Aggregation of [70]fullerene in presence of acetonitrile: A chemical kinetic experiment

Abstract

[70]fullerene solutions in carbon tetrachloride and o-xylene exhibit a noteworthy spectral variation with time when acetonitrile is added. This has been ascribed to self-aggregation of [70]fullerene caused by the repulsion between polar acetonitrile and hydrophobic [70]fullerene, and the aggregation numbers have been determined from a kinetic scheme and also from a scanning electron microscopic study. The numbers thus obtained follow a cuboctahedral stacking pattern proposed recently and also agree with the magic formula n=55+3m (m=1 to 14) proposed by Branz et al. for [60]fullerene clusters [Phys. Rev. B. 66, 094107 (2002)].

Comparison of Cluster Formation, Film Structure, Microwave Conductivity, and Photoelectrochemical Properties of Composites Consisting of Single-Walled Carbon Nanotubes with C60, C70, and C84

“…In parallel, dynamic light scattering (DLS) measurements were also performed to complement the results of the FE-SEM measurements (Figure S2, Supporting Information). The FE-SEM image of (C 70 ) m discloses cuboid particles with a size of 250−350 nm (Figure a). , DLS measurement of (C 70 ) m reveals a relatively narrow size distribution of (C 70 ) m with an average diameter ( D av ) of 330 nm (Figure S2a, Supporting Information), which is consistent with the observed size of (C 70 ) m in Figure a. The FE-SEM image of (C 60 ) m manifested spherical particles with a size of 150−350 nm, whereas the DLS measurements exhibited comparable particles with an average diameter of 200 nm .…”

“…This drastic change in the absorption spectra of C 70 is attributed to the formation of C 70 clusters (denoted as (C 70 ) m ) by lyophobic interaction in the mixed solvent in addition to π-π interaction in C 70 . [87][88][89][90][91][92][93] Similar absorption behavior is noted for the (C 60 ) m cluster. 61 The UV-vis-NIR absorption spectrum of f-SWNT in ODCBacetonitrile (Figure 1Bb and inset) is virtually similar to that in ODCB (Figure 1Ab and inset), exhibiting the characteristic peaks associated with the transitions between symmetric van Hove singularities in the density of states for SWNT.…”

“…In the ODCB−acetonitrile solution, the intense peak at 471 nm observed in ODCB disappears and a new broad band around 695 nm emerges with an absorption tail extending to NIR (Figure Ba). This drastic change in the absorption spectra of C 70 is attributed to the formation of C 70 clusters (denoted as (C 70 ) m ) by lyophobic interaction in the mixed solvent in addition to π−π interaction in C 70 . − Similar absorption behavior is noted for the (C 60 ) m cluster . The UV−vis−NIR absorption spectrum of f-SWNT in ODCB−acetonitrile (Figure Bb and inset) is virtually similar to that in ODCB (Figure Ab and inset), exhibiting the characteristic peaks associated with the transitions between symmetric van Hove singularities in the density of states for SWNT. , This implies that the formation of f-SWNT clusters (denoted as (f-SWNT) m ) is suppressed owing to the large steric hindrance of the swallow-tailed substituents around f-SWNT .…”

Formation, Stability, and Coagulation of Fullerene Organosols: C70 in Acetonitrile–Toluene Solutions and Related Systems

“…Formation of fullerene aggregates in the toluene–acetonitrile binary solvent is well documented. ,,− Recently, we conducted some new experiments, which allowed us to make additional observations for this and related systems. The data are typified in Figure .…”

Good Solvent Effects of C70 Cluster Formations and Their Electron-Transporting and Photoelectrochemical Properties

“…One of the most frequently employed approaches to prepare fullerene assemblies is rapid injection technique first demonstrated by Sun and Bunker, where a poor solvent (e.g., acetonitrile) is rapidly injected into a solution of fullerene dissolved in good solvent (e.g., benzene, toluene, etc.) or vice versa. – The lyophobic interaction between the mixed solvent and fullerene molecules as well as the π−π interaction between fullerene molecules is responsible for formation of the metastable colloidal aggregates in the mixed solvent. Most prominent advantage of the rapid injection method is its capability to be followed by subsequent electrophoretic deposition, which results in film deposition on an electrode from colloidal dispersions .…”