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Updated: Jul 19, 2026

Real-time Monitoring of Ligand-receptor Interactions with Fluorescence Resonance Energy Transfer
Published on: August 20, 2012
BF2 complex of fluorinated dipyrrolyldiketone: a new class of efficient receptor for acetate anions
Hiromitsu Maeda1, Yoshihiro Ito
1Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu 525-8577, Japan. maedahir@se.ritsumei.ac.jp
Abstract:
The beta-fluorinated derivative (2b) of the 1,3-dipyrrolyl-1,3-propanedione BF2 complex has been prepared from 3,4-difluoropyrrole and malonyl chloride, followed by treatment with BF3.OEt2. Despite the simple, acyclic, and neutral structure, 2b exhibits efficient 1:1 binding for anions in CH2Cl2 using the bridging CH and pyrrole NH as interaction sites. The binding constant (Ka) of 2b for acetate (CH3CO(2-)), associating more effectively than anions such as F-, Cl-, Br-, H2PO(4-), and HSO(4-), is estimated to be 9.6 x 10(5) M(-1), approximately 9 times larger than that of the beta-H derivative 2a (1.1 x 10(5) M(-1)). The UV-vis and fluorescence spectral changes of 2b elucidate the effective recognition of an amino acid, such as phenylalanine, in the anionic form; this is also supported by CD spectral changes with mirror images by L- and D-isomers. Furthermore, in the solid state, BF2 complex 2b provides Cl- -bridged supramolecular networks and, in sharp contrast, deprotonated "anionic" self-assembled structures by F- binding.
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