Design and synthesis of chiral spirobifluorenes

Ozcelik, Ani; Peña‐Gallego, María de los Ángeles; Pereira-Cameselle, Raquel

doi:10.1002/chir.23186

Cited by 8 publications

(8 citation statements)

References 37 publications

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“…More recently, our synthetic methodologies have opened access to surface functionalization with SBFs using thioacetates, [27] as well as tuning their optical properties by the incorporation of metallaaromatic rings [28] . In addition, we have performed the cyclic oligomerization of diethynylspirobifluorene (DES) leading to all‐carbon double helices and flexible shape‐persistent macrocycles [29] .…”

Section: Methodsmentioning

confidence: 99%

“…[25] Since such compounds may also feature axial chirality if adequatelyf unctionalized, we theoretically proposed SBFs as ar obust alternative to allenes. [26] More recently,o ur synthetic methodologiesh ave opened accesst os urfacef unctionalization with SBFs using thioacetates, [27] as well as tuning their optical properties by the incorporationo fm etallaaromatic rings. [28] In addition, we have performed the cyclic oligomerization of diethynylspirobifluorene (DES) leading to all-carbon doubleh elices and flexible shapepersistentm acrocycles.…”

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confidence: 99%

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Distinct Helical Molecular Orbitals through Conformational Lock**

Ozcelik

Aranda

Gil‐Guerrero

et al. 2020

Chemistry A European J

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Several theoretical studies have proposed strategies to reach helical molecular orbitals (Hel-MOs) in [n]cumulenes. While chiral even-[n] cumulenes feature Hel-MOs, odd-[n] cumulenes may also present them if the terminal groups lie on different planes. However, the hitherto proposed systems have been either experimentally unfeasible or resulted in opposite pseudodegenerated Hel-MOs, impeding their use in real applicatons. To overcome this challenge, we hereby demonstrate the introduction of a remarkable energy difference between helical orbitals of opposite twist by fixing the torsion angle between the terminal groups in butadiyne fragments. In order to experimentally lock the conformation of the terminal groups, we designed cyclic architectures by combining acetylenes with chiral spirobifluorenes. A straightforward synthetic strategy along with the high stability allowed the isolation and full characterization of systems presenting distinct helical orbitals. Finally, a thorough computational analysis revealed that the most significant optical responses of these systems originate mainly from the exciton coupling between the featured diphenylbutadiyne fragments. This novel strategy opens now access to the development of systems with distinct helical molecular orbitals suitable for their implementation into chiroptical and optoelectronic applications Scheme 1. General representation of acetylene (top left), [2]cumulene (top center), [3]cumulene (top right) and schematic representation of two possible paths for the formation of helical orbitals in [2]cumulenes (bottom left) and acetylenes (bottom right). Black spheres represent functional groups that can be the same or different and grey lobes stand for p atomic orbitals.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

Distinct Helical Molecular Orbitals through Conformational Lock**

Ozcelik

Aranda

Gil‐Guerrero

et al. 2020

Chemistry A European J

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“…24 Since such compounds may also feature axial chirality if adequately functionalised, we theoretically proposed SBFs as a robust alternative to allenes. 25 More recently, our synthetic methodologies have opened access to surface functionalization with SBFs using thioacetates, 26 as well as tuning of the optical properties by the incorporation of metallaaromatic rings. 27 In addition, we performed the cyclic oligomerization of diethynylspirobifluorene (DES) leading to all-carbon double helices and flexible shape-persistent macrocycles.…”

Section: Design Of Conformationally Locked Oligoynesmentioning

confidence: 99%

Distinct Helical Molecular Orbitals Through Conformational Lock

Ozcelik¹,

Aranda²,

Gil‐Guerrero³

et al. 2020

Preprint

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Several theoretical studies have proposed strategies to reach helical molecular orbitals (Hel-MOs) in [n]cumulenes. While chiral even-[n] cumulenes feature Hel-MOs, odd-[n] cumulenes may also present them if the terminal groups lie on different planes. However, the hitherto proposed systems have been either experimentally unfeasible or resulted in opposite pseudo-degenerated Hel-MOs, impeding their use in real applicatons. To overcome this challenge, we hereby demonstrate the introduction of a remarkable energy difference between helical orbitals of opposite twist by fixing the torsion angle between the terminal groups in butadiyne fragments. In order to experimentally lock the conformation of the terminal groups, we designed cyclic architectures by combining acetylenes with chiral spirobifluorenes. A straightforward synthetic strategy along with the high stability allowed the isolation and full characterization of systems presenting distinct helical orbitals. Finally, a thorough computational analysis revealed that the most significant optical responses of these systems originate mainly from the exciton coupling between the featured diphenylbutadiyne fragments. This novel strategy opens now access to the development of systems with distinct helical molecular orbitals suitable for their implementation into chiroptical and optoelectronic applications.

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“…More recently, we have functionalized chiral SBFs with anchoring groups to enable surface functionalization (Scheme 1). [35] Poriel and co‐workers have also documented that electronic and steric effects play a critical role in the optical properties of SBF derivatives [36] . Yet, in the literature there are only very limited studies on structure‐spiroconjugation relationships in SBFs [7] .…”

Section: Introductionmentioning

confidence: 99%

ON/OFF Spiroconjugation through Peripheral Functionalization: Impact on the Reactivity and Chiroptical Properties of Spirobifluorenes

et al. 2022

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In memory of Prof. Dr. François Diederich Spirobifluorenes are an important class of spiro compounds frequently used in the field of organic electronics. However, harnessing spiroconjugation to obtain high-performance in such structural motifs remains unexplored. We herein propose that peripheral functionalization may serve as a useful tool to control spiroconjugation in an ON/OFF manner on both chemical reactivity and photophysical properties. In particular, the ratio of mono-and di-functionalized spirobifluorenes found experimentally during their synthesis were found to be 3/2, 7/2, and 12/2 for phenyl, nitro-phenyl and amino-phenyl analogues, respectively. These remarkable reactivity differences correlate with the spiroconjugation character evaluated theoretically at the CAM-B3LYP/6-31G(d,p) level of theory. Additionally, comparison of experimental and predicted optical and chiroptical responses shows that spiroconjugated molecular orbitals have a significant or negligible involvement on the main electronic transitions depending on the peripheral functionality of the spirobifluorene.

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Design and synthesis of chiral spirobifluorenes

Cited by 8 publications

References 37 publications

Distinct Helical Molecular Orbitals through Conformational Lock**

Distinct Helical Molecular Orbitals through Conformational Lock**

Distinct Helical Molecular Orbitals Through Conformational Lock

ON/OFF Spiroconjugation through Peripheral Functionalization: Impact on the Reactivity and Chiroptical Properties of Spirobifluorenes

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