A resorcinarene-based Zn(ii) complex presenting a hemilabile imidazole arm allows endo-coordination of acidic guests and catalyzes of acetonitrile hydration.
Enantiopure hemicryptophanes efficiently discriminate chiral ammonium neurotransmitters. The ephedrine and norephedrine molecules associate with hemicryptophane hosts to form 1:1 and 1:2 host-guest complexes. Binding constants are determined by fitting the ¹H nuclear magnetic resonance (NMR) titration curves to give β₁ and β₂ values, which are used to characterize the diastereomeric and enantiomeric discriminating potentials of the hosts.
A hemicryptophane ligand soluble in water at neutral pH was obtained thanks to the derivatization of the cyclotribenzylene unit with three carboxylate groups. The corresponding Cu(ii) complex was then synthesized and its spectroscopic and electrochemical properties in water were investigated, showing that water solubilisation retains the geometry of the complex around the metal center but strongly affects its redox properties, compared to previously reported Cu(ii)@hemicryptophane complexes soluble in organic solvents.
Molecular recognition in water is an important topic, but ac hallenging task due to the very competitive nature of the medium. The focusofthis study is the comparison of two different strategies for the water solubilization of ab iomimetic metallo-receptor based on ap oly(imidazole) resorcinarene core. Thef irst relies on an ew synthetic path for the introduction of hydrophilic substituents on the receptor,a taremote distance from the coordination site. The second involves the incorporation of the organosoluble metallo-receptor into dodecylphosphocholine (DPC) micelles, which mimic the proteic surrounding of the active site of metallo-enzymes.T he resorcinarene ligand can be transferred into water through both strategies,i nw hich it binds Zn II over aw ide pH window.Q uite surprisingly,v ery similar metal ion affinities, pH responses, and recognition properties were observed with both strategies. The systems behavea s remarkable receptors for small organic anionsi nw ater at near-physiologicalp H. These results show that, provided the biomimetic site is well structured and presents ar ecognition pocket, the micellar environmenth as very little impacto n either metal ion binding or guest hosting.H ence, micellar incorporation represents an easy alternative to difficult synthetic work, even for the binding of charged species( metal cations or anions), which opens new perspectivesf or molecular recognition in water,w hether for sensing, transport, or catalysis.[a] Dr.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.
A biomimetic receptor allows selective recognition of organophosphates in water thanks to multipoint recognition associating coordination, electrostatics and cavity hosting.
A poly(imidazole)–resorcinarene‐based biomimetic receptor performs efficiently for Zn2+ coordination and anionic guest hosting when encapsulated in micelles or functionalized with water‐solubilising groups. Despite very different microenvironments, binding constants and pH windows are strikingly similar; these results are related to the structuration of the receptor that mimics the active site of metalloenzymes. Micellar incorporation thus represents an easy alternative to difficult synthetic work, which opens many of perspectives for molecular recognition in water. More information can be found in the Full Paper by K. Bartik, O. Reinaud et al. on page 17964.
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