Photoresponsive Crown Ethers. 4. Influence of Alkali Metal Cations on Photoisomerization and Thermal Isomerization of Azobis(benzocrown ether)s

Seiji Shinkai, Toshiyuki Ogawa, Yumiko Kusano, Osamu Manabe, Kiyoshi Kikukawa, Tokio Goto, Tsutomu Matsuda

Research output: Contribution to journalArticle

131 Citations (Scopus)

Abstract

Five photoresponsive azobis(benzocrown ether)s, 1(4,4), 1(5,5), 1(6,6), 2(5,5), and 2(6,6), were synthesized, where numbers in parentheses denote the number of oxygens in benzocrown ethers, and crown series 2 have two tert-butyl groups in the 2 and 2′ position of the azo linkage. We have found that (i) in the presence of alkali metal cations, the concentration of cis isomers (cis %) under the photostationary state is enhanced and the rate of the thermal cis-to-trans isomerization (k) is suppressed, the optima of cis-1(5,5) and cis-1(6,6) being observed for Rb+ and Cs+, respectively, (ii) Rb+ and Cs+ are extracted most efficiently from an aqueous solution to an organic phase (o-dichlorobenzene) with cis-1(5,5) and cis-1(6,6), respectively, (iii) cis % and k of 2(5,5) and 2(6,6) are affected by alkali metal cations smaller than those of corresponding 1(5,5) and 1(6,6), and (iv) cis % and k of 1(4,4) are less affected by added alkali metal cations and the extractability is very low. The increase in cis % and the suppression of the thermal isomerization rate are rationalized in terms of the “tying effect” of complexed cations requiring the additional energy to disrupt the crown-cation interaction. The correlation of the extractability with cis % and k implies that alkali metal cations are extracted under photoirradiation as intramolecular 1:2 cation/crown complexes and the ion selectivity is associated with the fitness between the ion size and the size of the spacial cavity provided by two crown ethers of cis forms. The ion selectivity suggests that (i) the cavity size of cis-1(6,6) is greater than that of cis-1(5,5) and (ii) the cavity sizes of crown series 2 are smaller than those of crown series 1 probably owing to the steric repulsion of the tert-butyl groups. Hence, the ion selectivity in the photocontrolled solvent extraction is effected by the crown ring size and the steric crowding around the azo linkage.

Original languageEnglish
Pages (from-to)1960-1967
Number of pages8
JournalJournal of the American Chemical Society
Volume104
Issue number7
DOIs
Publication statusPublished - Jan 1 1982
Externally publishedYes

Fingerprint

Alkali Metals
Crown Ethers
Photoisomerization
Crown ethers
Alkali metals
Isomerization
Ether
Cations
Ethers
Hot Temperature
Positive ions
Crowns
Isomers
Ions
Solvent extraction
Oxygen

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Photoresponsive Crown Ethers. 4. Influence of Alkali Metal Cations on Photoisomerization and Thermal Isomerization of Azobis(benzocrown ether)s. / Shinkai, Seiji; Ogawa, Toshiyuki; Kusano, Yumiko; Manabe, Osamu; Kikukawa, Kiyoshi; Goto, Tokio; Matsuda, Tsutomu.

In: Journal of the American Chemical Society, Vol. 104, No. 7, 01.01.1982, p. 1960-1967.

Research output: Contribution to journalArticle

Shinkai, Seiji ; Ogawa, Toshiyuki ; Kusano, Yumiko ; Manabe, Osamu ; Kikukawa, Kiyoshi ; Goto, Tokio ; Matsuda, Tsutomu. / Photoresponsive Crown Ethers. 4. Influence of Alkali Metal Cations on Photoisomerization and Thermal Isomerization of Azobis(benzocrown ether)s. In: Journal of the American Chemical Society. 1982 ; Vol. 104, No. 7. pp. 1960-1967.
@article{0aaed6a58ce74d1e8a70dccc3541802a,
title = "Photoresponsive Crown Ethers. 4. Influence of Alkali Metal Cations on Photoisomerization and Thermal Isomerization of Azobis(benzocrown ether)s",
abstract = "Five photoresponsive azobis(benzocrown ether)s, 1(4,4), 1(5,5), 1(6,6), 2(5,5), and 2(6,6), were synthesized, where numbers in parentheses denote the number of oxygens in benzocrown ethers, and crown series 2 have two tert-butyl groups in the 2 and 2′ position of the azo linkage. We have found that (i) in the presence of alkali metal cations, the concentration of cis isomers (cis {\%}) under the photostationary state is enhanced and the rate of the thermal cis-to-trans isomerization (k) is suppressed, the optima of cis-1(5,5) and cis-1(6,6) being observed for Rb+ and Cs+, respectively, (ii) Rb+ and Cs+ are extracted most efficiently from an aqueous solution to an organic phase (o-dichlorobenzene) with cis-1(5,5) and cis-1(6,6), respectively, (iii) cis {\%} and k of 2(5,5) and 2(6,6) are affected by alkali metal cations smaller than those of corresponding 1(5,5) and 1(6,6), and (iv) cis {\%} and k of 1(4,4) are less affected by added alkali metal cations and the extractability is very low. The increase in cis {\%} and the suppression of the thermal isomerization rate are rationalized in terms of the “tying effect” of complexed cations requiring the additional energy to disrupt the crown-cation interaction. The correlation of the extractability with cis {\%} and k implies that alkali metal cations are extracted under photoirradiation as intramolecular 1:2 cation/crown complexes and the ion selectivity is associated with the fitness between the ion size and the size of the spacial cavity provided by two crown ethers of cis forms. The ion selectivity suggests that (i) the cavity size of cis-1(6,6) is greater than that of cis-1(5,5) and (ii) the cavity sizes of crown series 2 are smaller than those of crown series 1 probably owing to the steric repulsion of the tert-butyl groups. Hence, the ion selectivity in the photocontrolled solvent extraction is effected by the crown ring size and the steric crowding around the azo linkage.",
author = "Seiji Shinkai and Toshiyuki Ogawa and Yumiko Kusano and Osamu Manabe and Kiyoshi Kikukawa and Tokio Goto and Tsutomu Matsuda",
year = "1982",
month = "1",
day = "1",
doi = "10.1021/ja00371a027",
language = "English",
volume = "104",
pages = "1960--1967",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "7",

