Exploitation of the Z-scan technique as a method to optically probe pK(a) in organic materials: application to porphyrin derivatives

Citation
Ag. Bezerra et al., Exploitation of the Z-scan technique as a method to optically probe pK(a) in organic materials: application to porphyrin derivatives, OPTICS LETT, 25(5), 2000, pp. 323-325
Citations number
20
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Optics & Acoustics
Journal title
OPTICS LETTERS
ISSN journal
01469592 → ACNP
Volume
25
Issue
5
Year of publication
2000
Pages
323 - 325
Database
ISI
SICI code
0146-9592(20000301)25:5<323:EOTZTA>2.0.ZU;2-S
Abstract
We demonstrate the use of the Z-scan technique as a method to measure a che mical parameter, the pK(a) value, that characterizes the equilibrium consta nt in acid-base reactions. The measurements were performed with picosecond pulses at 532 nm in Fe(III)-meso-tetrakis(4-N-methyl-pyridyl) porphyrin. Th e results were compared with linear absorption measurements and electron pa ramagnetic resonance, the usual techniques employed to determine pK(a) valu es in aqueous solutions, and showed excellent agreement. (C) 2000 Optical S ociety of America. OCIS codes: 190.3270, 190.4400, 160.4670, 160.4760.