Sterically induced conformational relaxation and structure of meso-diaryloctaalkyl porphyrins in the excited triplet state: Experimental and DFT studies
Journal article, 2002

The excited triplet state conformations of zinc and free base 5,15-diaryloctaalkylporhyrins are studied by experimental and computational (density functional theory, DFT) methods. From the observations of an unusual triplet state dynamics, i.e., fast nonradiative and biexponential decay, it has been suggested that these porphyrins exist in two distinguishable conformers in the lowest excited triplet state. X-ray crystallography and,DFT (B3LYP/6-31G(d)) optimization of the ground state show that the porphyrins are planar prior to excitation. However, in the excited triplet state, the planar structure relaxes to an out-of-plane distorted saddle-shaped conformer. This distorted conformer and the lowest triplet potential energy surface are characterized by DFT calculations. It is suggested that the conformational relaxation explains the unusual triplet dynamics of this class of porphyrins.


Alexander Kyrychenko

Department of Physical Chemistry

Joakim Andreasson

Department of Physical Chemistry

Jerker Mårtensson

Chalmers, Department of Chemistry and Bioscience, Organic Chemistry

Bo Albinsson

Department of Physical Chemistry

Journal of Physical Chemistry B Materials

1089-5647 (ISSN)

Vol. 106 48 12613-12622

Subject Categories

Physical Chemistry



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