Topology-Controlled Selective Fe³⁺ Binding in Water by δ-Peptides with a Dihydropyrimidinone-Containing Amino Acid

Abstract

The effect of topology on the structure, self-assembly, and selective Fe3+ binding of δ-peptides has been investigated. A series of δ-peptides with an amino acid containing dihydropyrimidinone and o-, m-, and p-aminobenzoic acids have been designed to study the structure–function relationship. A new amino acid containing dihydropyrimidinone was synthesized by the Biginelli reaction of ethyl acetoacetate, urea, and o-nitrobenzaldehyde followed by reduction with iron powder and acetic acid. X-ray crystallography sheds some light on the conformations, self-assembly, and the diverse degrees of π–π stacking of adjacent δ-peptide molecules. Peptides with o- or m-aminobenzoic acid form eight-membered intramolecular hydrogen-bonded turn conformations and self-assemble through intermolecular hydrogen bonds between dihydropyrimidinone units to form a butterfly-like structure. However, the δ-peptide containing p-aminobenzoic acid forms a water-mediated cage-like structure. Irrespective of the presence of the same functional groups, only the δ-peptide with o-aminobenzoic acid can selectively bind Fe3+ in methanol as well as in water. The topology plays a crucial role in the selective Fe3+ ion binding by the δ-peptide.

Synthesis, structure and stimulus-responsive properties of a metallogel of a designer ferrocene appended peptide mimetic

“…We designed and developed peptide based functional materials. [40][41][42][43] We recently reported dipeptides with varying steric constraints which exhibited diverse self-assemblies and formed a selective metallogel of Cu(II), Zn(II) and Pb(II). 44 Herein, we report a simple protocol for the synthesis of ferrocene substituted benzoic acid, as well as an efficient synthetic approach towards a ferrocene appended peptide mimetic providing a high reaction rate, yield and purity of the target products.…”

Versatility in self-assembly and morphology of non-coded anthranilic acid and phenylglycine based dipeptide stereoisomers

“…8 Furthermore, they discussed topology-governed solid-state self-assembly of δ-peptides bearing dihydropyrimidinone and ( o / m / p )-aminobenzoic acid and application in selective Fe 3+ ion binding. 9 Tai and his co-workers explored the formation of several nanostructures with Boc- m -ABA-Aib-OMe (Aib: 2-aminoisobutyric acid) under the treatment of various chemical and physical stimuli. 10 They further observed that the two isomeric dipeptides Boc- m -ABA-Aib-OMe and Boc-Aib- m -ABA-OMe created various structures.…”