Unusual redox behavior of a water soluble malonic acid derivative of C{sub 60}. Evidence for possible cluster formation

Journal Article · Thu Sep 07 04:00:00 EDT 1995 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/j100036a026· OSTI ID:106771

Guldi, D M; Asmus, K D ^[1]; Hungerbuehler, H ^[2]

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1. Hahn-Meitner-Institut, Berlin (Germany)
2. Univ. of Notre Dame, IL (United States)

Although fullerenes are known to be easily and efficiently reduced, no such reaction could be observed between one of the most powerful reductants, the hydrated electron, and water-soluble C{sub 60}C(COO{sup -}){sub 2}, a malonic acid derivative of C{sub 60}. This lack of reactivity is attributed to clustering of this functionalized fullerene in the aqueous phase, in which it is suggested to form kind of a micellar aggregate with the hydrophobic C{sub 60} core in the center and the hydrophilic carboxyl groups sticking into the water phase. Reduction of C{sub 60}C(COO{sup -}){sub 2} by {epsilon}{sub uq}{sup -} readily occurs, however, if clustering is prevented by embedding an isolated single fullerene molecule into {gamma}-cyclodextrin. Further evidence for clustering in polar environment (water and lower alcohols) is provided by the ground state absorption spectrum of C{sub 60}C(COO{sup -}){sub 2}, which shows considerable line broadening in conjunction with lower extinction coefficients as compared with C{sub 60}C(COOH){sub 2} in less polar, e.g. toluene, solutions. The clustering concept is also supported by the short lifetime of the triplet excited state, ({sup 3}C{sub 60})C(COO{sup -}){sub 2}, in water (t{sub 1/2} = 0.4 {mu}s) as compared to that of the {gamma}-cyclodextrin encapsulated ({sup 3}C{sub 60})C-(COO{sup -}){sub 2}/{gamma}-CD (t{sub 1/2} = 55 {mu}s). 59 refs., 7 figs., 1 tab.

• Sponsoring Organization: USDOE
• OSTI ID: 106771
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 36 Vol. 99; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
ABSORPTION SPECTRA
ACTIVATION ENERGY
ANIONS
EXCITED STATES
FULLERENES
GROUND STATES
MALONIC ACID
REDOX REACTIONS
SOLID CLUSTERS