Control of Circularly Polarized Luminescence by Using Open‐ and Closed‐Type Binaphthyl Derivatives with the Same Axial Chirality

Kimoto, Takaya; Tajima, Nobuo; Fujiki, Michiya; Imai, Yoshitane

doi:10.1002/asia.201200725

Cited by 117 publications

(51 citation statements)

References 42 publications

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“…Theresults indicated that the average molar ratio between chiral emitters and Hmim is 0.015 in both R-ZIF and S-ZIF.Under UV irradiation, R-ZIF exhibited bright blue emission in the solid state ( Figure 2a). [15] This chirality inversion was further confirmed by CPL measurements (Figure 2d and Figure S2 c, d). Absorption spectra showed that there was no obvious change in R-ZIF compared to R-1, which indicated that there was no severe aggregation of the chiral emitters on the skeleton of ZIF-8 ( Figure 2b).…”

supporting

confidence: 62%

“…The CD spectrum of R-1 located around 375 nm (S 0 -S 1 transition) showed apositive Cotton effect while anegative Cotton effect was found for R-ZIF.The chirality inversion can be explained by the dihedral angle (q)c hange of the axially chiral compounds.T he change of the dihedral angle would lead to an inversion of the chirality. [15] This chirality inversion was further confirmed by CPL measurements (Figure 2d and Figure S2 c, d).…”

supporting

confidence: 62%

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Enhanced Circularly Polarized Luminescence from Reorganized Chiral Emitters on the Skeleton of a Zeolitic Imidazolate Framework

et al. 2019

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supporting

confidence: 62%

supporting

confidence: 62%

Enhanced Circularly Polarized Luminescence from Reorganized Chiral Emitters on the Skeleton of a Zeolitic Imidazolate Framework

et al. 2019

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“…In the ground state, conversely, the predicted first ECD band is always positive for (a R )‐ 2 a along a large portion of the torsional energy curve, in particular that comprised between and including the two minima (Supporting Information, Figure S3). A pronounced dependence of CPL on the aryl–aryl torsion has been reported for other biaryls, for example 1,1′‐binaphthyl derivatives . In these cases, however, the observed CPL bands are allied with weak transitions of the naphthalene 1 L b ‐type, and do not belong to the main exciton couplet between naphthalene 1 B b ‐type transitions, in contrast with BODIPY DYEmers.…”

Section: Resultsmentioning

confidence: 72%

“…In particular, it was interesting to study the CPL behavior of compounds, which showed the peculiar exciton‐coupled ECD spectra discussed above. In fact, bis‐chromophoric exciton‐coupled compounds have been studied systematically only in the related context of fluorescence‐detected circular dichroism (FDCD), whereas covalent exciton‐coupled systems have been considered only occasionally in CPL measurements . On the contrary, there is much interest in CPL as a means for the detection and characterization of chiral supramolecular aggregates of chromophoric species, which are also exciton‐coupled.…”

Section: Introductionmentioning

confidence: 99%

Circularly Polarized Luminescence from Axially Chiral BODIPY DYEmers: An Experimental and Computational Study

Zinna

Bruhn

Guido

et al. 2016

Chemistry A European J

131

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With our new home-built circularly polarized luminescence (CPL) instrument, we measured fluorescence and CPL spectra of the enantiomeric pairs of two quasi-isomeric BODIPY DYEmers 1 and 2, endowed with axial chirality. The electronic circular dichroism (ECD) and CPL spectra of these atropisomeric dimers are dominated by the exciton coupling between the main π-π* transitions (550-560 nm) of the two BODIPY rings. Compound 1 has strong ECD and CPL spectra (g =4×10 ) well reproduced by TD-DFT and SCS-CC2 (spin-component scaled second-order approximate coupled-cluster) calculations using DFT-optimized ground- and excited-state structures. Compound 2 has weaker ECD and CPL spectra (g =4×10 ), partly due to the mutual cancellation of electric-electric and electric-magnetic exciton couplings, and partly to its conformational freedom. This compound is computationally very challenging. Starting from the optimized excited-state geometries, we predicted the wrong sign for the CPL band of 2 using TD-DFT with the most recommended hybrid and range-separated functionals, whereas SCS-CC2 or a DFT functional with full exact exchange provided the correct sign.

