Transport of Anions across the Dialytic Membrane Induced by Complexation toward Dendritic Receptors

An Insight into Anion Extraction by Amphiphiles: Hydrophobic Microenvironments as a Requirement for the Extractant Selectivity

Coupling of electron-deficient urea units with aliphatic chains gives rise to amphiphilic compounds that bind to phosphate and benzoate anions in the hydrogen bonding competitive solvent (DMSO) with KAss = 6 580 M-1 and KAss = 4 100 M-1, respectively. The anchoring of these receptor moieties to the dendritic support does not result in a loss of anion binding and enables new applications. Due to the formation of a microenvironment in the dendrimer, the high selectivity of the prepared compound toward benzoate is maintained even in the presence of aqueous media during extraction experiments. In the presence of binding sites at 5 mM concentration, the amount of benzoate corresponding to the full binding site occupancy is transferred into the chloroform phase from its 10 mM aqueous solution. A thorough investigation of the extraction behavior of the dendrimer reported here, supported by a series of molecular dynamics simulations, provides new insight into the fundamental principles of extraction of inorganic anions by amphiphiles.

Adaptive Synthesis of Functional Amphiphilic Dendrons as a Novel Approach to Artificial Supramolecular Objects

Supramolecular structures, such as micelles, liposomes, polymerosomes or dendrimerosomes, are widely studied and used as drug delivery systems. The behavior of amphiphilic building blocks strongly depends on their spatial distribution and shape of polar and nonpolar component. This report is focused on the development of new versatile synthetic protocols for amphiphilic carbosilane dendrons (amp-CS-DDNs) capable of self-assembly to regular micelles and other supramolecular objects. The presented strategy enables the fine modification of amphiphilic structure in several ways and also enables the facile connection of a desired functionality. DLS experiments demonstrated correlations between structural parameters of amp-CS-DDNs and the size of formed nanoparticles. For detailed information about the organization and spatial distribution of amp-CS-DDNs assemblies, computer simulation models were studied by using molecular dynamics in explicit water.

Controlled Anchoring of (Phenylureido)sulfonamide-Based Receptor Moieties: An Impact of Binding Site Multiplication on Complexation Properties

The repetition of urea-based binding units within the receptor structure does not only lead to monomer properties multiplication. As confirmed by spectroscopic studies, UV-Vis and ¹H-NMR in classical or competitive titration mode, the attachment to a carrier allocates the active moieties to mutual positions predetermining the function of the whole receptor molecule. Bivalent receptors form self-aggregates. Dendritic receptors with low dihydrogen phosphate loadings offer a cooperative complexation mode associated with a positive dendritic effect. In higher dihydrogen phosphate concentrations, the dendritic branches act independently and the binding mode changes to 1:1 anion: complexation site. Despite the anchoring, the dendritic receptors retain the superior efficiency and selectivity of a monomer, paving the way to recyclable receptors, desirable for economic and ecological reasons.