Synthesis, structure, and transannular π-π interaction of three- and four-layered [3.3]paracyclophanes

Masahiko Shibahara, Motonori Watanabe, Tetsuo Iwanaga, Taisuke Matsumoto, Keiko Ideta, Teruo Shinmyozu

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

(Figure Presented) The synthesis of three- and four-layered [3.3]paracyclophanes ([3.3]PCPs) 3-5 has been accomplished by utilizing the (p-ethylbenzenesulfonyl)methyl isocyanide (EbsMIC) method. The structures of the three- to four-layered [3.3]PCPs 3-5 and their diones 8, 10, and 11 have been elucidated based on the 1H NMR spectra and finally by X-ray structural analysis. In the three-layered [3.3]PCP-dione 8, the trimethylene bridges of the [3.3]PCP unit assume a chair conformation similar to that of 2, while the [3.3]PCP-2,11-dione unit assumes a boat conformation different from that of [3.3]PCP-dione 1 with a chair conformation. On the other hand, the two [3.3]PCP units in three-layered [3.3]PCP 3 both assume a boat conformation. In the four-layered [3.3]PCP-dione 10, the two outer [3.3]PCP units assume a boat conformation while the inner dione unit has a chair conformation. The trimethylene bridges in the four-layered [3.3]PCP 4 are highly disordered even at -150°C. All the outer benzene rings are distorted into a boat form while the inner ones are distorted into a twist form. In the electronic spectra, bathochromic shift and hyperchromic effect are observed, but the magnitude decreases with an increase in the number of layers and the spectra become structureless. In the charge-transfer (CT) bands of the three- to four-layered [3.3]PCPs 3-5 with tetracyanoethylene (TCNE), two absorption maxima (λmax) are observed. The effect of an increase in the layers becomes significant, and the changes in the longest wavelength λmax values from two to three and three to four are ca. 60 and 50 nm, respectively. By comparison of the stereoisomeric four-layered [3.3]PCPs 4 (meso) and 5 (racemic), the helical arrangement of the trimethylene bridges of 5 shows a more efficient transannular π-electronic interaction. In the three- to four-layered [3.3]PCP-diones, a magnitude of the CT interaction almost comparable to that of [3.3]PCP 2 was observed, and this indicates that the -CH2COCH2- bridges inhibit the CT interaction and that this tendency is supported by the calculated HOMO energy levels and observed oxidation potentials. Three- and four-layered [3.3]PCPs 3-5 show reversible redox processes, and 4 and 5 show an electron-donating ability almost comparable to that of [36]CP. Very good correlation between the λλmax of the CT bands with TCNE and the oxidation potentials is observed.

Original languageEnglish
Pages (from-to)4433-4442
Number of pages10
JournalJournal of Organic Chemistry
Volume73
Issue number12
DOIs
Publication statusPublished - Jun 20 2008

Fingerprint

Conformations
Boats
Charge transfer
Oxidation
Benzene
Structural analysis
Electron energy levels
(2.2)paracyclophane
Nuclear magnetic resonance
X rays
Wavelength
Electrons
cyclopropane
tetracyanoethylene

All Science Journal Classification (ASJC) codes

  • Organic Chemistry

Cite this

Synthesis, structure, and transannular π-π interaction of three- and four-layered [3.3]paracyclophanes. / Shibahara, Masahiko; Watanabe, Motonori; Iwanaga, Tetsuo; Matsumoto, Taisuke; Ideta, Keiko; Shinmyozu, Teruo.

In: Journal of Organic Chemistry, Vol. 73, No. 12, 20.06.2008, p. 4433-4442.

