Stereochemical Effect of Even−Odd Connecting Links on Supramolecular Assemblies Made of 1-Glucosamide Bolaamphiphiles

Abstract

Bolaamphiphiles with a 1-glucosamide-head group at each end, N,N‘-bis(β-d-glucopyranosyl)alkane-1, n-dicarboxamide [Glc-NC( n )CN-Glc, n = 6, 9, 10, 11, 12, 13, and 14], have been synthesized. Self-assembled supramolecular structures in water strongly depend on whether n is even or odd, which respectively give rise to fibrous assemblies or planar platelets as well as amorphous solids. In connection with this even−odd effect of the hydrocarbon links, internal molecular arrangements of the solid fibers were investigated using FT-IR spectroscopy, X-ray diffraction and crystal analyses, and transmission electron microscopy. The oligomethylene groups of the Glc-NC(12)CN-Glc pack in a monoclinic or an orthorhombic mode in the fiber. We propose a possible self-assembled model based on a monolayer sheet, which is stabilized by hydrogen-bond networks via sugar-head and amide groups.

Molecular Self-Assembly into One-Dimensional Nanotube Architectures and Exploitation of Their Functions

“…31 It should be noted here that well developed penetration of the staining reagent phosphotungstate into the hollow cylinder enables us to directly measure the inner diameter. Except for 18 (12), the observed values indeed increased in line with eq 1 with increasing spacer length of 18 (14), 18(16), 18 (18), and 18 (20) bolaamphiphiles. Furthermore, the observed values are in good agreement with the calculated ones.…”

“…12 We also demonstrated dimension and morphology control of the nanofibers, the elucidation of molecular packing, and novel functions specific to the nanostructures. 23,28,29 Nano-and microtube formation with sugar-or peptide-based amphiphiles coincidentally took place on the occasion of a large number of self-assembling experiments.…”

“…Possible molecular shapes and spatial arrangement of each functional group, and the local environment of solvophilic and solvophobic moieties allow us to produce a variety of discrete organic nanotubes, together with different types of self-assembly strategy. 2,11 We have been investigating the self-assembly behavior of synthetic amphiphilic molecules that append sugar, [12][13][14][15][16][17][18] peptide, [19][20][21] and nucleic acid moieties [22][23][24][25][26] as hydrophilic headgroups. 27 Those structural components in nature are wellknown to form diverse and multiple hydrogen-bond networks.…”

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

“…When saturated, hot aqueous solutions containing 1(n) or 3(n) were allowed to gradually cool and stand at room temperature, a variety of supramolecular fibers (nanofibers) with nanometer-sized dimension spontaneously and reproducibly appeared, strongly dependent on both the spacer length and the even/odd spacer carbon numbers ( Figure 2). 59,60 Interestingly, we found that physical properties and morphological stability of the obtained fibers are quite different from those of fibrous molecular assemblies made of synthetic bilayer-forming compounds. [61][62][63] The obtained fibers are highly crystalline and thermally stable even at temperatures around 200 • C after dehydration, proving that they can be isolated from the solution.…”

Novel pH sensitive composite hydrogel based on functionalized chitosan/clay for the controlled release of a calcium channel blocker

“…[26] Through a simple modification of oleic acid by diamines, new amphiphilic molecules were obtained with great transformation in solubility (increase in organic solvents) and configuration (oil to solid). It has been reported that synthetic amphiphiles with cyclic sugars as hydrophilic moieties of oleic acid derivatives are convenient to produce chiral supramolecular fibres and ribbons by self-assembly in aqueous media, [27][28][29][30][31][32][33][34] and the nanostructures can also be generated through a direct self-assembly of oleic acid on a hydroxylated aluminium surface. [35] Diltiazem hydrochloride (Figure 1), a nondihydropyridine member of the class of drugs known as calcium channel blockers, is used in the treatment of hypertension, angina pectoris and some types of arrhythmia.…”