Fluorescence studies of the sol–gel transition using aminopyrene

In Situ Probing of Oxygen-Containing Groups on Acid-treated Carbon Nanofibers using Aromatic Molecules

“…The excitation wavelength for the fluorescence spectra was 350 nm, and the emission wavelength for the excitation spectra was 420 nm. The broad bands of fluorescence around 440 nm and fluorescence excitation around 350−400 nm are assigned to AP in the liquid phase of the suspension since they coincide with the spectra of 1-AP in neutral polar solvents (Hite et al, 1986;Miller et al, 2005). The shape of this excitation spectral band is also similar to that of the absorption spectra of 1-AP shown in Figure 4.…”

“…Their relative intensities increased with ultrasonic irradiation time. The spectra of APH + are structurally similar to those of pyrene because the interaction between the free electron pair of nitrogen and the π-electrons in the pyrene ring is blocked by protonation of the amino group (Hite et al, 1986;Miller et al, 2005). These results of the fluorescence indicate that 1-AP is adsorbed on the CNF surface to form APH + -like species.…”

“…These are generated by the π−π interaction between 1-NP and the graphene sheet (Chen et al, 2001b;Long & Yang, 2001) and the hydrogen-bonding interaction between 1-NP and proton-accepting groups the oxidized groups, such as -COOH (-COO -) and -C=O (Nishikiori et al, 2004;Kubota et al, 2005a;Kubota et al, 2005b), generated at the acid-treated CNF surface (Hammon et al, 2002;Lakshminarayanan et al, 2004). 1-Aminopyrene (1-AP) is a Brönsted base and is expected to interact with acidic groups on a solid surface (Hite et al, 1986;Miller et al, 2005). Therefore, oxygen-containing functional groups produced on the surface of the acid-treated CNFs, especially acidic groups such as -COOH (Chen et al, 2001a;Kahn et al, 2002), are characterized by the fluorescence measurements using 1-AP as a molecular probe (Nishikiori et al, 2008).…”

Quantitative characterization of acidic groups on acid-treated multi-walled carbon nanotubes using 1-aminopyrene as a fluorescent probe

“…1-Aminopyrene (1-AP) is a Brönsted base and is expected to interact with acidic groups on a solid surface [30,31]. In our previous study [32], oxygen-containing functional groups produced on the surface of the acid-treated CNFs have been characterized by UV-visible spectroscopy and the 4 fluorescence measurements using 1-AP as a probe molecule in order to focus on such acidic groups such as -COOH [33,34].…”

Preparation and structure of graphite oxide functionalized with 1-aminopyrene

“…When it is once protonated, the fluorescence from it is rather similar to that from pyrene without amino group and fine vibrational structure around 400 nm is observed. This is because the interaction between the free electron pair on nitrogen atom and the π-electrons in the pyrene ring is blocked 21), 22) . Moreover, upon the adsorption of it on graphene via π-π interaction, the fluorescence from it is quenched 23)-25) .…”