Resonance Raman and electronic absorption study of free-base tetraphenylporphine diacid dispersed in polymethylcyanoacrylate

✍ Scribed by G. S. S. Saini; Amit Sharma; Sukhwinder Singh; J. M. Abbas; S. K. Tripathi; Sarvpreet Kaur; C. G. Mahajan; H. H. Thanga; A. L. Verma

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 285 KB
• Volume: 38
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/jrs.1802

✦ Synopsis

Abstract

We report a resonance Raman study on free‐base tetraphenylporphine (H~2~TPP) and its chemically prepared diacid dispersed in polymethylcyanoacrylate (PMCA). Photoexcitation of the neutral porphine by laser light leads irreversibly to the formation of the diacid, with the π‐cation radical as intermediate species. Resonance Raman (RR) spectra of the diacid dispersed in the polymer obtained with 441.6 nm in the wavenumber region of 100–1650 cm^−1^ are recorded. Wavenumbers with other excitation lines are also reported for the diacid species. Some bands assigned to out‐of‐plane vibrational modes and forbidden under ideal D~2__h__~ symmetry are also observed in the resonance Raman spectra of the diacid. These bands arise from the out‐of‐plane distortions, which reduce the symmetry of the molecule. These findings are supported by the electronic absorption studies of the diacid in the polymer. Copyright © 2007 John Wiley & Sons, Ltd.