Enantiopure lanthanide complexes incorporating a tetraazatriphenylene sensitiser and three naphthyl groups: exciton coupling, intramolecular energy transfer, efficient singlet oxygen formation and perturbation by DNA binding.

In cationic nine-coordinate chiral terbium and europium complexes incorporating exciton-coupled naphthyl groups and a tetraazatriphenylene sensitising chromophore, efficient intramolecular energy transfer occurs leading to population of the naphthyl triplet state. With the terbium complex, the absolute quantum yield of singlet oxygen formation is 51% (lambda(exc) 355 nm), and for the Eu complex the intensity of metal-based emission increases by up to 350% on binding to poly(dGdC) or calf-thymus DNA, and was greater for the delta-isomer.

Luminescent nonacoordinate cationic lanthanide complexes as potential cellular imaging and reactive probes.

Nonacoordinate delta- and lambda-Eu and Tb complexes have been tested as imaging and reactive probes in mouse fibroblast (NIH 3T3) cells. The uptake of these complexes by the cells was assessed by fluorescence microscopy. Complex-induced DNA damage was studied by gel electrophoresis and shown to be a function of complex chirality.

Ternary complexes between cationic GdIII chelates and anionic metabolites in aqueous solution: an NMR relaxometric study.

The (1)H and (17)O NMR relaxometric properties of two cationic complexes formed by Gd(III) with a macrocyclic heptadentate triamide ligand, L(1), and its Nmethylated analogue, L(2), have been investigated in aqueous media as a function of pH, temperature and magnetic field strength. The complexes possess two water molecules in their inner coordination sphere for which the rate of exchange has been found to be sensibly faster for the Nmethylated derivative and explained in terms of electronic effects (decrease of the charge density at the metal center) and perturbation of the network of hydrogen-bonded water molecules in the outer hydration sphere. The proton relaxivity shows a marked dependence from pH and decreases of about six units in the pH range 6.

Highly emissive, nine-coordinate enantiopure lanthanide complexes incorporating tetraazatriphenylenes as probes for DNA.

The interaction of q = 0 delta- and lambda-Tb and Eu complexes with poly(dAdT), poly(dGdC) and calf-thymus DNA has been examined by absorption, emission and chiroptical spectroscopy and is sensitive to complex helicity, base-pair type and the nature of the lanthanide excited state.