Rod-shaped Oligophenyleneethynylenes Modified by Donor and Acceptor Groups in a Block Manner: Synthesis and Light-emitting Characteristics

Ochi, Takanori; Yamaguchi, Yoshihiro; Kobayashi, Shigeya; Wakamiya, Tateaki; Matsubara, Yoichi; Yoshida, Zen‐ichi

doi:10.1246/cl.2007.794

Cited by 12 publications

(1 citation statement)

References 17 publications

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“…Recent progress in biological, chemical, and materialsscience utilizing organic fluorescent materials has resulted in the strong requirement for highly efficient fluorophores. However a general concept or method for the creation of highly fluorescent materials in a desired wavelength region has not been established yet, even though various attempts to achieve this goal have been made . Thus the development of a method for the creation of highly fluorescent materials should be an urgent and significant subject.…”

Section: Introductionmentioning

confidence: 99%

Photophysical Properties of Oligophenylene Ethynylenes Modified by Donor and/or Acceptor Groups

et al. 2008

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To create highly fluorescent organic compounds in longer wavelength regions, and to gain physical chemistry insight into the photophysical characteristics, we investigated photophysical properties (Phi(f), lambda(em), tau, lambda(abs), epsilon, k(r), and k(d)) and their controlling factor dependence of the following pi-conjugated molecular rods consisting of p-phenyleneethynylene units modified by donor (OMe) and/or acceptor (CN): (1) side-donor modification systems (SD systems), (2) side-acceptor modification systems (SA systems), and (3) systems consisting of donor block and acceptor block (BL systems). As a result, very high Phi(f) values (>0.95) were obtained for BL systems. Bathochromic shifts of lambd(em) in the same pi conjugation length were largest for BL systems. Thus we succeeded in the creation of highly efficient light emitters in the longer wavelength region by block modification (e.g., Phi(f) = 0.97, lambda(em) = 464 nm for BL-9), contrary to expectation from energy gap law. Considerably intense solid emission (Phi(f) approximately 0.5) in the longer wavelength region (500-560 nm) was also found for BL systems, presumably because of molecular orientation that hinders the self-quenching of fluorescence in solids. From (1) a Lippert-Mataga plot, (2) density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations, and (3) the positive linear relationship between the optical transition energy (nu(em)) and the difference between the highest occupied molecular orbital of the donor and the lowest unoccupied molecular orbital of the acceptor (HOMO(D)-LUMO(A) difference), it is elucidated that the excited singlet (S1) state of BL systems has a high charge transfer nature. The number (n) of energetically equivalent dipolar structure (EEDS) units in the oligoarylene ethynylenes is shown to be a measure of the effective pi conjugation length in the S1 state. The S1 state planarity increases with n values of EEDS units and by the introduction of donor and/or acceptor groups. It is worth noting that the Phi(f) values increase linearly with the n values of EEDS units.

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Section: Introductionmentioning

confidence: 99%

Photophysical Properties of Oligophenylene Ethynylenes Modified by Donor and/or Acceptor Groups

et al. 2008

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Tetrathiafulvalene–Oligo(para‐phenyleneethynylene) Conjugates: Formation of Multiple Mixed‐Valence Complexes upon Electrochemical Oxidation

Lipnická

Bělohradský

Kolivoška

et al. 2013

Chemistry A European J

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Short monodisperse oligo- (para-phenyleneethynylene) (pOPE) units bearing laterally attached tetrathio-substituted tetrathiofulvalene (TTF) units have been synthesised from functionalised aromatic building blocks by using the Sonogashira cross-coupling methodology. The unusual redox properties of these TTF-pOPE conjugates were observed by employing electrochemical methods, such as cyclic voltammetry and exhaustive electrolysis. We found that formally one half of the TTF units in the pOPE monomer 1, dimer 2, and trimer 3 (with 2, 4, and 6 TTF units, respectively) are electrochemically silent during the first-step oxidation at 0.49 V. We propose the formation of persistent mixed-valence complexes from the TTF and TTF(+·) units present in an equal ratio. Such mixed-valence dyads (single or multiple in the partially oxidised 1-3) exhibit an unusual stability towards oxidation until the potential of the second oxidation at 0.84 V is achieved. This finding suggests that below this potential the oxidation of the respective mix-valence complexes is extremely slow.

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New highly fluorescent hybrids (benz)imidazol-2-aminonicotinonitrile and -2-aminoisophthalonitrile: synthesis, characterization, fluorescence study, and theoretical calculations

Boulebd¹,

Ismaïli²,

Khatyr³

et al. 2018

Monatsh Chem

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Rod-shaped Oligophenyleneethynylenes Modified by Donor and Acceptor Groups in a Block Manner: Synthesis and Light-emitting Characteristics

Cited by 12 publications

References 17 publications

Photophysical Properties of Oligophenylene Ethynylenes Modified by Donor and/or Acceptor Groups

Photophysical Properties of Oligophenylene Ethynylenes Modified by Donor and/or Acceptor Groups

Tetrathiafulvalene–Oligo(para‐phenyleneethynylene) Conjugates: Formation of Multiple Mixed‐Valence Complexes upon Electrochemical Oxidation

New highly fluorescent hybrids (benz)imidazol-2-aminonicotinonitrile and -2-aminoisophthalonitrile: synthesis, characterization, fluorescence study, and theoretical calculations

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