Photophysics of Cyanine Dyes on Surfaces: Laser-Induced Photoisomer Emission of 3,3'-Dialkylthiacarbocyanines Adsorbed on Microcrystalline Cellulose

[img]PDF - Authorized users only
Language: English
117Kb
Title:Photophysics of Cyanine Dyes on Surfaces: Laser-Induced Photoisomer Emission of 3,3'-Dialkylthiacarbocyanines Adsorbed on Microcrystalline Cellulose
Creators:
Oliveira, Anabela S.
Almeida, Paulo
Vieira Ferreira, Luis Filipe
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 64, 3, pp. 459-473
Uncontrolled Keywords:Microcrystalline cellulose, H and J aggregates, Diffuse reflectance, Photoisomers, Laser-induced luminescence, Cyanine dyes, Two-photon absorption processes

Abstract

The photophysics of three thiacarbocyanine dyes, 3,3'-dimethylthiacarbocyanine iodide (DMTCC), 3,3'-diethylthiacarbocyanine iodide (DETCC), and 3,3′-dipropylthiacarbocyanine iodide (DPTCC) was studied when adsorbed on microcrystalline cellulose in the concentration range from 5.0&nbsp;·&nbsp;10<sup>-4</sup> to 10.0 μmol g<sup>-1</sup>. Using ground-state diffuse reflectance absorption technique, only H aggregate formation was detected for all the probes. The amount of aggregate formed depends on the hydration degree of the sample, always decreasing with sample dryness. The fluorescence quantum yields for all the adsorbed dyes are one order of magnitude higher than those observed in nonviscous solvents, being 0.98 for DMTCC, 0.96 for DETCC, and 0.63 for DPTCC. Laser-induced fluorescence emissions were recorded (using an intensified-charge-coupled-device detection system) as a function of the laser power, showing that for dry concentrated samples irradiated with high laser intensity, a second fluorescence emission band (bathochromically shifted relative to the monomer emission) was detected. This emission shows a supralinear dependence on laser power. The new emissions here detected arise from fluorescent photoisomers formed <i>via</i> singlet monomers, by a two-photon absorption process. <p>

Title:Photophysics of Cyanine Dyes on Surfaces: Laser-Induced Photoisomer Emission of 3,3'-Dialkylthiacarbocyanines Adsorbed on Microcrystalline Cellulose
Creators:
Oliveira, Anabela S.
Almeida, Paulo
Vieira Ferreira, Luis Filipe
Uncontrolled Keywords:Microcrystalline cellulose, H and J aggregates, Diffuse reflectance, Photoisomers, Laser-induced luminescence, Cyanine dyes, Two-photon absorption processes
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:64
Number:3
Page Range:pp. 459-473
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19990459UNSPECIFIED
ID Code:1488
Item Type:Article
Deposited On:06 Feb 2009 17:10
Last Modified:06 Feb 2009 16:10

Citation

Oliveira, Anabela S.; Almeida, Paulo; Vieira Ferreira, Luis Filipe (1999) Photophysics of Cyanine Dyes on Surfaces: Laser-Induced Photoisomer Emission of 3,3'-Dialkylthiacarbocyanines Adsorbed on Microcrystalline Cellulose. Collection of Czechoslovak Chemical Communications, 64 (3). pp. 459-473. ISSN 0010-0765

Repository Staff Only: item control page