Photoinduced Intramolecular Charge Transfer Reaction in (E)-3-(4-Methylamino-phenyl)-acrylic Acid Methyl Ester:  A Fluorescence Study in Combination with TDDFT Calculation

Abstract

A donor-acceptor substituted aromatic system (E)-3-(4-Methylamino-phenyl)-acrylic acid methyl ester (MAPAME) has been synthesized, and its photophysical behavior obtained spectroscopically has been compared with the theoretical results. The observed dual fluorescence from MAPAME has been assigned to emission from locally excited and twisted intramolecular charge transfer states. The donor and acceptor angular dependency on the ground and excited states potential energy surfaces have been calculated both in vacuo and in acetonitrile solvent using time dependent density functional theory (TDDFT) and TDDFT polarized continuum model (TDDFT-PCM), respectively. Calculation predicts that a stabilized twisted excited state is responsible for red shifted charge transfer emission.

Chemically Induced Unfolding of Bovine Serum Albumin by Urea and Sodium Dodecyl Sulfate: A Spectral Study with the Polarity‐Sensitive Charge‐Transfer Fluorescent Probe (E)‐3‐(4‐Methylaminophenyl)acrylic Acid Methyl Ester

“…It shows a strong absorption peak at about 350 nm for the pp* transition of the aromatic ring. [1] Compared to the parent benzene molecule this pp* absorption band is shifted to the red due to the presence of conjugation and the amino substituent, which facilitate resonance stabilization. As shown in Figure 1 a, the absorption spectrum of MAPAME changes in peak position and shape with varying BSA concentration.…”

“…The hydrophobic proteinous environment around the BSA-bound probe cuts out the non-radiative decay paths which are available to MAPAME in polar hydrogen-bonding solvents like water. [1] Once the non-radiative paths are deactivated, the overall intensity of the CT emission is bound to increase. Figure 2 shows the usual Benesi-Hildebrand [10] plot for 1:1 complexation between BSA and MAPAME.…”

Excited States from Time‐Dependent Density Functional Theory

“…69,70 In the realm of photochemistry, 71 properties of chromophores [72][73][74][75][76] and dyes [77][78][79][80][81][82][83] have been computed. For these and other systems, there is great interest in charge-transfer excitations, [84][85][86][87][88][89][90][91][92] but, as we later discuss, intermolecular charge transfer is a demanding problem for TDDFT.…”

Spectroscopic study of excited state intramolecular charge transfer in ethyl ester of N,N′-Dimethylaminonaphthyl-(acrylic)-acid

“…Over the past years, the photophysical study of donoracceptor systems linked to a chromophore has drawn considerable interest for basic and applied research [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The first observation of dual fluorescence of the model compound 4-N,N 0 -dimethylaminobenzonitrile (DMABN) by Lippert et al [1] was a major breakthrough in the realm of photoinduced donor-acceptor charge transfer process.…”