Local molecular motion of polystyrene model compounds measured by using picosecond pulse radiolysis. 1. Diastereoisomeric styrene dimers: Multicomponent fluorescence decay curves, concentration dependence, and alkyl end-group effect on excimer formation

Hideyuki Itagaki, Kazuyuki Horie, Itaru Mita, Masakazu Washio, Seiichi Tagawa, Yoneho Tabata, Hisaya Sato, Yasuyuki Tanaka

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

The dynamic process of intramolecular excimer formation in meso and racemic 4,6-diphenylnonanes (PS2(propyl)), diastereoisomeric dimer models of polystyrene, was investigated by using a picosecond pulse radiolysis technique. In dilute cyclohexane solution, the monomeric fluorescence of racemic PS2(propyl) decays single exponentially with a time constant of 11 ns, while that of meso PS2(propyl) was found to decay dual exponentially with time constants of 6 and 0.5 ns. These multicomponent fluorescence decays were found to be explicable by the local motion of conformational change. In conclusion, each time required for the conformational change (g+t/tg-) → tt, (g+t/tg-) → g+g-, and g+g- → (g+t/tg-) in meso PS2(propyl) is estimated to be 0.7, 2.5 and 6 ns, respectively, at room temperature. The proposition that fluorescence decay of diastereoisomeric dimers is influenced by molecular motion (conformational change) is also valid for explaining the profile of the transient fluorescence spectra of racemic PS2(propyl). The present result is an indication that multicomponent fluorescence decay observed in some polymer systems may be mainly due to the conformational change motion in meso dyads. The concentration dependence of the time constants of meso and racemic PS2(propyl) was also measured. In addition, an alkyl end-group effect on intramolecular excimer formation in styrene dimers is found to exist by comparing time constants of styrene dimers with methyl ends, propyl ends, and pentyl ends.

Original languageEnglish
Pages (from-to)2774-2782
Number of pages9
JournalMacromolecules
Volume20
Issue number11
Publication statusPublished - 1987
Externally publishedYes

Fingerprint

Radiolysis
Styrene
Polystyrenes
Dimers
Fluorescence
Cyclohexane
Polymers

ASJC Scopus subject areas

  • Materials Chemistry

Cite this

Local molecular motion of polystyrene model compounds measured by using picosecond pulse radiolysis. 1. Diastereoisomeric styrene dimers : Multicomponent fluorescence decay curves, concentration dependence, and alkyl end-group effect on excimer formation. / Itagaki, Hideyuki; Horie, Kazuyuki; Mita, Itaru; Washio, Masakazu; Tagawa, Seiichi; Tabata, Yoneho; Sato, Hisaya; Tanaka, Yasuyuki.

In: Macromolecules, Vol. 20, No. 11, 1987, p. 2774-2782.

Research output: Contribution to journalArticle

@article{f3ec8c20b06e4147b68dee537968df9b,
title = "Local molecular motion of polystyrene model compounds measured by using picosecond pulse radiolysis. 1. Diastereoisomeric styrene dimers: Multicomponent fluorescence decay curves, concentration dependence, and alkyl end-group effect on excimer formation",
abstract = "The dynamic process of intramolecular excimer formation in meso and racemic 4,6-diphenylnonanes (PS2(propyl)), diastereoisomeric dimer models of polystyrene, was investigated by using a picosecond pulse radiolysis technique. In dilute cyclohexane solution, the monomeric fluorescence of racemic PS2(propyl) decays single exponentially with a time constant of 11 ns, while that of meso PS2(propyl) was found to decay dual exponentially with time constants of 6 and 0.5 ns. These multicomponent fluorescence decays were found to be explicable by the local motion of conformational change. In conclusion, each time required for the conformational change (g+t/tg-) → tt, (g+t/tg-) → g+g-, and g+g- → (g+t/tg-) in meso PS2(propyl) is estimated to be 0.7, 2.5 and 6 ns, respectively, at room temperature. The proposition that fluorescence decay of diastereoisomeric dimers is influenced by molecular motion (conformational change) is also valid for explaining the profile of the transient fluorescence spectra of racemic PS2(propyl). The present result is an indication that multicomponent fluorescence decay observed in some polymer systems may be mainly due to the conformational change motion in meso dyads. The concentration dependence of the time constants of meso and racemic PS2(propyl) was also measured. In addition, an alkyl end-group effect on intramolecular excimer formation in styrene dimers is found to exist by comparing time constants of styrene dimers with methyl ends, propyl ends, and pentyl ends.",
author = "Hideyuki Itagaki and Kazuyuki Horie and Itaru Mita and Masakazu Washio and Seiichi Tagawa and Yoneho Tabata and Hisaya Sato and Yasuyuki Tanaka",
year = "1987",
language = "English",
volume = "20",
pages = "2774--2782",
journal = "Macromolecules",
issn = "0024-9297",
publisher = "American Chemical Society",
number = "11",