}

TY - JOUR

T1 - Photoresponsive Crown Ethers. 4. Influence of Alkali Metal Cations on Photoisomerization and Thermal Isomerization of Azobis(benzocrown ether)s

AU - Shinkai, Seiji

AU - Ogawa, Toshiyuki

AU - Kusano, Yumiko

AU - Manabe, Osamu

AU - Kikukawa, Kiyoshi

AU - Goto, Tokio

AU - Matsuda, Tsutomu

PY - 1982/1/1

Y1 - 1982/1/1

N2 - Five photoresponsive azobis(benzocrown ether)s, 1(4,4), 1(5,5), 1(6,6), 2(5,5), and 2(6,6), were synthesized, where numbers in parentheses denote the number of oxygens in benzocrown ethers, and crown series 2 have two tert-butyl groups in the 2 and 2′ position of the azo linkage. We have found that (i) in the presence of alkali metal cations, the concentration of cis isomers (cis %) under the photostationary state is enhanced and the rate of the thermal cis-to-trans isomerization (k) is suppressed, the optima of cis-1(5,5) and cis-1(6,6) being observed for Rb+ and Cs+, respectively, (ii) Rb+ and Cs+ are extracted most efficiently from an aqueous solution to an organic phase (o-dichlorobenzene) with cis-1(5,5) and cis-1(6,6), respectively, (iii) cis % and k of 2(5,5) and 2(6,6) are affected by alkali metal cations smaller than those of corresponding 1(5,5) and 1(6,6), and (iv) cis % and k of 1(4,4) are less affected by added alkali metal cations and the extractability is very low. The increase in cis % and the suppression of the thermal isomerization rate are rationalized in terms of the “tying effect” of complexed cations requiring the additional energy to disrupt the crown-cation interaction. The correlation of the extractability with cis % and k implies that alkali metal cations are extracted under photoirradiation as intramolecular 1:2 cation/crown complexes and the ion selectivity is associated with the fitness between the ion size and the size of the spacial cavity provided by two crown ethers of cis forms. The ion selectivity suggests that (i) the cavity size of cis-1(6,6) is greater than that of cis-1(5,5) and (ii) the cavity sizes of crown series 2 are smaller than those of crown series 1 probably owing to the steric repulsion of the tert-butyl groups. Hence, the ion selectivity in the photocontrolled solvent extraction is effected by the crown ring size and the steric crowding around the azo linkage.

AB - Five photoresponsive azobis(benzocrown ether)s, 1(4,4), 1(5,5), 1(6,6), 2(5,5), and 2(6,6), were synthesized, where numbers in parentheses denote the number of oxygens in benzocrown ethers, and crown series 2 have two tert-butyl groups in the 2 and 2′ position of the azo linkage. We have found that (i) in the presence of alkali metal cations, the concentration of cis isomers (cis %) under the photostationary state is enhanced and the rate of the thermal cis-to-trans isomerization (k) is suppressed, the optima of cis-1(5,5) and cis-1(6,6) being observed for Rb+ and Cs+, respectively, (ii) Rb+ and Cs+ are extracted most efficiently from an aqueous solution to an organic phase (o-dichlorobenzene) with cis-1(5,5) and cis-1(6,6), respectively, (iii) cis % and k of 2(5,5) and 2(6,6) are affected by alkali metal cations smaller than those of corresponding 1(5,5) and 1(6,6), and (iv) cis % and k of 1(4,4) are less affected by added alkali metal cations and the extractability is very low. The increase in cis % and the suppression of the thermal isomerization rate are rationalized in terms of the “tying effect” of complexed cations requiring the additional energy to disrupt the crown-cation interaction. The correlation of the extractability with cis % and k implies that alkali metal cations are extracted under photoirradiation as intramolecular 1:2 cation/crown complexes and the ion selectivity is associated with the fitness between the ion size and the size of the spacial cavity provided by two crown ethers of cis forms. The ion selectivity suggests that (i) the cavity size of cis-1(6,6) is greater than that of cis-1(5,5) and (ii) the cavity sizes of crown series 2 are smaller than those of crown series 1 probably owing to the steric repulsion of the tert-butyl groups. Hence, the ion selectivity in the photocontrolled solvent extraction is effected by the crown ring size and the steric crowding around the azo linkage.

UR - http://www.scopus.com/inward/record.url?scp=0001729751&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0001729751&partnerID=8YFLogxK

U2 - 10.1021/ja00371a027

DO - 10.1021/ja00371a027

M3 - Article

AN - SCOPUS:0001729751

VL - 104

SP - 1960

EP - 1967

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 7

ER -