title: Two-photon absorption of metal-organic DNA-probes.
abstract: We report remarkable multiphoton absorption properties of DNA intercalating ruthenium complexes: (1) [Ru(phen)(2)dppz](2+); (2) [(11,11'-bidppz)(phen)(4)Ru(2)](4+); (3) [11,11'-bipb(phen)(4)Ru(2)](4+). Two-photon spectra in the range from 460 to 1100 nm were measured using the Z-scan technique. In particular, complex 2 was found to exhibit very strong two- and three-photon absorption properties, which could be an effect of symmetric charge transfer from the ends towards the middle of the conjugated dimeric orbital system. We propose that these molecules could provide a new generation of DNA binding nonlinear chromophores for wide applications in biology and material science. The combination of a large two-photon cross section and strong luminescence quantum yields for the molecules when intercalated makes the compounds uniquely bright and photo-stable probes for two-photon luminescence imaging and also promising as enhanced photosensitizers in two-photon sensitizing applications.
authors.affiliation: Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden. piotr.hanczyc@chalmers.se
authors.forename: Piotr
authors.initials: P
authors.lastname: Hanczyc
authors.forename: Bengt
authors.initials: B
authors.lastname: Norden
authors.forename: Marek
authors.initials: M
authors.lastname: Samoc
mesh_terms: D015342:DNA Probes / Q000737:chemistry*; D007364:Intercalating Agents / Q000737:chemistry; D049449:Luminescence; D009942:Organometallic Compounds; D017785:Photons; D017319:Photosensitizing Agents / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*
chemical_list: D015342:DNA Probes; D007364:Intercalating Agents; D009942:Organometallic Compounds; D017319:Photosensitizing Agents; D012428:Ruthenium