TY - JOUR
T1 - Self-Assembled Cagelike Receptor That Binds Biologically Relevant Dicarboxylic Acids via Proton-Coupled Anion Recognition
AU - Wang, Feiyue
AU - Sen, Sajal
AU - Chen, Chuang
AU - Bähring, Steffen
AU - Lei, Chuanhu
AU - Duan, Zhiming
AU - Zhang, Zhan
AU - Sessler, Jonathan L.
AU - Jana, Atanu
PY - 2020
Y1 - 2020
N2 - 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 pKa 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), H2SO4, 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.
AB - 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 pKa 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), H2SO4, 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.
U2 - 10.1021/jacs.9b11566
DO - 10.1021/jacs.9b11566
M3 - Journal article
C2 - 31895551
SN - 0002-7863
VL - 142
SP - 1987
EP - 1994
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 4
ER -