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Understanding and controlling the efficiency of Au24M(SR)18 nanoclusters as singlet-oxygen photosensitizers† † Electronic supplementary information (ESI) available: Chemicals, determination of relevant kinetic and thermodynamic parameters, further experimental procedures, Table S1 and Fig. S1–S9. See DOI: 10.1039/d0sc00520g

ABSTRACT: Singlet oxygen, 1O2, can be generated by molecules that upon photoexcitation enable the 3O2 → 1O2 transition. We used a series of atomically precise Au24M(SR)18 clusters, with different R groups and doping metal atoms M. Upon nanosecond photoexcitation of the cluster, 1O2 was efficiently generated. Detection was carried out by time-resolved electron paramagnetic resonance (TREPR) spectroscopy. The resulting TREPR transient yielded the 1O2 lifetime as a function of the nature of the cluster. We found that: these clusters indeed generate 1O2 by forming a triplet state; a more positive oxidation potential of the molecular cluster corresponds to a longer 1O2 lifetime; proper design of the cluster yields results analogous to those of a well-known reference photosensitizer, although more effectively. Comprehensive kinetic analysis provided important insights into the mechanism and driving-force dependence of the quenching of 1O2 by gold nanoclusters. Understanding on a molecular basis why these molecules may perform so well in 1O2 photosensitization is instrumental to controlling their performance. Atomically precise Au24M(SR)18 clusters were used as singlet-oxygen photosensitizers. Comprehensive kinetic analysis provided insights into the mechanism and driving-force dependence of the quenching of 1O2 by gold nanoclusters.

SUBMITTER: Agrachev M

PROVIDER: S-EPMC8524663 | biostudies-literature |

REPOSITORIES: biostudies-literature

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