Dynamic Covalent Self-Assembly of Chloride- and Ion-Pair-Templated Cryptates

While supramolecular hosts capable of binding and transporting anions and ion pairs are now widely available, self‐assembled architectures are still rare, even though they offer an inherent mechanism for the release of the guest ion(s). In this work, we report the dynamic covalent self‐assembly of tripodal, urea‐based anion cryptates that are held together by two orthoester bridgeheads. These hosts exhibit affinity for anions such as Cl⁻, Br⁻ or I⁻ in the moderate range that is typically advantageous for applications in membrane transport. In unprecedented experiments, we were able to dissociate the Cs⋅Cl ion pair by simultaneously assembling suitably sized orthoester hosts around the Cs⁺ and the Cl⁻ ion.

Turn-on detection of assorted phosphates by luminescent chemosensors

This review illustrates a variety of luminescent chemosensors for the selective detection of assorted phosphates via the “Turn-On” emission mechanism with focus on their design aspects, chemical structures and sensing mechanism.

Selective encapsulation and extraction of hydrogenphosphate by a hydrogen bond donor tripodal receptor

Intramolecular N–H⋯OC hydrogen bonding between the inner amide groups dictates the receptor–anion complementarity in a tripodal receptor towards selective encapsulation of hydrogenphosphate in the outer urea cavity by multiple hydrogen bonds.

New fluorescent chemosensors based on mononuclear copper complex for highly selective and sensitive detection of phosphate anion in aqueous solution and living cells

Three new probes, named, [Cu(L1)₂]Cl₂ (C1), [Cu(L2)₂]Cl₂ (C2) and [Cu(L3)₂]Cl₂ (C3) were synthesized and well characterized. The probes C1, C2 and C3 were successfully achieved for the efficient detection of PO₄^3- as turn-on fluorescence chemosensors in DMSO/H₂O (v:v = 2:8, Tris-HCl pH = 7.20). The limit of detection (LOD) of probes C1, C2 or C3 for PO₄^3- could be as low as 0.029 μM, 0.048 μM, 0.079 μM, respectively, which were effectively applied for the determination of the PO₄^3- concentration in environmental water of swimming pool. What's more, the binding constant between probes C1, C2, C3 and PO₄^3- are estimated to be 3.11 × 10⁷ M^-1 (R² = 0.9992), 1.84 × 10⁷ M^-1 (R² = 0.9956), 1.93 × 10⁷ M^-1 (R² = 0.9976), respectively. The proposed mechanism for the "on-off-on" fluorescence response was confirmed by ESI-MS and fluorescence spectrum. Moreover, the membrane-permeable probe C1 was successfully demonstrated in monitoring of PO₄^3- in cultured HepG2 cells.

Visible colorimetric fluoride and hydroxide sensing by asymmetric tris-urea receptors: combined experimental and theoretical studies

A series of asymmetric tris-urea receptors with electron withdrawing group (EWG) or electron donating group (EDG), L1–L4, were synthesized and characterized by HRMS, NMR and single-crystal X-ray diffraction techniques.

Efficient and selective separation of aqueous sulfate through recognition and precipitation

Sulfate anions are selectively separated from aqueous solution in the form of precipitates by a mono-protonated organic receptor, constructed in situ through anion-templated chemical synthesis.

Anion recognition by oligo-(thio)urea-based receptors

Recent progress in the construction of metal-coordination-assisted and covalently connected oligourea receptors and their anion coordination chemistry is presented.