A new class of cryptand-like ionophore based on a bis calix[4]arene structure has been developed. These molecules proved highly selective for complexation of potassium over all group I metal cations and barium. A range of symmetric and asymmetric calix[4]tubes featuring either alkyl or phenyl substituents at the upper rim have been synthesized in exceptional yield. Alteration of the calix[4]arene upper rim environment enables fine-tuning of the rate of potassium uptake, which can be evaluated through the conformational change on binding by NMR studies. Selectivity of potassium complexation has been demonstrated using NMR and electrospray mass spectral techniques. Molecular modeling studies, derived from crystallographic data, confirm that the potassium metal cation is complexed via the axial route, passing through the calix[4]arene annulus, and provide evidence for complexation rate and selectivity.

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New lanthanide complexes of 3-hydroxypicolinic acid (HpicOH) were prepared: [Ln(H 2 O)-(picOH) 2 (µ-HpicO)]‚3H 2 O (Ln ) Eu, Tb, Er). The complexes were characterized using photoluminescence, infrared, Raman, and 1 H NMR spectroscopy, and elemental analysis. The crystal structure of [Eu(H 2 O)(picOH) 2 (µ-HpicO)]‚3H 2 O 1 was determined by X-ray diffraction. Compound 1 crystallizes in a monoclinic system with space group P2 1 /c and cell parameters a ) 9.105(13) Å, b ) 18.796(25) Å, and c ) 13.531(17) Å, and ) 104.86(1) deg. The 3-hydroxypicolinate ligands coordinate through both N,O-or O,O-chelation to the lanthanide ions, as shown by X-ray and spectroscopic results. Photoluminescence measurements were performed for the Eu(III) and Tb(III) complexes; the Eu(III) complex was investigated in more detail. The Eu(III) compound is highly luminescent and acts as a photoactive center in nanocomposite materials whose host matrixes are silica nanoparticles.

Chiral halogen bonding (S)-BINOL-based receptors are demonstrated to enhance the enantioselective recognition and sensing of chiral anions compared to their hydrogen bonding analogues. Computational studies attribute this behaviour to the strict linearity of halogen bonding (XB) and steric environment conferred by the XB donor groups bridged by the (S)-BINOL motif.

The first example of anion templated pseudorotaxane formation between two neutral components in solution and in surface assembled monolayers is described.

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Sulfate templation has been used in the synthesis of a novel tris-urea-based triply interlocked capsule, whose structure has been verified by DOSY NMR, mass spectrometry and molecular modelling investigations.

A new class of redox-active ionophore comprised of two calix[4]diquinone moieties connected through either alkylene or pyridylene linkages has been developed. Spectroscopic and electrochemical investigations, X-ray crystal structure analyses, and molecular modeling studies show butylene- and propylene-linked members of this family of redox-active receptors exhibit remarkable selectivity preferences and substantial electrochemical recognition effects toward cesium and rubidium cations.