Ubiquitous assembly of amphiphilic baskets into unilamellar vesicles and their recognition characteristics.

An amphiphilic basket of type 1 (339 Å(3)) has been found to assemble into unilamellar vesicles in water. The assembled host encapsulates organophosphonates (OPs) (119-185 A(3)) with a particularly high affinity (Ka ∼ 10(5) M(-1)) toward dimethyl phenylphosphonate (185 Å(3)) whose size and shape resemble that of soman (186 Å(3)). Importantly, the entrapment of OPs prompts a phase transformation of vesicular 1 into nanoparticles or larger vesicles as a function of the shape of the host-guest complex.

Recognition characteristics of an adaptive vesicular assembly of amphiphilic baskets for selective detection and mitigation of toxic nerve agents.

We used isothermal titration calorimetry to investigate the affinity of basket 1 (470 Å(3)) for trapping variously sized and shaped organophosphonates (OPs) 2-12 (137-244 Å(3)) in water at 298.0 K. The encapsulation is, in each case, driven by favorable entropy (TΔS° = 2.

Gated molecular baskets.

In this review, we describe the construction of gated molecular baskets, discuss their mechanism of action in regulating the exchange of guests and illustrate the potential of these concave hosts to act as catalysts for controlling chemical reactions. Importantly, a number of computational and experimental studies have suggested that gated baskets ought to unfold their gates at the rim for permitting the passage of guests to/from their inner space. These dynamic hosts are therefore offered as useful models for investigating the process of gating in artificial systems.

Trapping of organophosphorus chemical nerve agents in water with amino acid functionalized baskets.

We prepared eleven amino-acid functionalized baskets and used (1) H NMR spectroscopy to quantify their affinity for entrapping dimethyl methylphosphonate (DMMP, 118 Å(3) ) in aqueous phosphate buffer at pH=7.0±0.1; note that DMMP guest is akin in size to chemical nerve agent sarin (132 Å(3) ).

Assembly of amphiphilic baskets into stimuli-responsive vesicles. Developing a strategy for the detection of organophosphorus chemical nerve agents.

We designed basket 1 to comprise a C3-symmetric hydrophobic cage (477 Å(3)) at its southern edge and three polar ammonium caps at the northern edge. This amphiphilic molecule was observed to assemble into large unilamellar vesicles (350 nm, TEM) in water and thereby entrap dimethyl phenylphosphonate (184 Å(3)) in its cavity (K(app) = (1.97 ± 0.

The prospect of selective recognition of nerve agents with modular basket-like hosts. A structure-activity study of the entrapment of a series of organophosphonates in aqueous media.

We designed, prepared, and characterized three cup-shaped cavitands 1-3 for trapping organophosphonates (O═PR(OR')2, 118-197 Å(3)) whose shape and size correspond to G-type chemical warfare agents (132-186 Å(3)). With the assistance of computational (molecular dynamics) and experimental ((1)H NMR spectroscopy) methods, we found that host [1-H3](3+) orients its protonated histamine residues at the rim outside the cavity, in bulk water. In this unfolded form, the cavitand traps a series of organophosphonates 5-13 (K(app) = 87 ± 1 to 321 ± 6 M(-1) at 298.

Method for the preparation of derivatives of heptiptycene: toward dual-cavity baskets.

We have developed a novel synthetic method that enables the preparation of functional derivatives of heptiptycene, i.e., cavitands with two juxtaposed cavities.