Flavia Fucassi

Crown ether lanthanide complexes as building blocks for luminescent ternary complexes

Lanthanide complexes of the macrocyclic ligands 1,10-diaza-4,7,13,16-tetraoxacyclooctadecane-N,N′-diacetic acid (H2(dacda)) and 1,4,7,10-tetraoxa-13-azacyclopentadecane-13-acetic acid (H(macma)) have been isolated and characterised. The photophysical properties of the red and green emissive, Eu(III) and Tb(III), respectively, complexes have been elucidated. Upon addition of mono- or bi-dentate aromatic carboxylates or dibenzoylmethide in solutions of the Eu(III) macrocycles triggering of the lanthanide emission is observed. The formation of the ternary complex between the lanthanide macrocycle and the sensitiser is controlled by the available coordinaton sites of the lanthanide macrocycle prior to the binding event.

An artificial sodium ion channel from calix[4]arene in the 1,3-alternate conformation

The synthesis of a calix[4]arene with pendent polyether substituents is described. The compound was shown by NMR to bind Na+ when in the 1,3-alternate conformation and computational simulations suggest metal binding within the calixarene annulus. 1H NMR indicated that the complexed cation attracts water and the formation of a stable dihydrate was also indicated by in silico methods. Lipid bilayer experiments confirmed that the 1,3-alt calixarene functions as an artificial transmembrane ion in the presence of Na+ but not K+.

Artificial transmembrane ion channels from commercial surfactants

Sodium ion transport across a phospholipid bilayer has been demonstrated by a new class of transmembrane ion channel mimetic compounds in which the filtering effect of a calixarene has been coupled to the membrane penetrating qualities of a commercial surfactant.

Vitamin C induced decomposition of lipid hydroperoxides: direct evidence of genotoxin–DNA binding detected by QCRS

We report direct evidence for human DNA-binding to precursors of mutagenic lesion-inducing compounds, produced form the vitamin C induced decomposition of lipid hydroperoxides, using a quartz crystal resonant sensor assay.

Synthesis and applications of copillar[5]arene dithiols

Abstract A novel copillar[4+1]arene incorporating alkylthiol substituents was synthesised in three steps and structurally characterised as the first example of a pillar[n]arene to incorporate two terminal thiols on the same aromatic ring. The macrocycle was attached to gold electrodes through a standard dipping technique. Cyclic voltammetry demonstrated selectivity for Li+ over other alkali metal cations. The copillar[4+1]arene was also used as a capping agent in the preparation of 3 nm gold nanoparticles.

Characterisation of small molecule binding to DNA using a quartz crystal resonant sensor

A new development in quartz crystal resonant sensor (QCRS) technology allows real-time analysis of binding by small molecules to DNA and has been tested using superoxide dismutase mimics.

Metal chelation by a plant lignan, secoisolariciresinol diglucoside

Abstract Secoisolariciresinol diglucoside (SDG) is a polyphenolic phytoestrogen which is particularly abundant in flaxseed. As a diphenolic compound, SDG is expected to function as a metal chelating ligand. The affinity of SDG for metal cations was determined using a mass spectrometric approach. Experiments yielded equilibrium constants in aqueous solution for SDG·Ca2+, SDG·Cu2+, SDG·Pb2+, SDG·Ni2+, SDG·Fe2+ and SDG·Ag+ of 20.34, 5.99, 4.26, 2.77, 2.46 and 1.90, respectively. These values are consistent with those determined for plant phenolics. Semiempirical calculations for the SDG metal complexes yield an insight into their likely structures.Graphical Abstract.