Arborols molecular assemblies

The rods and tubules, described by Fuhrhop et al.,21 possess orientations analogous to that of the two-directional arborols. Lysine-based bolaphile 16 (Figure 4) generates a monolayer rod the addition of 11 methylene units and a second primary amide link to 16 gave the bolaam-phiphile 17 and resulted in a different supramolecular assembly. In general, 17 formed tubules rather than rods these tubules possess an internal dimension of ca. 50 nm and wall thickness of 4.4 nm.21 The presence of chirality also has an affect on these molecular assemblies, since racemic lysine bolaphile 16 did not result in rod or tubule formation. No effects due to the chiral purity were observed with 17. The effect... 

Synthetic bolaphilic membranes can be tailored to provide binding sites for guests,1317 or other functionality can be incorporated, such as redox- and/or photoactive moieties.4 The repertoire of bolaam-phiphilic assemblies include gels formed by specific two-directional arborols,3 18-20 and rods and tubules formed by a-(L-lysine)-co-aminobo-laphiles.21 Inclusion of polymerizable functionalities, in either the head groups or within the lipophilic spacer, can provide convenient routes to extended covalently linked domains.9,22 23 Bolaphiles also provide synthetic chemists with tools to explore novel molecular architectures, as well as interactions between juxtaposed structural elements. Examples cited herein illustrate recently reported work in this field. 

The rods and tubules, described by Fuhrhop et al. [17] follow an analogous pattern to that of these the 2-directional arborols. When the racemic form of the lysine bolaphile 4 was used (Scheme 2), no rod or tubule formation was noted in contrast, the racemate of the extended bolaphile 5 produced supramolecu-lar assemblies identical to those formed by the pure enantiomers. The effect of configuration in molecular monolayers was shown to depend on membrane curvature in the same manner as in bilayers. [17]... 

In their preliminary communication, Newkome and co-workers reported that their arborols formed a gel in aqueous solution. They commented in particular on the low molecular weight (1052) compared to a typical gel . Using transmission electron microscopy (TEM) they illustrated that a fibrous assembly was formed, and noted that a lwt/vol% solution exhibited no steady-state flow— analogous to a traditional crosslinked polymer gel. The authors suggested that the polar head groups became crosslinked via hydro-... 

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