Novel chiral norbornadiene–quadricyclane systems: substituent effect on chiroptical properties and stereochemical consequence of photochemical interconversion

Nishino, Hideo; Nakamura, Asao; Terada, Mariko; Kosaka, Atsuko; Fukui, Mieko; Aoki, Noriko; Inoue, Yoshihisa

doi:10.1016/s1010-6030(01)00633-5

Cited by 11 publications

(6 citation statements)

References 23 publications

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“…Anisotropy factor ( g = Δε/ε) has been frequently used as a quantitatively more reliable chirality measure. The g factor of 1 at the 1 L b band was found as large as 2 × 10 –2 , which is much larger than the typical values (1 × 10 –4 to ∼1 × 10 –5 ) for allowed transitions (Figure S2 in the Supporting Information). This may be explained by a mixing of the forbidden transition of the nitrogen lone pair.…”

Section: Results and Discussionmentioning

confidence: 60%

Protonation-Induced Sign Inversion of the Cotton Effects of Pyridinophanes. A Combined Experimental and Theoretical Study

2017

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The circular dichroisms (CDs) of planar chiral [2.2]- and [3.3]-pyridinophanes were investigated experimentally and theoretically. Strong multisignate Cotton effects, typical for cyclophane derivatives, were observed. The CD spectra of [2.2]- and [3.3]-paracyclophanes closely resembled in pattern each other, despite the much greater conformational variations in the latter. Upon protonation, both of the cyclophanes suffered dramatic CD spectral changes with accompanying complete sign inversion, which was attributed to the reversal of diploe moment of pyridinium versus pyridine moiety. This chiroptical property switching driven by protonation/deprotonation was temperature-dependent and hence applicable to thermal sensing. The protonated forms of pyridinophanes served as ideal model systems for studying the cation-π interactions and their effects on chiroptical properties. Thus, the molar CD (Δε) of the charge-transfer band of protonated [2.2]pyridinophane was 10-fold larger than that of protonated [3.3]pyridinophane, which exceeds the increased interplane electronic interactions assessed from the electronic coupling element values.

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Section: Results and Discussionmentioning

confidence: 60%

Protonation-Induced Sign Inversion of the Cotton Effects of Pyridinophanes. A Combined Experimental and Theoretical Study

2017

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“…The intensities of CEs were fairly strong, typical for cyclophanes of planar chirality . Anisotropy factors ( g = Δε/ε) of 1s / e at the 1 L b band were found as large as >5 × 10 –3 , which far exceed the typical values for allowed transitions (Figure S14) and are attributable to the forbidden nature of this transition. The experimental CD spectra of 1s and 1e were well reproduced in sign and magnitude and also in relative excitation energy by the theoretical calculations at the RI-CC2/def2-TZVPP level with geometries optimized at the DFT-D3(BJ)-TPSS/def2-TZVP level in the gas phase (Figure , dotted lines).…”

Section: Resultsmentioning

confidence: 84%

A Combined Experimental and Theoretical Study on the Circular Dichroism of Staggered and Eclipsed Forms of Dimethoxy[2.2]-, [3.2]-, and [3.3]Pyridinophanes and Their Protonated Forms

2017

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The circular dichroisms (CDs) of dimethoxy[2.2]-, [3.2]-, and [3.3]pyridinophanes and their protonated forms were investigated experimentally and theoretically. Characteristic multisignate Cotton effects (CEs), typical for planar chiral cyclophane derivatives, were observed. The CD spectral pattern was quite comparable for the staggered forms of [2.2]-, [3.2]-, and [3.3]cyclophanes, but significantly differed for the eclipsed forms. More interestingly, the patterns resembled, but the CE signs were practically opposite between staggered and eclipsed [2.2]pyridinophanes. Upon protonation, the signs of most CEs were inverted in both forms of cyclophanes, due to the reversal of dipole moment in the pyridine against the pyridinium moiety. Such a change in CD spectrum upon protonation was not apparent in [3.2]pyridinophane, and the CD spectral behavior was more complex in [3.3]pyridinophanes. The variation of CD caused by the protonation/deprotonation process was temperature-dependent and hence utilized as a thermal sensor. The protonated forms of the homologous pyridinophanes with different tether lengths in staggered and eclipsed forms served as a model system for systematically studying the cation-π interaction and its effects on chiroptical properties. A steady increase of electronic interaction became apparent for the smaller-sized cyclophanes from the increased excitation energy and electronic coupling element of the charge-transfer (CT) band, while the observed CE at the CT band was a more complex function of the original transition dipole of donor/acceptor pair and linker atoms, as well as the strength of the electronic interaction.

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“…However, the photochemical isomerization of NBD is very limited under sunlight irradiation, because the absorption edge of NBD is below 300 nm. Solutions previously reported to drive this photochemical process using higher wavelength irradiation sources and to improve the quantum yield include: the addition of sensitizers and chromophores, the conjugation of electron withdrawing substituents to the NBD moiety, and the use of NBD‐containing metal complex catalysts . In addition to conversion and storage of solar energy, the photochemical isomerization of NBD has been studied as a new alternative in the field of optoelectronics (memory, optical switches and other devices), as a photochromic system with potential application in the data storage technology, and as an energetic binder for solid rocket propellants .…”

Section: Introductionmentioning

confidence: 99%

Photoresponsive polyamides containing pentamethylated norbornadiene moieties: Synthesis and photochemical properties under sunlight irradiation

Oueslati

Abdelhedi

Merçier

et al. 2013

J. Polym. Sci. Part A: Polym. Chem.

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Photoresponsive polyamides containing main‐chain pentamethylated norbornadiene (NBD) moieties are obtained in quantitative yields via the Yamazaki–Higashi reaction between a pentamethylated NBD dicarboxylic acid and a series of aromatic diamines. Chemical structures are confirmed by 1H and 13C NMR and weight average molar masses measured by SEC are in the range of 21,500–28,600 g mol−1 with chain dispersities close to 2. Physical properties are investigated by FTIR, differential scanning calorimetry (DSC), thermogravimetric analysis, and viscosimetry. All obtained polyamides are amorphous with glass transition temperatures ranging from 68 to 124 °C. They are soluble at room temperature in common organic solvents and exhibit good thermal stabilities with Td10 values ranging from 175 to 276 °C. The photochemical isomerization of the NBD moiety into quadricyclane (QC) is studied by UV/vis spectroscopy after sunlight irradiation of polymer films. For all polyamides, a first‐order kinetic rate is observed for the conversion of NBD to QC. The thermal release of the stored energy associated to the reverse transformation of QC groups into NBD ones is about 90–95 kJ mol−1 as measured by DSC of the irradiated polymer films. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4650–4656

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Novel chiral norbornadiene–quadricyclane systems: substituent effect on chiroptical properties and stereochemical consequence of photochemical interconversion

Cited by 11 publications

References 23 publications

Protonation-Induced Sign Inversion of the Cotton Effects of Pyridinophanes. A Combined Experimental and Theoretical Study

Protonation-Induced Sign Inversion of the Cotton Effects of Pyridinophanes. A Combined Experimental and Theoretical Study

A Combined Experimental and Theoretical Study on the Circular Dichroism of Staggered and Eclipsed Forms of Dimethoxy[2.2]-, [3.2]-, and [3.3]Pyridinophanes and Their Protonated Forms

Photoresponsive polyamides containing pentamethylated norbornadiene moieties: Synthesis and photochemical properties under sunlight irradiation

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