title: Stability of water-stable C60 clusters to OH radical oxidation and hydrated electron reduction.
abstract: Reactions of water-stable C(60) clusters (nC(60)) in water with OH radicals (*OH) and hydrated electrons (e(aq)(-)), generated by steady-state gamma-radiation, were observed and characterized. Ordered C(60) clusters were relatively recalcitrant to highly reactive *OH and e(aq)(-) species, with only a fraction of carbons oxidized and reduced, respectively. Pulse radiolysis suggested that the reactions of nC(60) with OH* and e(aq)(-) were diffusion limited, with rate constants of (7.34 +/- 0.31) x 10(9) M(-1) s(-1) and (2.34 +/- 0.02) x 10(10) M(-1) s(-1), respectively. Quantum mechanical calculations of binding energy of the C(60)-OH adduct as a function of C(60) clustering degree indicate, despite an initial fast reaction, a slower overall conversion due to thermodynamic instability of C(60)-OH intermediates. The results imply that ordered clustering of C(60) in the aqueous phase significantly hinders C(60)'s fundamental reactivity with radical species.
authors.affiliation: School of Civil and Environmental Engineering, and Department of Chemistry, Rice University, Houston, Texas 77005, USA.
authors.forename: Jaesang
authors.initials: J
authors.lastname: Lee
authors.forename: Weihua
authors.initials: W
authors.lastname: Song
authors.forename: Seung S
authors.initials: SS
authors.lastname: Jang
authors.forename: John D
authors.initials: JD
authors.lastname: Fortner
authors.forename: Pedro J J
authors.initials: PJ
authors.lastname: Alvarez
authors.forename: William J
authors.initials: WJ
authors.lastname: Cooper
authors.forename: Jae-Hong
authors.initials: JH
authors.lastname: Kim
mesh_terms: D004583:Electrons; D037741:Fullerenes / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D007700:Kinetics; D010084:Oxidation-Reduction; D011789:Quantum Theory; D013816:Thermodynamics; D014867:Water
chemical_list: D037741:Fullerenes; D014867:Water; D017665:Hydroxyl Radical; C069837:fullerene C60