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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Investigation of excited singlet state absorption and intersystem crossing mechanism of isomeric meso-tetra(pyridyl) porphyrins containing peripheral polypyridyl platinum(II) complexes

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Cocca, Leandro H. Z. [1] ; Gotardo, Fernando [1] ; Sciuti, Lucas F. [2, 1] ; Acunha, Thiago V. [3] ; Iglesias, Bernardo A. [3] ; de Boni, Leonardo [1]
Total Authors: 6
[1] Univ Sao Paulo, Inst Fis Sao Carlos, CP 369, BR-13560970 Sao Carlos, SP - Brazil
[2] Univ Sao Paulo, Escola Engn Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil
[3] Univ Fed Santa Maria, Dept Quim, Lab Bioinorgan & Mat Porfirin, BR-97105900 Santa Maria, RS - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Chemical Physics Letters; v. 708, p. 1-10, SEP 16 2018.
Web of Science Citations: 6

In the present work, the excited states (singlet and triplet) for three different porphyrins, with and without coordinated Pt(II) complex derivatives, were investigated by three different temporal laser regimes were employed in the Z-Scan technique. Intersystem crossing time (singlet to triplet conversion mechanism) was obtained by a combination of Z-Scan with single or with a train of picosecond laser pulses. These measurements have shown that the excited state absorption spectrum shows distinct absorption behaviors. Also, the absorption cross-section is equivalent to the ground state, describing no changes in the optical transmittance. Fluorescence lifetimes and quantum yields were determined, respectively, by time resolved fluorescence analysis. To determine the intersystem crossing time constant, two additional levels were incorporated to the rate equation model. Moreover, fluorescence decays, internal conversion and ISC times have shown a strong dependence in Pt(II) derivatives and their position to the porphyrin ring (meta or para position). (C) 2018 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 16/20886-1 - Ultrafast nonlinear optical spectroscopy: Transient Absorption and optical Kerr Gate with polarization control
Grantee:Leonardo De Boni
Support type: Regular Research Grants