The gold porphyrin first excited singlet state
Journal article, 2002

Gold porphyrins are often used as electron-accepting chromophores in artificial photosynthetic constructs. Because of the heavy atom effect, the gold porphyrin first-excited singlet state undergoes rapid intersystem crossing to form the triplet state. The lowest triplet state can undergo a reduction by electron donation from a nearby porphyrin or another moiety. In addition, it can be involved in triplet-triplet energy transfer interactions with other chromophores. In contrast, little has been known about the short-lived singlet excited state. In this work, ultrafast time-resolved absorption spectroscopy has been used to investigate the singlet excited state of Au(III) 5,15-bis(3,5-di-t-butylphenyl)-2,8,12,18,-tetraethyl-3,7,13,17-tetrameth ylporphyrin in ethanol solution. The excited singlet state is found to form with the laser pulse and decay with a time constant of 240 fs to give the triplet state. The triplet returns to the ground state with a lifetime of 400 ps. The lifetime of the singlet state is comparable with the time constants for energy and photoinduced electron transfer in some model and natural photosynthetic systems. Thus, it is kinetically competent to take part in such processes in suitably designed supermolecular systems.

energy-transfer

dimers

light-harvesting complex

cyclophanes

free-base

relaxation

charge-separated state

quinone

molecules

carotenoids

photoinduced electron-transfer

Author

Joakim Andreasson

Chalmers, Department of Chemistry and Bioscience

G. Kodis

S. Lin

A. L. Moore

T. A. Moore

D. Gust

Jerker Mårtensson

Department of Organic Chemistry

Bo Albinsson

Chalmers, Department of Chemistry and Bioscience

Photochemistry and Photobiology

0031-8655 (ISSN) 17511097 (eISSN)

Vol. 76 1 47-50

Subject Categories

Chemical Sciences

DOI

10.1562/0031-8655(2002)0760047TGPFES2.0.CO2

More information

Created

10/7/2017