Absorption and Luminescence Properties of [2.2]Paracyclophane due to Strong Transannular Interaction

Nurmukhametov, R. N.; Shapovalov, A. V.; Sergeev, A.

doi:10.1007/s10812-014-9885-x

Cited by 12 publications

(8 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The observed CD spectra, however, are not simply explained by the conventional excitonic coupling between the two substituted benzene chromophores. , Due to the effective σ–π interaction with the bridging linker, the relevant orbitals are degenerated to afford a more complex mixture of states . The cyclophane band is described by exciton and charge resonance interactions between the two facing phenes. , Thus, the apparent difference in the CD shapes of 1 and p - 2 and of m ′- 2 and o ′- 2 pairs is ascribable to the altered energy splitting of relevant orbitals due to the different interplanar interaction between the phenes. It is reasonable that the strengths of CEs in dibromocyclophanes are always comparable, as the number of bromine atoms or the steric hindrance derived therefrom is a decisive factor for the cyclophane structure (i.e., dihedral angle Φ) rather than the electronic factor.…”

Section: Resultsmentioning

confidence: 98%

“…The characteristic spectral features based on the distinctive electronic structure of [2.2]paracyclophane are apparent in their UV–vis spectra, exhibiting absorption peaks at around 270, 230, and 200 nm, which are assignable to the 1 L a , 1 L b , and 1 B bands, respectively. Additionally, weak absorption assignable to the cyclophane band was observed as a tail at around 310 nm, which is known as the specific transition observable only for [2. n ]cyclophanes. ,, In parent [2.2]paracyclophane, the lowest transition of B 2 u symmetry appears at 329 nm in single crystals at 20 K and at ≈305 nm in liquid media. , The corresponding CD peaks were observed for all of the brominated cyclophanes 1 – 2 . Accordingly, the band A with positive CE is assignable to the cyclophane band.…”

Section: Resultsmentioning

confidence: 98%

“…11,24,25 In parent [2.2]paracyclophane, the lowest transition of B 2u symmetry appears at 329 nm in single crystals at 20 K and at ≈305 nm in liquid media. 26,27 The corresponding CD peaks were observed for all of the brominated cyclophanes 1−2. Accordingly, the band A with positive CE is assignable to the cyclophane band.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…34 The cyclophane band is described by exciton and charge resonance interactions between the two facing phenes. 25,27 Thus, the apparent difference in the CD shapes of 1 and p - 2 and of m ′- 2 and o ′- 2 pairs is ascribable to the altered energy splitting of relevant orbitals due to the different interplanar interaction between the phenes. It is reasonable that the strengths of CEs in dibromocyclophanes are always comparable, as the number of bromine atoms or the steric hindrance derived therefrom is a decisive factor for the cyclophane structure (i.e., dihedral angle Φ) rather than the electronic factor.…”

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

Circular Dichroisms of Mono- and Dibromo[2.2]paracyclophanes: A Combined Experimental and Theoretical Study

2018

View full text Add to dashboard Cite

Circular dichroisms (CDs) of planar chiral 4-bromo[2.2]paracyclophane ( 1 ) and three isomeric dibromo[2.2]paracyclophanes ( p - 2 , m ′- 2 , and o ′- 2 ) were investigated experimentally and theoretically. They all exhibited strong multisignate Cotton effects (CEs) at the 1 L b , 1 L a , and 1 B transitions of the component (bromo)benzene chromophore and were comparable to each other. For all of the cyclophanes examined, the enantiomer that eluted earlier from a chiral high-performance liquid chromatography column (Chiralcel IA or IB) exhibited negative and positive CEs at the 1 L b and 1 L a bands, respectively, which were followed by a more complicated pattern of CDs at the higher-energy bands. These CD features were well reproduced by quantum chemical calculations, allowing us to unambiguously assign the absolute configurations of the first-eluted enantiomers as R p in all of the cases examined. Interestingly, the CDs of 1 and 2 , although largely comparable in shape, were still sensitive to the number and pattern of bromine substitution, showing closer resemblance between m ′- 2 and o ′- 2 and between p - 2 and 1 . The theoretical calculations also reproduced successfully these spectral resemblance between them. The anisotropy ( g ) factors for the 1 L b bands of these cyclophanes were considerably large (∼10 –2 ), whereas those for the 1 L a band were conventional in the order of 10 –3 . In addition, a weak CE was observed in the low-energy region at around 320 nm, which turned out to originate from the interplanar interaction and is hence assigned to the “cyclophane band”. The experimental g factors of this band were fairly large in the order of 10 –2 , but the computation turned out to be quite challenging and were less well reproduced theoretically, ascribable to the forbidden nature of the transition.

