Full-colour solvatochromic fluorescence emitted from a semi-aromatic imide compound based on ESIPT and anion formation

Abstract

A multi-colour solvatochromic fluorophore was developed by substituting a fully organic 3-amino-N-cyclohexyl phthalimide group with a p-toluenesulfonyl (tosyl) group. This compound is essentially colourless in the visible region and exhibits...

Theoretical insights into effects of solvent polarity on excited‐state N–H proton transfer behavior for a new fluorophore of 3‐tosylamino‐N‐cyclohexylphthalimide

“…In order to be consistent with the experiment, the absorption and fluorescence spectra of 3TsAPI in ACN, acetone, chloroform, toluene, and cyclohexane solvents are theoretically calculated and listed in Table 3 (the experimental values are shown in parentheses [ 52 ] ). In accordance with the order of decreasing polarity of solvents, the absorption peaks of the normal structure of 3TsAPI are 340.8 nm (337.0 nm), 341.0 nm (337.0 nm), 342.2 nm (341.0 nm), 343.0 nm (342.0 nm), and 342.8 nm (341.0 nm), respectively, which is completely in agreement with the experimental data.…”

“…Recently, Tabuchi and coworks developed a solvated organic fluorophore, 3‐tosylamino‐ N ‐cyclohexylphthalimide (3TsAPI), by introducing a p ‐toluenesulfonyl (tosyl) group to achieve red fluorescence with high fluorescence intensity and suppress the aggregation caused quenching (ACQ) in solutions. [ 52 ] Due to the strong electron‐absorbing ability and steric hindrance of tosyl group, the proton on the amino group can be transferred to the carbonyl group, forming a nearly perfect N–H···O‐type six‐membered ring hydrogen bonding, which provides us an excellent system for studying the kinetics and thermodynamics of ESIPT reaction. In addition, in order to further investigate the solvent effects of 3TsAPI, we optimize the ground‐state structure of 3TsAPI in five solvents with different polarity, including acetonitrile (ACN, Polarity Parameter: 6.2), acetone (Polarity Parameter: 5.4), chloroform (Polarity Parameter: 4.4), toluene (Polarity Parameter: 2.4), and cyclohexane (Polarity Parameter: 0.1) by using density functional theory (DFT), and optimize the excited‐state structure by using time‐dependent density functional theory (TD‐DFT).…”

Synthesis and Characterization of White-Light Luminescent End-Capped Polyimides Based on FRET and Excited State Intramolecular Proton Transfer

“…We have recently reported that the fluorescent color can be tuned by changing the substituent of 3-amino-N-cyclohexylphthalimide [45]. The targets of the molecular design for fluorophores in this study are (1) high transparency and colorlessness in the visible region and (2) intense yellowish fluorescence under UV irradiation for mixed white-color emission.…”

“…In our previous studies [21,45], we reported that ESIPT molecules are sensitive to the surrounding environment and may induce dissociation of the hydrogen atom in the amide group, generating an anionic form. The formation of anions in organic solvents was effectively suppressed with the addition of a small amount of TFA.…”

“…In our previous study, a yellow fluorescent imide compound with ESIPT ability was synthesized by substituting the trifluoroacetylamino (-NHCOCF 3 ) group at the 3-position of N-cyclohexylphthalimide (3TfAPI, Scheme S1); its fluorescent properties were briefly reported [45]. In this study, we resumed a detailed investigation of the structure and optical properties of 3TfAPI in the crystalline and solution states and we developed novel white light luminescent PI films by attaching a novel ESIPT anhydride having the same skeletal structure as 3TfAPI (3TfAPA, Scheme 1) as an end-capping agent for blue-fluorescent PIs (ODPA/DCHM or ODPA/tDACH).…”