Chemistry of Singlet Oxygen with a Cadmium-Sulfur Cluster: Physical Quenching versus Photooxidation

David A. Cagan, Arman C. Garcia, Kin Li, David Ashen-Garry, Abegail C. Tadle, Dong Zhang, Katherine J. Nelms, Yangyang Liu, Jeffrey R. Shallenberger, Joshua J. Stapleton, Matthias Selke

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Abstract

We investigated the chemistry of singlet oxygen with a cadmium-sulfur cluster, (Me 4 N) 2 [Cd 4 (SPh) 10 ]. This cluster was used as a model for cadmium-sulfur nanoparticles. Such nanoparticles are often used in conjunction with photosensitizers (for singlet oxygen generation or dye-sensitized solar cells), and hence, it is important to determine if cadmium-sulfur moieties physically quench and/or chemically react with singlet oxygen. We found that (Me 4 N) 2 [Cd 4 (SPh) 10 ] is indeed a very strong quencher of singlet oxygen with total rate constants for 1 O 2 removal of (5.8 ± 1.3) × 10 8 M -1 s -1 in acetonitrile and (1.2 ± 0.5) × 10 8 M -1 s -1 in CD 3 OD. Physical quenching predominates, but chemical reaction leading to decomposition of the cluster and formation of sulfinate is also significant, with a rate constant of (4.1 ± 0.6) × 10 6 M -1 s -1 in methanol. Commercially available cadmium-sulfur quantum dots ("lumidots") show similar singlet oxygen quenching rate constants, based on the molar concentration of the quantum dots.

Original languageEnglish (US)
Pages (from-to)67-71
Number of pages5
JournalJournal of the American Chemical Society
Volume141
Issue number1
DOIs
StatePublished - Jan 9 2019

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All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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