Photophysical and Photochemical Processes of Excited Singlet and Triplet [3n]Cyclophanes (n = 2-6) Studied by Emission Measurements and Steady-State and Laser Flash Photolyses

Minoru Yamaji, Hideki Okamoto, Yuhko Hakoshima, Teruo Shinmyozu

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Photophysical and photochemical features of [3n]cyclophanes (3nCPs) (n = 2-6) in solution were investigated by emission and transient absorption measurements. The studied 3nCPs show excimer fluorescence without locally excited fluorescence whereas some of them emit excimer phosphorescence in rigid glass at 77 K. The probability of excimeric phosphorescence from transannular π-electron systems was shown to strictly depend on the symmetric molecular structures. A feature of intersystem crossing from an excimeric fluorescence state to the excimeric triplet state was observed. Transient absorption spectra obtained upon laser flash photolysis of 3nCP revealed formation of the triplet excimer states. Triplet sensitization of 33CP using xanthone as the sensitizer demonstrated formation of triplet 33CP via triplet energy transfer whereas from the xanthone ketyl radical formation, it was inferred that triplet xanthone undergoes H atom abstraction from 32CP, providing a benzylic 32CP radical as the counter species. Based on kinetic and spectroscopic data obtained upon laser flash photolysis, differences in photochemical reactions of triplet xanthone between 32CP and 33CP were discussed.

Original languageEnglish
Pages (from-to)1867-1874
Number of pages8
JournalJournal of Physical Chemistry A
Volume119
Issue number10
DOIs
Publication statusPublished - Mar 12 2015

Fingerprint

Photolysis
excimers
flash
photolysis
phosphorescence
Phosphorescence
fluorescence
Lasers
Fluorescence
lasers
photochemical reactions
atomic energy levels
Photochemical reactions
counters
molecular structure
energy transfer
Energy transfer
Molecular structure
absorption spectra
Absorption spectra

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Photophysical and Photochemical Processes of Excited Singlet and Triplet [3n]Cyclophanes (n = 2-6) Studied by Emission Measurements and Steady-State and Laser Flash Photolyses. / Yamaji, Minoru; Okamoto, Hideki; Hakoshima, Yuhko; Shinmyozu, Teruo.

In: Journal of Physical Chemistry A, Vol. 119, No. 10, 12.03.2015, p. 1867-1874.

Research output: Contribution to journalArticle

@article{4857dae1c2ce4dd689929c64ad734c6d,
title = "Photophysical and Photochemical Processes of Excited Singlet and Triplet [3n]Cyclophanes (n = 2-6) Studied by Emission Measurements and Steady-State and Laser Flash Photolyses",
abstract = "Photophysical and photochemical features of [3n]cyclophanes (3nCPs) (n = 2-6) in solution were investigated by emission and transient absorption measurements. The studied 3nCPs show excimer fluorescence without locally excited fluorescence whereas some of them emit excimer phosphorescence in rigid glass at 77 K. The probability of excimeric phosphorescence from transannular π-electron systems was shown to strictly depend on the symmetric molecular structures. A feature of intersystem crossing from an excimeric fluorescence state to the excimeric triplet state was observed. Transient absorption spectra obtained upon laser flash photolysis of 3nCP revealed formation of the triplet excimer states. Triplet sensitization of 33CP using xanthone as the sensitizer demonstrated formation of triplet 33CP via triplet energy transfer whereas from the xanthone ketyl radical formation, it was inferred that triplet xanthone undergoes H atom abstraction from 32CP, providing a benzylic 32CP radical as the counter species. Based on kinetic and spectroscopic data obtained upon laser flash photolysis, differences in photochemical reactions of triplet xanthone between 32CP and 33CP were discussed.",
author = "Minoru Yamaji and Hideki Okamoto and Yuhko Hakoshima and Teruo Shinmyozu",
year = "2015",
month = "3",
day = "12",
doi = "10.1021/jp511105v",
language = "English",
volume = "119",
pages = "1867--1874",
journal = "Journal of Physical Chemistry A",
issn = "1089-5639",
publisher = "American Chemical Society",
number = "10",

}

TY - JOUR

T1 - Photophysical and Photochemical Processes of Excited Singlet and Triplet [3n]Cyclophanes (n = 2-6) Studied by Emission Measurements and Steady-State and Laser Flash Photolyses

AU - Yamaji, Minoru

AU - Okamoto, Hideki

AU - Hakoshima, Yuhko

AU - Shinmyozu, Teruo

PY - 2015/3/12

Y1 - 2015/3/12

N2 - Photophysical and photochemical features of [3n]cyclophanes (3nCPs) (n = 2-6) in solution were investigated by emission and transient absorption measurements. The studied 3nCPs show excimer fluorescence without locally excited fluorescence whereas some of them emit excimer phosphorescence in rigid glass at 77 K. The probability of excimeric phosphorescence from transannular π-electron systems was shown to strictly depend on the symmetric molecular structures. A feature of intersystem crossing from an excimeric fluorescence state to the excimeric triplet state was observed. Transient absorption spectra obtained upon laser flash photolysis of 3nCP revealed formation of the triplet excimer states. Triplet sensitization of 33CP using xanthone as the sensitizer demonstrated formation of triplet 33CP via triplet energy transfer whereas from the xanthone ketyl radical formation, it was inferred that triplet xanthone undergoes H atom abstraction from 32CP, providing a benzylic 32CP radical as the counter species. Based on kinetic and spectroscopic data obtained upon laser flash photolysis, differences in photochemical reactions of triplet xanthone between 32CP and 33CP were discussed.

AB - Photophysical and photochemical features of [3n]cyclophanes (3nCPs) (n = 2-6) in solution were investigated by emission and transient absorption measurements. The studied 3nCPs show excimer fluorescence without locally excited fluorescence whereas some of them emit excimer phosphorescence in rigid glass at 77 K. The probability of excimeric phosphorescence from transannular π-electron systems was shown to strictly depend on the symmetric molecular structures. A feature of intersystem crossing from an excimeric fluorescence state to the excimeric triplet state was observed. Transient absorption spectra obtained upon laser flash photolysis of 3nCP revealed formation of the triplet excimer states. Triplet sensitization of 33CP using xanthone as the sensitizer demonstrated formation of triplet 33CP via triplet energy transfer whereas from the xanthone ketyl radical formation, it was inferred that triplet xanthone undergoes H atom abstraction from 32CP, providing a benzylic 32CP radical as the counter species. Based on kinetic and spectroscopic data obtained upon laser flash photolysis, differences in photochemical reactions of triplet xanthone between 32CP and 33CP were discussed.

UR - http://www.scopus.com/inward/record.url?scp=84938867337&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84938867337&partnerID=8YFLogxK

U2 - 10.1021/jp511105v

DO - 10.1021/jp511105v

M3 - Article

VL - 119

SP - 1867

EP - 1874

JO - Journal of Physical Chemistry A

JF - Journal of Physical Chemistry A

SN - 1089-5639

IS - 10

ER -