Cavity Size Effect on the Excited State Dynamics of Methyl 4-(Dimethylamino)benzoate−Cyclodextrin Complexes

Abstract

The effect of cyclodextrin (CD) complexation on the fluorescence properties of methyl 4-(dimethylamino)-benzoate (MDMAB) was studied. The complex with R-, -, and γ-CDs exhibited twisted intramolecular charge transfer (TICT) fluorescence whereas only the emission from the locally excited state was observed in aqueous solution without CD. In the case of the R-CD complex, dual TICT emission was observed, a low-energy emission was centered at 520 nm, and a higher-energy emission was centered at 450 nm. The dependence of TICT emission intensity on pH and R-CD concentration suggested that the lower and higher energy emission can be attributed to the TICT states of MDMAB in the 1:1 and 1:2 MDMAB-R-CD complexes. On the other hand, only the formation of 1:1 complex was observed in the presence of -and γ-CDs. The cavity size effect on the fluorescence properties of MDMAB was further discussed on the basis of time-resolved laser spectroscopy.

An Anthracene‐Appended β‐Cyclodextrin‐Based Dyad: Study of Self‐Assembly and Photoinduced Electron‐Transfer Processes

“…The 1 H NMR spectrum of ANCD exhibited peaks due to the b-CD part at d = 3.1-5.9 ppm and the aromatic residue at d = 7.5-8.6 ppm. The regiochemistry of ANCD was assigned based on a comparison of the 13 C NMR chemical shifts (see Supporting Information S2) with those reported for similar compounds. b-CD has seven glucose units and in monosubstituted b-CD systems, the 13 C NMR chemical shifts of six of the glucose units remain relatively unaffected by the substitution.…”

“…The regiochemistry of ANCD was assigned based on a comparison of the 13 C NMR chemical shifts (see Supporting Information S2) with those reported for similar compounds. b-CD has seven glucose units and in monosubstituted b-CD systems, the 13 C NMR chemical shifts of six of the glucose units remain relatively unaffected by the substitution. The 13 C NMR chemical shifts of the AN-attached glucose unit are expected to be modified.…”

“…If a 1:1 complex is formed between PMDI and b-CD, a plot of 1/(AÀA 0 ) against 1/A C H T U N G T R E N N U N G [b-CD] will be a straight line. [13] The double reciprocal plot was a straight line ( Figure 3b) and gave K a = 1288 m À1 .…”

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.…”

Spectral Properties and Solubilization Location of 2-Ethylhexyl 4-(N,N-Dimethylamino) benzoate in Micelles

“…For this reason, the absorption and dual fluorescence of EHDMAB were studied in the presence of typical surfactants in this work. Twisted intramolecular charge transfer (TICT) emission was further used to detect the location of EHDMAB in different micelles because it is highly sensitive to the microenvironmental polarity [20][21][22][23][24][25][26][27][28][29]. The location of EHDMAB in micelles was rationalized in terms of the molecular structures and sizes of EHDMAB and surfactants.…”