Odd−Even Effects in Supramolecular Assemblies of Diamide Bolaamphiphiles

Abstract

Bolaamphiphiles (“bolas”) containing two secondary amide groups at the ends of an oligomethylene chain and two amino acid type headgroups were synthesized. The structures of crystals, of noncovalent fibers, and of surface monolayers on gold strongly depended on odd−even effects. In the crystal structures of alanine−alanine dipeptides with C11- and C12-α,ω-amino acid linkers, helical (even number of methylene groups in the chain) or sheetlike (odd) arrangements of the headgroups were found. Bolas containing two different amino acid end groups, namely, d- or l-alanine and l-lysine, connected by the same C11- and C12 linkers did not crystallize. Only the even-numbered bolas gave fibers. l- and d- configurations of alanine headgroups affected the curvature of the fibers. Diamido bolas with terminal SH-groups self-assembled on gold. Only those with even-numbered chains gave rigid monolayers. Simple stereochemical arguments concerning the fitting of amide hydrogen bond chains on both ends of the bolas are given to explain the observed differences in crystals, fibers, and monolayers.

Bottom-Up Synthesis and Morphological Control of High-Axial-Ratio Nanostructures through Molecular Self-Assembly

“…Furthermore, the band frequencies of the amide I and II bands clearly show an even/odd effect for the chain length n (n ≥ 10), as shown in Figure 5b. Similar kinds of even/odd effect on the amide I and II adsorp-tion bands can also be seen upon the nanofiber formation from 2-glucosamide homologues 3(n) 57 or diamide bolaamphiphiles, 70 as well as for the cast films of azobenzene-containing amphiphiles. 71,72 Powder X-Ray diffraction (XRD) patterns of the selfassembled 1(n) displayed different types of diagrams in the wide-angle region, depending on the even/odd numbers of the oligo(methylene) chains.…”

Synthesis and aggregation behaviour of symmetric glycosylated bolaamphiphiles in water

“…These monostrand compounds often formed fibrous networks in aqueous solution, due to the setting up of intermolecular hydrogen bonds within the membranes. [7][8][9][10][11][12][13] On the other hand, few examples were reported describing the formation of vesicle systems by bolaform surfactants.…”

Krafft temperature and enthalpy of solution of N -acyl amino acid surfactants and their racemic modifications: effect of the counter ion

“…On the other hand, the concern with chiral discrimination of them has been growing since it has been reported that some amphiphiles containing peptide groups like as N-acyl amino acid were self-assembled to the micrometer-and nanometer-scale structures [3][4][5][6][7]. It has been known that the chiral discrimination of N-acyl amino acid surfactants is occurred remarkably in the concentrated molecular organizations like as solid [8][9][10], liquid crystal [11,12], and condensed interfacial film [13][14][15][16][17].…”

“…Furthermore we have concluded that both the peptide-peptide hydrogen bonding and the steric hindrance of the amino acid residue govern the chiral effect. There are some studies on crystal structures of N-acyl amino acid in which the hydrogen bonds between peptide-peptide groups and between peptide-carboxylic acid groups are suggested [6,[18][19][20]. In the case of N-acyl amino acid salt, however, the interaction through the counter ion should be taken into account in addition to the hydrogen bond.…”