Please use this identifier to cite or link to this item:
http://hdl.handle.net/1942/26749
Title: | Free base and protonated form fluorescence of the mixed 5,10,15,20-arylporphyrins | Authors: | Kruk, M.M. Vershilovskaya, I.V. Ngo, T. Scheblykin, I.G. Dehaen, W. MAES, Wouter |
Issue Date: | 2016 | Source: | Proceedings of BSTU, 4, p. 12-15 | Abstract: | Fluorescence spectra for a series of mixed phenyl-mesityl 5,10,15,20-tetraarylporphyrins – with Mes4, Mes3Ph, Mes2Ph2-trans, Mes2Ph2-cis, MesPh3 and Ph4 type architecture (Mes – mesityl, Ph – phenyl) – in their free base, mono- and diprotonated form are reported. Substitution of a single mesophenyl group with a sterically more demanding mesityl group is found to be sufficient to provide stabilization of the monoprotonated porphyrin species. A decrease in the number of mesityl substituents in the macrocycle leads to a decrease in the fluorescence quantum yield for protonated forms. The progressive replacement of ortho,ortho’-substituted mesityl groups with unhindered phenyls results in the additive pattern of spectral changes for the free base porphyrins, whereas for both protonated species a specific jump at the trans to cis transition is observed, along with a gradual additive pattern before and afterwards. This feature is interpreted as a signature of the transition between the hindered-like and unhindered-like conformations of the tetrapyrrolic macrocycles in the protonated forms. These two molecular conformations provide a different interaction of the two one-electron (a1u,eg) and (a2u,eg) configurations, which leads to changes of their contributions into electronic transitions. | Keywords: | porphyrins; free bases; protonated forms; molecular conformation; fluorescence | Document URI: | http://hdl.handle.net/1942/26749 | ISSN: | 1683-0377 | Category: | A2 | Type: | Journal Contribution |
Appears in Collections: | Research publications |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
Kruk.Free base (1).pdf | Published version | 650.5 kB | Adobe PDF | View/Open |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.