Research output: Contribution to journalArticle

Shibahara, Masahiko ; Watanabe, Motonori ; Iwanaga, Tetsuo ; Matsumoto, Taisuke ; Ideta, Keiko ; Shinmyozu, Teruo. / Synthesis, structure, and transannular π-π interaction of three- and four-layered [3.3]paracyclophanes. In: Journal of Organic Chemistry. 2008 ; Vol. 73, No. 12. pp. 4433-4442.
@article{b9006d4c2ce5449c84394b2bee7018a2,
title = "Synthesis, structure, and transannular π-π interaction of three- and four-layered [3.3]paracyclophanes",
abstract = "(Figure Presented) The synthesis of three- and four-layered [3.3]paracyclophanes ([3.3]PCPs) 3-5 has been accomplished by utilizing the (p-ethylbenzenesulfonyl)methyl isocyanide (EbsMIC) method. The structures of the three- to four-layered [3.3]PCPs 3-5 and their diones 8, 10, and 11 have been elucidated based on the 1H NMR spectra and finally by X-ray structural analysis. In the three-layered [3.3]PCP-dione 8, the trimethylene bridges of the [3.3]PCP unit assume a chair conformation similar to that of 2, while the [3.3]PCP-2,11-dione unit assumes a boat conformation different from that of [3.3]PCP-dione 1 with a chair conformation. On the other hand, the two [3.3]PCP units in three-layered [3.3]PCP 3 both assume a boat conformation. In the four-layered [3.3]PCP-dione 10, the two outer [3.3]PCP units assume a boat conformation while the inner dione unit has a chair conformation. The trimethylene bridges in the four-layered [3.3]PCP 4 are highly disordered even at -150°C. All the outer benzene rings are distorted into a boat form while the inner ones are distorted into a twist form. In the electronic spectra, bathochromic shift and hyperchromic effect are observed, but the magnitude decreases with an increase in the number of layers and the spectra become structureless. In the charge-transfer (CT) bands of the three- to four-layered [3.3]PCPs 3-5 with tetracyanoethylene (TCNE), two absorption maxima (λmax) are observed. The effect of an increase in the layers becomes significant, and the changes in the longest wavelength λmax values from two to three and three to four are ca. 60 and 50 nm, respectively. By comparison of the stereoisomeric four-layered [3.3]PCPs 4 (meso) and 5 (racemic), the helical arrangement of the trimethylene bridges of 5 shows a more efficient transannular π-electronic interaction. In the three- to four-layered [3.3]PCP-diones, a magnitude of the CT interaction almost comparable to that of [3.3]PCP 2 was observed, and this indicates that the -CH2COCH2- bridges inhibit the CT interaction and that this tendency is supported by the calculated HOMO energy levels and observed oxidation potentials. Three- and four-layered [3.3]PCPs 3-5 show reversible redox processes, and 4 and 5 show an electron-donating ability almost comparable to that of [36]CP. Very good correlation between the λλmax of the CT bands with TCNE and the oxidation potentials is observed.",
author = "Masahiko Shibahara and Motonori Watanabe and Tetsuo Iwanaga and Taisuke Matsumoto and Keiko Ideta and Teruo Shinmyozu",
year = "2008",
month = "6",
day = "20",
doi = "10.1021/jo8003309",
language = "English",
volume = "73",
pages = "4433--4442",
journal = "Journal of Organic Chemistry",
issn = "0022-3263",
publisher = "American Chemical Society",
number = "12",

}

TY - JOUR

T1 - Synthesis, structure, and transannular π-π interaction of three- and four-layered [3.3]paracyclophanes