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“…18 Chiral fluorophores 2 and 4 showed clear CPL behaviors with CPL = 438 nm for 2 and 401 nm for 4. Dimensionless Kuhn's anisotropy in the photoexcited state (g em ) is defined by:…”

Section: ¹4mentioning

confidence: 95%

π-Expanded Axially Chiral Biaryls and Their Emissions: Molecular Design, Syntheses, Optical Resolution, Absolute Configuration, and Circularly Polarized Luminescence of 1,1′-Bipyrene-2,2′-diols

et al. 2015

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Axially chiral biaryls based on pyrene, 1,1¤-bipyrene-2,2¤-diol derivatives 2, were designed and synthesized from 2-hydroxypyrene. Simple optical resolution was carried out and the absolute configuration was determined by diffraction study. Title compounds 2 and corresponding menthylcarbonate 4 showed clear circularly polarized luminescence (CPL) spectra. The degree of dimensionless Kuhn's anisotropy in the photoexcited state («g em «) of 2 and 4 were ca. 3.6 © 10 ¹4 and ca. 1.2 © 10 ¹3, respectively. Noteworthy properties were as follows: 1) high fluorescent quantum yields of 2 and 4, 0.57 and 0.80, respectively, in marked contrast to that of BINOL, 0.04 and 2) bathochromic shifts of CPL .Circularly polarized luminescence (CPL) is luminescence emitted by a chiral molecule. Because of the high sensitivity of steady-state luminescence, CPL spectroscopy has attracted much attention, particularly in the analysis and evaluation of naturally occurring chiral chromophores, such as chlorophyll (vide infra).1 Although CPL spectroscopy is a relatively new technique, a pioneering review was published as early as in 1977.2 Currently, CPL is regarded as an important chiroptical technique. The applications of CPL have shifted from the analytical chemistry of biological chiral molecules 2 to advanced science using polarized light, such as three-dimensional displays and quantum computing. 3CPL spectroscopy has flourished under the watch of physical chemists. However, the lack of a standard molecule having a large quantum yield (Φ fl ) and a large dimensionless Kuhn's anisotropy in the photoexcited state («g em «) (vide infra), 2 has hindered the development of new materials for CPL. Although 1,1¤-binaphthalen-2,2¤-diol (BINOL) 1 (Chart 1) and its corresponding derivatives are well used in this research field, Φ fl and g em are small (vide infra). In this study, our aim was to design a standard molecule for CPL spectroscopy. The expansion of the π-electronic system seemed to be the most promising strategy, i.e., replacement of the naphthalene moiety of BINOL with other π-expanded polycyclic aromatic hydrocarbons (PAHs). Generally, the expansion of the π-electronic system induces 1) a small HOMOLUMO gap and a resultant low excitation energy, 2) an increase in the fluorescence lifetime, 3) a low redox potential, and so on. 4 These properties are preferred for advanced materials. We focused on pyrene as PAH because it showed strong emission, long lifetime, and high quantum yield, making it one of the standard molecules for photochemistry. 5,6 We designed 1,1¤-bipyrene-2,2¤-diol 2, a pyrene-based axially chiral molecule, with a eye to improving the chiroptical properties of BINOLs.Optically pure title compounds 2 and reference 5 were prepared according to Scheme 1. 7 The issues to be addressed were 1) the solubility improvement of 2 and 2) optical resolution. PAHs are notorious for their poor solubilities and our targets 2, dimers of pyrene, ought to be sparingly soluble materials. To solve this problem, a tertbutyl group was intro...

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Control of Circularly Polarized Luminescence by Using Open‐ and Closed‐Type Binaphthyl Derivatives with the Same Axial Chirality

Cited by 117 publications

References 42 publications

Enhanced Circularly Polarized Luminescence from Reorganized Chiral Emitters on the Skeleton of a Zeolitic Imidazolate Framework

Enhanced Circularly Polarized Luminescence from Reorganized Chiral Emitters on the Skeleton of a Zeolitic Imidazolate Framework

Circularly Polarized Luminescence from Axially Chiral BODIPY DYEmers: An Experimental and Computational Study

π-Expanded Axially Chiral Biaryls and Their Emissions: Molecular Design, Syntheses, Optical Resolution, Absolute Configuration, and Circularly Polarized Luminescence of 1,1′-Bipyrene-2,2′-diols

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