she worked for a couple of months on luminescent logic gates with A. P. de Silva in Belfast (1995). She then moved to Strasbourg and obtained a PhD under the supervision of Jean-Paul Collin and Jean-Pierre Sauvage, working on iridium bis-terpyridine complexes as photosynthetic model systems (2000). She is currently working as a postdoctoral researcher in the group of Roeland J. M. Nolte in Nijmegen (the Netherlands).

The electronic absorption spectra, luminescence spectra and lifetimes (in MeCN at room temperature and in frozen n-C3H7CN at 77 K), and electrochemical potentials (in MeCN) of the novel dinuclear [(tpy)Ru(3)Os(tpy)]4+ and trinuclear [(tpy)Ru(3)Os(3)Ru(tpy)]6- complexes (3 = 2,5-bis(2,2':6',2''-terpyridin-4-yl)thiophene) have been obtained and are compared with those of model mononuclear complexes and homometallic [(tpy)Ru(3)Ru(tpy)]4+, [(tpy)Os(3)Os(tpy)]4+ and [(tpy)Ru(3)Ru(3)Ru(tpy)]6+ Complexes. The bridging ligand 3 is nearly planar in the complexes, as seen from a preliminary X-ray determination of [(tpy)Ru(3)Ru(tpy)][PF6]4, and confers a high degree of rigidity upon the polynuclear species. The trinuclear species are rod-shaped with a distance of about 3 nm between the terminal metal centres. For the polynuclear complexes, the spectroscopic and electrochemical data are in accord with a significant intermetal interaction. All of the complexes are luminescent (phi in the range 10(-4)-10(-2) and tau in the range 6-340 ns, at room temperature), and ruthenium- or osmium-based luminescence properties can be identified. Due to the excited state properties of the various components and to the geometric and electronic properties of the bridge, Ru --> Os directional transfer of excitation energy takes place in the complexes [(tpy)Ru(3)Os(tpy)]4+ (end-to-end) and [(tpy)Ru(3)Os(3)Ru(tpy)]6+ (periphery-to-centre). With respect to the homometallic case, for [(tpy)Ru(3)Os(3)Ru(tpy)]6+ excitation trapping at the central position is accompanied by a fivefold enhancement of luminescence intensity.

Carprofen (1a) is a photosensitizing nonsteroidal anti-inflammatory drug. It undergoes photodehalogenation from its triplet excited state. The resulting aryl radical (II) is able to abstract hydrogen atoms from model lipids, mediating their peroxidation by a type I mechanism. This aryl radical intermediate appears to be responsible for the observed photobiological effects of carprofen. The active involvement of the triplet state has been confirmed by direct detection of this species in laser flash photolysis and by quenching experiments with cyclohexadiene and naphthalene. Carprofen also photosensitizes singlet oxygen production with a quantum yield of 0.32. A minor reaction pathway is photodecarboxylation, which occurs from the excited singlet state and leads to an acetyl derivative (1b). In the case of the dehalogenated photoproduct (2a), photodecarboxylation to the ethyl (2d) and acetyl (2b) derivatives, together with singlet oxygen production (quantum yield = 0.18), is also possible. However, the biological activity of 2a in the linoleic acid photoperoxidation and photohemolysis tests is markedly lower than that of 1a, which constitutes further evidence in favor of the important role of photodehalogenation in the adverse photobiological effects of carprofen.

Diclofenac (1) is a photosensitizing nonsteroidal antiinflammatory drug. Its photodecomposition gives rise to chlorocarbazole 2a. This product undergoes photodehalogenation to 3a in a subsequent step. When the photobiological activities of 1, 2a, and 3a are compared by means of the photohemolysis test, it is clearly observed that chlorocarbazole 2a causes cell lysis with a markedly higher efficiency than the parent drug or the secondary photoproduct 3a. Laser flash photolysis studies suggest that photodehalogenation of 2a occurs from its excited triplet state via quenching by ground-state 2a and formation of an excimer. As a consequence, an aryl radical plus an N-centered carbazolyl radical are formed. These radical intermediates appear to be responsible for the observed photobiological effects of diclofenac, via hydrogen abstraction from the target biomolecules, which initiates a type-I photodynamic effect. The efficient peroxidation of model lipids, such as linoleic acid, photosensitized by 2a are in favor of this proposal. Thus, the photosensitizing properties of diclofenac appear to be associated with the photochemical and photobiological activity of its major photoproduct.