Eu(III)-cyclen-phen conjugate as a luminescent copper sensor: the formation of mixed polymetallic macrocyclic complexes in water.

The cationic cyclen based Eu(III)-phen conjugated 1.Eu was synthesised as a chemosensor for Cu(II), where the recognition in water at pH 7.4 gave rise to quenching of the Eu(III) luminescence and the formation of tetranuclear polymetallic Cu(II)-Eu(III) macrocyclic complexes in solution where Cu(II) was bound by three 1.Eu conjugates.

Delayed lanthanide luminescence sensing of aromatic carboxylates using heptadentate triamide Tb(III) cyclen complexes: the recognition of salicylic acid in water.

The coordinately unsaturated terbium complexes Tb.1 and Tb.2 possess two labile metal-bound water molecules that can be displaced upon metal chelation to aromatic carboxylic anions such as salicylic acid in water, which gives rise to large enhancements in the Tb(III) luminescence.

Luminescent sensing and formation of mixed f-d metal ion complexes between a Eu(iii)-cyclen-phen conjugate and Cu(ii), Fe(ii), and Co(ii) in buffered aqueous solution.

The synthesis and photophysical properties of the Eu(iii) complex , based on the use of 1,10-phenanthroline (phen) as a combined sensitizing antenna and a transition metal ion coordinating ligand, is described. The long-wavelength Eu(iii) emission from this complex was found to be highly pH sensitive, giving rise to a 'off-on-off' pH profile with maximum emission occurring within the physiological pH range. This allowed for the use of as a luminescent sensor for transition metal ions, where the titration with ions such as Cu(ii), Co(ii) and Fe(ii) gave rise to the formation of mixed f-d nuclear complexes, with concomitant changes in the photophysical properties of . Here, changes in both the ground and the singlet excited state properties of the phen antenna were observed, but the largest changes were observed for the delayed Eu emission, which was fully quenched upon titration with these ions in aqueous pH 7.4 buffered solutions. In comparison, no changes were observed in the Eu(iii) emission upon titration with ions such as Zn(ii) or group I and II ions. From these changes, we were able to demonstrate the binding stoichiometry and the binding constant for the formation of novel supramolecular complexes between and Cu(ii), Co(ii) and Fe(ii), which showed that either two or three equivalents of complexed to each of these transition metal ions, giving rise to the formation either linear f-d-f or branched f(3)-d based mixed nuclear complexes in solution.

Synthesis and characterisation of bis-cyclen based dinuclear lanthanide complexes.

The design and synthesis of several bis-macrocyclic cyclen (1,4,7,10-tetraazacyclododecane) ligands and their corresponding lanthanum or europium complexes is described; these dinuclear lanthanide systems were made by connecting two macrocyclic cyclen moieties through a rigid, covalent, p-xylylenediamide bridge or a flexible aliphatic hexane bridge. These ligands were subsequently functionalised with six acetamide pendant arms (CONR1R2: R1 = R2 = H or CH3, or R1 = H, R2 = CH3). The corresponding lanthanide bis-complexes were then formed by reaction with La(III) and Eu(III) triflates, yielding overall cationic (+VI charged) complexes.

A dinuclear lanthanide complex for the recognition of bis(carboxylates): formation of terbium(III) luminescent self-assembly ternary complexes in aqueous solution.

The synthesis and photophysical properties of a coordinatively unsaturated cationic dinuclear terbium complex, 2.Tb(2), that can detect the presence of mono- or bis(carboxylates) in buffered aqueous solution at physiological pH is described. Full ligand synthesis and structural characterization of 2.Na(2) are also described. Spectroscopic measurements determined that each Tb(III) metal center has two metal-bound water molecules (q = 2). The recognition or sensing of N,N-dimethylaminocarboxylic acid, 4, and the bis(carboxylate) terephthalic acid, 5, which can also function as sensitizing antennae, was found to occur through the binding of these carboxylates to the metal center via the displacement of the metal bound water molecules. This gave rise to the formation of luminescent ternary complexes in solution in 2:1 or 1:1 (ion:2.Tb(2)) stoichiometry, respectively. Aliphatic bis(carboxylates) also bind to 2.Tb(2) where the selectivity for the ion recognition and stoichiometry was dictated by the structure of the anion, being most selective for pimelic acid, 6. Binding of either l- or d-tartaric acid gave rise to the formation ternary complex formation, with 2:1 stoichiometry, where the ion recognition resulted in quenching of the lanthanide emission.

pH responsive Eu(III)-phenanthroline supramolecular conjugate: novel "off-on-off" luminescent signaling in the physiological pH range.

The formation of luminescent supramolecular ternary complexes in water: delayed luminescence sensing of aromatic carboxylates using coordinated unsaturated cationic heptadenatate lanthanide ion complexes.