A photoswitchable [2]catenane receptor.

A [2]catenane-based receptor functionalized with stiff-stilbene can be reversibly switched with 340/385 nm light between its - and -isomers, which leads to a considerable change in chloride binding affinity. Photoisomerization in the presence of chloride allows for on demand guest uptake and release.

A Photoswitchable Macrocycle Controls Anion-Templated Pseudorotaxane Formation and Axle Relocalization.

Important biological processes, such as signaling and transport, are regulated by dynamic binding events. The development of artificial supramolecular systems in which binding between different components is controlled could help emulate such processes. Herein, we describe stiff-stilbene-containing macrocycles that can be switched between (Z)- and (E)-isomers by light, as demonstrated by UV/Vis and H NMR spectroscopy.

Photoswitchable Bis(amidopyrroles): Modulating Anion Transport Activity Independent of Binding Affinity.

Toward photocontrol of anion transport across the bilayer membrane, stiff-stilbene, which has dimethyl substituents in the five-membered rings, is functionalized with amidopyrrole units. UV-vis and H NMR studies show high photostability and photoconversion yields. Where the photoaddressable ()- and ()-isomers exhibit comparable binding affinities, as determined by H NMR titrations, fluorescence-based transport assays reveal significantly higher transport activity for the ()-isomers.

Stimulus-Controlled Anion Binding and Transport by Synthetic Receptors.

Anionic species are omnipresent and involved in many important biological processes. A large number of artificial anion receptors has therefore been developed. Some of these are capable of mediating transmembrane transport.

Self-assembly of a water-soluble endohedrally functionalized coordination cage including polar guests.

Coordination cages containing endohedrally functionalized aromatic cavities are scarce in the literature. Herein, we report the self-assembly of a tetra-cationic super aryl-extended calix[4]pyrrole tetra-pyridyl ligand into a water-soluble Pd(ii)-cage featuring two endohedral polar binding sites. They are defined by the four pyrrole NHs of the calix[4]pyrrole unit and the four inwardly directed α-protons of the coordinated pyridyl groups.

Light-Modulated Self-Blockage of a Urea Binding Site in a Stiff-Stilbene Based Anion Receptor.

Anion binding to a receptor based on stiff-stilbene, which is equipped with a urea hydrogen bond donating group and a phosphate or phosphinate hydrogen bond accepting group, can be controlled by light. In one photoaddressable state (E isomer) the urea binding site is available for binding, while in the other (Z isomer) it is blocked because of an intramolecular interaction with its hydrogen bond accepting motif. This intramolecular interaction is supported by DFT calculations and H NMR titrations reveal a significantly lower anion binding strength for the state in which anion binding is blocked.

One-pot, modular approach to functionalized ketones via nucleophilic addition/Buchwald-Hartwig amination strategy.

A general one-pot procedure for the 1,2-addition of organolithium reagents to amides followed by the Buchwald-Hartwig amination with in situ released lithium amides is presented. In this work amides are used as masked ketones, revealed by the addition of organolithium reagents which generates a lithium amide, suitable for subsequent Buchwald-Hartwig coupling in the presence of a palladium catalyst. This methodology allows for rapid, efficient and atom economic synthesis of aminoarylketones in good yields.