Singlet oxygen generation by higher fullerene-based colloids

Abstract

In this paper, the results of the synthesis and characterization of higher fullerene-based colloids is presented. The generation of singlet oxygen 1O2 (1?g) by fullerene water-based colloids (nC60, nC70 and nC84) was investigated. It was found by electron paramagnetic resonance spectroscopy that the generation of singlet oxygen was the highest by the nC84 colloid. The amplitude of the electron paramagnetic resonance (EPR) signal was two orders of magnitude higher than the amplitude of the EPR signals which originated from nC60 and nC70. The surface morphology and the structure of the particles of the water-based colloids were investigated by atomic force microscopy (AFM). The AFM study showed that the average size of the nC60, nC70 and nC84 were 200 nm, 80 nm and 70 nm, respectively. In addition, the particle size distribution of the nC60, nC70 and nC84 colloids was determined by dynamic light scattering (DLS) measurements.

Aggregation Kinetics of Higher-Order Fullerene Clusters in Aquatic Systems

“…With the increase in carbon number, the symmetry of the HOF cages shifts from spherical or truncated icosahedrons (for C 60 ) to ellipsoidal (for C 70 ) to irregular (for C 76 ) . Larger carbon structures of HOFs with altered geometric shapes lead to differences in electronic properties and solvent interactions (compared to C 60 s). , Improved electrical properties of these higher carbon structures, i.e., lower band gap, ability to simultaneous display n- and p-type junction behavior, higher electron affinities, and charge mobility are considered valuable in organic field-effect transistors, solar cells, and photovoltaics. ,, Such properties have also shown to generate reactive oxygen species (ROS) . HOFs have also been utilized to encase transition and rare-earth metals and form endohedral metallofullerenes (EMFs).…”

“…2,11,12 Such properties have also shown to generate reactive oxygen species (ROS). 13 HOFs have also been utilized to encase transition and rare-earth metals and form endohedral metallofullerenes (EMFs). For example, EMFs produced by the stabilization of Gd, Sc, or Lu metal atoms inside C 60 and other HOF cages have shown to provide 20−500 times higher proton relaxation in magnetic resonance imaging (MRI) applications when compared to the results from commercially used chelated Gd.…”

Differential Photoactivity of Aqueous [C60] and [C70] Fullerene Aggregates

“…Our finding that nC 70 is significantly more photoactive than nC 60 contradicts past research that found nC 60 and nC 70 to both lack considerable photoactivity. 31 However, it is difficult to directly compare the results due to differences in fullerene concentrations and also because it remains unclear what light source and intensity were used in the previous study.…”

“…Although extensive research has been conducted on the aqueous behavior of [C 60 ] fullerene and [C 60 ] fullerene derivative aggregates, , few studies have examined the properties of aqueous aggregates of larger cage fullerene species. Past reports that have studied such fullerene aggregates typically focused on their formation, microscopic characterization, and physicochemical parameters ,− but generally ignored their photochemical properties. One report focused on the 1 O 2 production of higher fullerene colloids (nC 70, nC 84 ) via electron paramagnetic resonance (EPR) spectroscopy using a 1 O 2 spin-trapping agent for qualitative comparisons, yet it remains unclear what light source and corresponding intensity were used for fullerene excitation, making it difficult to ascertain this study’s environmental relevancy.…”

Self-assembly of carbon based nanoparticles films by Langmuir-Blodgett method

“…[52][53][54][55][56][57] Fullerene must be photosensitized by UV or visible light to generate highly reactive singlet oxygen or superoxide radicals. 58,59 Derivatized C 60 fullerene with cationic functional groups forms molecules that are more water-soluble and can mediate photodynamic therapy efficiently upon illumination and they can selectively bind to microbial cells. [60][61][62] Carbon nanotubes (CNTs) are another group of the carbon allotropes.…”