Search results for "Perylene bisimide"
showing 4 items of 4 documents
Insights into the anion effect on the self assembly of perylene bisimide diimidazolium salts
2017
Abstract We studied how changing the anion affects the self-assembly of three diimidazolium salts bearing a perylene bisimide spacer. In particular we used [BF 4 − ] and [NTf 2 − ] based salts together with a mixed salt bearing both [I − ] and [BF 4 − ] anions. Thermal as well as concentration and temperature dependent spectroscopic investigations revealed that changing the anion impacts on solid state and solution aggregation, leading to articulate thermotropic behaviors and contrasting solvent effects, respectively. We also studied the electrochemical behavior of the salts to verify if changing the anion alters the redox properties of the salts. Finally, different anions also lead to very…
Perylene Derivatives As Useful SERRS Reporters, Including Multiplexing Analysis
2015
Five perylene bisimide (PBI) derivatives were designed and synthesized, on the basis of quantum-chemical calculations. The influence of halogen substituents on the shape and energy of the frontier orbitals and the Raman spectra were calculated, in the prospect use in surface-enhanced resonance Raman scattering (SERRS) studies. The corresponding experiments confirmed a very strong SERRS response in the presence of pristine (i.e., uncoated) gold nanoparticles. These spectra can be used for multiplexing measurements, namely measurements in which, by using a single laser excitation, one can recognize the simultaneous presence of several analytes.
Modification of Nanocrystalline WO3 with a Dicationic Perylene Bisimide: Applications to Molecular Level Solar Water Splitting
2015
[(N,N?-Bis(2-(trimethylammonium)ethylene) perylene 3,4,9,10-tetracarboxylic acid bisimide)(PF6)2] (1) was observed to spontaneously adsorb on nanocrystalline WO3 surfaces via aggregation/hydrophobic forces. Under visible irradiation (? > 435 nm), the excited state of 1 underwent oxidative quenching by electron injection (kinj > 108 s-1) to WO3, leaving a strongly positive hole (Eox ? 1.7 V vs SCE), which allows to drive demanding photo-oxidation reactions in photoelectrochemical cells (PECs). The casting of IrO2 nanoparticles (NPs), acting as water oxidation catalysts (WOCs) on the sensitized electrodes, led to a 4-fold enhancement in photoanodic current, consistent with hole transfer from …
Aggregation processes of perylene bisimide diimidazolium salts
2015
The supramolecular aggregation of three diimidazolium- functionalized perylene bisimides, differing in the alkyl chain length was investigated. These salts form aggregates in solvents like chloroform, dichloromethane, and glycerol. Solvent-, concentration-, and temperature-dependent spectroscopic studies were carried out, evidencing the occurrence of an isodesmic, enthalpy-driven aggregation process, underpinned by p–p stacking and hydrogen bonding. Moreover, dynamic light scattering (DLS) measurements and SEM images revealed that these salts aggregate in chloroform into elongated structures.