Charge Transfer in Excited Donor‐acceptor Phenothiazine Derivatives

Abstract

A series of N-bonded donor-acceptor derivatives of phenothiazine containing phenyl (PHPZ), anisyl (ANPZ), pyridyl (PYPZ), naphthyl (NAPZ), acetylphenyl (APPZ), and cyanophenyl (CPPZ) as an electron acceptor have been synthesized. Their photophysical properties were investigated in solvents of different polarities by absorption and emission techniques. These studies clearly revealed the existence of an intramolecular charge transfer (ICT) excited state in the latter four compounds. The solvent dependent Stokes shift values were analyzed by the modified Lippert-Mataga equation to obtain the excited state dipole moment values. The large excited state dipole moment suggests that the full (or nearly full) electron transfer take place in the A-D systems. In the system of A-D phenothiazine derivatives, the transition dipole moments M flu were determined mainly by direct interactions between the solvent-equilibrated fluorescence 1 CT state and ground state because of their lack of significant change with increase of the solvent polarity. The electron structure and molecular conformation of phenothiazine derivatives will be significantly changed with the increase of the electron affinity of the N-10 substituent.

Modification of the Second Harmonic Generation and Fluorescence Efficiency of D289 Dye Based on a Donor–Acceptor Structure

“…However, the lower electron-donating capacity of the benzene groups than the ethyl groups in D289 may cause a lower intermolecular charge transfer (ICT) effect for TPAP, thus leading to a smaller NLO response. It is known that a strong electron pull–push effect has a positive influence on the NLO performance of molecules, , and a high electron-donating capacity in the D−π–A structure molecule benefits the ICT effect. − Therefore, the electron donating capacity of TPAP was further optimized by incorporating the TPA donor segment with electron-rich groups (methoxyls) to obtain the TPAPM structure. The pyridinium in TPAP and TPAPM was used as an electron-deficient segment connected to the π-conjugation with an electron donor.…”

Toward the Rational Design of Organic Catalysts for Organocatalysed Atom Transfer Radical Polymerisation

“…d Estimated using the phosphorescence lifetime [53,[66][67][68]]. e Photoexcitation data for PC1 are all measured in tetrahydrofuran [66], except that ϵ max is measured in cyclohexane [65]. f Photoexcitation data for PC2 are all measured in toluene [67].…”

Surface Engineering with Polymer Brush Photolithography

“…Common transition-metal-based and organic photoredox catalysts for use in light-mediated SI-CRP and their wavelength of maximum absorbance (λ max ) and molar extinction coefficients (ε). [137][138][139][140] Figure 2. (Top) Photomask and photopatterned panda by growth of poly(METAC) brushes on a Si substrate and (bottom) grapes (left to right) raw, coated with a polydopamine (PDA) adhesive layer, and subsequently coated with poly(SPMA) film through photopolymerization.…”

“…Common transition‐metal‐based and organic photoredox catalysts for use in light‐mediated SI‐CRP and their wavelength of maximum absorbance (λ max ) and molar extinction coefficients (ε). [ 137–140 ] …”