Structure and Excitation Relaxation Dynamics of Dimethylanthracene Dimer in a γ-Cyclodextrin Nanocavity in Aqueous Solution

Abstract

Dimethylanthracene (DMA), which exhibits almost no self-association in bulk organic solvents, forms a dimer and emits excimer-like fluorescence in a gamma-cyclodextrin nanocavity in a dilute aqueous solution. The 1Bb and 1La electronic transitions of the DMA dimer split by 2230 and 344 cm(-1), respectively, in a fluorescence excitation spectrum obtained with the excimer-like emission. From these energy splits, the structure of dimer in relation to a dielectric constant inside gamma-CD was discussed on the basis of atom-atom Lennard-Jones potential calculations including Coulombic interactions. Excitation relaxations of DMA in the presence of alpha-, beta-, and gamma-CDs in aqueous solutions were investigated by time-resolved fluorescence. The results suggest that both the hydrated and anhydrated species exist in the alpha- and gamma-CD complexes, while only the anhydrated species exists in the beta-CD complex.

Luminescent properties and structure of multicomponent naphthalene-β-cyclodextrin complexes. 1. Effect of adding third parties, o-carborane or/and adamantane

“…This is indicative of the inability of naphthalene to form dimers in the ground state. This resembles the behavior of dimethylanthracene, which exhibits almost no self-association, but forms a dimer and emits excimer-like fluorescence in the g-cyclodextrin nanocavity in dilute aqueous solutions [17].…”

Quantum Interference Signal from an Inhomogeneously Broadened System Excited by an Optically Phase-Controlled Laser-Pulse Pair

“…(Douhal, 2004) We intuitively imagined that the confinement of a guest molecule within the CD nanocavity will reduce perturbations from the surrounding environment which causes decoherence. Several studies on CD complexes with aromatic compounds using steady-state and ultrafast time-resolved spectroscopy have been reported (Hamai, 1991;Vajda et al, 1995;Chachisvilis et al, 1998;Matsushita et al, 2004;Pistolis &Malliaris, 2004;Sato et al, 2006). However, there were no experiments, to our knowledge, which interrogate the effect of CD inclusion on the inhibition of decoherence.…”

Cyclodextrin Nanocavity Caging Effect on Electronic Dephasing

“…Several authors report that water molecules are encapsulated into the CD cavities, together with aromatic guests. [6][7][8][9][10] Therefore, the key factor for the decoherence moderation may be the suppression of solvent relaxation of captured water molecules inside the CD. Indeed, the very small Stoke's shift, which was always accompanied by spectral narrowing, strongly infers a suppression of the solvent relaxation.…”