor for aromatic amino acids and dipeptides . A PDI–polyetheramine compound has been found to show interesting fluorogenic responses toward live cells .…”

“…[3] For example, ac rown ether modified PDI derivativeh as been designed as as ensor for aromatic amino acids and dipeptides. [4] AP DI-polyetheramine compound has been found to show interesting fluorogenic responses toward live cells. [5] Ad-ditionally, fluorescent multi-cationic and amphiphilic PDI compoundsh ave been used as gene-delivery vectors [6] and imaging reagents.…”

Selective Recognition of Amino Acids and Peptides by Small Supramolecular Receptors

“…A different approach for detection of aromatic amino acids and small peptides containing these residues was presented by Weißenstein et al [153]. In their studies they joined the properties of two different moieties-as readout mechanism they used a perylene bisimide dye (PBI), which has high fluorescence quantum yield and can be quenched by photoinduced electron transfer (PET)-this process can occur when this group forms bonds with electron rich moieties, e.g., aromatic amino acids which can bind to PBI by π-π stacking of aromatic groups; the other distinct moiety is composed of two crown ethers that serve as a receptor for ammonium cations, e.g., the N-terminal of short peptides or amine groups present in cationic amino acids.…”