Molecular recognition of the guanidinium/phosphate pair was investigated at microscopic interfaces of aqueous micelles and bilayers. Monoalkyl and dialkyl amphiphiles with guanidinium head groups were synthesized and dispersed in water to form micelles and bilayers having guanidinium groups at the aggregate surface. Binding of nucleotides such as AMP to these functionalized aggregates was evaluated by using an equilibrium dialysis (ultrafiltration) method. The observed binding constants of 102−104 M-1 are much larger than the corresponding binding constant reported for a monomerically dispersed pair in the aqueous phase (1.4 M-1) but are smaller than those found at the macroscopic air−water interface (106−107 M-1). Therefore, the macroscopic interface promotes guanidinium−phosphate interaction more effectively than the microscopic interface. The present finding indicates that the microscopic interface can strengthen hydrogen bonding and/or electrostatic interaction even in the presence of water. Saturation binding phenomena were different between micelles and bilayers. All of the guanidinium groups in fluid micelles are effective for phosphate binding, but part of the guanidinium group in bilayers are not effective probably because of steric restriction.

Three 1-O-methyl-4, 6-O-benzylidene derivatives of monosaccharides (D-glucose, D-galactose and D-mannose) were synthesised: they acted as versatile gelators of various organic fluids, indicating that saccharides are useful as potential building-blocks for molecular design of chiral gelators.

Four alkyl melamine amphiphiles cach containing identical triads of hydrogen-bonding sites (hydrogen donor, acceptor, and donor) but different numbers of alkyl chains were examined in order to determine their monolayer properties and binding behavior towards barbituric acid (BA). Their structural organization in supramolecular assemblies at the air-water interface was affected by the bulkiness of the hydrophobic part of the

A monolayer of 2-amino-4,6-di(dodecylamino)-1,3,5triazine 1 transferred from barbituric acid solution onto a mica plate is observed by atomic force microscopy (AFM) to show regularly arrayed terminal methyl groups of 1 as a result of hydrogen-bond networking.We have recently reported multisite molecular recognition between multicomponent monolayers on water and flavin adenine dinucleotide (FAD) in water. 1 This result opened the possibility to control the alignment of component amphiphiles within a monolayer.2 We extended this concept one step further in the present study and examined extended hydrogen-bond network formation between a monolayer of 2-amino-4,6-di(dodecylamino)-l,3,5-triazine 17 and aqueous barbituric acid.

At the air−water interface N,N‘-dialkylmelamine amphiphiles bind barbituric acid (BA) in the aqueous phase and produce a linearly extended supramolecular network (sometimes referred as supramolecular strand, ribbon, or tape) linked through complementary hydrogen bonds. An amphiphile with more than two hydrogen-bonding sites may produce cross-linked hydrogen-bonded networks on water with the aid of an appropriate aqueous binding counterpart. Thus, we synthesized new amphiphilic molecules, Δ(m,n), that bear three melamine (2,4,6-triamino-1,3,5-triazine) rings and six alkyl chains. The lengths of the inside three alkyl chains (C m H2 m +1) and the outside three alkyl chains (C n H2 n +1) were varied. The influence of alkyl chain length on the monolayer properties and the binding behavior to aqueous BA was examined for Δ(12,10), Δ(12,12), Δ(12,14), Δ(12,18), and Δ(18,12). From FT-IR and X-ray photoelectron spectroscopic measurements of Δ(m,n) LB films, BA was found to bind to one melamine moiety each of Δ(m,n) in a 1:1 ratio through complementary hydrogen bonds. Plausible network models were proposed on the basis of binding stoichiometry and conformational consideration of the tris(melamine) amphiphile.