Open AccessSelf-Assembled Cagelike Receptor That Binds Biologically Relevant Dicarboxylic Acids via Proton-Coupled Anion Recognition
Author(s) -
FeiYue Wang,
Sajal Sen,
Chuang Chen,
Steffen Bähring,
Chuanhu Lei,
Zhiming Duan,
Zhan Zhang,
Jonathan L. Sessler,
Arundhati Jana
Publication year - 2020
Publication title -
journal of the american chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.115
H-Index - 612
eISSN - 1520-5126
pISSN - 0002-7863
DOI - 10.1021/jacs.9b11566
Subject(s) - chemistry , oxalic acid , malonic acid , dicarboxylic acid , maleic acid , carboxylate , dimer , acetic acid , hydrogen bond , trifluoroacetic acid , succinic acid , polymer chemistry , medicinal chemistry , organic chemistry , molecule , copolymer , polymer
We report here a fully organic, self-assembled dimeric receptor, constructed from acyclic naphthyridyl-polypyrrolic building blocks. The cagelike dimer is stable in the solid state, in solution, and in gas phase, as inferred from X-ray diffraction and spectroscopic analyses. This system acts as a receptor for oxalic acid, maleic acid, and malonic acid in the solid state and in THF solution. In contrast, acetic acid, propionic acid, adipic acid, and succinic acid, with p K a values > ca. 2.8, were not bound effectively within the cagelike cavity. It is speculated that oxalic acid, maleic acid, and malonic acid serve to protonate the naphthyridine moieties of the host, which then favors binding of the corresponding carboxylate anions via hydrogen-bonding to the pyrrolic NH protons. The present naphthyridine-polypyrrole dimer is stable under acidic conditions, including in the presence of 100 equiv trifluoroacetic acid (TFA), p -toluenesulfonic acid (PTSA), H 2 SO 4 , and HCl. However, disassembly may be achieved by exposure to tetrabutylammonium fluoride (TBAF). Washing with water then regenerates the cage. This process of assembly and disassembly could be repeated >20 times with little evidence of degradation. The reversible nature of the present system, coupled with its dicarboxylic acid recognition features, leads us to suggest it could have a role to play in effecting the controlled "capture" and "release" of biologically relevant dicarboxylic acids.