Two-photon absorption of metal-organic DNA-probes

ArticleinDalton Transactions 41(11):3123-5 · February 2012with6 Reads
DOI: 10.1039/c2dt12264b · Source: PubMed
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.
    • "Sznitko et al. [13] successfully demonstrated amplified spontaneous emission and lasing action in deoxyribonucleic acid blended with cetyltrimethyl-ammonium chloride surfactant and doped with 3-(1,1-dicyanoethenyl1)-1phenyl-4,5dihydro-1H-pyrazol e organic dye. Hanczyc et al. [14] observed remarkable multiphoton absorption properties of DNA intercalating ruthenium complexes: 1) []4 + in the spectral range of 460 to 1100 nm. Nonlinear optical (NLO) properties of DNA in solution form [15] and in silica films [16] has been investigated recently. "
    [Show abstract] [Hide abstract] ABSTRACT: We present our results from the measurements of third-order optical nonlinearity in DNA doped Rhodamine 6G/PVA films achieved through Z-scan measurements using ~2 picosecond (ps) pulses at a wavelength of 800 nm. The films demonstrated negative nonlinear refractive index (n 2) with magnitudes of (0.065 -2.89) × 10 –14 cm 2 /W with varying concentration of DNA. Open aperture data demonstrated strong two-photon absorption with a magnitude of ~1.6 cm/GW for films doped with 2 wt% of DNA. The recovery time of excited state population, retrieved from the degen-erate pump-probe experimental data, was <4 ps. These data suggests that DNA is promising material for applications such as optical switching.
    Full-text · Article · Jan 2012
  • [Show abstract] [Hide abstract] ABSTRACT: The Z-scan technique was used to determine the spectral dependence of the nonlinear absorption in well-known DNA intercalators: ethidium bromide and its homodimer. It is found that the compounds show essentially the same features of their nonlinear absorption spectra with the magnitudes of the relevant cross sections scaling with molecular weight of chromophore compound.
    Article · Aug 2012
  • [Show abstract] [Hide abstract] ABSTRACT: N-arylpyrrole-based dyes possessing excellent opto-electronic properties are promising candidates for two-photon fluorescence labeling materials. The systematic investigation of novel N-arylpyrrole derivatives is of great importance for both fine-tuning electronic spectra and designing two-photon absorption (2PA) materials. We thoroughly studied influences of the π-conjugated center and N-substituted pyrrole moieties on the linear optical and 2PA properties. Our results show that introducing N-arylpyrrole produces bathochromic-shifts of the absorption and emission bands and an enhancement of the 2PA cross section (δ(max)), demonstrating that the electron-rich pyrrole moieties can efficiently increase intramolecular charge transfer. Substitution of fluorenyl with benzothiadiazole produces the lower energy gap, higher emission lifetime, red-shift of 2PA spectra and larger δ(max). The absorption and emission bands are highly dependent on the nature of the active building blocks. The aromatic rings attached to pyrrole can modulate the absorption peaks in the high energy and thus subtly modify the electronic properties.
    Article · Aug 2012
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