Henchy, Chris and McCaffrey, John G. and Arabei, Serguei and Pavich, Tatiana and Galaup, Jean-Pierre and Shafizadeh, Niloufar and Crepin, Claudine (2014) Free base tetraazaporphine isolated in inert gas hosts: Matrix influence on its spectroscopic and photochemical properties. Journal of Chemical Physics, 141 (12). p. 124303. ISSN 0021-9606

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Abstract

The absorption, fluorescence, and excitation spectra of free base tetraazaporphine (H2TAP) trapped in Ne, N2, and Ar matrices have been recorded at cryogenic temperatures. Normal Raman spectra of H2TAP were recorded in KBr discs and predicted with density functional theory (DFT) using large basis sets calculations. The vibrational frequencies observed in the Raman Spectrum exhibit reasonable agreement with those deduced from the emission spectra, as well as with frequencies predicted from large basis set DFT computations. The upper state vibrational frequencies, obtained from highly resolved, site selected excitation spectra, are consistently lower than the ground state frequencies. This contrasts with the situation in free base phthalocyanine, where the upper state shows little changes in vibrational frequencies and geometry when compared with the ground state. Investigations of the photochemical properties of H2TAP isolated in the three matrices have been performed using the method of persistent spectral hole-burning (PSHB). This technique has been used to reveal sites corresponding to distinct N–H tautomers which were not evident in the absorption spectra. An analysis of the holes and antiholes produced with PSHB in the Qx (0-0) absorption band made it possible to identify inter-conversion of distinct host sites.

Item Type:	Article
Keywords:	Free base tetraazaporphine; inert gas hosts; Matrix influence; spectroscopic properties; photochemical properties;
Academic Unit:	Faculty of Science and Engineering > Chemistry
Item ID:	7765
Identification Number:	https://doi.org/10.1063/1.4894761
Depositing User:	Dr. John McCaffrey
Date Deposited:	16 Jan 2017 17:01
Journal or Publication Title:	Journal of Chemical Physics
Publisher:	American Institute of Physics
Refereed:	Yes
URI:	http://aip.scitation.org
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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