AU - Shibahara, Masahiko

AU - Watanabe, Motonori

AU - Iwanaga, Tetsuo

AU - Matsumoto, Taisuke

AU - Ideta, Keiko

AU - Shinmyozu, Teruo

PY - 2008/6/20

Y1 - 2008/6/20

N2 - (Figure Presented) The synthesis of three- and four-layered [3.3]paracyclophanes ([3.3]PCPs) 3-5 has been accomplished by utilizing the (p-ethylbenzenesulfonyl)methyl isocyanide (EbsMIC) method. The structures of the three- to four-layered [3.3]PCPs 3-5 and their diones 8, 10, and 11 have been elucidated based on the 1H NMR spectra and finally by X-ray structural analysis. In the three-layered [3.3]PCP-dione 8, the trimethylene bridges of the [3.3]PCP unit assume a chair conformation similar to that of 2, while the [3.3]PCP-2,11-dione unit assumes a boat conformation different from that of [3.3]PCP-dione 1 with a chair conformation. On the other hand, the two [3.3]PCP units in three-layered [3.3]PCP 3 both assume a boat conformation. In the four-layered [3.3]PCP-dione 10, the two outer [3.3]PCP units assume a boat conformation while the inner dione unit has a chair conformation. The trimethylene bridges in the four-layered [3.3]PCP 4 are highly disordered even at -150°C. All the outer benzene rings are distorted into a boat form while the inner ones are distorted into a twist form. In the electronic spectra, bathochromic shift and hyperchromic effect are observed, but the magnitude decreases with an increase in the number of layers and the spectra become structureless. In the charge-transfer (CT) bands of the three- to four-layered [3.3]PCPs 3-5 with tetracyanoethylene (TCNE), two absorption maxima (λmax) are observed. The effect of an increase in the layers becomes significant, and the changes in the longest wavelength λmax values from two to three and three to four are ca. 60 and 50 nm, respectively. By comparison of the stereoisomeric four-layered [3.3]PCPs 4 (meso) and 5 (racemic), the helical arrangement of the trimethylene bridges of 5 shows a more efficient transannular π-electronic interaction. In the three- to four-layered [3.3]PCP-diones, a magnitude of the CT interaction almost comparable to that of [3.3]PCP 2 was observed, and this indicates that the -CH2COCH2- bridges inhibit the CT interaction and that this tendency is supported by the calculated HOMO energy levels and observed oxidation potentials. Three- and four-layered [3.3]PCPs 3-5 show reversible redox processes, and 4 and 5 show an electron-donating ability almost comparable to that of [36]CP. Very good correlation between the λλmax of the CT bands with TCNE and the oxidation potentials is observed.

AB - (Figure Presented) The synthesis of three- and four-layered [3.3]paracyclophanes ([3.3]PCPs) 3-5 has been accomplished by utilizing the (p-ethylbenzenesulfonyl)methyl isocyanide (EbsMIC) method. The structures of the three- to four-layered [3.3]PCPs 3-5 and their diones 8, 10, and 11 have been elucidated based on the 1H NMR spectra and finally by X-ray structural analysis. In the three-layered [3.3]PCP-dione 8, the trimethylene bridges of the [3.3]PCP unit assume a chair conformation similar to that of 2, while the [3.3]PCP-2,11-dione unit assumes a boat conformation different from that of [3.3]PCP-dione 1 with a chair conformation. On the other hand, the two [3.3]PCP units in three-layered [3.3]PCP 3 both assume a boat conformation. In the four-layered [3.3]PCP-dione 10, the two outer [3.3]PCP units assume a boat conformation while the inner dione unit has a chair conformation. The trimethylene bridges in the four-layered [3.3]PCP 4 are highly disordered even at -150°C. All the outer benzene rings are distorted into a boat form while the inner ones are distorted into a twist form. In the electronic spectra, bathochromic shift and hyperchromic effect are observed, but the magnitude decreases with an increase in the number of layers and the spectra become structureless. In the charge-transfer (CT) bands of the three- to four-layered [3.3]PCPs 3-5 with tetracyanoethylene (TCNE), two absorption maxima (λmax) are observed. The effect of an increase in the layers becomes significant, and the changes in the longest wavelength λmax values from two to three and three to four are ca. 60 and 50 nm, respectively. By comparison of the stereoisomeric four-layered [3.3]PCPs 4 (meso) and 5 (racemic), the helical arrangement of the trimethylene bridges of 5 shows a more efficient transannular π-electronic interaction. In the three- to four-layered [3.3]PCP-diones, a magnitude of the CT interaction almost comparable to that of [3.3]PCP 2 was observed, and this indicates that the -CH2COCH2- bridges inhibit the CT interaction and that this tendency is supported by the calculated HOMO energy levels and observed oxidation potentials. Three- and four-layered [3.3]PCPs 3-5 show reversible redox processes, and 4 and 5 show an electron-donating ability almost comparable to that of [36]CP. Very good correlation between the λλmax of the CT bands with TCNE and the oxidation potentials is observed.

UR - http://www.scopus.com/inward/record.url?scp=45249099127&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=45249099127&partnerID=8YFLogxK

U2 - 10.1021/jo8003309

DO - 10.1021/jo8003309

M3 - Article

C2 - 18498196

AN - SCOPUS:45249099127

VL - 73

SP - 4433

EP - 4442

JO - Journal of Organic Chemistry

JF - Journal of Organic Chemistry

SN - 0022-3263

IS - 12

ER -