}

TY - JOUR

T1 - Local molecular motion of polystyrene model compounds measured by using picosecond pulse radiolysis. 1. Diastereoisomeric styrene dimers

T2 - Multicomponent fluorescence decay curves, concentration dependence, and alkyl end-group effect on excimer formation

AU - Itagaki, Hideyuki

AU - Horie, Kazuyuki

AU - Mita, Itaru

AU - Washio, Masakazu

AU - Tagawa, Seiichi

AU - Tabata, Yoneho

AU - Sato, Hisaya

AU - Tanaka, Yasuyuki

PY - 1987

Y1 - 1987

N2 - The dynamic process of intramolecular excimer formation in meso and racemic 4,6-diphenylnonanes (PS2(propyl)), diastereoisomeric dimer models of polystyrene, was investigated by using a picosecond pulse radiolysis technique. In dilute cyclohexane solution, the monomeric fluorescence of racemic PS2(propyl) decays single exponentially with a time constant of 11 ns, while that of meso PS2(propyl) was found to decay dual exponentially with time constants of 6 and 0.5 ns. These multicomponent fluorescence decays were found to be explicable by the local motion of conformational change. In conclusion, each time required for the conformational change (g+t/tg-) → tt, (g+t/tg-) → g+g-, and g+g- → (g+t/tg-) in meso PS2(propyl) is estimated to be 0.7, 2.5 and 6 ns, respectively, at room temperature. The proposition that fluorescence decay of diastereoisomeric dimers is influenced by molecular motion (conformational change) is also valid for explaining the profile of the transient fluorescence spectra of racemic PS2(propyl). The present result is an indication that multicomponent fluorescence decay observed in some polymer systems may be mainly due to the conformational change motion in meso dyads. The concentration dependence of the time constants of meso and racemic PS2(propyl) was also measured. In addition, an alkyl end-group effect on intramolecular excimer formation in styrene dimers is found to exist by comparing time constants of styrene dimers with methyl ends, propyl ends, and pentyl ends.

AB - The dynamic process of intramolecular excimer formation in meso and racemic 4,6-diphenylnonanes (PS2(propyl)), diastereoisomeric dimer models of polystyrene, was investigated by using a picosecond pulse radiolysis technique. In dilute cyclohexane solution, the monomeric fluorescence of racemic PS2(propyl) decays single exponentially with a time constant of 11 ns, while that of meso PS2(propyl) was found to decay dual exponentially with time constants of 6 and 0.5 ns. These multicomponent fluorescence decays were found to be explicable by the local motion of conformational change. In conclusion, each time required for the conformational change (g+t/tg-) → tt, (g+t/tg-) → g+g-, and g+g- → (g+t/tg-) in meso PS2(propyl) is estimated to be 0.7, 2.5 and 6 ns, respectively, at room temperature. The proposition that fluorescence decay of diastereoisomeric dimers is influenced by molecular motion (conformational change) is also valid for explaining the profile of the transient fluorescence spectra of racemic PS2(propyl). The present result is an indication that multicomponent fluorescence decay observed in some polymer systems may be mainly due to the conformational change motion in meso dyads. The concentration dependence of the time constants of meso and racemic PS2(propyl) was also measured. In addition, an alkyl end-group effect on intramolecular excimer formation in styrene dimers is found to exist by comparing time constants of styrene dimers with methyl ends, propyl ends, and pentyl ends.

UR - http://www.scopus.com/inward/record.url?scp=20744450001&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=20744450001&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:20744450001

VL - 20

SP - 2774

EP - 2782

JO - Macromolecules

JF - Macromolecules

SN - 0024-9297

IS - 11

ER -