Jump to main content
Jump to site search

Issue 12, 2012
Previous Article Next Article

Photo-excitation energy transfer between a titanium(IV)–porphyrin complex and oxygen molecule

Author affiliations

Abstract

The Ti-TPyP reagent, i.e. an acidic aqueous solution of oxo[5,10,15,20-tetra(4-pyridyl)-porphyrinato]titanium(IV) complex, denoted as TiO(tpyp), was developed as a highly sensitive and specific reagent for detecting hydrogen peroxide. In our previous paper, the photosensitizing effect of the TiO(tpyp) complex on the detection of hydrogen peroxide using this reagent was explored based on the experimental findings. In the present paper, computational analysis was carried out for the molecular level elucidation of the energy transfer mechanism between the photo-excited TiO(tpyp) complex and triplet oxygen to form singlet oxygen under aqueous acidic conditions. The protonated form of the TiO(tpyp) complex, i.e. [TiO(tpypH4)]4+ complex, was found to be the entity responsible for the energy transfer to triplet oxygen. The interaction sites between the [TiO(tpypH4)]4+ complex with triplet oxygen were then discussed based on their molecular orbital characteristics and the potential energy changes accompanying the approach of triplet oxygen molecule Σ3O2 to the [TiO(tpypH4)]4+ complex. The obtained results show that the C–N portion of the porphyrin ring plays a predominant role in the energy transfer from the photo-excited porphyrin to Σ3O2. Σ3O2 is then converted to Δ1O2 through Σ1O2. The Δ1O2 molecule reaches its stable state at the distance of 3.21 Å from the C–N portion of the porphyrin ring with its stabilization energy of 0.99 kcal mol−1. The stabilization energy for the Δ1O2 molecule thus formed is small, implying no stable bond formation between the Δ1O2 molecule and the [TiO(tpypH4)]4+ complex and that it moves away from the C–N portion immediately after the energy transfer from the photo-excited porphyrin.

Graphical abstract: Photo-excitation energy transfer between a titanium(iv)–porphyrin complex and oxygen molecule

Back to tab navigation

Supplementary files

Publication details

The article was received on 02 Jul 2012, accepted on 05 Oct 2012 and first published on 05 Nov 2012


Article type: Paper
DOI: 10.1039/C2AY25683E
Citation: Anal. Methods, 2012,4, 4289-4294

  •   Request permissions

    Photo-excitation energy transfer between a titanium(IV)–porphyrin complex and oxygen molecule

    T. Matsumoto and K. Takamura, Anal. Methods, 2012, 4, 4289
    DOI: 10.1039/C2AY25683E

Search articles by author

Spotlight

Advertisements