show abstract

Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 98%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Circular Dichroisms of Mono- and Dibromo[2.2]paracyclophanes: A Combined Experimental and Theoretical Study

2018

View full text Add to dashboard Cite

show abstract

“…The Stokes shift values of K4C , K3C , K2C ‐1, K2C ‐2, K2C ‐3, K2C ‐4 and K2M in toluene, defined by the difference in peak frequency between emission and absorption, were approximately 3938, 2813, 1512, 5210, 3991, 3465, and 1812 cm −1 , respectively. The Stokes shift values of the aforementioned PCP derivatives with rigid structures were similar to that of the pristine PCP (4500 cm −1 ) [14] . The relatively small Stokes shift value of K2C ‐1 arises from the localized transition in the IFO‐based chromophore, as presented by K2M [4] …”

Section: Methodsmentioning

confidence: 58%

New [2,2]Fluorenophanes Give Insights into Asymmetric Charge Transfer‐Mediated Exciton Delocalization along the π‐π Packing Direction

Wang

Wei

Pan

et al. 2021

Chemistry A European J

View full text Add to dashboard Cite

A series of new [2,2]fluorenophanes has been synthesized and characterized; among them, molecules of crystallographically asymmetric anti‐[2.2](1,4)(4,1)fluorenophane (K2C‐2) aggregate to form one‐dimensional supramolecular chain structures through effective intermolecular π‐π overlapping. This, in combination with the synergistic intramolecular π‐π interaction, leads to prominent dual emission mediated by charge transfer (CT) exciton delocalization. Support of this new insight is given by mapping the transition density along the π‐π packing direction where the intramolecular excitation and intermolecular CT coexist in K2C‐2.

show abstract

[2.2]Paracyclophanes: From Selective Functionalization to Optical Properties

Wu,

Felder,

Brom

et al. 2024

Advanced Optical Materials

View full text Add to dashboard Cite

Since their discovery, [2.2]paracyclophane (pCp) and its derivatives have fascinated the scientific community due to their original molecular architecture and unusual electronic behavior. Over the years, significant efforts have been devoted to the development of substituted pCps for a variety of applications in different fields, ranging from organic synthesis and asymmetric catalysis to polymer chemistry and material science. This review describes a series of useful approaches that allow chemists to selectively decorate pCps, control the planar chirality that these molecules can display as soon as they are functionalized, and tune their photophysical behaviors. For each of these aspects of paracyclophane chemistry, selected examples of major advances are presented, and possible directions for future research are outlined. The application of pCp as central core for the development of uncommon 3D luminophores is finally highlighted. Emphasis is placed on the potential use of planar chiral luminescent paracyclophanes as antennas or ligands for the design of multifunctional lanthanide complexes, a quite underdeveloped but highly promising area for future research endeavors.

show abstract

Absorption and Luminescence Properties of [2.2]Paracyclophane due to Strong Transannular Interaction

Cited by 12 publications

References 27 publications

Circular Dichroisms of Mono- and Dibromo[2.2]paracyclophanes: A Combined Experimental and Theoretical Study

Circular Dichroisms of Mono- and Dibromo[2.2]paracyclophanes: A Combined Experimental and Theoretical Study

New [2,2]Fluorenophanes Give Insights into Asymmetric Charge Transfer‐Mediated Exciton Delocalization along the π‐π Packing Direction

[2.2]Paracyclophanes: From Selective Functionalization to Optical Properties

Contact Info

Product

Resources

About