Unusual role of oxygen in electron-transfer processes.
Molecular oxygen's unique involvement in electron-transfer processes is demonstrated on a series of dyads between porphyrin derivatives and fullerene C60. It has been shown for the first time that oxygen can serve as an inhibitor of back electron transfer by enhancing intersystem crossing of a singlet radical ion pair into its triplet state. The effect is observed only when energy of the charge-separated state is lower than that of the locally excited triplet states. Due to the spin statistics, the reverse intersystem crossing is less efficient, allowing use of oxygen and other paramagnetic species for impeding charge recombination in various electron-transfer systems.
Smirnov
Sergei
S
Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico, USA. snsm@nmsu.edu
Vlassiouk
Ivan
I
Kutzki
Olaf
O
Wedel
Michael
M
Montforts
Franz-Peter
FP
D002244:Carbon / Q000737:chemistry*; D004583:Electrons; D037741:Fullerenes; D008665:Metalloporphyrins / Q000737:chemistry*; D018716:Molecular Mimicry; D010100:Oxygen / Q000737:chemistry*; D010777:Photochemistry; D010788:Photosynthesis; D011166:Porphyrins / Q000737:chemistry*
D037741:Fullerenes; D008665:Metalloporphyrins; D011166:Porphyrins; C017802:zinc hematoporphyrin; C006969:chlorin; D002244:Carbon; C069837:fullerene C60; D010100:Oxygen